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L-Soft international, Inc.

Developers Guide
for
LISTSERV®, version 1.8d

22 March 2001
Revision 2

The reference number of this document is 0103-MD-02.

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Reference Number 9908-MD-02

Table of Contents

1. LISTSERV's Archive Search Functions

1.1. Preface
1.2. A basic search session
1.3. Narrowing the search
1.4. The SEARCH command 1.4.1. Basic search functions
1.4.2. Date specifications
1.4.3. Keyword search specifications
1.4.4. Phonetic search
1.4.5. What to do about "100 matches (more available)."
1.4.6. Specifying the last n posts as a range
1.4.7. Exact syntax description

2. LISTSERV "Commands-Job" Feature and CJLI Interpreter

2.1. Introduction
2.2. Overview -- the JOB entity
2.3. Control Cards -- general syntax rules
2.4. The JOB control card
2.5. The EOJ control card
2.6. The DD control card
2.7. The //*MSG control card
2.8. Special considerations

3. Relayed File Distribution and the DISTRIBUTE Command

3.1. Introduction
3.2. What is Relayed File Distribution?
3.3. A technical description of Relayed File Distribution Requests
3.4. Creating and sending a mail RFDR ("DISTRIBUTE") job
3.4.1. RFDR job options
3.4.2. DISTRIBUTE Command Options
3.5. Advanced LISTSERV applications using DISTRIBUTE
3.5.1. "List-free" bounce processing for one-shot lists (1.8d)

4. DBMS and mail-merge support

4.1. Overview
4.1.1. DBMS support
4.1.2. Why require Oracle 8?
4.1.3. Mail-merge
4.1.4. Why require LSMTP?
4.2. Pre-installation tasks
4.2.1. Selecting a suitable DBMS product
4.3. Installation
4.3.1. Windows NT
4.3.2. OpenVMS Alpha
4.3.3. Digital Unix, AIX, Solaris
4.3.4. Verification
4.4. Post-installation tasks
4.4.1. Mail-merge
4.4.2. ODBC interface
4.4.3. OCI interface
4.4.4. Generic DBMS post-installation tasks
4.4.5. Performance options
4.5. Creating DBMS lists
4.5.1. Configuring a list to use the DBMS
4.5.2. Importing subscribers into a DBMS list
4.5.3. ADD IMPORT benchmark
4.5.4. Updating DBMS lists from an external application
4.5.5. Format of the OPTIONS column
4.5.6. Sample OPTIONS column settings
4.5.7. Preserving options when migrating from non-DBMS to DBMS lists
4.6. Using the mail-merge functions
4.6.1. Using the web interface
4.6.2. Sending DISTRIBUTE jobs to LISTSERV
4.6.3. Using substitutions
4.6.4. Using conditional blocks

5. List Exits

5.1. What is a "list exit"?
5.2. List Exit Points
5.2.1. ADD/SUBSCRIBE exit points
5.2.2. DELETE/SIGNOFF/CHANGE entry points
5.2.3. Other exit points
5.2.4. General remarks
5.3. Local command definition (non-VM)
5.4. A practical example: HAPPY99

6. The LISTSERV TCPGUI interface

6.1. Setting up the TCPGUI interface
6.2. Running lcmdx
6.3. Sending LISTSERV commands directly from your application
6.4. Advanced TCPGUI Programming Issues
6.4.1. Creating or replacing a list header
6.4.2. Adding or replacing a password
6.4.3. Bulk operations
6.4.4. Commands that respond over e-mail
6.4.5. Application-friendly commands
6.4.6. Error handling
6.5. LCMDX.C

Revision History


1. LISTSERV's Archive Search Functions

DOCUMENTATION NOTE

The information in this chapter applies to the "SEARCH" command introduced in LISTSERV 1.8c. It does not contain information pertaining to the old VM "DATABASE" command syntax, nor to LISTSERV DBMS support introduced in version 1.8d.

1.1. Preface

This chapter is an introduction to the LISTSERV archive search functions first implemented in L-Soft's LISTSERV 1.8c and later. It is intended to be a reference document for general users with little or no knowledge of database systems. It does not contain any technical information that general users would have to worry about.

Note: For LISTSERV on VM only, this chapter can be used with current versions (1.8c or later) of LISTSERV. For 1.8b or earlier VM servers, the "INFO DATABase" command will retrieve the manual for the old command syntax. The old database documentation is also available at L-Soft's ftp site in the file

ftp://ftp.lsoft.com/documents/old-listdb.memo

This chapter will discuss the syntax and operational characteristics of the LISTSERV database subsystem. It is assumed that the reader is familiar with his or her e-mail client and familiar with sending commands to a LISTSERV server.

If you just need a "quick start", read the next two sections for basic instructions. If you want a detailed tutorial on how to use the SEARCH command itself, you might want to skim the next two sections and then start reading with the section entitled "The SEARCH Command".

1.2. A basic database session

Let's say that you are looking for messages in the EASE-HOME mailing list that pertain to the list header keyword "Digest=".

To search for the term "Digest=" in the EASE-HOME list on HOME.EASE.LSOFT.COM, create a new mail message addressed to LISTSERV@HOME.EASE.LSOFT.COM and in the body (not the subject) of the message, simply type:

Search 'Digest=' in EASE-HOME

LISTSERV might respond to you with the following:

  +--------------------------------------------------------------------+
  | > Search 'Digest=' in EASE-HOME                                    |
  | -> 10 matches.                                                     |
  |                                                                    |
  | Item # Date     Time    Recs Subject                               |
  | ------ ----     ----    ---- -------                               |
  | 000058 96/01/26 14:44   41   What happened                         |
  | 000059 96/01/26 18:14   38   Re: What happened                     |
  | 000066 96/02/02 22:51   31   Digest Problem                        |
  | 000074 96/02/03 15:01   75   Re: Digest Problem                    |
  | 000075 96/02/03 18:52   49   Re: Digest Problem                    |
  | 000076 96/02/03 16:27   52   Re: Digest Problem                    |
  | 000112 96/02/13 23:37   29   not receiving mail                    |
  | 000126 96/02/25 20:20   63   error/bounce msg posted to list How?  |
  | 000172 96/03/13 09:11   12   Digest Mailing Time                   |
  | 000483 96/06/22 17:36   34   Header Info                           |
  |                                                                    |
  | To order a copy of these postings, send the following command:     |
  |                                                                    |
  |             GETPOST EASE-HOME 58-59 66 74-76 112 126 172 483       |
  |                                                                    |
  | >>> Item #58 (26 Jan 1996 14:44) - What happened                   |
  |    I never touched the Limits= command or the notebook= All I did  |
  | was try and add: Digest= Yes,Daily                                 |
  |                  ^^^^^^^                                           |
  | I have tryed this several times with the same reply message:       |
  |                                                                    |
  | >>> Item #59 (26 Jan 1996 18:14) - Re: What happened               |
  | >   I never touched the Limits= command or the notebook= All I did |
  | >was try and add: Digest= Yes,Daily                                |
  |                   ^^^^^^^                                          |
  +--------------------------------------------------------------------+
Figure 1.1. Sample SEARCH output (further output deleted)

Note that LISTSERV includes excerpts from the indexed postings showing the context of the search term(s). We've deleted all but the first 2 in the example above to save space.

You would then use the GETPOST command to order the specific posts you wanted to read. For instance, we want to read posts numbered 66, 74 through 76, and 126. You would make another new message (or reply to the response from LISTSERV without quoting the text) and type in the body:

GETPOST 66 74-76 126

LISTSERV would then respond with the desired postings. For the non-VM servers, GETPOST is analogous to the old database command "PRINT". There is no corresponding command for the old database command INDEX, since the response to a SEARCH command includes the index of matching postings.

1.3. Narrowing the search

It is possible to add further parameters to your search in order to narrow it. You can limit a search by date with a "since. . . " predicate. Likewise, you can limit by sender and/or by the subject line with a "where . . ." predicate. For instance:

Search 'Digest=' in LSTOWN-L since 94/01/01
Search 'Digest=' in LSTOWN-L where sender contains 'Thomas'
Search * in LSTOWN-L where sender is ERIC@SEARN
Search * in LSTOWN-L since 94/01/01 where subject contains 'Digest'

are all valid search commands that will (depending on how well you've crafted your predicate) dramatically reduce the number of entries returned to you.

1.4. The SEARCH command

This chapter will introduce the formal syntax of the SEARCH command. (Note: The minimum abbreviation of this command is "S".)

The syntax of this command is a bit complex, and will be introduced step by step.

1.4.1. Basic search functions

The two most important things you have to indicate when you search list archives are:

  1. The name of the list whose archives you want to search.

  2. What you want to search the individual documents for.

The name of the list to be searched is specified after the words or phrases to be sought and is prefixed with an IN keyword. For example, we might do this:

Search Rosemary in MOVIES

This would select all the entries from list "MOVIES" containing the string "ROSEMARY".

Now if you just wanted to see the list of all the movies you can see, you could have used an asterisk as search argument to select all the entries in the list:

Search * in MOVIES

Note that the mailing list name doesn't have to be uppercased.

If you want to "narrow" your previous search, i.e. perform additional tests on the documents that have been previously selected, you must omit the IN keyword. In that case, the search will be applied to the previous "hits" and will create a new "hit list".

But in most cases, we will want to search for something longer than one word, for example part of a "key" sentence.

Search Hardware problem with a 4381 in IBMFORUM

Another problem is that we might not remember the exact original sentence. This is not very important, since LISTSERV will search each word individually: in the above example, any entry that contained the words "hardware", "problem", "with", "a" and "4381" would have matched the search, even if the words appeared in a different order.

But what if the original document had "4381-13" in it, instead of "4381"? This is again no problem, as LISTSERV does not require the word to be surrounded by blanks to find a match. Case is also ignored when performing the search operation. That is, "problem" would have found a match on "problems"... and "with" would have found a match on "without" or "withstand"! This may sound like inconsistent behaviour, but you should keep in mind that it is always possible to "narrow down" a search operation. However, once a document has been excluded from the list of "hits", it is very difficult to bring it back.

Now what if I want to search for an exact string? For example, I am interested in the string "in C". It is very likely that just any document in the database will contain both a "in" and the letter C. But what I am interested in is things which have been written, or programmed, or implemented, "in C". In that case, it is possible to force LISTSERV to group words together by quoting them, as in:

Search 'in C' in UTILITY

This method can also be used to insert extra blanks between or before words: leading and trailing blanks are normally removed automatically, but they are preserved inside quoted strings. Please note that quotes must be doubled when specified inside quoted strings, as in:

Search 'Rosemary''s baby' in MOVIES

The search for 'in C' resulted in over fifty hits, because a match was erroneously found against "in clear", "in core", etc. However, I do not want to search for 'in C ' because there might be hits with "in C." or "in C," in the database and I don't want to miss them. If the search respected the capital C, it would no longer find all those irrelevant hits. To do this, you must enclose your search string in double-quotes instead of single quotes, for example:

Search "in C" in UTILITY

Note that single quotes should not be doubled inside double-quoted strings, and vice-versa. Only quotes of the same type as the string should be doubled.

It is important to understand the difference between the two types of quoting. If you request a search for 'TEXT', you will find a match on "TEXT", "Text", "text" or even "teXt". This is the same behaviour as unquoted text. However, if you request a search for "TEXT", it will only find a match on "TEXT", not on "text" or "Text".

Quoting is also the only way to search for a reserved keyword like "IN": if you tried "Search in in UTILITY", LISTSERV would report that database "IN" does not exist and would reject the command. This is because the keyword IN indicates the end of your search arguments. If you quote it, however, it will not be recognized and will be searched as you wanted it done. Similarly, if you want to search for an asterisk, you will have to quote it since

Search *

indicates that all entries should be selected.

Now the problem is that there may be sentences starting with a capital I, e.g. "In C, it would be coded this way:". How can I catch these sentences?

Actually, you have been using "complex search expressions" from the beginning without even being aware of it. When you specified a search on

Hardware problem with a 4381

, you had in fact been asking LISTSERV for: "Hardware NEAR problem NEAR with NEAR a NEAR 4381". The "NEAR" is implicit, but it may be overriden.

[Note that this is a change from the way the "locate" clause was implemented in 1.8b and earlier. Earlier versions used a default of "AND" instead of "NEAR" between discrete search terms. The difference is that

Search JOE SMITH in XYZ-L

looks for JOE and SMITH close to each other rather than simply looking for instances of both terms in the entire document. You can still use AND explicitly. Note that 'a NEAR b NEAR c' is defined as '(a NEAR b) AND (b NEAR c)', so the NEAR operator is not fully commutative.]

You may even use parenthesis if needed:

Search ("in C" or "In C") and program in UTILITY

The "NEAR" can still be implied, as in:

  +--------------------------------------------------------------------+
  | Search wooden chair (blue or green) in CHAIRS                      |
  | Search (wooden chair) or (plastic chair) in CHAIRS                 |
  | Search plastic chair (blue or green but not streaked) in CHAIRS    |
  |                                                                    |
  | The following commands are strictly equivalent:                    |
  |  Search (wooden chair) or (plastic chair not blue) in CHAIRS       |
  |  Search chair (wooden or (plastic not blue)) in CHAIRS             |
  |  Search chair (wooden or (plastic but not blue)) in CHAIRS         |
  |  Search chair NEAR (wooden OR (plastic AND NOT blue)) in CHAIRS    |
  +--------------------------------------------------------------------+
Figure 1.2. Sample SEARCH commands using complex document search arguments

1.4.2. Date specifications

Since each document has been assigned a "date/time" field, it is possible to select documents based on this date field. This is accomplished by appending "date search rules" to the search expression, as in:

  +--------------------------------------------------------------------+
  | Search problem (serious or severe) in BBOARD since july            |
  | Search problem in BBOARD since oct 85                              |
  | Search symptom in BBOARD since 12/28                               |
  | Search error report from 12 january to august in BBOARD            |
  | Search user complaint until 18 sept in BBOARD                      |
  | Search data check since today 11:53 in EREP                        |
  +--------------------------------------------------------------------+

Figure 1.3. Sample SEARCH commands using date search arguments

The default values for omitted arguments are always chosen so as to exclude as few entries as possible. For example, "July" would mean "1 July 00:00:00" in a SINCE specification, and "31 July 23:59:59" in an UNTIL clause. The only exception is the year field, which always defaults to the current year.

1.4.3. Keyword search specifications

The last thing you may wish to search is the "keywords" list. For example, you might want to select those plastic chairs which cost less than 50 dollars. It is assumed that the price will vary often (maybe almost daily), and that it is therefore kept externally from the document describing the chair. Thus, you would have a "Price" keyword which you could search in the following way:

Search plastic chair in CHAIRS where price < 50

You may of course use complex expressions (with parenthesis) in the WHERE clause. There are new comparison operators available for this clause, like IS, CONTAINS, all the usual arithmetical comparison operators, and some more. However, the AND operation is no longer implied, but it can still be specified explicitly of course:

Search plastic chair in CHAIR where price < 50 and avail > 4

The problem now is that, as the search commands become more and more complex, they will no longer fit in a single line. To solve this problem, we begin the command with the string "// " (two front-slashes and a space) and follow it with the SEARCH command and the search specifications. Any database command ending in a comma indicates that more is to follow on the next line. This process can be repeated several times if desired.

  +--------------------------------------------------------------------+
  | // Search chair (wooden or (blue or green but not streaked)) ,     |
  |        in CHAIRS ,                                                 |
  |        where price < 50 & avail > 4                                |
  |                                                                    |
  | // Search chair (wooden or (blue or green but not streaked)) ,     |
  | in CHAIRS where price < 50 & avail > 4                             |
  |                                                                    |
  | // Search chair (wooden or ( ,                                     |
  | blue or green but not streaked) ,                                  |
  | ) ,                                                                |
  | in CHAIRS where price < 50 & avail > 4                             |
  +--------------------------------------------------------------------+

Figure 1.4. Sample SEARCH commands with continuation lines: All these commands are strictly identical, although the first one is obviously more legible.

The only "trick" about this continuation line business is that you should always keep quoted strings on a single line. The process of identifying continuation lines and concatenating them afterwards may cause unwanted blanks to be inserted in the command line, which is no problem outside a quoted string since blanks are ignored, but might cause erroneous results in a quoted string.

If you want to search for several possible values in a given keyword, you do not have to repeat the keyword name and operator:

  +--------------------------------------------------------------------+
  | // Search * in BBOARD where ,                                      |
  | subject contains (PC or (Personal and computer))                   |
  |                                                                    |
  | is strictly equivalent to:                                         |
  |                                                                    |
  | // Search * in BBOARD where ,                                      |
  | subject contains PC or ,                                           |
  | (subject contains Personal and subject contains computer)          |
  +--------------------------------------------------------------------+

Figure 1.5. Sample use of "factorization"

However, it should be noted that this "factorization" is performed according to the rules of logic, which may not necessarily match those of English grammar. This removes any possible ambiguity as to the meaning of these clauses. Let's consider the following example:

machine does not contain (IBM and DEC)

This clause will get translated into:

machine does not contain IBM and machine does not contain DEC

In English you would probably say "machine contains neither IBM nor DEC" . This is how LISTSERV will understand it. However, if you read the clause aloud, you will probably not pronounce the parenthesis and will end up saying "machine does not contain IBM and DEC", in other words, "machine does not contain both IBM and DEC" , which is a totally different thing (and would most probably be true all the time). The "English meaning" could be obtained with the following clause:

not (machine contains (IBM and DEC))

In the former case, the negative "does not contain" operator is inserted inside the parenthesis. In the latter, only "contains" is moved, and the negation remains outside.

  +--------------------------------------------------------------------+
  | // Search gateway problem ,                                        |
  |   in BBOARD ,                                                      |
  |   since sept 86 ,                                                  |
  |   where sender contains (john or paul but not mick) ,              |
  |   and subject does not contain lost                                |
  |                                                                    |
  | -> 5 matches.                                                      |
  |                                                                    |
  | Item #   Date   Time  Recs   Subject                               |
  | ------   ----   ----  ----   -------                               |
  | 000012 87/10/18 13:09   12   The gateway has stopped working       |
  | 000017 87/08/24 09:18    9   Glory glory alleluja! Again!!!        |
  | 000018 87/10/18 13:09    8   You know what? It WORKS!!!            |
  | 000024 87/10/18 13:09    7   Guess what happened today?            |
  | 000205 87/10/04 16:59    9   Who's going to babysit it today?      |
  |                                                                    |
  |                                                                    |
  | You  might now wish to narrow your search down to exclude postings |
  | whose subject contains "work".  For instance,                      |
  |                                                                    |
  | // Search gateway problem ,                                        |
  |   in BBOARD ,                                                      |
  |   since sept 86 ,                                                  |
  |   where sender contains (john or paul but not mick) ,              |
  |   and subject does not contain (lost or work)                      |
  |                                                                    |
  | -> 3 matches.                                                      |
  |                                                                    |
  | Item #   Date   Time  Recs   Subject                               |
  | ------   ----   ----  ----   -------                               |
  | 000017 87/08/24 09:18    9   Glory glory alleluja! Again!!!        |
  | 000024 87/10/18 13:09    7   Guess what happened today?            |
  | 000205 87/10/04 16:59    9   Who's going to babysit it today?      |
  +--------------------------------------------------------------------+

Figure 1.6. Sample SEARCH commands with keyword search clauses

1.4.4. Phonetic search

There may be cases where you are looking for a certain value of a keyword, the exact spelling of which you cannot remember. In these cases, it may be useful to try a phonetic search. A phonetic search will yield a match for anything that "sounds like" your search string, as dictated by a predefined algorithm which is of course not perfect. It may give a hit for something which does not actually sound like your search string, or, more rarely, omit a keyword which did sound like what you entered. The main reasons for this are that the algorithm must be fast to execute on the machine and therefore not too sophisticated, and that the way a given word is pronounced depends on the idiom in which the word was written. For example, the phonetical transcription of the name "Landau" will be different in French, English, German and Russian. Thus, it is impossible to decide whether a word sounds like another if the language in which the words are pronounced is not known (and of course LISTSERV does not have, a priori, any way to know it).

Phonetic searches are performed through the use of the SOUNDS LIKE and DOES NOT SOUND LIKE operators, which are syntactically similar to CONTAINS and DOES NOT CONTAIN. That is, you could do something like:

Search * in PHONEBOOK where NAME sounds like WOLF

There is a little trick with the SOUNDS LIKE operator that you should be aware of. If your search string (WOLF in our above example) is a single word, it will be compared individually to all the words in the reference string (i.e. the data from the database), and will be considered a hit if it "sounds like" any of the words in the reference string. Thus, the search word "Ekohl" sounds like the reference string "Ecole Normale Superieure" because it matches the first word. If the search string contains more than one word, the search and reference strings will be compared phonetically as a whole (and "Ekohl Dzentrahll" will therefore not match "Ecole Normale Superieure"). Note that any search string containing more than a single word must be quoted, as explained in the previous sections of this chapter.

  +--------------------------------------------------------------------+
  | > Search * in BITEARN where site sounds like (COHRNEAL and         |
  | LAPORRADRY)                                                        |
  |                                                                    |
  | -> 3 matches.                                                      |
  |                                                                    |
  | Ref# Conn  Nodeid   Site name                                      |
  | ---- ----  ------   ---------                                      |
  | 0292 87/03 CRNLASSP Cornell University Cornell Laboratory of Atomic|
  | 0301 87/03 CRNLION  Cornell University Cornell Laboratory of Plasma|
  | 0307 87/06 CRNLNUC  Cornell University Laboratory of Nuclear Studes|
  |                                                                    |
  | > Search * in BITEARN where SITE sounds like HOPTIKK               |
  |                                                                    |
  | -> 2 matches.                                                      |
  |                                                                    |
  | Ref# Conn Nodeid Site name                                         |
  | ---- ---- ------ ---------                                         |
  | 0751 87/09 FRIHAP31 Assistance Publique - Hopitaux de Paris        |
  | 2120 87/04 UOROPT University of Rochester The Institute of Optics  |
  |                                                                    |
  | > Search * in BITEARN where SITE sounds like SCHIKAGO              |
  |                                                                    |
  | -> 1 match.                                                        |
  |                                                                    |
  | Ref# Conn Nodeid Site name                                         |
  | ---- ---- ------ ---------                                         |
  | 0140 86/03 BMLSCK11 Studiecentrum voor Kernenergie (SCK/CEN), Mol, |
  +--------------------------------------------------------------------+

Figure 1.7. Sample SEARCH commands involving phonetic match

In the figure above, the first command shows an example of accurate phonetic match, where the result is exactly what the user expected. In the second example, the user found what he was looking for ("Optics"), but an additional unwanted entry was selected. This is by far the most common case. The last command is a typical example of phonetic clash, where the algorithm did not translate the search string into phonetics as the user expected it, with the result that the desired name ("Chicago") was not found and that completely irrelevant entries were presented instead.

The phonetic matching algorithm used by LISTSERV is a slightly modified version of SOUNDEX -- a well-known algorithm that provides reasonably accurate matches at a very low CPU cost. Although it gives best results with the English language, for which it was originally designed, it is not too strongly tied to it and can still be used with other languages. It is of course absolutely impossible to write an program that would work for all the languages in the world, or even for the most widely used ones, since their interpretation of the most common combinations of letters are completely incompatible.

1.4.5. What to do about "100 matches (more available)."

LISTSERV limits the number of matching records in a given response to no more than 100. This is done primarily to stop hackers from tying up the server with SEARCH requests on lists with thousands of archived postings, but it also keeps the size of the response down to a manageable level. For instance, sending a "SEARCH *" command for an old, very large list could result in a response measuring in megabytes if not for the 100-record limitation.

There are a couple of different approaches to a solution:

  • (Preferred) Narrow your search parameters as explained in 1.3 and following.

  • Specify the first record for your search so that LISTSERV knows to start in a certain place. For instance, if you sent a search command like

    search * in lstown-l where sender contains nathan@lsoft.com

    that resulted in more than 100 "hits", and the last four hits were something like

    >  +--------------------------------------------------------------------+
      | 007696 95/08/23 16:02   13   Re: How to send 'urgent' messages to  |
      | digest users?                                                      |
      | 007698 95/08/23 18:10   52   Re: Blocking expletives               |
      | 007699 95/08/23 20:00   41   Re: How to send 'urgent' messages to  |
      | digest users?                                                      |
      | 007716 95/08/25 10:34   33   Re: ignore subsequent lines to        |
      | listserv?                                                          |
      +--------------------------------------------------------------------+

    you could send a followup search command using the following syntax:

    search * in lstown-l.7716- where sender contains nathan@lsoft.com

    to get the next 100 hits starting with message number 7716. Note that it is important to include the trailing hyphen after the starting message number, as otherwise you will get back a response containing only a reference to the message number you specified.

1.4.6. Specifying the last n posts as a range

Starting with LISTSERV 1.8d it is possible to specify that your search criteria be applied to only the last n posts in the archive. For instance, say you are only interested in checking the last 50 postings of LSTOWN-L to see if nathan@lsoft.com posted. You would send

search * in lstown-l.last50- where sender contains nathan@lsoft.com

Again you would have to use the hyphen after the number. The number n can be any integer, but as with any other search, if LISTSERV finds more than 100 hits only the first 100 will be returned to you. Thus it would be possible for n to be 1000, or even 10,000, but you will still have to narrow your search if you want more hits.

1.4.7. Exact syntax description

This section describes the exact syntax of the "SEARCH" command in technical terms. You can skip it if you are not interested in learning about the details of this command.

General syntax

  +--------+-----------------------------------------------------------+
  |        |                                                           |
  | Search |  search-rules  <optional-rules>                           |
  |        |                                                           |
  |        |  Optional rules are:                                      |
  |        |                                                           |
  |        |    date-rules                                             |
  |        |    keyword-rules                                          |
  +--------+-----------------------------------------------------------+

The optional "date-rules" and "keyword-rules" arguments may appear in any order.

Date rules specification

You may optionally restrict the search to only those entries that lay within a given interval of time. This is accomplished by specifying one of the following date rules:

SINCE date-spec <time-spec>
FROM date-spec1 <time-spec1> TO date-spec2 <time-spec2>
UNTIL date-spec <time-spec>

The format of a "date-spec" is quite complex because of the number of different ways date/time specifications are usually expressed:

TODAY
yy
dd mm
<dd><->monthname<-><yy>
mm/yy
mm-yy
yy/mm/dd
yy-mm-dd
yyyymmdd

(yyyymmdd is accepted by LISTSERV version 1.8d and following.)

Month names can be abbreviated to any length. If there is an ambiguity, the first month in chronological order is retained. For example, "J" would mean "January", "JU" would be "June" and "JUL" would unambiguously select "July".

The format of a "time-spec" is simply <hh:mm<:ss>>.

  +--------------------------------------------------------------------+
  | FROM 14 july TO oct 97                                             |
  | SINCE 96                                                           |
  | UNTIL 23-JUN-97                                                    |
  | SINCE today 11:30                                                  |
  +--------------------------------------------------------------------+

Figure 1.8. Sample date clauses

NOTE: Case is irrelevant in date specifications. The keywords (SINCE, UNTIL, etc) have been capitalized only for better legibility, and can be entered in lower case if desired.

Keyword rules specification

You may request the actual document search to take place only for those entries which match a set of "keyword comparison" rules. The syntax is the following:

 WHERE kwd-expression
 WITH kwd-expression

"kwd-expression" is, generally speaking, an mathematical expression of keyword/value comparisons, possibly bound by logical operators. Comparison operators have a higher precedence than logical operators, that is, "A>10 AND B=20" is interpreted as "(A>10) AND (B=20)". The available comparison operators are listed below. All the operators appearing on a given line are synonyms.

  +--------------------------------------------------------------------+
  | = IS                                                               |
  | ^= <> IS NOT                                                       |
  | >                                                                  |
  | <                                                                  |
  | >=                                                                 |
  | <=                                                                 |
  | SOUNDS LIKE                                                        |
  | DOES NOT SOUND LIKE                                                |
  | CONTAINS                                                           |
  | DOES NOT CONTAIN                                                   |
  +--------------------------------------------------------------------+

Figure 1.9. Comparison operators for WHERE clauses

All these operators are self-explanatory, except the last two which allow you to search the keyword value for a given "substring". That is, "Sender contains jeff" would be true if the value of the "Sender" keyword was "Jeff Smith" or "Jeffrey Donaldson". The case is ignored during the comparison unless the search operand is double-quoted.

If no valid comparison operator is specified between two arguments, "IS" (identity) is assumed.

The available logical operators are:

  +--------------------------------------------------------------------+
  | ^ NOT                                                              |
  | & AND BUT                                                          |
  | | / OR                                                             |
  +--------------------------------------------------------------------+

Figure 1.10. Logical (boolean) operators

Please note that the logical operators AND and OR have equal precedence and are evaluated left-to-right.

Finally, keywords and operators can be "factorized" when the same comparison is to be applied to a given keyword and a series of comparands. For example, you might enter:

Search * where sender contains ('CS Dept' and (Jack or Phil))

This is internally expanded to:

// SEARCH * WHERE sender CONTAINS 'CS Dept' AND ,
   (sender CONTAINS Jack OR sender CONTAINS Phil)

Please note that the expression must always be enclosed in parenthesis, even if it is a simple one:

Search * where sender contains (Joe or Morris)

This stems from the fact that comparison operators have a higher priority than logical (boolean) ones.

  +--------------------------------------------------------------------+
  | WHERE Sender is "Arthur Dent" ,                                    |
  | and Subject does not contain tea                                   |
  |                                                                    |
  | WITH Refcode 8467272 and Location Roubaix                          |
  |                                                                    |
  | WITH (QTY > 100 | PRICE > 1000) & MAT = COPPER                     |
  |                                                                    |
  | Where Sender is (Atiaran@Land or Elena@Land) ,                     |
  | and Subject contains ('Be true' but not Ur-Lord)                   |
  +--------------------------------------------------------------------+

Figure 1.11. Sample WHERE clauses

Search rules specification

Finally, you must specify what is to be searched inside the document. If you do not want anything to be sought at all (e.g. if you are only selecting known items from the database), you can specify an asterisk as a placeholder to waive the search. Otherwise you must specify a mathematical expression where arguments are search strings, possibly bound by logical operators (see Figure 10 for a comprehensive list). The default operator is AND, so that a search for "INTERPRET STEM PROBLEM" will select all entries where "INTERPRET", "STEM" and "PROBLEM" can be found (not necessarily in the same line).

  +--------------------------------------------------------------------+
  | Search *                                                           |
  |                                                                    |
  | Search 'I/O' Error                                                 |
  |                                                                    |
  | // Search Interpret (performance or tips ,                         |
  | but not (bug or question))                                         |
  +--------------------------------------------------------------------+

Figure 1.12. Sample document-search clauses

Reserved words and quoting

When to quote strings

Keyword names and search arguments need not be quoted, unless:

  • They are formed of more than one word (search arguments only).

  • They contain leading or trailing blanks (search arguments only).

  • Their name matches one of the "reserved keywords" of the LISTSERV database system, and appears in a context where it can be mistaken for such. The "reserved keywords" are: FROM, IN, SINCE, TO, UNTIL, WHERE, WITH.

  • They contain a parenthesis, logical operator or comparison operator symbol. More generally, you should quote any string that contains one of the following characters:

    ( ) < > = | & ^ /

Any non-quoted word will be stripped of leading and trailing blanks and converted to uppercase before the search.

Single-quoted strings

Strings quoted in single-quotes (') are converted to upper case and cause case to be ignored during the search. That is, they behave in the same manner as un-quoted strings as far as the search algorithm is concerned. As a rule of thumb, any string can be single-quoted if desired, even if it does not have to.

Single quotes must be doubled inside single-quoted strings, but double quotes should not:

Search '"T''amo, ripetilo, si caro accento' in OPERA

Double-quoted strings

Strings quoted in double-quotes (") are not converted to upper case. They result in a case-sensitive search, which means that you should never double-quote a string unless you want case to be respected during the search.

Double quotes must be doubled inside double-quoted strings, but single quotes should not:

Search """T'amo, ripetilo, si caro accento" in OPERA


2. LISTSERV "Commands-Job" Feature and CJLI Interpreter

2.1. Introduction

The "Commands-Job" feature of LISTSERV was designed in an attempt to allow for powerful inter-LISTSERV (and more generally, program-to-LISTSERV) command transmission with message redirection and multi-line arguments capability, while still allowing inexpert users to send commands to LISTSERV for execution in a very simple, intuitive" way.

The implementation of Commands-Jobs has therefore been split into two different layers: the 'core' command job language interpreter, with its exacting, powerful but stern control cards syntax, and the 'outer' interface to the user which provides the required default control cards whenever they have been omitted, translating an "intuitive" series of commands to execute into an actual commands-job that can be processed by the 'core' interpreter.

Since this documentation is primarily intended for postmasters and LISTSERV applications programmers, it will be oriented towards a description of the 'core' interpreter. The work of the 'outer interface' will only be mentioned for better understanding. The 'core' interpreter will be referred to as 'Commands Job Language Interpreter' (CJLI) in the following discussion.

Warning: if you are familiar with MVS and JCL, you will probably notice some similarity between command job control cards and JCL. This similarity is purposeful and was intended to make CJLI easier to understand for JCL adepts and to make MVS users more comfortable with CJLI (MVS users who do not have any mailing system such as UCLA mail and have difficulties sending/receiving messages are often forced to use (basic) CJLI control cards to send commands to LISTSERV). However, there are a number of differences between CJLI and JCL and you should not assume that a given JCL card has the same meaning and syntax as its CJLI counterpart. Some JCL features which were deemed to be unnecessary (eg dataset concatenation with a blank DD card) have not been implemented, and new features have been implemented whenever required.

2.2. Overview -- the JOB entity

As soon as the 'outer' interface detects that a file contains commands (as opposed to a mail or non-mail file intended for redistribution to a list), it passes it to the CJLI for execution. This physical file will contain one or more logical 'JOB's with interspersed comment lines. Each 'JOB' will contain zero or more commands, start with a "// JOB" card and end with a "// EOJ" card. The 'outer' interface will provide these cards if omitted, but this will be detailed later on. Anything before the first "// JOB" card, after the last "// EOJ" or between "// EOJ" and "// JOB" cards is ignored. Notably, mail headers and "Acknowledge-To:" fields (at the bottom of the mail file) would be ignored. A physical job file containing two jobs might look like this:

(any number of header lines, ignored)
 //jobname1 JOB options
 .
 .
 .
 //jobname1 EOJ
(any number of lines, ignored)
 //jobname2 JOB options
 .
 .
 .
 //jobname2 EOJ
(any number of lines before EOF, ignored)

Each job in the physical file is a completely independent entity which contains commands and the 'dataset' definitions required to execute the commands properly. Jobs are executed in sequential order; if a job does not execute successfully, the other jobs in the physical file are still executed, unless the job has been terminated by a 'global' error (eg error reading the physical file), in which case the CJLI terminates after transferring the file to the postmaster. Within a given job, commands are executed in sequential order regardless of the result of the previous commands.

Each job generates a separate 'output', which is sent to its recipients (see below) before the next sequential job is executed. This 'output' consists in a series of messages which are (unless specified otherwise -- see below) sent back as a single mail file.

There are basically three kind of cards in a job stream:

    A. Control cards, which start with "//" in column 1 and are interpreted by the CJLI. Control cards further subdivide into three categories:

    1. Pre-execution control cards, of the form: "//label kwd args". "label" and "args" can be omitted but there must still be a blank between the "//" string and the keyword name, ie "// kwd". If CJLI does not recognize the keyword, it strips off the leading "//" and considers the card as a command-card (see below).

    2. Comments, of the form: "//* any_comment_text". These cards are ignored by CJLI. Note the blank between the asterisk and the first character of the comment text.

    3. Execution-time control cards, of the following format: "//*kwd args". Note that the keyword is concatenated to the "//*" string to differentiate this from a comment. If the keyword is not recognized, the card is treated as a comment control card and ignored. It is otherwise processed by CJLI at execution time, as if it were a normal command card, and in sequence order with the other command cards. These cards are actually commands which are only available from within a command job because they would be irrelevant outside of a job context.

    B. Command cards, which contain the text of the actual commands to be executed. They are ignored by CJLI which passes them to the main LISTSERV command interpreter for execution. If the card starts with an asterisk, it is treated as a comment and ignored.

    C. Data cards, which are assembled into a dataset under control of a "// DD" control card. They are removed from the job stream by CJLI and are kept in a separate pool for later reference at command execution time.

2.3. Control Cards -- general syntax rules

All control cards, except comment control cards, follow the same syntactic rules:

  1. Control card starts with the string "//" in column 1.

  2. Control cards can span any number of physical records: continuation cards can be defined by placing a comma at the end of the first physical line, and having the continuation card start with the string "// " (note the blank) in column 1. This process can be repeated any number of times. No blank is inserted between the end of the first card and the beginning of the continuation card; however, anything before the comma is kept. Examples:

     //card1 DD "Some very long text which,
     // requires a continuation card"
     --> "Some very long text whichrequires a continuation card"
    
     //card1 DD "Some very long text which ,
     // requires a continuation card"
     --> "Some very long text which requires a continuation card"

    Since this approach makes it impossible to "cut" a line which ends in a large string of blanks, an alternate method was designed for blanks-sensitive cutting. If the continuation card starts with the string "//+ " in column 1 instead of just "// ", the continuation card is not stripped of leading blanks and data from columns 5-80 is appended to the first card. Example:

     //card1 DD "Some very long text which,
     //+ requires a continuation card"
     --> "Some very long text which requires a continuation card"

  3. Control cards can contain a label of any length starting in column 3. This label is translated to uppercase. If the label is omitted, there must be a blank in column 3. The label can contain any character, except blank and the slash sign ("/").

  4. The label is followed by at least one blank. The next word in the card is the "card name", which is translated to uppercase.

  5. Arguments can be specified after the "card name", and must be separated from it by at least one blank. Arguments are separated by commas, and there must not be any blank before or after the comma. There are two categories of arguments:

      a. Positional arguments, which must appear in the correct order (which will usually depend on action being performed).

      b. Keywords, of the form "name=data". They can appear in any order and can be freely intermixed with positional keywords. They do not affect the sequence order of positional keywords. Keyword names are translated to uppercase, and can contain any character except blank, comma, double-quote or equal sign.

    For example,

    //JOB1 JOB XDZ,ECHO=NO,FRECP11,PW=EMERALD
    //JOB1 JOB PW=EMERALD,XDZ,FRECP11,ECHO=NO
    //JOB1 JOB Echo=NO,pW=EMERALD,XDZ,FRECP11

    are three different wordings of the same arguments string.

    There are furthermore two different forms of "data" for arguments:

      a. Quoted data: in that case the data is enclosed in double quotes and can contain one or more blank delimited words as well as leading or trailing blanks. Quoted data is case-sensitive, and can contain any character except a double-quote.

      b. Non-quoted data: in that case the data consists of a single word (i.e., blanks cannot appear in the data), which is translated to uppercase. Non-quoted data cannot contain blanks, commas or double-quotes.

    In the above example, specifying 'Echo=No' is functionally identical to 'ECHO=NO', while 'Echo="No"' would leave the argument in mixed case. Quoted data is used for list of recipients, full-names, etc.

  6. Comments can be included at the end of the card, and must be separated from the arguments by at least one blank. If you did not specify any argument string, and still want to place comments at the end of the control card, you must specify a null argument string before the comments by putting a ", " before the comment text, e.g.:

    //JOB1 JOB , These are comments
    //JOB1 JOB XDZ,FRECP11 These are comments too

2.4. The JOB control card

The JOB control card indicates the start of a new job and allows you to define several "execution options" for the job. The format of the JOB card is:

//jobname JOB options

'jobname' is the name you want to assign to the job. If you leave it blank, CJLI will default it to be your 'userid'.

The following options are available:

  • Echo=YES|NO

    The default value (if the keyword is omitted) is YES and indicates that each command must be echoed to the job output before execution. The command is then prefixed with a "> ", and preceded by a blank line on the job output.

  • Reply-to=Sender|None|"u@n1 u@n2..."

    The default value is "Sender" and indicates that the output of the job is to be sent to the sender of the job. "None" indicates that no output should be generated, and is used whenever the sender is a server which is not programmed to parse the output of a LISTSERV job. Also it makes sure that no loop can ever occur due to an error in a job. "u@n1 u@n2..." can be used whenever replies are to be sent to a different person/list of persons. These persons will first receive a separate message telling them that they are receiving the output of another person's job.

  • Reply-via=Mail|Message|MSG

    The default value, "Mail", indicates that the job output is to be sent to its recipients in the form of a mail file. "Message" and "MSG" both indicate that interactive messages are desired. Note that an attempt to send interactive messages to a node which cannot handle them will result in LISTSERV sending a piece of mail containing the text of the various messages.

  • Stat=YES|NO

    (Starting with 1.8d) Determines whether or not server statistics ("Summary of resource utilization") for a given JOB are output in the command response to the invoker. The default is YES. A server-wide default (also starting with 1.8d) may be set with the JOB_STAT_DEFAULT site configuration variable.

  • PW=password

    Is the default password to use on commands where an explicit "PW=" keyword has not been specified. It makes it easier to write jobs performing several maintenance commands on the same distribution list, for example.

All other keywords, as well as positional parameters, are ignored. If an invalid value is specified for a valid keyword, the job is terminated by CJLI but the remaining jobs in the physical file are still executed.

If the JOB card is omitted, the 'outer' interface provides the following default JOB card:

//userid JOB Echo=Yes,Reply-to=Sender,Reply-via=Mail,Stat=Yes,PW=""

2.5. The EOJ control card

The EOJ card indicates the end of a job; its syntax is very simple:

//anything EOJ

where 'anything' can be any valid label and is completely ignored. The 'outer' interface provides an EOJ card at the end of the physical job file, as well as before a new JOB card, if none was provided by the user.

2.6. The DD control card

The DD control card allows you to define single or multi-line 'datasets' for use by the various commands in the job stream. The syntax of the DD card is the following:

//ddname DD "single-line-constant"
             *
             *,EOF
             *,EOF,Res=Disk
             *,EOF,Res=Storage

'ddname' is the name the dataset is to be given. It must follow the general label naming convention, cannot be omitted and cannot appear more than once in the job stream. That is, datasets cannot be concatenated by means of several DD cards.

"single-line-constant" denotes a single-line dataset, whose value is that of the first (quoted) argument. The length of this argument must not exceed 255 bytes.

'*' denotes a multi-line dataset, whose successive lines immediately follow the DD card. Any number of lines can thus be included in a dataset, with a "/*" line indicating the end of the dataset. The JCL "DD DATA,DLM='xxxx'" is not implemented. Note that unlike JCL, CJLI does NOT end the dataset when a control card (ie one starting with "//") is encountered; the "/*" must always be specified.

'*,EOF' denotes a multi-line dataset, whose successive lines immediately follow the DD card and end at the end of the PHYSICAL job file. This option is used when transmitting "unknown" data in a dataset which could a priori contain any kind of character string. Needless to say, there can be only one such dataset in the job file, and it must be the last dataset in the last job.

'Res=' indicates whether the dataset is to reside in storage ("Res=Storage") or on disk ("Res=Disk"). In some cases it may be necessary to keep a large dataset on disk to avoid running out of storage and to improve execution speed when a disk-file is to be generated anyway by the command using the dataset. The "Res=" keyword is therefore ignored on all datasets except the '*,EOF' one (if present), and causes a disk file to be generated with the remainder of the input deck. Please note that not all commands will support the "Res=Disk" option: commands which do not expect to receive a large dataset as input will usually expect to find it in storage and report an error when the "Res=Disk" option is used. For example, DISTRIBUTE fully supports "Res=Disk" while DELETE doesn't.

An invalid dataset declaration causes the job to be terminated by CJLI with the remaining jobs in the physical file still being executed.

2.7. The //*MSG control card

The "//*MSG" execution-time control card allows you to selectively halt/resume 'typing on the job output' or to discard messages which have been previously output during execution of the job. Note that the latter option has no effect when the output of the job is sent as interactive messages, as it is intended to control mail job output.

The syntax of the "//*MSG" control card is:

//*MSG option1,option2,...

Valid options are: ON, OFF, FLUSH

FLUSH discards all messages previously sent to the job output and leaves the message-receipt status unchanged.

OFF turns message receipt off, as if "Reply-to=None" had been specified in the JOB card.

ON turns message receipt back on. This does NOT override a possible "Reply-to=None" in the JOB card, though.

2.8. Special considerations

This section contains more information on the trickiest parts of CJLI as well as some useful hints for application programmers.

LISTSERV treats anything mailed to the LISTSERV userid as a set of commands to execute. Thus, as soon as an unknown command is encountered in the job stream, the whole physical job file (not just the current job) is immediately flushed and discarded. This avoids 'executing' hundreds of unknown commands and sending back a huge job output when a regular mailfile is sent to the LISTSERV userid by someone who thought it would be distributed to a list. Note that errors from known commands do not cause termination of the job -- only completely unknown commands such as "Hiya!!" would terminate the job.

Although CJLI is based on the network standard 80-characters card images, LISTSERV accepts command jobs in several network formats, including Disk Dump and Netdata. In that case it will accept records of up to 255 characters as input, and you may find this very convenient when sending long commands to the server.

Alternatively, continuation cards can be used to split long commands into several 80-characters cards. In that case you must insert a "// " string before the command text so that CJLI considers it as a control card and performs the required concatenation; it will then realize that the "card name" is unknown and transform the card into a regular command card. If you opt for that method, you will find the "//+" continuation card feature very convenient for a program (but not for a human person). This method is used by LISTSERV when transmitting "DISTRIBUTE" commands to other LISTSERVs.

There is no limit at all on the final size of a control card, i.e., on the number of continuation cards you can specify; however, you must make sure that no line in any of the 'datasets' ever exceeds 255 characters. In particular, if the physical job file is sent in Netdata format, you must make sure that the file lrecl is not higher than 255.

Note for VM servers: Due to internal coding considerations, it is recommended that physical job files be sent to LISTSERV in PUNCH format. This will make it easier for the 'outer' interface to detect the job file for what it is and will save some CPU time to the server, thereby improving job response time. Please keep in mind that DD lines longer than 80 characters cannot be sent in PUNCH format.

For more information on how to send commands to LISTSERV for execution, see LISTSERV MEMO.


3. Relayed File Distribution and the DISTRIBUTE Command

Note that DISTRIBUTE is also documented in RFC1429.

3.1. Introduction

The Relayed File Distribution (also known as DISTRIBUTE) feature was developed in an attempt to provide an efficient and network-resources-saving means whereby files and mail could be distributed to a large number of persons on the network by ANY network user, without having to resort to predefined distribution lists (which have other advantages but are basically static).

This chapter is composed of three independent sections. The first one (3.2) is a description of the distribution algorithm used by Relayed File Distribution. It is general enough to be accessible to inexpert computer users, but does not explain how to send a Relayed File Distribution Request (RFDR) to LISTSERV. The second section (3.3) gives a detailed technical description of RFDRs and assumes the reader is familiar with the basic concepts of the Commands-Jobs Language Interpreter (CJLI). More information about CJLI is available in Chapter 2, above. The third section (3.4 and 3.5) is a more practical tutorial regarding the construction of RFDR jobs. The general user who wishes only to learn how to set up simple RFDR jobs and who is not interested in the technical issues involved may therefore skip sections 3.2 and 3.3, moving directly to 3.4.

Please note that while "RFDR Job" is actually the correct nomenclature for a job sent out using Relayed File Distribution, the more common (if not as entirely correct) term "DISTRIBUTE Job" may also be used herein, interchangeably, to describe such jobs.

Starting with LISTSERV 1.8d, a new security validation feature has been added to the DISTRIBUTE command. The new feature changes the default behavior of DISTRIBUTE in two ways:

  1. Only a LISTSERV maintainer (i.e., a user who is identified in LISTSERV's site configuration file as a POSTMASTER=) or a "trusted" user (identified in LISTSERV's site configuration file in the DIST_ALLOWED_USERS= variable) may issue the DISTRIBUTE command; and

  2. The DISTRIBUTE command must be validated with the issuer's personal LISTSERV password (obtained with the PW ADD command).

The new default can be relaxed back to the previous (pre-1.8d) behavior by setting the new DIST_SECURITY site configuration variable appropriately. See Appendix C of the Site Manager's Operations Manual for details.

3.2. What is Relayed File Distribution?

Relayed File Distribution is a service provided by the ever-growing network of L-Soft LISTSERV servers to all users connected to the Internet who are allowed to send and receive files or messages. (The origins of the service were on BITNET and associated services where it was possible to send files, as opposed to messages.) The user desiring to send the message (whom we will call the 'sender') provides his nearest L-Soft LISTSERV host with a copy of the message to be distributed and the list of persons who are to receive it. He can optionally indicate the full name of these persons as well as his own full name, and they will be used in information messages and mail headers as appropriate. The LISTSERV hosts will then relay the file to each other as explained below and distribute the file to all the indicated recipients in the most efficient way they could 'manage'.

The server that initially receives the file from the sender will first distribute the file to the (possible) recipients of its local node, which does not generate any network traffic. It will then examine the list of non-local recipients and determine, for each of them, which of the L-Soft LISTSERV servers is nearest.1 Whenever it finds itself to be the nearest server, it distributes the file directly, and removes the recipient from the list. It then uses a rather complex algorithm to "route" the remaining recipients through its nearest servers, and transmits the request to them. This will be best illustrated by an example.

User X@FRECP11 sends a file distribution request for the following list of people:

Y@FRECP11,X@CEARN,Y@CEARN,X@CZHRZU1A,X@NEUVM1,X@IBACSATA, X@EARNET, X@PSUVM

We will assume that a L-Soft LISTSERV server has been installed at the following sites: FRECP11, CEARN, DEARN, DKEARN, EARNET

Finally we will assume the following topology, which will not necessarily reflect the actual network topology at the time you read this chapter (it has been simplified and nodes which do not participate in the transfer have been removed)

                                   CZHRZU1A
                                      |
                                      |
                                      V
FRECP11 --> FRORS31 --> FRHEC11 --> CEARN --> DEARN --> DKEARN --> NEUVM1
                                      |         |
                                      |         |
                                      |         V
                                      |       GWUVM --> PSUVM
                                      V
                                    EARNET --> IBACSATA

The file is distributed by LISTSERV@FRECP11 to Y@FRECP11, and then forwarded to LISTSERV@CEARN, which will distribute to the two CEARN recipients and to X@CZHRZU1A. LISTSERV@CEARN then forwards one copy of the file to LISTSERV@DEARN and one to LISTSERV@EARNET, with the appropriate list of recipients. LISTSERV@EARNET distributes to the EARNET recipient and to X@IBACSATA. LISTSERV@DEARN distributes to X@PSUVM, and also to X@NEUVM1. LISTSERV@DKEARN does not receive anything because it would have served only a unique recipient, and in that case a direct send can only be better.

The file has therefore crossed a total of 11 links. If it had been sent the normal way from FRECP11, it would have had to cross 32 links, i.e. thrice more. The reduction is very important because we assumed that a server is installed at all the central nodes in the network, which is not necessarily the case in practice.

3.3. A technical description of Relayed File Distribution Requests

Relayed File Distribution Requests ("RFDR Jobs") must imperatively be transmitted as a commands-job file. It is recommended that you read Chapter 2 of this manual if you are not familiar with the basic concepts of CJLI.

Beginning with 1.8d, by default DISTRIBUTE may only be executed by a LISTSERV maintainer (defined in the POSTMASTER= variable in the site configuration file) or a "trusted" user (identified in LISTSERV's site configuration file in the DIST_ALLOWED_USERS= variable) and requires a password (the invoker's personal LISTSERV password).

The job sent to the server must contain:

  • A JOB card with the "Echo=No" option to avoid tracing the unique command to the job output. The "Reply-via=" keyword can be set to "Message" if so desired, although this is not recommended. The job name can be anything you want, eg filename.filetype

  • A DISTRIBUTE command with the appropriate arguments:

    DISTribute < <MAIL> <DD=ddname> <FROM=u@n | FROM=DD=ddname>
                 <ACK=NOne | MAIL | MSG> <TO DD=ddname | TO u@n1
                     <...>> >
                 <PRIOR=* | nn> <INFORM=MSG | MAIL>
                 PW=password

    All the keywords (except PW=) can be omitted, but must be specified in the indicated order. The "PRIOR" and "INFORM" keywords are indepedent from the others and can appear anywhere in the command line. Beginning with LISTSERV 1.8d the DISTRIBUTE command requires a password (PW=password , above) for validation purposes. A description of the keywords follows:

    • MAIL indicates that the file to be distributed is a mailfile, to be sent to the MAILER at the destination node. The contents of the file are proofread and the "mail origin" is verified so that users cannot send forged mail. MAIL-type distribution is 100% transparent to the mail recipient, which is not the case with file distribution -- a file would come from the LISTSERV userid instead of the sender's userid. The mailfile must contain a blank "To:" line where the actual name and network address of each recipient will be automatically inserted as the file is distributed to him.

      All DISTRIBUTE jobs sent from non-VM servers will be MAIL-type DISTRIBUTE jobs. Non-MAIL DISTRIBUTE is available only on VM.

    • DD=ddname is the ddname corresponding to the data to be transmitted (ie the file or mailfile). The default is "DD=DATA"

    • FROM=xxxx indicates either the network address of the file sender or the name of a dataset of which the first line indicates the network address and full name of the file sender, eg FROM=DD=XXX and //XXX DD "JPB@BIGNODE John P. Brown". The default is FROM= your-userid.

      This field contains the address you want bounces to go to (the RFC821 MAIL FROM: address) and it can be used to redirect bounces2 that should not normally go to the user invoking DISTRIBUTE--eg, it can be set to a special address set up specifically to handle errors for this particular DISTRIBUTE job.

      Under 1.8c and earlier, only LISTSERV maintainers were allowed to use the FROM= field. General users were not allowed to specify an origin different from their own network address, so the FROM= option would have had no effect unless the user wanted to specify his full name. Under 1.8d and later, general users (those who are not otherwise defined in the DIST_ALLOWED_USERS site configuration parameter) do not have access to DISTRIBUTE to begin with.

      You do not have to indicate your name when distributing MAIL-type files -- put your name in the "From:"/"Sender:"/whatever field, as appropriate.

    • ACK= indicates the amount of acknowledgement you want to get. The default is NOne and indicates you do not want to receive messages as the file is distributed. MAIL indicates mail acknowledgements while MSG indicate interactive messages.

    • TO indicates the list of recipients for the file or mailfile. It can either be a list of network addresses ("TO u@n1 u@n2...."), which must not cause the physical command line to exceed 255 characters (use continuation cards in that case), or a ddname of which each line is a "userid@node <full name>" pair. The former is best suited to file distribution while the latter should be preferred for MAIL-type distribution since the recipient's full name will be inserted in the "To:" field of the mail file. The default is "TO DD=TO". Note that distributing a file to a LISTSERV userid will cause it to be interpreted as a command job for execution or a PUT request, as appropriate. Releases 1.5b and earlier did not accept such a destination for DISTRIBUTEd files and ignored the recipient.

    • PRIOR is the network transmission priority you want to assign to the file. If specified, it can be either "*" or an integer number between 0 and 99, inclusive. "*" indicates that the file priority is left up to LISTSERV, which will use an internal algorithm to assign a reasonable priority to the file according to its number of records.

    • INFORM (effective on VM only) specifies the media by which you want users to be informed of the arrival of the file. The default is MSG for interactive messages -- specify MAIL if you want LISTSERV to notify recipients via mail. Note that this option is ignored when MAIL distribution has been selected.

    • Finally, a password is required to validate the command invoker for versions 1.8d and higher of LISTSERV. This is a standard LISTSERV personal password, set with the PW ADD command (q.q.v.).

  • A dataset for the "FROM=DD=" keyword, if specified -- the DD "text" syntax is recommended since the dataset will contain only a single line of data.

  • A dataset for the "TO DD=" keyword, if specified -- the DD * syntax is best suited to this dataset. This dataset contains network addresses (imperatively) and per-address options, one address/options per line. The per-address options are a real-name field and the keywords BSMTP or PROBE (BSMTP and PROBE are mutually-exclusive; only one can be specified per address). For instance a TO dataset could contain lines like

    janecustomer@abc.com
    jacktechie@def.edu Jack Techie
    johndoe@ghi.org BSMTP
    joe@example.com PROBE
    sue@example.edu Sue User BSMTP
    petergunn@example.edu Pete Gunn PROBE

    When the BSMTP option is specified, LISTSERV will combine the address along with any other addresses for which BSMTP is specified into a multi-recipient BSMTP envelope (which is much more efficient, since not using BSMTP tells LISTSERV to create a separate SMTP envelope for each address). For general DISTRIBUTE jobs (ie, non-mail-merge jobs), it is probably most efficient to specify BSMTP for all addresses in the job.

    When the PROBE option is specified, LISTSERV will process the address as a PROBE. This is most useful when using a backend list or a changelog file for error processing (see the section on "Advanced LISTSERV applications using DISTRIBUTE", below, for more information on these features; also see the sections on LISTSERV's address probing in the Site Manager's Operations Manual and/or in the List Owner's Manual). PROBE should not be used on one-off DISTRIBUTE jobs which do not require specialized error processing, as it has no particular usefulness otherwise.

    Again, BSMTP and PROBE are mutually-exclusive; you may specify one or the other but not both.

  • Finally, a dataset for the "DD=" keyword, to contain the mail message or file. This should be the last dataset in the file and the DD *,EOF syntax should be used to ensure that the dataset is not prematurely ended by a possible "/*" card in the data. On VM, for storage space saving and performance considerations, the "Res=Disk" option should be specified on that DD card, ie: DD *,EOF,Res=Disk. Statistics have shown that this decreases the CPU time required to process the request by a factor of six.

Mail-type RFDR under VM must IMPERATIVELY use raw-image (PUNCH) format for the mail dataset, since the header will be scanned and modified by the server. File-type RFDRs can use any type of network file format -- the contents of the "data" dataset will be sent "as is" to the recipients, without anything added on top or bottom of it. The only difference will be the RSCS file origin -- the file will come from the LISTSERV userid instead of the sender's userid. The file class, spool fileid and DIST-code are preserved, but the FORM is changed to QU-DIST to trigger the "quiet file transfer" feature installed in some RSCSs in the network.

Non-BITNET recipients are routed to their gateway, as determined by the DOMAIN NAMES file. The first server in the chain that finds itself unable to determine the gateway distributes the file directly. Whenever non-mail file is distributed to a non-BITNET user, LISTSERV generates a standard mail envelope with the current date, sender's name and address, recipient's address and transfers it to the mailer. Any possible rejection mail will be sent directly to the sender by the mailing system (and not to the LISTSERV userid).

3.4. Creating and sending a mail RFDR ("DISTRIBUTE") job

The instructions below are for sending plain-text messages to a one-time list via LISTSERV. If you wish to send MIME-encoded mail messages (for instance, to send encoded binaries or HTML mail), you must create and add the appropriate MIME headers along with the file (in the case of an encoded binary) to be sent.

The syntax described here is for 1.8d running with the default of DIST_SECURITY=1 in the site configuration. We have not attempted to discuss the differences between 1.8d and previous versions of LISTSERV in writing RFDR jobs.

A very basic RFDR job is shown below. This job would be sent to LISTSERV@NODE, where NODE is the NODE= site configuration setting for your local LISTSERV server.

//WIDGET1 JOB
DISTRIBUTE MAIL PW=XXXXXXXX
//To DD *
janecustomer@abc.com BSMTP
email-address1@domain.com BSMTP
email-address2@domain2.com BSMTP
/*
//Data DD *,EOF
Date:      Tue, 13 Jan 1998 12:25:00 -0400
From:      joe.techie@xyz.com
Subject:   Release of XYZ's WIDGET Model 2
Reply-to:  joe.techie@xyz.com
To:        Widget Customers <customers@widget.com>

Your text here

Below is a detailed description of each element of the job.

//WIDGET1 JOB

The JOB "card" is the required first line of any RFDR job. It signifies to LISTSERV that everything that follows in this particular message is part of the same job. In this case we have called the job WIDGET1. Each RFDR job should have a name, but if for some reason you don't want it to, you simply format the JOB card with a space between "//" and "JOB".

DISTRIBUTE MAIL PW=XXXXXXXX

This is the actual DISTRIBUTE command that tells LISTSERV that this is an RFDR job, and that specifically you want LISTSERV to distribute a piece of mail. PW=XXXXXXXX is part of the security mechanism described in 3.1. You replace XXXXXXXX with your personal LISTSERV password that you've previously set with LISTSERV's PW ADD command.

//To DD *
janecustomer@abc.com BSMTP
email-address1@domain.com BSMTP
email-address2@domain2.com BSMTP
/*

This part of the job tells LISTSERV to whom you want the mail distributed. There are a few options for the addresses themselves as you've probably noticed. The basic syntax for an address in the "To DD" is as follows:

userid@host.domain [Personal Name] [BSMTP | PROBE]

for instance, any of the following are correct:3

janecustomer@abc.com Jane Customer
janecustomer@abc.com BSMTP
janecustomer@abc.com PROBE
janecustomer@abc.com Jane Customer PROBE

The only part of this syntax that is required is the first token (userid@host.domain). You can follow it with the user's personal name, if available. Then you can add the token "BSMTP", which tells LISTSERV to use "Batch SMTP" processing for this address, or the token "PROBE", which tells LISTSERV to send the message to the specified address as a passive PROBE. Please note carefully that the BSMTP and PROBE options cannot be used together for the same address.

If you use the BSMTP option, it isn't necessary to specify a "personal name" as LISTSERV won't use it for anything. BSMTP jobs are sent out in the same manner as regular LISTSERV list mail for users who have the FULLBSMTP user option set; that is, the To: line of the mail contains the address you have specified on the To: line in the data (message text) portion of the RFDR job. This is the most efficient way to send mail via DISTRIBUTE as it "bundles" recipients into a few large outgoing jobs rather than creating a separate outgoing job for each recipient. If you need to "personalize" each message then you do not want to use the BSMTP option. However, most large RFDR jobs will probably be sent using BSMTP since it is more efficient.

If you do not use either BSMTP or PROBE and use just the e-mail address, e.g., janecustomer@abc.com or janecustomer@abc.com Jane Customer, the recipient's e-mail address will be specified in the To: field, regardless of what you define in the To: field header further down in the job. As noted above, this is an attractive way to do the mailings but uses FAR more resources since you are creating a separate outgoing copy of the message for each subscriber. The marketing benefits of personalized mail are obvious but not using BSMTP is something that you should test to see if the return is worth the cost. Utilizing BSMTP allows your job to be processed as if it were a traditional LISTSERV list and should be used when greatest efficiency is desired.

The "/*" at the end of the "To DD" is required and may not be omitted. It tells LISTSERV where the DD ends. It must be on a line by itself. If it does not exist in the job stream, the job will fail.

//Data DD *,EOF

This card tells LISTSERV where the actual message begins. There is no end card for the "Data DD" as it ends at the end of the message you send the job in. This is important to note as it means that you must disable any signature file that normally is sent with your mail--otherwise it will appear as part of the RFDR job and be sent out!

Date:      Tue, 13 Jan 1998 12:25:00 -0400
From:      joe.techie@xyz.com
Subject:   Release of XYZ's WIDGET Model 2
Reply-to:  joe.techie@xyz.com
To:        Widget Customers <customers@widget.com>

Following the "Data DD" job card are the RFC822 message headers for your message. The only required headers here are Date:, From:, and To:. However, while you do not technically need to provide a Subject: or a Reply-To: field, you will probably want to do so for completeness' sake. There is no specified order for these header fields so you may arrange them as suits you best.

If you do not specify a value for the Date: line, but rather simply insert a "Date:" header without a following value, LISTSERV will insert its local time and date as of when it received the job for execution. In the following example:

Date:      
From:      joe.techie@xyz.com
Subject:   Release of XYZ's WIDGET Model 2
Reply-to:  joe.techie@xyz.com
To:        Widget Customers <customers@widget.com>

LISTSERV will fill the Date: header in by itself. Otherwise LISTSERV will accept any Date: field you provide without comment. If on the other hand you do not at least specify a "Date:" header line, no date will be inserted at all.

If you do not specify a From: line, LISTSERV will insert a From: line containing the address of the command invoker (you!) unless you have specified a FROM= option in the DISTRIBUTE command (see either below or in the preceding technical section for specific DISTRIBUTE options), in which case the value of the DISTRIBUTE FROM= option will be inserted. It is probably wise in most cases to ensure that there is a From: line in the "Data DD" as otherwise the result may not be as you planned.

If you do not specify a To: line, LISTSERV will insert a To: line as follows:

To:           Multiple recipients <LISTSERV@NODE>

where "NODE" is the NODE= value for your LISTSERV server. As with the From: line, this is probably not what you want people to see, so you have a couple of options. For jobs which contain only BSMTP recipients, you should specify a To: value, which should point back to a real address in case someone decides to write back to it. For instance, in our example above,

To:        Widget Customers <customers@widget.com>

and we'll assume that "customers@widget.com" is a customer-service address where people can write, or even an existing LISTSERV list out of which you've pulled a subset of addresses for this particular RFDR job.

If you have all non-BSMTP and non-PROBE recipients, you can simply leave the To: field blank (as with Date:, above) and LISTSERV will fill the field in with the data you've provided in the "To DD". For instance, in the following example,

Date:      
From:      joe.techie@xyz.com
Subject:   Release of XYZ's WIDGET Model 2
Reply-to:  joe.techie@xyz.com
To:        

both the Date: and To: fields will be filled in by LISTSERV for you.

Please note that the blank line at the end of the RFC822 headers is not a misprint. According to RFC822 you MUST provide a blank line between the last header and the beginning of the message body, and LISTSERV expects it to be there. If it is not there, the job will fail with an RFC822 parser error:

> DISTRIBUTE MAIL
Invalid RFC822 field found in mail header: "Your text here--forgot 
blank line". Mail not delivered.

Finally, we get to the final element: the message body.

Your text here

This element is fairly self-explanatory; you simply add the actual body of the message you are sending out. Again, make sure that there is a blank line between the body of the message and the last RFC822 header as mentioned previously.

3.4.1. RFDR job options

There are two options that might be of use in the JOB card (the first line of the RFDR job as noted above). These options are:

1. ECHO=NO

This option suppresses the resource usage summary you would otherwise get upon completion of your delivery. Omitting it returns a mail message containing a summary like the following example to the e-mail address from which the RFDR job was sent.

Job "WIDGET1" started on 10 Feb 1998 13:33:34

> DISTRIBUTE MAIL

Job "WIDGET1" ended on 10 Feb 1998 13:33:36

Summary of resource utilization
-------------------------------
CPU time: 0.000 sec
Overhead CPU: 0.030 sec
CPU model: 100MHz Pentium (64M)
Job origin: joe.techie@XYZ.COM

To use this option and suppress the summary from being sent, simply type ECHO=NO at the end of the JOB card, e.g.,

//WIDGET1 JOB ECHO=NO

2. PRIME=prime-time-specification

This option controls when the job runs, if you do not want it to run immediately.

This function of this option is identical to the function of the "Prime=" keyword setting for LISTSERV mailing lists, where "Prime=" defines (on a list by list basis) times during which LISTSERV should not process mail for the list. By default this option is set to "PRIME=Yes", meaning that the job can be processed at any time. If you set this option to "PRIME=No", it uses the value set globally by LISTSERV's PRIMETIME= site configuration variable, which by default is set to have no prime time (in other words, by default, mail can still be processed at any time even with "PRIME=No"). The PRIME= option for RFDR jobs can be set to an explicit time definition if necessary. For instance, you might have a very large RFDR job (e.g., a newsletter) that should not be processed until after midnight (when network traffic is low and more machine resources are generally available).

RFDR jobs sent to LISTSERV during prime time are automatically held until non-prime time and then distributed normally, without requiring further intervention by anyone. For instance you could set the "PRIME=" option to

PRIME="MON-FRI: 00:00-23:59"

This means that you could send the job anytime during the regular work week--Monday morning through Friday afternoon--and know that it won't be distributed until Friday at midnight or shortly thereafter.

As another example, if you want the job only to be processed between midnight and 6 AM on weekends, you might set it to

PRIME="MON-FRI: 00:00-23:59; SAT-SUN: 06:00-23:59"

Note that the specifications for PRIME= must be enclosed in quotes and the format (spaces) should be identical to the examples.

VERY IMPORTANT: You should always leave yourself at the very least an hour processing window, and even more so for large jobs, since PRIME checks are done once each hour, on the hour, and very large jobs may require extended processing time. Also note that if running in Networked mode, even more time is required since jobs passed across the LISTSERV network for other servers to deliver also contain the PRIME setting, and depending on which time zone it is passed to, it may miss the "window" altogether. For example,

PRIME="MON-FRI: 00:00-23:59; SAT-SUN: 06:00-23:59"

leaves six hours of processing for your DISTRIBUTE job on Saturday and Sunday, i.e., 12 hours total processing time over the two days. So if the job does not get to, say, a server in Japan before the PRIME deadline on Saturday, it will be processed the next day during non-prime time. In actuality it is probably not necessary to use such small windows on the weekend, so

PRIME="MON-FRI: 00:00-23:59"

is probably all you would need for a job to be delivered over the weekend.

To use the PRIME option, simply type it following the JOB operand. If you need to specify ECHO=, note that it must follow PRIME= or a syntax error will result. For example:

//WIDGET1 JOB PRIME="MON-SUN: 09:00-23:59" ECHO=NO

or

//WIDGET1 JOB PRIME="MON-SUN: 09:00-23:59"

Please make sure that you test the PRIME= option setting with test jobs first to make sure that the proper syntax is being used before sending mission critical jobs to be processed during off-prime hours.

3.4.2. DISTRIBUTE Command Options

There are four options that might be of use in the DISTRIBUTE command (the second line of the RFDR job as noted above). These options are:

1. ACK=MAIL

This option tells LISTSERV to confirm deliveries with an acknowledgement sent by mail (the default is not to send delivery confirmations, but rather to simply acknowledge receipt and processing of the job), as in the following example (note that ECHO=YES in the JOB card for this particular example):

Job "WIDGET1" started on 10 Feb 1998 13:33:34

> DISTRIBUTE MAIL

Mail delivered to janecustomer@abc.com

Job "WIDGET1" ended on 10 Feb 1998 13:33:36

Summary of resource utilization
-------------------------------
CPU time: 0.000 sec
Overhead CPU: 0.030 sec
CPU model: 100MHz Pentium (64M)
Job origin: joe.techie@XYZ.COM

Use of this option in the DISTRIBUTE command line is as follows:

DISTRIBUTE MAIL ACK=MAIL PW=XXXXXXXX

Other than the default ACK=NONE, the only other setting for this option is "MSG", which is obsolete except for NJE servers.

2. DEBUG=YES

This option produces a report showing how the various recipients will be routed over the LISTSERV backbone, but WITHOUT actually delivering the message. Before sending out your actual posting, you may want to send the RFDR job with this option enabled to see how the mail will be routed.

Examples of the use of this option in the DISTRIBUTE command line:

DISTRIBUTE MAIL ACK=MAIL DEBUG=YES PW=XXXXXXXX

DISTRIBUTE MAIL DEBUG=YES PW=XXXXXXXX

3. TRACE=YES

This option produces a report showing how the various recipients will be routed over the LISTSERV backbone, and actually delivers the message (similar to DEBUG=YES but the message is actually delivered).

Examples of the use of this option in the DISTRIBUTE command line:

DISTRIBUTE MAIL ACK=MAIL TRACE=YES PW=XXXXXXXX

DISTRIBUTE MAIL TRACE=YES PW=XXXXXXXX

4. FROM=netaddress

This option can point to a particular address that will receive the bounced mail, notifications of delivery problems, etc. Specifically this option sets the RFC821 MAIL FROM: address to which all compliant mailers will bounce non-deliverable mail. The single parameter netaddress
is an Internet address in the standard format (userid@host.domain).

Examples of the use of this option in the DISTRIBUTE command line:

DISTRIBUTE MAIL ACK=MAIL TRACE=YES FROM=john@example.com PW=XXXXXXXX

DISTRIBUTE MAIL FROM=john@example.com PW=XXXXXXXX

DISTRIBUTE MAIL ACK=MAIL FROM=john@example.com PW=XXXXXXXX

DISTRIBUTE MAIL TRACE=YES FROM=john@example.com PW=XXXXXXXX

3.5. Advanced LISTSERV applications using DISTRIBUTE

Depending on your specific needs, it is possible for sites to "get creative" and use traditional LISTSERV lists as "back-ends" in conjunction with DISTRIBUTE jobs to handle bounces in the same way they are handled for a regular LISTSERV list, without ever using the list itself for posts.

Let's say that, to begin with, you collect addresses from a guestbook web page that you've set up for your company. You want to send out periodical updates to these people using RFDR "DISTRIBUTE" jobs but you know that you are going to have the usual 15-20% or more bad addresses from typos, pranksters, and plain old attrition. How do you find the bouncing addresses so you can purge them from your database without having to read each bounced message and determine what address actually bounced?

Simply create a traditional list with the appropriate error handling setting desired (see other sections of this manual and of the List Owner's Manual for LISTSERV for more information). Set "Change-Log= Yes" and "Auto-Delete= Yes,Full-Auto,Delay(0)" in the list's header ("Change-Log" requires LISTSERV 1.8d and later). Use an ADD IMPORT job as detailed in chapter 4.3 of the List Owner's Manual to add all of the addresses from your database to the list.

Then in your RFDR job, set the following in the FROM= option of the DISTRIBUTE command line:

DISTRIBUTE MAIL FROM=owner-listname@yourdomain.com PW=XXXXXXXX

where listname
is the name of the list created. For instance, if the list was named bouncelist1 and the LISTSERV host name was LISTSERV.EXAMPLE.COM, then the DISTRIBUTE command would be as follows:

DISTRIBUTE MAIL FROM=owner-bouncelist1@listserv.example.com PW=XXXXXXXX

Once you have the bounce list set up (and we'll continue to use our bouncelist1 example), you simply check the BOUNCELIST1.CHANGELOG file for a listing of addresses LISTSERV has auto-deleted from bouncelist1 since you sent out your RFDR job. You can then use this changelog file to update your database and clean out the bad addresses.

Do keep in mind, however, that in order for LISTSERV to take action on permanent bounces that come to the owner-bouncelist1 address and are, furthermore, in a format understandable by LISTSERV, the bouncing address(es) must also be listed as subscribers in the back-end bouncelist1 list (so do not forget to bulk add the addresses before sending the DISTRIBUTE job, as explained above).

To take this a step further, you could also use this same back-end bounce processing list as a front-end list to handle automatic subscribe and unsubscribe requests for each mailing, allowing for total flexibility for both yourself and the customers being mailed to.

3.5.1. "List-free" bounce processing for one-shot lists (1.8d)

Starting with LISTSERV 1.8d you can bounce-process a one-shot list without needing a back-end list for the bounces to come back to (as outlined above).

To use the new "list-free" feature, you create and send a standard DISTRIBUTE job with the FROM= address set to OWNER-NOLIST-xxx@hostname (where 'xxx
' can be anything and 'hostname
' is LISTSERV's host name), for instance OWNER-NOLIST-MYDIST@LISTSERV.MYHOST.COM. While 'xxx
' can be anything, OWNER-NOLIST@whatever doesn't work--you must provide '-xxx
'. Within the job you then use PROBE for each address in the manner documented above.

After sending the job, you get a NOLIST-xxx.CHANGELOG in LISTSERV's A directory with entries for every bounce. (In our example above, this file would be called NOLIST-MYLIST.CHANGELOG.)The entries read BOUNCE followed by the e-mail address. As there is no monitoring and no decision to delete, the entry does not read AUTODEL, and thus bounce reporting for "list-free" DISTRIBUTE jobs is passive. By definition, however, you can't monitor one-shot jobs; monitoring (if desired) must be provided by collating all the one-shot jobs into a big monitoring database, or something similar (all jobs from client such and such, etc).

Note carefully that if you are running under unix with sendmail, you will have to patch sendmail in order for it to properly accept and route bouncing probe messages. As a convenience, L-Soft provides third-party sendmail patches for this purpose on its FTP site (in ftp://ftp.lsoft.com/listserv/unix/CONTRIB) but please be aware that L-Soft did not write and does not support these patches in any way; they are strictly for use at your own risk and you must contact the author(s) of the patches for help with them.


4. DBMS and mail-merge support

4.1. Overview

Two of the most significant enhancements in version 1.8d of LISTSERV are DBMS and mail-merge support. In this chapter, you will find a brief description of these new features, along with installation instructions and a few samples.

While the DBMS and mail-merge functions were designed to work together, they can also be used independently from each other. That is, you may find the DBMS support useful even if you have no need for mail-merge functionality, and likewise you can use the mail-merge functions without a DBMS back-end. Both functions require LISTSERV Classic or LISTSERV HPO, and are unavailable in LISTSERV Lite. Additionally, mail-merge requires that LSMTP Classic version 1.1b or later be installed as your outgoing mail transfer agent.

4.1.1. DBMS support

LISTSERV's DBMS support allows you to:

  • Direct LISTSERV to store subscriber information in a DBMS, on a list by list basis. That is, you may have a mix of traditional LISTSERV lists and DBMS lists. Furthermore, you can adjust the layout of your DBMS lists to match existing or current applications. You can map each list to a private table if this is what makes sense for you, or you can put all the lists in the same table, place related lists in one table, etc. You can add as many columns as you want to store additional information about subscribers.

  • Use the DBMS as a back-end for mail-merge jobs. LISTSERV can execute arbitrary SQL SELECT statements to extract recipients from your DBMS, and make related information (name, country, account number, etc.) available for mail-merge operations.

DBMS support is available through Microsoft's ODBC interface on Windows NT, and Oracle's OCI 8 interface on Windows NT, OpenVMS Alpha, Digital Unix, AIX and Solaris (SPARC only).

4.1.2. Why require Oracle 8?

Oracle has introduced major changes to the OCI API in version 8. While many of the concepts remain similar, all the function calls have been renamed and most have a different calling sequence. Supporting both OCI 7 and OCI 8 would require more than a handful of #ifdef statements -- we would need to develop and support a separate interface for OCI 7. In addition, we would need to license Oracle 7 on all supported systems, which would significantly increase our development costs. While we recognise that there is a large Oracle 7 installed base, a year or so from now most of them will have upgraded to Oracle 8, thus the cost for developing an OCI 7 interface and purchasing six Oracle 7 licenses would have to be amortised over a period of about a year, leading to much higher licensing costs for the OCI 7 version. Furthermore, it is possible to use LISTSERV's OCI interface with an Oracle 7 server: the only component which must be at version 8 is the client, i.e. SQL*Net. As Oracle-based LISTSERV installations typically run on a separate, dedicated system, this simply means that you need to purchase a version 8 client license for the system in question. It is not necessary to upgrade the server to Oracle 8. Oracle 7 is also supported through the ODBC interface.

4.1.3. Mail-merge

Documented Restriction: Note that LISTSERV's mail merge functionality REQUIRES the use of LSMTP Classic as the outgoing MTA. Mail merge does not work with sendmail, qmail, Post.Office, Netscape Mail Server, Microsoft Exchange, PMDF, MX, or any other MTA except L-Soft's LSMTP Classic mailer.

Under unixes not supported by LSMTP Classic this may require that you set SMTP_FORWARD= accordingly in go.user, to point to a separate machine running LSMTP (for instance, a dedicated Windows NT LSMTP machine). Under OpenVMS or Windows NT can run LSMTP Classic either on the same machine (the preferred method), or on a separate machine if desired. The main point is that the outgoing mail-merge postings MUST be handled by LSMTP Classic. (LSMTP Lite does not support mail-merge.)

LISTSERV's mail-merge support allows you to send individually customised messages to large numbers of recipients with very high throughput. The mail-merge functions support:

  • Simple substitutions, such as "Dear &firstname;".

  • Conditional blocks, such as a birthday greeting sent when the message happens to coincide with the recipient's birthday, or a warning when the balance of the account is negative.

  • Special facilities to send promotional banners to a randomly generated subset of the recipients. For instance, you can indicate that a first banner should be sent to a random subset of 200 recipients, while another banner is sent to a randomly selected (but distinct) series of 500 recipients, and others receive a third banner, or no banner at all.

  • Easy support for "few of many" topic subscription, such as a service offering news about movie actors (many registered actors, while most people will only want news about a handful of them).

  • Full integration with the DBMS interface, allowing recipients to be selected through arbitrary SELECT statements, while every column that can be converted to a character string is made available as a mail-merge field.

  • A simple bounce processing and collection system -- LISTSERV processes and decodes all bounces, and writes the failing addresses to a plain-text file. You can group related mailings in the same bounce file or use a separate file for each mailing, whichever makes the most sense in your context. As each message is sent in "probe" format, even non-standard bounces will be processed accurately, as long as the remote MTA sends bounces to the correct (RFC821 MAIL FROM:) address.

Mail-merge support requires version 1.1b of LSMTP Classic (LSMTP Lite does not support mail-merge operations). LSMTP is currently available for Windows NT and OpenVMS Alpha, and will shortly be available for Digital Unix, AIX and Solaris (SPARC only) - the same systems for which the DBMS interface is available. Note that LSMTP and LISTSERV need not reside on the same hardware; by way of example, it would be possible to run the DBMS-enabled version of LISTSERV on any supported unix platform, with LSMTP Classic 1.1b running on Windows NT.

4.1.4. Why require LSMTP?

The largest obstacle to the successful deployment of a full-scale mail-merge operation is performance. The feedback we received from the customers who participated in the design and early testing of this system was unanimous -- a mail-merge system would have no value to them unless it could be scaled to at least hundreds of thousands of recipients, if not millions. Unsurprisingly, while customers were willing to pay a moderate surcharge in hardware costs for the mail-merge functionality, they were unable to budget order of magnitude increases. Their requirement, and our design goal, was the ability to run a "normal" 6 figure mail-merge workload on a single high-end PC system. Performance requirements varied from as little as 10,000 hourly deliveries to a demanding 250,000/hour.

Out of the box, a normal sendmail configuration running on a high-end PC system will not even reach the 10,000/hour mark. A mail-merge job leads to a large number of spool files (one recipient = one message), and a large spool is sendmail's bane. If you were to construct an artificial workload to demonstrate sendmail's technical flaws, it would be very close to a typical mail-merge workload with the usual 20% of bad addresses.

To get an idea of the maximum mail-merge throughput from a system not specifically designed for this purpose, we conducted "brute force" (one recipient = one message) performance tests using LSMTP 1.1a on a 1-CPU, 200MHz Pentium Pro system. Using live traffic from our outsourcing customers and jobs in the 200-300,000 recipient range, we were able to sustain 150,000 hourly deliveries. While well within the target range of 10-250,000/hour, the resulting I/O rate was close to the reasonable practical limit of (then) current disk technology. With a (then) hypothetical 400MHz Pentium Pro CPU, we expected to achieve 175-200,000/hour rather than 300,000/hour. Clearly, the "brute force" approach could only be a short-term solution, as CPU performance improves much faster than I/O throughput.

With the "one message = many recipients" approach we adopted in LSMTP 1.1b, we were able to achieve same-LAN throughput rates on the order of 1,000,000/hour on a 200MHz Pentium Pro. While LAN figures are meaningless as an estimate of actual performance with live addresses, in the present case they clearly indicate that I/O is no longer a bottleneck.

We chose not to give customers the option of using sendmail, because the programming for a "brute force" approach is vastly different from LSMTP 1.1b's. Development and support costs for the mail-merge functions would have about doubled, whereas the only value of the "brute force" implementation would be in demonstrating that LSMTP is required for good performance.

4.2. Pre-installation tasks

Before installing DBMS and mail-merge support, please review the following steps and make sure that your selected target system is ready to receive this update.

  • DBMS support requires version 1.8d of LISTSERV Classic. Mail-merge support requires version 1.8d of LISTSERV Classic and version 1.1b of LSMTP Classic.

  • If you are planning to use the DBMS interface, you must install vendor-supplied DBMS support files on the target machine before installing the LISTSERV update. For ODBC (Windows NT), the appropriate ODBC support files are shipped with the LISTSERV installation kit and are installed when you install LISTSERV if they do not already exist on your machine.4 For OCI, you need to install and configure the Oracle8 client files (SQL*Net et al.) This material is typically licensed and not freely redistributable, and thus does not come with the LISTSERV kit.

  • If you are using Windows NT, you must install SP3 (4.0) or otherwise procure and install ODBC support (3.51) prior to installing the update, even if you do not plan to use the DBMS support features. ODBC is now a standard component of Windows NT, and applications that contain ODBC system calls will not launch if the ODBC DLLs are not present on the system. Again, NT will not launch the application at all, even if it does not make any ODBC call. As noted above, L-Soft ships these files with LISTSERV for your convenience, but the versions L-Soft ships may not be the latest versions. The simplest way to obtain the latest versions of the ODBC support files is to upgrade to NT 4.0 SP3.

  • If you are planning to use the mail-merge functions, you must upgrade LSMTP to version 1.1b. While you can upgrade LISTSERV first, it is best to start with LSMTP. Upgrading LSMTP requires a 1.1b license key from your sales representative.

  • If using the DBMS interface, you may want to create a DBMS username for LISTSERV in advance, and grant it the CREATE SESSION (mandatory) and CREATE TABLE (optional) privileges. If you are planning to create all tables yourself, you should not grant CREATE TABLE to LISTSERV's DBMS username.

  • Note that a compiler is required to use the OCI interface on unix systems. L-Soft may not legally ship pre-linked executables containing the SQL*Net library.

4.2.1. Selecting a suitable DBMS product

This section applies only to ODBC users, as OCI users will always be using Oracle, which does not exhibit any of the problems mentioned in this section.

While L-Soft does not ordinarily recommend or endorse specific hardware or software brands, some database products (especially low-end PC offerings) may not be suitable for use together with LISTSERV. Without advocating one brand over another, L-Soft recommends the use of a DBMS that does not exhibit the problems mentioned below. All error messages are in reference to the diagnostics printed by the LISTSERV ODBC interface during startup.

  • [FATAL] LIKE operator has no ESCAPE clause, errors will occur!

    This error indicates that the DBMS does not support any kind of "escape clause" for the LIKE operator. In practice, it means that whenever LISTSERV attempts a search containing a percent sign or underscore, the results will be incorrect (you may also get an ODBC error). This makes the DBMS unusable as a data store for LISTSERV lists. However, if you only plan to use the DBMS for mail-merge jobs, this restriction may be immaterial as LISTSERV will only be executing the SQL statements that you provide in the mail-merge job.

    SQL Server users should note that ESCAPE support was added in version 6.5. L-Soft will not support SQL Server 6.0 or older as a data store for LISTSERV lists. The Microsoft Access DBMS product also appears to have this restriction.

  • [SEVERE] Max active stmt: 1 - expect uncommitted read & unrequested commits

    With a maximum of one active statement per transaction, the ODBC interface is unable to carry out typical SELECT ... UPDATE ... UPDATE ... COMMIT sequences using a single transaction, because the SELECT remains active until the COMMIT and prevents the execution of the UPDATE statements. To bypass this problem, the ODBC interface will use two transactions for these sequences. However, the two transactions will typically look like independent applications to the DBMS, and will suffer from "transaction isolation," a vital DBMS feature that permits shared database access by multiple unrelated applications. As LISTSERV expects that an update will be reflected in a subsequent search, whether it has been committed or not, the ODBC interface will be forced to commit updates before beginning a new SELECT, even when LISTSERV had not requested a commit. In addition, if the DBMS does not support row-level locking, the ODBC interface will hang when attempting to execute the UPDATE statement, because the table is locked by the transaction containing the SELECT! To avoid this, the ODBC interface may switch to the lowest level of transaction isolation, "uncommitted read." If LISTSERV is the only application writing to the tables containing the data, this will be of no consequence, otherwise LISTSERV may see uncommitted changes made by other applications.

    SQL Server artificially exhibits this condition. In reality, SQL Server does support multiple statements per transaction, but its ODBC driver reports otherwise, and will only allow one statement per transaction unless using dynamic cursors (or a related option). Dynamic cursors, however, will only work (with SQL Server) if the table contains a unique index; otherwise, the cursor is downgraded and leads to the one-statement behaviour. It is possible that third-party ODBC drivers may allow and report unlimited statements per transaction.

  • [SEVERE] FOR UPDATE clause not supported, no locking will occur

    Some entry-level DBMS products may not support locking at all, or may only support it through a proprietary interface (rather than via SQL commands). In that case, LISTSERV will be unable to lock the rows it is in the process of updating, which may lead to incorrect behavior if you have other applications updating the tables.

  • [SEVERE] '=' operator is case-insensitive, results may be incorrect!

    With some DBMS products, the equality operator is case-insensitive. While LISTSERV is generally case-insensitive, it does of course have the ability to make case-sensitive searches, and will do so on occasion. LISTSERV's built-in data management functions typically use the e-mail address as a unique, case-sensitive, primary index into the list, and LISTSERV assumes that it can use the e-mail address as a kind of "row ID" if the need arises. LISTSERV is not programmed to "doubt" the equality of a successful search for an e-mail address it had previously retrieved, as this is algorithmically impossible with its built-in functions. While this is a severe error in that it can lead to incorrect results, in practice it only has limited impact.

    SQL Server usually has case-insensitive equality configured by default. While it is possible to change this setting, this can only be done by reinstalling the product from scratch, which is usually unacceptable. In addition, the setting is global and affects all tables, all users, etc. In practice, the impact does not warrant the re-installation of an existing system.

  • Cursor behaviour limits ability to commit before logical close

    This warning indicates that the DBMS will "forget" the results of any active SELECT statement whenever a transaction is committed. As LISTSERV's built-in data management functions do not have this restriction, LISTSERV will often commit changes while a search is in progress. For instance, if you issue the command SET XYZ-L DIGEST FOR *@AOL.COM, LISTSERV will search for users matching the pattern *@AOL.COM and, for each match, update the subscription options, send an e-mail message, and commit. This way, if the command is interrupted and re-executed, users who already received an e-mail notice will not receive a second copy. When this warning is printed, the ODBC interface will ignore any commit request from LISTSERV that would abort an active search. The transaction will always be committed when the LISTSERV command completes, so the final results will always be accurate. However, in extreme cases (such as a SET command updating every record in the database), the transaction might generate a very large amount of uncommitted data, and require a lot of rollback space.

    SQL Server users should note that while the SQL Server ODBC driver will cause this message to be displayed unless a non-standard ODBC call has been issued in advance, in practice it has no operational impact as the ODBC interface will have to use a separate transaction for update activity anyway. Thus, the ODBC interface is free to commit whenever requested by LISTSERV. SQL Server itself is able to preserve active SELECT statements across a commit, it is the ODBC driver which requests the "close cursors on commit" behavior.

  • Multi-row operations are unavailable

    This is a performance warning indicating that bulk ADD operations may be slowed down. In practice, this warning only occurs with DBMS packages that offer limited performance anyway, and can be safely ignored.

Except as specifically indicated above, any error marked as FATAL or SEVERE can potentially lead to incorrect results. If you are planning to use the DBMS as a data store for LISTSERV lists, FATAL errors are unacceptable and SEVERE errors need to be investigated carefully. If you are only planning to use the DBMS interface for mail-merge operations, both SEVERE and FATAL errors may be acceptable as LISTSERV will only be executing the SQL statements provided in the mail-merge job. The script or person providing these statements is then responsible for making the necessary adjustments to work around the DBMS restrictions.

4.3. Installation

Installation instructions have been broken down by operating system. Make sure that your 1.8d license is installed before you begin, and that you have made a backup of your LISTSERV directory tree. All kits are located on FTP.LSOFT.COM under the appropriate LISTSERV/platform directory (ie, LISTSERV/unix, LISTSERV/Windows, LISTSERV/VMS).

4.3.1. Windows NT

The Windows NT kits include support for ODBC and mail-merge. While OCI is also available for Windows NT, OCI kits cannot launch unless SQL*Net is installed, so OCI support cannot be included in the default NT kits. There are three available kits:

  • winnt-intel.zip for Intel systems using ODBC.
  • winnt-axp.zip for Alpha systems using ODBC.
Note that the above two kits are the standard installation kits; ODBC connectivity is shipped by default. If you already have LISTSERV 1.8d installed, you already have ODBC connectivity and do not need to download a new kit.

  • intel-oci.zip for Intel systems using OCI.
(The OCI feature is not currently available for Alpha systems.)

The OCI kits are designed to be overlaid on top of an existing standard LISTSERV installation. This means that in order to install OCI support, you must stop LISTSERV, CD to the root LISTSERV directory (usually C:\LISTSERV) and UNZIP the kit on top of your existing installation. Your SITE.CFG will not be overwritten. If you are using the web interface, make sure to copy the WA.EXE shipped with the OCI kit to your CGI script directory.

4.3.2. OpenVMS Alpha

The OpenVMS kits include mail-merge support and optional OCI support (selected at LINK time). Two kits are available:

  • axp.zip for all Alpha systems.

  • axp-ev56.zip for Alpha systems with an EV56 processor (this build uses the new byte instructions and must be used only on systems with an EV56 or EV6 processor, if in doubt use the other kit).

This is a standard VMSINSTAL kit. If you want to install the OCI interface, you must run the appropriate ORAUSER.COM procedure before installing the kit. Otherwise, you will not be asked whether you want to install OCI support.

If you do install OCI support, you will need to modify your LISTSERV startup procedures to execute ORAUSER.COM before starting LSV.EXE.

4.3.3. Digital Unix, AIX, Solaris

The unix kits listed below include mail-merge support and mandatory OCI support. Contact L-Soft if you need a kit with mail-merge only. The following kits are available, note that you must install common.tar.Z in addition to the system-specific kit:

  • OSF1-OCI.tar.Z for Digital Unix.

  • AIX-OCI.tar.Z for AIX.

  • Solaris-OCI.tar.Z for Solaris SPARC.

  • common.tar.Z for all systems. This archive is REQUIRED in addition to the system specific kit.

These are standard LISTSERV upgrade kits. Create a temporary directory, untar both files to that directory, customize the LISTSERV Makefile, stop LISTSERV and type make install to proceed with the upgrade.

Makefile notes: OCI support requires that you provide references in the Makefile to the Oracle connection libraries for your specific Oracle version. This is done by including -l switches for these OCI connection libraries in the CFLAGS_`uname` macro for your OS (ie, either CFLAGS-Solaris, CFLAGS-OSF1, or CFLAGS-AIX, all of which are found just below the end of the "user customization" area in the LISTSERV Makefile). Please note carefully that the location and name of the library or libraries you need for this step can change and can depend on the version of SQL*Net you are running. Our experience indicates that we cannot simply say "add -lxxxx to the CFLAGS_`uname` macro" and expect it to work 100% of the time. However, by way of example only, if you are running Solaris and the Oracle documentation indicates that you need to add support for the 'clntsh' library, you would make the following change to the Makefile:

#CFLAGS_Solaris=-lsocket -lnsl
CFLAGS_Solaris=-lsocket -lnsl -lclntsh

(It's always recommended to comment out the default in case you have to revert to it for some reason.)

If there is any question about which library or libraries to use, please refer to the Oracle documentation or contact Oracle support. L-Soft's support department cannot provide this information for the reasons noted above.

These are standard LISTSERV upgrade kits. Create a temporary directory, untar both files to that directory, customize the makefile (make sure to include -l switches for the OCI libraries), stop LISTSERV and type make install to proceed with the upgrade.

4.3.4. Verification

When done, start LISTSERV normally and send a few test commands before proceeding with the post-installation tasks. This will ensure that the installation was successful and that, where applicable, the appropriate environment is configured for the OCI library. Note that the DBMS interface will not be enabled until you add the necessary authentication/login information to your configuration files.

4.4. Post-installation tasks

Post-installation instructions have been broken down by feature. References to the "LISTSERV configuration" correspond to SITE.CFG under Windows NT, SITE_CONFIG.DAT under OpenVMS and go.user for unix systems. Do not forget to export configuration variables under unix.

4.4.1. Mail-merge

For best performance, make sure that MAXBSMTP is set to at least 5000. If you want to allow individual list owners to send mail-merge messages for their respective lists, set the DIST_OWNER_MAIL_MERGE configuration variable to the value 1. By default, this option is disabled as it requires LSMTP 1.1b. Note that the LISTSERV administrator is always allowed to send mail-merge messages; it is assumed that the administrator knows whether LSMTP 1.1b is installed, whereas individual list owners may not have this information.

4.4.2. ODBC interface

To activate the ODBC interface, you must first create a system-wide ODBC data source. Open the Control Panel, double-click on the "ODBC 32" icon, select the "System DSN" tab, click "Add..." then select the appropriate driver and fill out the driver-specific form. L-Soft does not recommend supplying passwords in a system-wide DSN (if offered at all by the driver) because any Windows NT user has access to this information.

For the purposes of this example, we will assume that the DSN you just created is called GREEN. You would then add the following lines to SITE.CFG:

ODBC_DSN=GREEN
ODBC_UID=...
ODBC_AUTH=...

Replace the ellipses with appropriate (DBMS-specific) authentication information. While officially called the "authentication string" in the ODBC specifications, ODBC_AUTH is often called "password" in vendor documentation.

See also "Generic DBMS post-installation tasks", below, for instructions that are common to ODBC and OCI.

4.4.3. OCI interface

To activate the OCI interface, you must add an OCI_CONNECT parameter to your LISTSERV configuration. Its value should be an OCI configuration string, typically a service name from TNSNAMES.ORA. In addition, you may need to add OCI_UID and OCI_PWD parameters. If you do not supply a userid and password, the OCI interface will login with external (i.e. operating system) authentication.

Note that, under Windows NT, external authentication is based on the NT userid under which the application (LISTSERV) is running. When you run LISTSERV interactively, you are usually not running LISTSERV under the same NT userid as when it is started as a service. Thus, if using external authentication, Oracle may fail to login when started as a service. To circumvent this problem, use standard authentication (IDENTIFIED BY password) or use the Control Panel to change the account under which the LISTSERV service is running.

See also "Generic DBMS post-installation tasks", below, for instructions that are common to ODBC and OCI.

4.4.4. Generic DBMS post-installation tasks

A number of additional configuration variables are available to alter the default behaviour of the DBMS interface. In the following discussion, a "DBMS list" refers to a list whose membership data is stored in a DBMS, as opposed to a traditional LISTSERV list where LISTSERV keeps the membership data in the xxx.LIST file.

  • DBMS_DEFAULT_TABLE (default: LISTSERV) -- default value for the name of the table in which DBMS lists are stored. Specify either a valid table name, or an asterisk to name the table after the list.

  • DBMS_DEFAULT_EMAIL (default: EMAIL) -- default value for the name of the column containing the subscriber's e-mail address.

  • DBMS_DEFAULT_UEMAIL (default: empty string) -- default value for the name of the optional column containing an upper-case copy of the subscriber's e-mail address. If set to the empty string, no such column is created or used. See below for more information on this performance option.

  • DBMS_DEFAULT_NAME (default: NAME) -- default value for the name of the column containing the subscriber's name.

  • DBMS_DEFAULT_OPTIONS (default: *) -- default value for the name of the column containing the subscriber's LISTSERV subscription options. An asterisk indicates that the column should be named after the list.

  • DBMS_NO_HOSTNAME_ALIASING (default: 0) -- when set to 1, disables hostname aliasing for increased performance with some DBMS products. L-Soft recommends using the default value of 0.

When using all the default options, DBMS lists will be kept in a table called LISTSERV, with the e-mail address in a column called EMAIL, the name in a column called NAME, and one additional column for each DBMS list. The name and e-mail address will be shared, that is, a change in the user's name for list A is automatically reflected in list B. Of course, each of the layout parameters can be overridden on a per-list basis.

4.4.5. Performance options

The DBMS interface offers two options to improve lookup performance and overcome a fundamental difficulty in obtaining good e-mail lookup performance from a traditional SQL DBMS. An Internet e-mail address, as stored by LISTSERV in the DBMS, has the following format:

userid@hostname

Both halves of the address present a performance challenge.

The userid is case-sensitive. Internet standards and current industry practice demand that the case of the userid be respected. Failure to do so will lead to undelivered mail. Thus, LISTSERV must store the userid in the DBMS exactly as it was provided to LISTSERV. People, on the other hand, are not used to making a difference between JOE and Joe. When asking LISTSERV to remove Joe from the list, they will expect JOE's subscription to be cancelled, not a message claiming that there is nobody named Joe on the list. Thus, LISTSERV must make a case-insensitive search when looking up an address:

SELECT ... WHERE UPPER(EMAIL) = 'JOE@XYZ.COM';

Unfortunately, even on an indexed column, this search will typically require a full table scan. While it would be technically possible for the DBMS to use the index together with the UPPER function, in practice this optimization has not been implemented, because it is not frequently required in a typical DBMS environment. To alleviate this problem, LISTSERV supports the optional use of an additional column, containing an upper case copy of the e-mail address. The above search can then be rewritten as:

SELECT ... WHERE UEMAIL = 'JOE@XYZ.COM';

This search will make use of any available indexes. The drawback is that the column takes up additional space and must be set and changed together with the e-mail address, or lookup results will be incorrect. If the table is to be updated by applications external to LISTSERV, L-Soft recommends adding a CHECK clause to make sure that the UEMAIL column is always set correctly. If LISTSERV is the only writer, this is not necessary.

While the hostname is not case-sensitive, many sites use mail systems where users appear to have a different hostname based on a variety of technical factors. LISTSERV supports a feature called "hostname aliasing" which allows it to know that, for instance, joe@classic.msn.com and joe@msn.com are the same person. Thus, when your customer support department receives a complaint from joe@msn.com asking to be deleted from your mailing lists, LISTSERV will automatically delete joe@classic.msn.com rather than report that Joe is not subscribed to the mailing list. The drawback, however, is that LISTSERV must formulate the lookup as follows:

SELECT ... WHERE UEMAIL LIKE 'JOE@%';

LISTSERV then reviews the selected entries and determines whether they are a valid match for joe@msn.com. With a good DBMS, this will not introduce any performance problem. The DBMS will use the index for LIKE searches until the first wildcard is encountered, and in practice there will not be many entries left to scan. Some DBMS, however, may simply not use the index for LIKE searches. In this case, you may want to set the DBMS_NO_HOSTNAME_ALIASING configuration parameter to 1, to disable the hostname aliasing feature for DBMS lists. The drawback, of course, is that LISTSERV will not be able to match joe@msn.com to joe@classic.msn.com. L-Soft recommends upgrading to a more advanced DBMS product rather than disabling hostname aliasing.

4.5. Creating DBMS lists

4.5.1. Configuring a list to use the DBMS

This section assumes that the reader is familiar with the process of creating LISTSERV lists and updating their list header. Refer to the Site Manager's Operations Manual for more information.

The use of the DBMS as a data store for list membership information is controlled by the "DBMS=" list header keyword. To create a DBMS list, specify a "DBMS=" keyword as follows:

DBMS= Yes[,TABLE(xxx)][,EMAIL(xxx)][,NAME(xxx)][,UEMAIL(xxx)][,OPTIONS(xxx)]

Brackets indicate optional parameters. That is, "DBMS= Yes" defines a DBMS list with the default values for TABLE, EMAIL, NAME, UEMAIL and OPTIONS, as described in Generic DBMS post-installation tasks above. The EMAIL, NAME, UEMAIL and OPTIONS column should have a data type compatible with VARCHAR (not CHAR or other fixed-length data types). The UEMAIL column, if used, should be the primary key (at a minimum, it must be indexed), and should have the same width as EMAIL; the EMAIL column should not be indexed. You can set the column widths as you want, however LISTSERV will assume that EMAIL is at least 80 characters wide, and OPTIONS should allow at least 40 characters. If you let LISTSERV create the table, it will use a width of 128 for all columns.

Under Windows NT, it is possible to use both ODBC and OCI interfaces simultaneously. In this case, you can use "DBMS= OCI,..." or "DBMS= ODBC,..." to tell LISTSERV which interface to use for a particular list. You can also use "DBMS= Yes,..." if you add a DBMS_DEFAULT_INTERFACE parameter to SITE.CFG with the value ODBC or OCI.

When migrating an existing list to use a DBMS, you are responsible for migrating the subscriber data to the DBMS, if necessary (in many cases, the subscriber data will already be in the DBMS, possibly in a slightly different format). Once you add the "DBMS= Yes" keyword, LISTSERV stops accessing subscriber data from the xxx.LIST file and uses the DBMS instead.

4.5.2. Importing subscribers into a DBMS list

Subscribers can be imported into a DBMS list using the ADD IMPORT command, also known as "bulk add." However, despite the name this is not an "import" operation in the database sense; it does not disable logging or rollback and is based on normal transactional operations. You may be able to obtain better performance using specialized import tools provided by your DBMS vendor.

While ADD IMPORT is very efficient with a traditional LISTSERV list, it still eliminates duplicates and, when appropriate, updates existing rows with the data in the ADD IMPORT job. That is, it does not assume that all the new data can simply be inserted into the table. In SQL terms, an ADD IMPORT job is a series of SELECT ... UPDATE and SELECT ... INSERT sequences. Even with an index, this kind of workload tends to have transaction rates in the dozens or at best hundreds per second, rather than thousands.

With hostname aliasing disabled, a UNIQUE constraint on the e-mail address, and ignoring case-sensitivity issues, it would be possible to just issue INSERT statements, let the DBMS reject those for which a row with the unique key already exists, and re-issue them as UPDATE statements. However, most people will use hostname aliasing, there can be no guarantee that a UNIQUE constraint is present, and case-sensitivity is not easily ignored. Instead, a new option was added to ADD IMPORT, directing LISTSERV to preload the existing e-mail keys in memory before starting the transaction. This allows LISTSERV to skip most of the SELECT statements and just issue a large number of INSERTs.

To activate this option, simply add PRELOAD after the word IMPORT:

ADD XYZ-L DD=NEWSUB IMPORT PRELOAD
//NEWSUB DD *
joe@xyz.com Joe Doe
Helen Doe <hdoe@abc.def.com>
...
/*

You should use this option whenever importing a new list into the DBMS, or whenever adding a very large number of new users. If you need to add 100 entries to a table with a million rows, it will actually be slower to preload the rows, at least if you have an index.

The PRELOAD option is not necessary for traditional LISTSERV lists and does not normally lead to a significant performance improvement. However, when importing a new list (no existing subscribers), it does reduce CPU usage somewhat, and was used in the benchmark suite in order to provide an apple to apple comparison.

4.5.3. ADD IMPORT benchmark

The purpose of this benchmark is to give you a rough idea of the maximal performance that can be expected from an ADD IMPORT job. The benchmark adds 100,000 users to an empty list, without duplicates. That is, while LISTSERV still needs to determine that there are no duplicates, the job ends up being a pure INSERT workload. On a 1-CPU 300MHz Pentium II system with one IDE drive and Windows NT 4.0, the results were as follows:

DBMS and options

Throughput

Percent of traditional list

SQL Server 6.0 Base

1,240/sec

9.7%

SQL Server 6.5 SP4

1,370/sec

10.7%

Oracle 8.0.4 (ODBC interface)

6,800/sec

53.1%

Oracle 8.0.4 (OCI interface)

7,300/sec

57.0%

Traditional list (without PRELOAD)

12,500/sec

97.7%

Traditional list (with PRELOAD)

12,800/sec

100%

Note: the UEMAIL column was not used in this benchmark, and the table was created with no index. In a typical DBMS import scenario, the index is not created until all the data has been imported, as this would significantly impact import performance. Hostname aliasing was enabled, which is the recommended setting.

Even with the slower DBMS products, bulk add times will usually be deemed satisfactory. However, traditional lists are always faster, because their data organization and access methods are optimized for LISTSERV's purposes. The difference is even more noticeable with a real-world workload containing duplicates and a higher proportion of SELECT statements, as illustrated by the following benchmark, in which 1% of the addresses in the ADD IMPORT job were duplicates (LISTSERV searched for the entry and updated the NAME field). Here an index was used on the UEMAIL column, as 1,000 full table scans would have led to unacceptable performance.

DBMS and options

Throughput

Percent of traditional list

SQL Server 6.5 SP4

101/sec

0.8%

Oracle 8.0.4

2,270/sec

18.5%

Traditional list

12,300/sec

100%

Note again that an index was created as the recipients were added, whereas the first benchmark populated a table that would need to be indexed after the fact.

Whereas the first benchmark was a best-case scenario, 1% of duplicates could be considered the worst likely possibility. As you can see, duplicates have virtually no impact on LISTSERV's built-in data management functions, which were designed specifically for this purpose. The DBMS, on the other hand, are required to create an index on the fly, which is contrary to normal practice and significantly decreases performance. On the other hand, 1,000 full table scans would have taken even longer.

4.5.4. Updating DBMS lists from an external application

DBMS lists can be updated from an external application (by directly making changes to the DBMS tables) with essentially no restrictions and no particular precautions. If you are using an UEMAIL column, however, you must make sure to keep it synchronized with EMAIL, as LISTSERV will assume that, for every row, UEMAIL = UPPER(EMAIL). L-Soft recommends using a trigger procedure or adding a CHECK clause if using an UEMAIL column with an external application directly updating the table.

To delete a subscriber from a DBMS list, you can either delete the row or set the OPTIONS column (which is typically named after the list) to NULL. By definition, if the OPTIONS column is NULL, the user is not subscribed to the corresponding list. When LISTSERV deletes a subscriber from a DBMS list, it deletes the row if the table is named after the list (i.e. if you have the list in a separate, dedicated table). If the table is shared, it sets the OPTIONS column to NULL.

To add a subscriber to the list, simply set the OPTIONS column to the empty string (or insert a new row with OPTIONS set to the empty string). This subscribes the users with all the default options for the list in question.

Please note carefully that most if not all database applications make a distinction between a NULL value and the empty string. If you are having trouble making users added from an external application show up when you review the list, ensure that you are setting the OPTIONS column to "" (the empty string) rather than NULL.

Conversely, if you are having trouble deleting users via an external application, ensure that you are really setting the OPTIONS column to NULL rather than to the empty string.

You can change NAME at any time and without any special precautions. Likewise, you can change EMAIL at any time, as long as you update UEMAIL simultaneously (if you are using an UEMAIL column).

4.5.5. Format of the OPTIONS column

The simplest way to change subscription options is to use the TCP/IP command interface (the "TCPGUI" interface, see chapter 6) to submit a SET command. However, you can also do this by changing the value of the OPTIONS column, which is a series of numbers (in decimal form) separated with semicolons, as follows:

4;flags_1;flags_2;reserved;subscription_date;topics;...

The first number is a version identifier, and must always have the value 4. The second number, flags_1, is a bitmask defining a first set of subscription options, as follows:

Option name

Value

(decimal)

May not be set together with...
ACK 1 MSGACK,NOACK
MSGACK 2 ACK,NOACK
NOACK 4 ACK,MSGACK
NOMAIL 8 --
DIGEST 16 INDEX
INDEX 32 DIGEST
NOFILES 64 --
REPRO 128 --
IETFHDR 256 *HDR
DUALHDR 512 *HDR
FULLHDR 1024 *HDR
xxx822header 2048 DUALHDR,IETFHDR,SUBJHDR
NORENEW 4096 --
reserved 8192 --
CONCEAL 16384 --
EDITOR 32768 NOPOST,REVIEW
REVIEW 65536 EDITOR,NOPOST
NOPOST 131072 EDITOR,REVIEW
MIME 262144 --
SUBJHDR 524288 *HDR
reserved 1048576 --
HTML 2097152 MIME must be set

Bit positions marked as "reserved" must be left unchanged if updating an existing entry, and set to zero when creating a new entry. They do not correspond to subscription options and are used for internal book-keeping purposes. Please note that certain options are incompatible with each other, or require that other options be enabled. If these restrictions are not observed, results will be unpredictable.

The third number, flags_2, is a bitmask reserved for future use. While no bits are currently defined, make sure to leave its value unchanged when updating an existing entry, and to set it to zero when creating a new entry. The fourth number is used internally by LISTSERV and should be handled similarly.

The fifth number is the date at which the user subscribed to the list. You should leave it unchanged when updating an existing entry. For new entries, you can either set it to zero (in which case LISTSERV will report the subscription date as unknown), or set it to the number of complete days (i.e. not counting today) elapsed since and including January 1, 0001. For verification, this number is congruent to zero modulo seven on Mondays. It is equal to the C language expression time(0)/86400 + 719162 or, for OpenVMS users, to the Smithsonian base date plus 678575.

The sixth number is a bitmask indicating which topics the user is subscribed to. The lowest order bit (value 1) corresponds to the pre-defined OTHER topic. The second lowest order bit (value 2) corresponds to the first topic in the "Topics=" keyword, and so forth. If you set this number to zero, the user will not be subscribed to any topics. To subscribe a user to all topics, use the value 16777215.

When updating an existing entry, make sure to preserve any information following the topics number (when creating a new entry, do not provide any such information).

4.5.6. Sample OPTIONS column settings

Sometimes using the list's pre-set defaults by setting the column value to the empty string is not acceptable or useful. In that case you can set the OPTIONS column values per the table above. This section provides a typical example of how the OPTIONS column values are used. (See also 4.5.7, below, if you are migrating from a "standard" LISTSERV list to a DBMS-type list.)

(Note carefully that if you are changing existing values, you should not change the values in the third and fourth positions, as they are reserved for LISTSERV's internal use. Only when adding new users should these positions be set to zero.)

If you want the simplest defaults (which is not recommended, because the default when set this way is to use SHORTHDR and at minimum you should set new users to FULLHDR), you set

4;0;0;0;0;0

in the OPTIONS column and the users are added to the list. (Remember that the OPTIONS column is normally named after the list; we are not talking about a table column that is explicitly named "OPTIONS".)

If you want the standard default options that LISTSERV normally assumes if you don't make any special settings in the list header, you would use

4;1024;0;0;0;0

This sets the user to MAIL FULLHDR NOREPRO NOACK, which are the standard defaults. You might want to change NOACK to ACK (or possibly NOREPRO to REPRO instead), in which case the value in the second position would be 1025 (for ACK) or 1132 (for REPRO).

Note that you simply add the numbers from the table together to combine option settings; if you want the user to be set to the FULLHDR and REPRO options, you set the value to 1024 + 128 = 1132. However, you cannot set it to a value such as 1536 (1024 + 512), which would be FULLHDR DUALHDR -- an impermissible combination as the two values are mutually exclusive.

If you want the user to be set to ALL topics (if topics are defined for the list) by default, you put the value 16777215 in the last position, ie,

4;1024;0;0;0;16777215

Finally, if you want the user's subscription date to be included, you find the value per the specification found above and add it in the fifth position. Assuming that today's date is 23 June 1999, the value on that date is 729927, so the setting would now be:

4;1024;0;0;729927;16777215

Then a QUERY command sent for this user (for example, JOE@XYZ.COM in a list called ODBCTEST) would result in the following output:

>QUERY ODBCTEST FOR JOE@XYZ.COM                                              
Subscription options for Joe Doe <joe@XYZ.COM>, list ODBCTEST:               
                                                                             
MAIL           You are sent individual postings as they are received         
FULLHDR        Full (normal) mail headers                                    
NOREPRO        You do not receive a copy of your own postings                
NOACK          No acknowledgement of successfully processed postings         
                                                                             
Subscription date: 23 Jun 1999                                               
                                                                             
The topics you subscribe to are: All

4.5.7. Preserving options when migrating from non-DBMS to DBMS lists

When migrating an existing (standard) LISTSERV mailing list to the DBMS type, note that it is possible to preserve existing user options without having to figure out the bit values for every user's existing options by hand.

A standard LISTSERV subscriber entry is a 100-column string, of which the first eighty characters are the subscriber's e-mail address and "real name" field. Columns 81-100 contain an encoded string that holds the various user option settings, for instance:

3AEAQABMcBMe////

If you take columns 81-100 from an existing list file, insert a semicolon after the first character, and store this in the option field, all the settings will be successfully migrated. So for instance if you have '3AEAQABMcBMe////' in columns 81-100, you store '3;AEAQABMcBMe////' in the option field. Note that the column value is not automatically converted to '4;' format until the value is updated, ie, until a change is made to the user options or LISTSERV otherwise updates the value. LISTSERV will then use '4;' format when updating the value, but until then it will remain as it was and LISTSERV will be able to use it without any trouble. Do not change the value of the first character from 3 to 4 when migrating as this is guaranteed to cause breakage.

4.6. Using the mail-merge functions

The mail-merge functions can be used at three different levels:

  1. Using the web interface.

  2. By sending DISTRIBUTE jobs to LISTSERV.

  3. By connecting to port 25 of LSMTP and sending mail-merge command streams.

The first two methods will be described in this document. The web interface is ideal when the mail-merge process is supervised by a person, whereas the second method is best suited to automated procedures. In most cases, the third method requires significantly more complex programming to duplicate functions which are provided by LISTSERV when using one of the first two methods.

Please read the description of the web interface for background information even if you are only interested in the DISTRIBUTE interface.

4.6.1. Using the web interface

The web interface can be used for mail-merge operations where the data source is either a DBMS or a traditional LISTSERV list. That is, if the addresses and names of the subscribers are in, say, a proprietary application that you have purchased or developed, you will need to write a script to extract the information from the application in question and create a DISTRIBUTE job.

To prepare a mail-merge job using a DBMS back-end, go to the following URL:

http://.../wa.exe?P1&0=M

or

http://.../wa?P1&0=M

(depending on your OS of course, the former for Windows NT and OpenVMS, the latter for unix).

You will be prompted to enter an arbitrary SELECT statement to select the recipients who should receive a copy of the message. Every column in the SELECT statement which can be mapped to a character string is then available as a substitution in the message, HTML-style. That is, if you have a column called ACCTNO with the customer's account number, you can substitute it in the text of your message using &ACCTNO; (a NULL value is mapped to the empty string).

Only the LISTSERV administrator and other users allowed to use DISTRIBUTE (as defined by the DIST_ALLOWED_USERS configuration variable) can use the above URL and send arbitrary DBMS-based mail-merge messages. This is because this method allows you to issue arbitrary SELECT statements, which are not limited to the membership of a particular list. List owners can use another URL to send mail-merge jobs to their respective lists:

http://.../wa.exe?P1&0=M&L=listname (for NT/OpenVMS)
http://.../wa?P1&0=M&L=listname (for unix)

This interface does not prompt you for a SELECT statement -- it implicitly selects all the subscribers matching the MAIL/NOMAIL/DIGEST/INDEX subscription criteria. In addition, you can provide a boolean expression to further restrict the recipient list, such as:

(&age < 15) and (&country = Canada)

If the target list is a DBMS list, all the columns in the table which can be mapped to a character string are available as substitutions. If the target list is a traditional LISTSERV list, only &EMAIL and &NAME are available, in addition of course to all the special substitutions, such as &*DATE (see below).

4.6.2. Sending DISTRIBUTE jobs to LISTSERV

The purpose of this section is to describe the mail-merge enhancements to the DISTRIBUTE function, rather than DISTRIBUTE itself. While it will usually not be necessary to learn all the details of the DISTRIBUTE function to prepare mail-merge jobs, please refer to chapter 3, above, if you do need further information about DISTRIBUTE.

A traditional (non mail-merge) DISTRIBUTE job has the following format:

//XYZNEWS-215 JOB ECHO=NO
DISTRIBUTE MAIL FROM=owner-nolist-xyznews@xyznews.com PW=xxxxx
//TO DD *
joe@xyz.com Joe Doe
hdoe@abc.def.com Helen Doe
...
/*
//DATA DD *
Date: Sat, 4 Jul 1998 22:47:24 +0200
From: XYZnews editor 
Subject: XYZnews issue #215
To: XYZnews recipients

Welcome to issue #215 of XYZnews!
...
/*

The job must be mailed to LISTSERV, either from the LISTSERV administrator's address (not recommended) or from an address defined in the DIST_ALLOWED_USERS configuration variable. The personal LISTSERV password corresponding to the sending address must be provided, or the job will be rejected. The "ECHO=NO" option suppresses the message that is normally returned to indicate when the job starts and ends, on the assumption that this information is not wanted (if an error occurs, a message is sent anyway). XYZNEWS-215 is an arbitrary job name for problem tracking purposes.

There are three types of mail-merge DISTRIBUTE jobs:

  1. Jobs based on a DBMS back-end with an arbitrary SELECT statement

  2. Jobs where the recipient data is extracted from an existing LISTSERV list (either a DBMS list or a traditional list)

  3. Jobs where the recipient data is totally external to LISTSERV and is provided in the job stream, for instance after being extracted from a proprietary customer database with no DBMS functionality

The only differences are the options provided on the DISTRIBUTE command line, and the format of the //TO section. The format of the message section is the same with all three types of mail-merge jobs.

Note that some DISTRIBUTE command lines can get quite long and may wrap in your mail client, causing an error when the job is processed by LISTSERV. To avoid this you can use one or more "continuation cards" (see chapter 2.3 of this manual) to split the command over multiple physical lines. See for instance the second example below.

DISTRIBUTE job with DBMS back-end

These jobs are the simplest and use the following syntax. (This example assumes that your database contains the fields referenced, ie, EMAILADDR, ACCTNO, NAME, etc.)

//XYZNEWS-215 JOB ECHO=NO
DISTRIBUTE MAIL-MERGE DBMS=YES FROM=owner-nolist-xyznews@xyznews.com PW=xxxxx
//TO DD *
SELECT EMAILADDR,ACCTNO,NAME FROM ...
WHERE ...
AND ...
...
/*
//DATA DD *
Date: &*DATE;
From: XYZnews editor 
Subject: XYZnews issue #215
To: &*TO;

Welcome to issue #215 of XYZnews!
...
/*

The DISTRIBUTE command line now reads DISTRIBUTE MAIL-MERGE DBMS=YES (Windows NT users with both ODBC and OCI interfaces active may have to use DBMS=ODBC or DBMS=OCI instead), and the recipient section contains one or more SELECT statements. If multiple SELECT statements are included, you must end them with a semicolon, and you may not have more than one statement per line. The &*DATE; and &*TO; substitutions are not required, and simply serve to illustrate the fact that substitutions can now be placed in the message text (including the mail headers).

With the syntax shown above, the first column in the SELECT statement must be the one containing the e-mail address. The other columns are made available as substitutions (&NAME, etc.) This is the recommended syntax when writing a script to prepare the jobs, as only the columns actually used for substitutions are transferred from the DBMS server. Sometimes, however, the script may not know in advance which columns will or will not be used. In this case, a SELECT * may be used, as follows:

//XYZNEWS-215 JOB ECHO=NO
// DISTRIBUTE MAIL-MERGE DBMS=YES(EMAIL=EMAILADDR) ,
FROM=owner-nolist-xyznews@xyznews.com PW=xxxxx
//TO DD *
SELECT * FROM ...
WHERE ...
AND ...
...
/*
//DATA DD *
Date: &*DATE;
From: XYZnews editor 
Subject: XYZnews issue #215
To: &*TO;

Welcome to issue #215 of XYZnews!
...
/*

(Note the use of a "continuation card" in the DISTRIBUTE command line above, used because the line was so long it wrapped. See chapter 2.3 of this manual for more information on JOB card syntax.)

The EMAIL=EMAILADDR option tells LISTSERV the name of the column containing the e-mail addresses. All the other columns are made available for substitutions, provided of course that they can be mapped to a character string. Note, however, that even large columns (LONG et al.) will be transferred from the DBMS server. As a rule, this syntax should be avoided whenever you would normally avoid doing a SELECT * against the table.

DISTRIBUTE job with existing LISTSERV list

These jobs use the following syntax:

//XYZNEWS-215 JOB ECHO=NO
DISTRIBUTE MAIL-MERGE DBMS=LIST(XYZLIST,MAIL,DIGEST,INDEX) PW=xxxxx
//TO DD "(&age < 15) and (&country = Canada)"
//DATA DD *
Date: &*DATE;
From: XYZnews editor 
Subject: XYZnews issue #215
To: &*TO;

Welcome to issue #215 of XYZnews!
...
/*
Please note carefully that the example assumes that the database table containing the list also contains "AGE" and "COUNTRY" fields for the conditional selection.

This job selects all the recipients from the XYZLIST list whose subscription options are either MAIL, DIGEST or INDEX and for which the expression (&age < 15) and (&country = Canada) is true. By default, if you specify only DBMS=LIST(XYZLIST), LISTSERV will only select recipients with the MAIL option. The options you can include in this fashion are MAIL, NOMAIL, DIGEST and INDEX. Note that the FROM=owner-nolist-xyznews@xyznews.com option has been removed -- bounces are automatically integrated with the XYZLIST bounce stream and do not need to be redirected to a change log. If desired, however, you can override this behaviour by providing a FROM= keyword.

In addition, you can specify a boolean expression in the //TO section. This expression is in the same format as the conditional expressions used in LISTSERV's mail template files (described in the list owner's guide). If you do not want to do any further filtering, just set //TO to the empty string, or to the value "1" (true).

For a DBMS list, this syntax is functionally equivalent to a SELECT * job, that is, every column that can be mapped to a character string is available as a substitution. For a traditional LISTSERV list, only &EMAIL and &NAME are available. This can still have its uses, for instance, to send a mail-merge message to AOL recipients only, you could use:

//TO DD "&email =* '*@AOL.COM'"

(note the single quotes surrounding the selection criteria--these are required).

DISTRIBUTE job with external mail-merge data

To provide the mail-merge data as part of the DISTRIBUTE job stream, use the following syntax:

//XYZNEWS-215 JOB ECHO=NO
DISTRIBUTE MAIL-MERGE FROM=owner-nolist-xyznews@xyznews.com PW=xxxxx
//TO DD *
*XDFN NAME="Joe Doe" AGE=23 country="Canada"
joe@xyz.com PROBE
*XDFN name="Helen Doe" Age=47 country=USA
hdoe@abc.def.com
...
/*
//DATA DD *,EOF
Date: &*DATE;
From: XYZnews editor 
Subject: XYZnews issue #215
To: &*TO;

Welcome to issue #215 of XYZnews!
...
/*
With this syntax, all the substitutions are provided in the job, preceding the e-mail address they refer to. There is no DBMS access, no reference to an existing LISTSERV list and no filtering or selection of recipients -- you are providing an exact recipient list. Note that when the DISTRIBUTE command's FROM= option is set to an owner-xxx address, LISTSERV generates the mail merge message as a passive probe of the recipient. The probe comes at no extra resource cost when sending a mail-merge message.

You can provide multiple *XDFN lines, which can have any number of keyword=value pairs. There must be no spaces either before or after the equal sign. Keywords are not case sensitive, so the case of the keyword name is not relevant. The value must be enclosed in double quotes if it contains spaces, double quotes or backslash characters. To escape a backslash or double quote in such a quoted string, precede it with a backslash. While LISTSERV will support *XDFN lines of up to 64k, bear in mind that you will probably send the job to LISTSERV via e-mail, in which case a lower limit may apply depending on your mail system. It is good practice to keep *XDFN lines to 998 characters or less, as this is the maximum length guaranteed to be successfully transmitted over the SMTP protocol.

Automatic bounce processing

In most cases, you will want LISTSERV to process all the bounces automatically for you. If you are using the DBMS=LIST syntax, bounces are, by default, integrated with the regular bounce stream for the list in question, and you have access to the full range of LISTSERV bounce processing features (see the description of the "Auto-Delete=" keyword in the list owner's guide for more information). Otherwise, L-Soft recommends using the "change log" feature in order to keep track of bounces. This is accomplished by including the following keyword in the DISTRIBUTE command line:

FROM=owner-nolist-logname@hostname

Where logname is an arbitrary name for the "change log" in which LISTSERV will be recording bounce activity, and hostname is the host name of the machine on which LISTSERV is running. You can use a different log file for every message, one file for each set of related messages, or just one for all the mail-merge messages you send; the decision is left up to you. The file will be located in LISTSERV's main directory (the one where, among others, permvars.file is located) and will be called nolist-logname.changelog. You do not need to create a list called NOLIST-logname and, in fact, you must not do that. The change log is a standard text file containing entries of the form:

19980704100221 BOUNCE jack@xyz.com
19980704100223 BOUNCE Joe.Doe@abc.def.com

LISTSERV will process all bounces silently, and store the bouncing addresses in the change log. Note that there may be other entries in the change log -- be sure to ignore any lines which do not contain BOUNCE in the second column (in practice, "nolist" change logs only contain BOUNCE entries, but this could change in a future version). Because mail-merge messages automatically use passive probing, bounce processing is extremely accurate, even if the target mail server normally returns bounces in an unintelligible format.

If you want to process bounces yourself, simply provide a FROM= keyword pointing to the desired target address.

Using DBMS or list-based jobs without mail-merge

It is possible to use the DBMS= keyword to extract and select recipients from either a DBMS or a LISTSERV list, without using the mail-merge functions. Simply use the formats shown above, substituting DISTRIBUTE MAIL for DISTRIBUTE MAIL-MERGE. Naturally, you are then unable to put substitutions in the message text, however the message may use significantly less bandwidth and will usually be delivered faster.

4.6.3. Using substitutions

Mail-merge substitutions work just like HTML substitutions -- you embed them in the target message using a sequence such as:

&NAME;

If the substitution is not defined (in the above example, if there is no column called NAME in the DBMS), no substitution is performed and the resulting message will contain the text '&NAME;'. In addition to the substitutions provided through the DBMS, list or DISTRIBUTE job stream, a number of special substitutions are always available:

  • &*DATE; is an RFC822 date field (without the "Date:" keyword) suitable for insertion in mail headers. This makes it easier to develop scripts that prepare DISTRIBUTE jobs, and there is no performance penalty as this is a "false substitution" -- one that has the same value for all recipients and is pre-processed by LISTSERV. By the time LSMTP gets the message, it no longer contains a substitution.

  • &*WA_URL; is the URL of the LISTSERV web interface script, up to and including the script name. You would typically add a question mark and parameter list afterwards. As it is a false substitution, there is no performance penalty for using it. If the web interface has not been installed, it translates to the empty string.

  • &*TO; is the e-mail address of the current recipient, suitable for insertion in a "To:" field.

  • &*INDEX; is a unique, random number ranging from 1 to the total number of recipients. It can be used in conditional blocks (see below) to send a particular message to a random sample of recipients -- an invitation to preview a new web site or an ad banner, for instance. This special substitution can only be used in a conditional block, and cannot actually be inserted in the text of the message.

  • &*TICKET(listname); and &*TICKET_URL(listname,command); are special substitutions used to issue command tickets, which are described next.

Using command tickets

Documented restriction: While it is possible to tell LISTSERV to issue a command ticket to a list owner address, for security reasons list owners cannot use command tickets for authentication of commands sent for the lists they own. If a list owner attempts to use a ticketed command on a list he owns, LISTSERV will respond

For security reasons, list owners may not issue ticketed commands. The
ticket was otherwise valid - this is not an error on your part.

When testing ticketed commands it is thus necessary that the list owner do the testing from an account that is not listed in Owner= for the list in question.

Command tickets allow you to provide safe, authenticated, single-click subscribe, unsubscribe or SET commands in a mail-merge message. They are implemented through a two-step mechanism. In the first step, LISTSERV generates a cryptographically protected ticket through a mail-merge substitution. This ticket allows anyone to execute a limited set of commands on behalf of the user for whom it was issued, and only for the list for which the ticket was issued. Typically, you would use the substitutions to construct a URL, or perhaps a HTML form with a number of buttons triggering various changes in subscription options or status.

In the second step, the user activates the URL or form, which presents the ticket to LISTSERV for verification. If the ticket is valid and has not expired yet, the command is executed. There is no need to use passwords or OK confirmations. Tickets are safe because they are, by design, only ever mailed to the person for whom they are issued. They are also limited to a particular list, and may only be issued at the request of the owner of that list (who does not need to use tickets to affect the user's subscription to the list in question). Finally, tickets expire after a month, to limit the impact of incidents where printouts of e-mail messages were misplaced, etc.

A ticket allows the use of SUBSCRIBE, SIGNOFF and SET commands, with arbitrary parameters. However, the name of the list is extracted from the ticket, and may not be changed. In fact, you do not specify the name of the list in the command. The simplest way to format a ticket URL is as follows:

<a href="&*TICKET_URL(XYZ-L,SET NOMAIL);">Turn off mail receipt</a>

This substitution expands into a URL which will execute a SET XYZ-L NOMAIL command when activated. To use a ticket in a form with several buttons, you could do as follows:

<form action="&*WA_URL;">
<input type=hidden name=TICKET value="&*TICKET(XYZ-L);">
<input type=hidden name=L value="XYZ-L">
<input type=submit name=c value="Unsubscribe">
<input type=submit name=c value="SET NOMAIL">
<input type=submit name=c value="SET MAIL">
</form>
You could also use an image map pointing to a script of your own making, a Java applet, etc. To execute the command, simply redirect the browser to:

http://.../wa.exe?TICKET=ticket&c=command&L=listname

The list name is optional: it is not required to use the ticket, but can be provided to direct the LISTSERV web interface to use the HTML templates for the list in question. You can customise the response on a per-list basis using the standard web template customisation features, which are described in the list owner's guide.

Performance considerations with command tickets

Unlike OK cookies, command tickets do not use up any disk space or require any kind of house-keeping. You can use them as often as you wish without ending up with gigabytes of pending cookie data on your LISTSERV server, as would be the case with OK cookies and a large daily newsletter offering multiple one-click commands. However, being cryptographically protected, they do require some amount of CPU time for generation, without which they would not provide much protection at all. So, do not worry if LISTSERV does not acknowledge execution of your 500,000 recipient job after 30 seconds as usual.

LISTSERV will only generate the tickets once, even if you refer to the same ticket multiple times in the message. Thus, you do not need to worry about using tickets in a single big form rather than multiple smaller forms, or once at the top and once at the bottom of the message. While it does cost a small amount of resources for the ticket to be merged with the message text in multiple locations, the CPU-intensive ticket generation only occurs once.

If you have a very large list which must be delivered very quickly at a specific time, as can often be the case in the news industry, command tickets may present a challenge. In this case, the best solution is to make use of the SMTP worker pool feature, rather than the "PRIME=" job option, to schedule the delivery of the message. Whereas "PRIME=" will hold the entire job and require you to estimate execution time in order to open the execution window long enough in advance, the SMTP worker pool feature5 can be used to create a worker pool which does not begin delivery until a specific time. You can then execute the job long in advance, but suspend delivery until the desired time.

4.6.4. Using conditional blocks

In addition to simple substitutions, you can include "conditional blocks" in your mail-merge messages. A conditional block is a group of lines which is only included if certain conditions are met. Here is an example of a mail-merge message with conditional blocks:

Date: &*DATE;
From: birthdays@xyz.com
Subject: Happy birthday, &FNAME;!
To: &*TO;

Happy birthday!

...

To celebrate the occasion, XYZweb is pleased to credit your account with 
$10.00 in birthday credits. You can spend these credits anywhere in our 
online store, but there's a catch! They will expire in a week if you do 
not use them! So wait no further and go to your personalized web page at:

&PERS_URL;

.* Special offer for people who turn 18
.bb &age = 18
Now that you are 18, you can finally do what you have been waiting for
all your life - sign up for your very own XYZweb online cash management
account! We are waiving the first year's fee if you apply within the next 
2 weeks! Apply now at:

http://...

.eb
.* Special offer for younger children, but not around Christmas though!
.bb (&age <= 10) and (DEC not in &*DATE)
Congratulations! You have won an XYZweb teddy bear! Order it now by going 
to:

http://...

.eb
.* Two randomly selected people every day get a free T-shirt
.* Note: &*index is randomized with every run. If we ran the job
.* twice, the prize would go to different people
.bb &*index <= 2
Congratulations! You have won a free XYZweb T-shirt!...

.eb
.* Another 10 randomly selected people get a free baseball cap
.bb (&*index > 2) and (&*index <= 12)
.* Make that a free pair of sunglasses in Texas!
.bb (&country = USA) and (&state = TX)
Congratulations! You have won a free pair of XYZweb sunglasses!...

.else
Congratulations! You have won a free XYZweb basecall cap!...

.eb
.eb

.* Plug our travel partner if user checked TRAVEL category on web
.* signup form
.bb TRAVEL
Are you by any chance making travel plans? If so, our partner, ZYX
Travels, have a special offer for you! Simply follow this URL for more
information:

http://...

.eb

.* Special for AOL users
.bb &*to =* "*@aol.com"
Did you know that you can access XYZweb's store directly from AOL?
Simply do...

.eb
.* That's it!

A conditional block starts with a .BB (begin block) statement, may include a .ELSE statement, and ends with .EB (end block). The .BB statement contains a conditional expression in the format used in LISTSERV mail templates (described in the list owner's guide). If it evaluates to TRUE, the text is included for the recipient in question, otherwise it is skipped.

Using &*INDEX to select random samples

Every recipient is assigned a unique, random number ranging from 1 to the total number of recipients. Or, in other words, every number from 1 to the total number of recipients is assigned to a particular, randomly selected recipient. This number is called &*INDEX, and can be used in conditional blocks to select random samples of recipients. Typically, you will use a sequence such as the following:

.BB (&*index >= min) and (&*index < max)

The conditional block will be sent to all the recipients whose index ranges from min (inclusive) to max (exclusive). Thus, it will be sent to max-min recipients.

Using the PARTS option

While traditional LISTSERV lists provide support for up to 23 topics, there are cases where LISTSERV's topic functions are difficult to use. For instance, imagine a web site where people can subscribe to news about movie stars. Presumably, while there would be hundreds of actors to choose from, most people would only be interested in a handful of them. However, it is likely that a small number of people will be interested in dozens of actors!

LISTSERV's built-in topic support cannot be used, because there will be a lot more than 23 topics. The straightforward approach is to create one mailing list for each actor, and this will work well for people who are only interested in a few actors. However, the avid fans who subscribed to dozens of actors may resent the number of individual messages they receive from the service, and sign off. This would be unfortunate, as they probably represent a non-negligible fraction of the purchases of fan-related material.

The PARTS feature allows you to define any number of topics in the mail-merge message, using conditional blocks of the form:

.BB Maxine_Bahns

To determine whether a particular recipient is subscribed to news about this actress, LISTSERV checks whether the comma-separated PARTS field contains the topic Maxine_Bahns. For a mail-merge job using a DBMS back-end, the PARTS field is a DBMS column, whose name is specified either in the web interface form or in the "DBMS=" keyword on the DISTRIBUTE command, as follows:

DISTRIBUTE MAIL-MERGE DBMS=YES(EMAIL=EMAIL,PARTS=ACTORS)

In practice, you would probably maintain the mapping between subscriber and actors using a separate table and foreign keys, but LISTSERV cannot make use of this kind of data layout efficiently, as it would require issuing one SELECT statement per recipient. However, you could use a trigger procedure to update the comma-separated ACTORS column whenever a change is made to the mapping table.

In a mail-merge job with external data source (that is, a job which includes *XDFN declarations), you include the PARTS field in the job stream, with the following syntax:

*PARTS part1,part2,...

This declaration can come either before or after the *XDFN lines, however it can occur only once.

In some cases, you may want to send some information to people who subscribe to any of a variety of topics. You can do so using the &*PARTS substitution and the IN operator of the LISTSERV expression evaluator. LISTSERV sets &*PARTS from the PARTS field, but replaces all commas with spaces in order to allow the use of IN/NOT IN. For instance, you could have the following:

.BB (Maxine_Bahns in &*PARTS;) or (Edward_Burns in &*PARTS;)
Maxine Bahns and Edward Burns have broken up! Millions of fans 
were in turmoil as the news was announced today at...
.EB

You should use the simpler syntax whenever possible, because it allows LISTSERV to bypass the expression evaluator. While very fast, the expression evaluator does add some overhead considering that typical PARTS jobs will have scores of different topics, which must be evaluated for each of the hundreds of thousands of recipients. Thus, the likely order of magnitude of the number of evaluations is in the 1-10 million range.


5. List Exits

Background for non-technical users: an "exit" is a program supplied by the customer to modify the behavior of a product (such as LISTSERV) in ways that the supplier of the product could not anticipate, or could not afford to support via standard commands or options. The product checks for the presence of the "exit" program and calls it on a number of occasions, called "exit points". In some cases, the "exit" program supplies an answer ("return code") to the main program, which adjusts its behavior accordingly. For instance, LISTSERV may ask an exit program "Is it ok to add JOE@XYZ.EDU to the ABC-L list?", and the program will answer yes or no, and possibly send a message to the user explaining why his subscription was accepted or rejected. In other cases, the "exit point" call is purely informative: the exit program gets a chance to do something, such as sending an informational message to a user, but does not return any answer. Because the exit is a computer program, it must be prepared by a technical person and installed by the LISTSERV maintainer.

5.1. What is a "list exit"?

Starting with version 1.8a, list "exits" have been available to control the major events associated with list maintenance. While the implementation of list exits is necessarily system dependent, the list exits themselves (i.e. the tasks that they may carry out, as opposed to how such tasks would be carried out on a particular operating system) are system independent.

To prepare a list exit, you must go through the following steps:

  1. Create an appropriate exit program, as explained below. Let's assume that the program's name is XYZ. (Note that exit programs should be named with only alphanumeric characters, ie, A-Z, 0-9.)

  2. Modify the LIST_EXITS configuration option in the LISTSERV site configuration file (create one if none was present in your configuration). This variable lists the names of all the "known" exits. For security reasons, LISTSERV will not call an exit which is not listed there. To enable XYZ and ABC as valid list exits, you would set LIST_EXITS to "XYZ ABC" (with or without the quotes, depending on your operating system). You must reboot LISTSERV after making this change.

    Note carefully that you do not code the extension of the exit program (if any) into the LIST_EXITS configuration variable. For instance if you are running under Windows NT and your exit is called XYZ.CMD, you set LIST_EXITS to "XYZ". Under OpenVMS, if your exit is called ABC.COM, you set LIST_EXITS to "ABC".

  3. Modify the header of all the lists which should call the XYZ exit, and add "Exit= XYZ". This tells LISTSERV to call the XYZ exit at various exit points.

IMPORTANT SECURITY NOTE: Once an exit has been listed in the LIST_EXITS option, ANY list owner may activate it for his own lists. In other words, step 2 merely tells LISTSERV that the program is a "bona fide" exit. There is no mechanism to restrict the use of an exit to a particular list, because it is very easy to implement this in the exit itself, by checking that the name of the list is what you expect or allow.

LISTSERV exits receive one or more parameters as input, and may provide a numeric and (in a few cases) supplemental string result as output. Each operating system has its own set of numeric return codes for various kinds of failures, but LISTSERV always uses the same internal return code system for its exits - anything else would quickly become unmanageable. The value 0 always means "success" or "normal/default action". Positive values indicate various non-default actions, depending on the particular exit point. Negative values indicate system errors. Exit programs are responsible for doing their own error reporting, since LISTSERV has no way to know which errors they may or may not run into.

The location, name, programming language and calling conventions of the exit program vary from one operating system to another. Let's examine the basics first:

  • On VM, the program must be called XYZ EXEC A1 (on LISTSERV's A-disk) and must be written in REXX.

  • On OpenVMS™, the program must be called XYZ.COM on LISTSERV's [.MAIN] subdirectory (LISTSERV_LISTS_DIR) and must be written in DCL.

  • On unix®, the program must be called XYZ and must be located in the 'home/' subdirectory (i.e., $A). To distinguish them from the standard L-Soft-provided scripts and executables, exit programs must always be named in upper case. Thus, the program must be called XYZ and not xyz. It can be written in any supported language and LISTSERV must have execute permission.

  • On Windows NT™, the program must be called XYZ.CMD and must be located in the MAIN subdirectory. It must be written in the NT batch language.

  • On Windows 95™, the program must be called XYZ.BAT and must be located in the MAIN subdirectory. It must be written in the DOS batch language.

Naturally, you are free to call a program in another language from your exit program. The programming language restriction only applies to the exit program itself.

IMPORTANT: Even though the exit program is usually called from LISTSERV's root directory, it should not make any assumption about its current directory. For optimal portability, the program should always use absolute pathnames to access the various files it might need. For instance, list files should be accessed (if at all) as $A/ or A: or %A%\, and so forth.

The exit may receive one or more string parameters as input. Most operating systems provide a mechanism to pass one parameter to a script or program, with some restrictions. However, LISTSERV may need to pass several parameters, and the restrictions may not be acceptable. Thus, a system independent parameter passing convention had to be designed. This convention is used by all systems except VM, where multiple parameters of arbitrary length and contents may be passed to a REXX program. On VM, the system independent convention is never used, because it is unnecessary and less efficient than the native method. VM exits use the standard PARSE ARG directive to retrieve their parameters.

The system independent convention uses a disk file called 'exit.input' in the same directory as the exit program. This is a standard text file, where each record is one input string parameter. This file is always created if there are 2 or more string parameters for the exit, or if the EXIT_INPUT configuration parameter is set to the value 1. In addition, it is always created on Windows™ operating systems. Under OpenVMS™ and unix®, the file is not created when there is only one parameter and EXIT_INPUT defaults to 0. Since most exits only have a single parameter, this improves performance in most cases. Note that LISTSERV will take care of deleting the 'exit.input' when appropriate.

Regardless of whether or not the 'exit.input' file is created, the first parameter is always passed to the exit using system-specific methods under OpenVMS™ and unix®. Under Windows™ systems, the first parameter is only passed through the 'exit.input' file. Again, this may simplify programming for simple exits.

IMPORTANT SECURITY NOTE: LISTSERV will always quote/escape the first parameter to prevent the recognition of special characters by the underlying operating system. However, your program should be very careful in its use of the parameters in any subsequent system call. For instance, if the parameter to your unix® exit is the string "a|b", LISTSERV will quote the vertical bar so that it does not result in the execution of the program 'b', and so that the value "a|b" is present in your argument vector. However, you must still be careful in the use of the arguments within your program, especially if you plan to launch a compiled program from a shell and pass it the same arguments. In that case L-Soft recommends the use of EXIT_INPUT = 1, which allows the second program to read its parameters safely from the 'exit.input' file.

For list exits, there is at least one input parameter, of the form (blank separated):

epname listname more

where 'epname' is the name of the entry point being called (SUB_FILTER, SUB_FAIL, etc), 'listname' is the name of the list, and 'more' depends on the particular exit point. Under VM, 'more' may contain '15'x characters delimiting additional parameters. Again, while 'epname' and 'listname' are unlikely to contain "tricky" characters, the same cannot be assumed about the remainder of the parameter string.

In most cases, your program will only handle a limited set of exit points. When it does not recognize the 'epname', it should exit with the numeric result 0, which tells LISTSERV to take the default action. To exit with the result 0, you can take a normal operating system dependent exit. In particular, success status codes are translated to 0 under OpenVMS™. To return any other numeric code, or to return a string code, you must use the system independent parameter return convention return below, except on VM where the operating system provides a suitable native convention for the return of one parameter of arbitrary length and contents. So, REXX programs return their results with a standard RETURN or EXIT statement. The first blank-delimited word is interpreted as the numeric result, and the rest, if any, is the string result. In other words, the return string is broken up into number and string in exactly the same manner as with a PARSE VAR RESULT NUMBER STRING instruction. On VM, the system independent return convention is not used, because it is unnecessary and less efficient than the native method.

The system independent convention is based on a file called 'exit.output', in the same directory as the exit program. LISTSERV erases this file before calling your program, and reads it when it regains control. This file is a standard text file, which contains a number of directives. To set the numeric return code, you use the EXIT directive:

EXIT 2

This would set the numeric return code to 2. To set the string result, use:

EXIT-STRING This is the exit string

Note that you must ALWAYS set the numeric code if you want the string result to have any effect. The default numeric code is 0, which means "default behavior", and the default behavior never uses the string you supply. By definition, the default behavior is whatever LISTSERV would do if the exit were not present.

In addition to EXIT and EXIT-STRING, a number of other directives are available. For instance, you can tell LISTSERV to send a message to the originating user, to explain why the exit rejected his subscription request. These directives are processed sequentially until the end of the file. Note that the EXIT directives merely set the final exit codes. They do not interrupt the processing of the 'exit.output' file, which is always read to the end of the file. This means that, if you change your mind about the exit code, you can write a new EXIT instructions and LISTSERV will use the last value that you supplied.

Each directive has 0 or more mandatory parameters, and may support a number of optional parameters, which are always listed after the mandatory ones. Some parameters may be simple blank-delimited keywords or options, while others may contain arbitrary data. The exit should not need to provide placeholders for optional parameters, and above all it should be possible to add new optional parameters without requiring all exits to be rewritten. To solve this problem, each directive was given two forms: a simple form, where the entire directive fits in a single line, and an explicit form, where you indicate the number of parameters that you intend to provide, and each parameter follows on a line by its own. In the simple form, the mandatory parameters are filled from the data supplied on the single directive line, and all the optional parameters are set to their default value. Each blank delimited word supplies one parameter, until the first N-1 parameters have been set. The remainder is used for the last parameter. Here is an example:

TELL jack@XYZ.COM The FOO-L list is only open to FOO Inc. employees.

Parameter 1 (mandatory): "jack@XYZ.COM"
Parameter 2 (mandatory): "The FOO-L list is only open to FOO Inc. employees."
Parameter 3 (optional): <default>

If, on the other hand, you want to send the message to more than one person, you need to use the explicit form:

TELL2
jack@XYZ.COM cc: honcho@FOO.COM
The FOO-L list is only open to FOO Inc. employees.

It is always safer to use the explicit form if you are not sure how many words you will have in the various parameters. The simple form is provided mostly for directives such as EXIT or EXIT-STRING which only take one parameter, and for hardcoded parameters.

Currently, the supported directives are as follows. The "VM API" indicates the corresponding REXX API for VM users (it is not possible to provide an API for non-VM systems because the exits run in a different virtual address space and may not call back into LISTSERV entry points).

Name:EXIT, EXIT-CODE, RETURN
P1:Numeric return code
Action:Sets numeric return code; does NOT abort exit.output processing!
VM API:EXIT/RETURN
 
Name:EXIT-STRING
P1:String result code
Action:Sets exit string result
VM API:EXIT/RETURN
 
Name:TELL, LTELL
P1:List of RFC822 addresses
P2:Message text
P3 (opt):Blank separated list of options (default = off)
- ECHO: echoes message to log
- RAGGED: flows but does not justify message
Action:Sends long (paragraph) message to specified users
VM API:LSVLTELL
 
Name:TELLNF
P1:List of RFC822 addresses
P2:Message text
P3 (opt):Blank separated list of options (default = off)
- ECHO: echoes message to log
Action:Sends unformatted message to specified users
VM API:LSVTELL
 

5.2. List Exit Points

The following list exit points are available as of Version 1.8d:

5.2.1. ADD/SUBSCRIBE exit points

Name:SUB_FILTER
Parameters:One; originator's e-mail address
Return Code:0=Accept, 1=Reject
Description:This exit point gives you a chance to reject a subscription request by returning a nonzero value. This adds to rather than replaces the "Filter=" keyword.
 
Name:SUB_FAIL
Parameters:One; originator's e-mail address
Return Code:Ignored/reserved - always return 0
Description:This exit point is called whenever a subscription is rejected (in particular, it is called if you return 1 from SUB_FILTER). You may send additional messages to the user, log the event, and so on.
 
Name:SUB_REQ
Parameters:One; originator's e-mail address
Return Code:Ignored/reserved - always return 0
Description:The user's request for subscription is being forwarded to the list owners. You may send additional messages to the user, log the event, and so on. To implement custom subscription/rejection, use the SUB_FILTER exit with "Subscription= Open". When SUB_REQ is called, it is too late to let the user through.
 
Name:SUB_NEW, ADD_NEW
Parameters:One; originator's e-mail address
Return Code:Ignored/reserved - always return 0
Description:This exit point notifies you that the user has been successfully subscribed to the list (SUB_NEW is for the SUBSCRIBE command, ADD_NEW corresponds to the ADD command). You can send additional messages, log the event, and so on.

5.2.2. DELETE/SIGNOFF/CHANGE entry points

Name:CHG_REQ
Parameters:Three; originator's e-mail address '15'x target subscriber's e-mail address '15'x new e-mail address
Return Code:0=Accept, 1=Reject
Description:This exit point is called for the CHANGE command, and allows you to reject the operation. If you return the value 1, LISTSERV rejects the operation.
 
Name:DEL_FILTER
Parameters:One or two; target e-mail address '15'x originator's address
Return Code:0=Accept, 1=Reject, 2=Interrupt processing of command
Description:This exit point is called for all SIGNOFF commands, and for DELETE commands issued by a registered Node Administrator. It is NOT called for DELETE commands originating from the list owner. If you return the value 1, LISTSERV does not delete the target e-mail address but continues to look for more addresses matching the pattern provided, and the exit will be called again as appropriate. If you return the value 2, LISTSERV simply interrupts the processing of the SIGNOFF command and terminates the command with no further message (i.e., you have to send your own explanation back to the command originator). If the request is rejected, you should check for the presence of the second parameter and send an explanatory message to that address, or to the target address if only one parameter was specified.
 
Name:DEL_SIGNOFF
Parameters:One; originator's e-mail address
Return Code:0=Continue, 1=Do not notify owner
Description:This exit point is called for the SIGNOFF command only, when a user has been successfully removed from the list. The farewell message, if any, has already been sent. You may issue additional messages, log the event, and so on. A return value of 1 directs LISTSERV not to mail the "SIGNOFF1" form to the list owners.
 
Name:DEL_DELETE
Parameters:Two; target e-mail address '15'x originator's address
Return Code:0=Continue, 1=Do not notify owner
Description:This exit point is called for the DELETE command only, after a user has been removed from the list. You may issue additional messages, log the event, and so on. A return value of 1 directs LISTSERV not to mail the "DELETE1" form to the list owners.

5.2.3. Other exit points

Name:SET_REQ
Parameters:Three; originator's address '15'x list of options to be altered '15'x target e-mail address
Return Code:0=Accept, 1=Reject, 2=Alter
Description:This exit point is called for all SET commands that do not originate from the list owner. The first parameter (originator's address) is the address you should use to send replies or informational messages to the command originator. The second parameter (list of options to be altered) is a blank-separated list of command options, in their canonical spelling. If topics have been specified, they are listed last, after the word 'TOPICS:', with the spelling provided by the user. Bear in mind that topic change requests are not necessarily a list of the new topics to be enabled, and may contain complex '+' or '-' directives. Finally, the third parameter (target e-mail address) is the address as it appears in the list, and is provided for the sake of completeness; in most cases you will not need to examine it. If you return the value 1, the command is rejected and no option is modified. A return value of 2 indicates that the list of options and/or topics should be altered before the changes are performed. The exit string must contain a replacement for the second input parameter, in the same format. LISTSERV will assume that any options or topics specified in this fashion are syntactically correct; while incorrect values will not cause any problem and will be properly rejected as invalid options, the error message(s) returned to the user may not be as helpful as they ordinarily would.
 
Name:POST_FILTER
Parameters:One; e-mail address of the poster.
Return Code:0=Accept, 1=Reject
Description:This exit point is called for messages posted to a list. It can be used to compare the e-mail address of the poster to a list of users who should (or should not) be allowed to post. It can further be used to scan the body of the e-mail message, ie, to accept or reject the message based on its content. The exit places the message to be checked in the file $D/listserv.cmsut1 (where $D is the value assigned with .SD D in system.cfg or CORPORAT SYSVARS, D= in go.sys, or D\ in system_config.dat, depending on your OS platform; in any case, by default this is LISTSERV's TMP directory or minidisk).

A return value of 0 indicates that LISTSERV should continue processing the posting, while a return value of 1 indicates that LISTSERV should reject the posting.

Note carefully that your exit program MAY NOT edit or alter the listserv.cmsut1 file as LISTSERV has already loaded it preparatory to processing it. The exit point ONLY allows you to accept or reject the message in toto.

5.2.4. General remarks

IMPORTANT: List exits may not make any change to the LIST file, because the command processor may have changes of its own to make to the file, or may have kept the file open for further processing. Under VM only, If you really have to change the file, use CP MSG * CMS EXEC to schedule a new call to the exit after command processing completes.

The template processor can be called from list exits. The syntax is:

Call LSVTMAIL recipients,template_name,listname,keywords

keywords = 'KWD1 value of first keyword'||'15'x'KWD2 second keyword'||...

Note the change in calling sequence from LSVIMAIL. LSVIMAIL was removed in version 1.8b and is no longer available.

5.3. Local command definition (non-VM)

It is possible to define "local" LISTSERV commands on non-VM systems. A "local" command is a locally developed extension to the LISTSERV command set, which can be installed without making any modification to LISTSERV itself. To install a local command, you must perform the following steps:

  1. Create an exit program to implement the command, as described below. Let's assume the program is called ABC. Command and list exits share the same basic attributes and programming interface, and in particular they are located in the same directory and follow the same naming and calling conventions.

  2. Choose a name for your local command. Names starting with a letter are reserved for L-Soft use; other names are reserved for customer use. You could call your command /ABC for instance.

  3. Modify (or create) the file 'localcmd.file' in the main LISTSERV subdirectory (the same directory where the lists, exits and other LISTSERV files are located). You must register the command in this file to define its existence to LISTSERV and indicate which exit should be called to execute the command. The format is:

    /ABC 3 ABC DEF

    /ABC is the full name of the command, 3 is the minimum abbreviation (allowing /AB or /ABC), ABC is the name of the exit program to execute, and DEF is an optional parameter to be passed to the exit (this allows multiple similar commands to be served by the same exit).

  4. Optionally, modify (or create) the file 'localcmd.helpfile' in the same directory to provide a brief (1-2 lines) description of your new command. This is a free form file whose contents are appended to the standard HELP message. If the command is important, you may want to mention it there.

You do not need to reboot LISTSERV for the changes to take effect.

The ABC program is called as an exit with two parameters. The first one takes the following form:

origin command arguments

where 'origin' is the address of the command originator, 'command' is the name of the command ('/ABC' in the present example), and 'arguments' are the command arguments, if any, provided by the user. The second parameter is the optional DEF parameter from 'localcmd.file'.

Typically, your program will parse the arguments, decide on a course of action, and issue a number of messages to the user. The exit code is immaterial; there is no particular course of action to select for command processing.

5.4. A practical example: HAPPY99

In late 1998/early 1999 a worm called HAPPY99 surfaced on the Internet. In an attempt to keep the worm off of lists, an L-Soft engineer wrote the following exit in Regina REXX to run under the Windows NT version of LISTSERV 1.8d.

Before proceeding, note this obligatory warning:

USE AT YOUR OWN RISK: THIS SOFTWARE IS PROVIDED ON AN 'AS IS' BASIS. L-SOFT DOES NOT MAKE ANY EXPRESS OR IMPLIED WARRANTY OF ANY KIND WHATSOEVER WITH RESPECT TO THE SOFTWARE, INCLUDING, WITHOUT LIMITATION, ANY WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
Neither L-Soft nor any of its employees, officers or agents will be liable for any direct, indirect or consequential damages, even if L-Soft had been advised of the possibility of such damage. No support is available from L-Soft or from the author for this program. If you give a copy of this program to someone else for their use, you must provide it with both the copyright notice and this paragraph intact. You are not authorized to make this program available for public access via anonymous FTP or by any other means of mass distribution.

First we wrote HAPPY99.REXX, which looks like this:

/* HAPPY99.REXX : Sample Windows NT list exit programming */
/* Added (0.1b) support for VBS.Freelink detection. */
versionno = '0.1b 1999/12/05'
/* By Nathan Brindle  */
/* Copyright (c) 1999 L-Soft international, Inc. */
/* All rights reserved */
/*
   USE AT YOUR OWN RISK: THIS SOFTWARE IS PROVIDED ON AN 'AS IS' BASIS. L-SOFT
   DOES NOT MAKE  ANY EXPRESS OR IMPLIED WARRANTY OF  ANY KIND WHATSOEVER WITH
   RESPECT TO  THE SOFTWARE,  INCLUDING, WITHOUT  LIMITATION, ANY  WARRANTY OF
   MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. Neither L-Soft nor any
   of  its employees,  officers  or  agents will  be  liable  for any  direct,
   indirect or consequential  damages, even if L-Soft had been  advised of the
   possibility of such damage. No support is available from L-Soft or from the
   author for this program. If you give a copy of this program to someone else
   for their use, you must provide  it with both the copyright notice and this
   paragraph intact. You are not authorized to make this program available for
   public access via anonymous FTP or by any other means of mass distribution.
*/

/*****************************************************************************/
/*                          WARNING WARNING WARNING                          */
/*****************************************************************************/
/* THIS PROGRAM IS NOT INTENDED TO BE USED WITHOUT MODIFICATION.  IT IS ONLY A 
   SAMPLE OF HOW LIST EXIT PROGRAMMING MIGHT BE DONE UNDER WINDOWS NT.  WHILE
   THE EXAMPLES HAVE BEEN TESTED AND DO WORK, L-SOFT DOES NOT RECOMMEND SIMPLY
   INSTALLING THIS EXIT AND USING IT WITHOUT MODIFICATION AS THE RESULTS WILL
   PROBABLY NOT BE WHAT YOU EXPECT.  NOTE CAREFULLY THAT THERE IS NO SUPPORT 
   AVAILABLE WHATSOEVER FOR THIS SAMPLE EXIT.
 */	

/* List exits are documented in the Developer's Guide for LISTSERV, available
   at L-Soft's FTP and WWW sites.  
 */

/*****************************************************************************/
/*                   USER CONFIGURATION AREA STARTS HERE                     */
/*                                                                           */
/* infile =  the full path (drive, directory, filename) pointing to          */
/*           the exit.input file.  This must be the path to \LISTSERV\MAIN   */
/*           and the filename must be 'exit.input'.                          */
/* outfile = the full path (drive, directory, filename) pointing to          */
/*           the exit.output file.  This must be the path to \LISTSERV\MAIN  */
/*           and the filename must be 'exit.output'.                         */
/* tmpdir  = the full path (drive and directory) pointing to LISTSERV's TMP  */
/*           directory.  Typically this is something like C:\LISTSERV\TMP ;  */
/*           in any case it is the directory pointed to by the .SD D setting */
/*           in SYSTEM.CFG.                                                  */
/* node =    the value from NODE= in your SITE.CFG file, i.e., the name of   */
/*           your LISTSERV machine in DNS.                                   */
/*****************************************************************************/
infile = 'e:\listserv\main\exit.input'
outfile = 'e:\listserv\main\exit.output'
tmpdir = 'E:\ListPlex\PEACH\TMP'  
node = 'PEACH.EASE.LSOFT.COM' /* replace with NODE= value from site.cfg */
/*****************************************************************************/
/*                    USER CONFIGURATION AREA ENDS HERE                      */
/*****************************************************************************/

parms = linein(infile)
 
parse var parms epname listname more

if epname == 'POST_FILTER' then signal postfilter

/* otherwise, leave */
call lineout(outfile,'EXIT 0')
exit 

/*****************************************************************************/
/* END OF PROGRAM if no epname is recognized                                 */
/*****************************************************************************/

/*****************************************************************************/
/* POST_FILTER                                                               */
/*****************************************************************************/
postfilter:

  /* Note that you could conceivably reject messages based on the value of 'c',*/
  /* which is the total number of bytes in the message (including all headers, */
  /* attachments, etc.).                                                       */

  filtermsg = 'FALSE'
  c = chars(tmpdir'\listserv.cmsut1') 
  msgin = charin(tmpdir'\listserv.cmsut1',1,c)
  call charout(tmpdir'\listserv.cmsut1')

  /* Grab Date: and Subject: headers */
  msgdate = ''
  msgsubject = ''
  p = pos("Date:",msgin)
  if p > 0 then do
                  e = pos('0d'x,msgin,p) - 1
                  msgdate = substr(msgin,p+5,(e-p)-4)
                  msgdate = strip(msgdate)
                end
  if msgdate == '' then msgdate = 'undated message'
                   else msgdate = 'message dated' msgdate
  p = pos("Subject:",msgin)
  if p > 0 then do
                  e = pos('0d'x,msgin,p) - 1
                  msgsubject = substr(msgin,p+8,(e-p)-7)
                  msgsubject = strip(msgsubject)
                  if left(msgsubject,1) == '0d'x then msgsubject = ''
                end
  if msgsubject == '' then msgsubject = 'with no subject'
                      else msgsubject = 'with subject "'||msgsubject||'"'

  /* Check for uuencoded Happy99.exe virus */
  filter = 'begin 644 Happy99.exe' 
  p = pos(translate(filter),translate(msgin))
  if p > 0 then filtermsg = 'TRUE'
  say '>>>' p
  if filtermsg == 'TRUE' then do
    explanation = 'Your' msgdate msgsubject 'sent'
    explanation = explanation 'to the 'listname' mailing list has been'
    explanation = explanation 'rejected because it appears to contain the'
    explanation = explanation 'Happy99.EXE virus.  It is strongly suggested'
    explanation = explanation 'that you run an anti-virus program before'
    explanation = explanation 'posting again.'
  end
  if filtermsg == 'TRUE' then signal done

  /* deal with links.vbs (FreeLink) */
  
  filter = 'Have fun with these links.'
  p = pos(translate(filter),translate(msgin))
  if p > 0 then filtermsg = 'TRUE'
  say '>>>' p 
  if filtermsg == 'TRUE' then do
    explanation = 'FREELINK: Your' msgdate msgsubject 'sent'
    explanation = explanation 'to the 'listname' mailing list has been'
    explanation = explanation 'rejected because it appears to contain the'
    explanation = explanation 'VBS.Freelink virus.  It is strongly suggested'
    explanation = explanation 'that you run an anti-virus program before'
    explanation = explanation 'posting again.'
  end
  if filtermsg == 'TRUE' then signal done

  /* More filtering conditionals could be put in here */

done:

  if filtermsg = 'FALSE' then call lineout(outfile,'EXIT 0')
  if filtermsg = 'FALSE' then exit 

  /* Otherwise we've found reason to reject the message. */
  /* Construct an explicit TELL directive to inform the user.  The TELL */
  /* directive has 3 parameters, which will be passed one per line.     */
  call lineout(outfile,'TELL3')

  /* First parameter, the command originator, comes from the "more" */
  /* variable. */
  call lineout(outfile,word(more,1))

  /* Next we pass second parameter, which we've already built above */
  call lineout(outfile,explanation)

  /* Third (optional) parameter, echo to the LISTSERV log */
  call lineout(outfile,ECHO)

  /* Now, reject the message. */
  call lineout(outfile,'EXIT 1')

  /* Finished. */
  exit

/* end of program */

Then we wrote the following HAPPY99.CMD file, and placed it in the \LISTSERV\MAIN directory. This CMD file, when executed by LISTSERV, calls the Regina interpreter and in turn tells it to run the HAPPY99.REXX file we wrote above.

REM be sure to change the directories to point to the right places!
c:\util\reskit\rexx.exe e:\listserv\main\happy99.rexx

Next, SITE.CFG was modified and the line LIST_EXITS=HAPPY99

was added. LISTSERV was then stopped and restarted to pick up the change.

Finally, the exit was enabled for certain lists by adding

* Exit= HAPPY99

to the list headers.

Note that the program makes no attempt to determine if the message actually contains a working copy of the virus. Its only function is to attempt to identify messages that MAY contain a working copy of the virus. Thus it may engender some false positives (but it's doubtful that anyone sending legitimate mail will send the specific strings searched for by the exit program).

Note further that the LISTSERV.CMSUT1 file that you search for evidence of the virus may not be edited "on the fly" to remove parts of the message--it is a read-only file for this purpose. You have only the option of accepting or rejecting the message in its entirety.

Since HAPPY99 still resurfaces from time to time (as does the VBS.Freelink worm), the HAPPY99 exit, exactly as shown above, is running to this day on several L-Soft-managed servers. Given that the "classic" version of HAPPY99 is not sent as a MIME attachment, it is not possible to block it with the Attachments= list header keyword introduced in the 2000a level set release of LISTSERV 1.8d, and the exit is the only way to guard against it.


6. The LISTSERV TCPGUI interface

The TCPGUI interface is the part of LISTSERV that listens for TCP/IP connections coming into the LISTSERV port on the LISTSERV host. To use the TCPGUI interface, you set up TCPGUI, then you send commands to it through TCP/IP. You have two options for sending commands to LISTSERV through TCP/IP:

  • Use the lcmdx program from your operating system's command line, or
  • Write a program to send the commands, using the code for lcmdx as a guide.

Most simple commands can be sent directly through the TCPGUI interface, but some advanced operations require special handling.

6.1. Setting up the TCPGUI interface

By default, LISTSERV listens to port 2306 on all the IP addresses assigned to the local host.

If it needs to be restricted to a given IP address, or if port 2306 is already in use by another application, LISTSERV must be set up so that it listens to the correct IP address and port.

To specify an IP address that LISTSERV should listen to, you need to add the TCPGUI_IPADDR parameter to your site configuration file.

For example, under Windows NT, you would add the following line to the SITE.CFG file:

TCPGUI_IPADDR=nnn.nnn.nn.nn

where nnn.nnn.nn.nn is the IP address assigned to the LISTSERV host.

You can instruct LISTSERV to listen to a different port by setting the TCPGUI_PORT parameter to an unused port number. For example:

TCPGUI_PORT=nnnn

Recall that you need to stop and restart LISTSERV for site configuration changes to take effect.

6.2. Running lcmdx

The lcmdx program (C language code at the end of the chapter) allows you to send a LISTSERV command from a command line (DOS, shell, or DCL prompt). Compile and link it (you may need to make minor changes to get it to compile, depending on your C compiler) to produce an executable.

You can run lcmdx from any computer that is connected via TCP/IP to the LISTSERV host (i.e. via the Internet or a TCP/IP-based intranet).

You need to have a password registered for your e-mail address in LISTSERV in order to send commands via TCP/IP. Instructions for registering a password are in section 2.12.8 of the List Owner's manual.

The format for the lcmdx command line is:

lcmdx hostname[:port] address password command

where

  • hostname is the DNS name of the LISTSERV host,
  • port is the LISTSERV port number (needed only if it is different from the default of 2306),
  • address is the e-mail address of the user sending the command,
  • password is the upper-case password registered with this LISTSERV host for that e-mail address, and
  • command is the one-line LISTSERV command.

Note that the password parameter MUST imperatively be typed in UPPER CASE.

For example, if francoise@lsoft.com wants to set her subscription to the MSVC list to digest, and her password on PEACH.EASE.LSOFT.COM (where this list is hosted) is "ABCDE", she can use the following command:

lcmdx PEACH.EASE.LSOFT.COM francoise@lsoft.com ABCDE SET MSVC DIGEST

LISTSERV responds:

Your subscription options have been successfully updated. You are being
mailed a short report with the exact settings now in use for your
subscription. Please take a few moments to check that this is indeed
what you wanted.

Any one-line command can be submitted to LISTSERV in this way. To use lcmdx directly from your application, just spawn a subprocess or send the lcmdx command using whatever means is provided by the operating system under which your application is running.

6.3. Sending LISTSERV commands directly from your application

The lcmdx program is convenient, as it doesn't require programming to use, but it does not allow much flexibility in how your application can react to LISTSERV's responses to the commands sent. For greater flexibility, you can integrate the techniques used in lcmdx for communicating with LISTSERV directly into your application.

The lcmdx source code consists of three C functions:

  • receive - used by LSV_send_command to receive a string of a given length from a socket

  • LSV_send_command - the function that sends a command from LISTSERV and returns the answer; this function can be used directly by your application with few or no changes.

  • main - the main function simply parses the command line for lcmdx into its component parts, passes them to LSV_send_command, and prints LISTSERV's response; your application would replace main.

The main change that you may want to make to the LSV_send_command function, will be to have it write the LISTSERV response to a string or an array of strings rather than to a file, as is the case in lcmdx. What you actually do with LISTSERV's response will be dictated by the needs of your application.

The only other changes that might be required are changes that relate to how sockets are implemented on your operating system. For example, if you are using Windows sockets (WINSOCK), you would have to add the Windows sockets initialization code at the start of your application, calling and checking the status of the WSAStartup routine; and the cleanup code at the end, calling the routine WSACleanup. With Windows sockets, you would also have to include the header file <winsock.h> instead of <sys/socket.h>, <netdb.h>, and <netinet/in.h>; and replace the call to close(ss) with a call to closesocket(ss).

The LSV_send_command function uses the following calling sequence:

int LSV_send_command(char *hostname, unsigned short port,
                     char *origin, char *pw, char *command, FILE *writeto)

where the return value is:

  • 0 if the command was sent and the answer received without a problem, from a TCP/IP point of view - this does not indicate that the command itself was successfully executed by LISTSERV: your application needs to look at the answer received from LISTSERV to determine whether the command itself was successful;

  • 1000 if a protocol error occurred while communicating with LISTSERV;

  • a socket error code if a socket error occurred while communicating with LISTSERV - the socket errors should be described in the documentation for socket functions for your C compiler.

and the parameters are:

  • hostname - a pointer to a character array containing the name of the LISTSERV host to which to send the command

  • port - the port number to which to connect (use 2306 unless otherwise specified in the site configuration file of the LISTSERV host)

  • origin - a pointer to a character array containing the e-mail address of the "originator" of the command

  • pw - a pointer to a character array containing the LISTSERV password registered for the originator's e-mail address (must be UPPER CASE)

  • command - a pointer to a character array containing the one-line command to send to LISTSERV

  • writeto - a pointer to the file in which to write LISTSERV's response; as mentioned above, depending on the needs of your application, you may want to change this parameter and the code within LSV_send_command that writes to this file.

Of course, if you use LSV_send_command without modification, you will be opening and closing a connection to LISTSERV for each command you send. You can make your application more efficient by opening up a connection to LISTSERV and sending a series of commands before closing the connection again. The LSV_send_command function will work "out of the box", but an experienced programmer can use it as a guide for developing customized functions for working with the TCPGUI interface.

6.4. Advanced TCPGUI Programming Issues

The technique described above, using the LSV_send_command function to send commands over TCP/IP to LISTSERV, will work for most one-line LISTSERV commands, such as ADD, DELETE, SET, SHOW, etc. However, some commands require a different or modified approach:

  • Creating or replacing a list header

  • Adding or replacing a password

  • Bulk operations

  • Commands that respond over e-mail

  • Application-friendly commands

There may also be some special error handling involved.

6.4.1. Creating or replacing a list header

Multi-line commands cannot be sent through the TCPGUI interface, therefore the usual approach for sending a list header to LISTSERV (the PUT command followed by the multiple lines of the header) cannot be used. Instead, TCPGUI has a special command for sending a list header: X-STL.

The syntax of the X-STL command is:

X-STL listname header-data

where header-data is a text string that contains every header line (including the leading asterisk), one after the other, each preceeded by a count of the characters on the line, followed by an underscore character. The last header line should not have any trailing spaces.

Thus, if the command you would use to put your list through e-mail was:

PUT listname PW=password
* test1
* Owner=francoise@lsoft.com
* Notebook=No
* Confidential=Yes

The command you send through the TCPGUI interface would be:

X-STL listname 6_* test1_*28_* Owner= francoise@lsoft.com13_* Notebook=No18_* Confidential=Yes

(Remember that this is a one-line command.)

Obviously, you need to use the "create" password when creating a new header, and an owner's or postmaster's personal password when replacing an existing header.

6.4.2. Adding or replacing a password

You canít send a "PW ADD" or "PW REP" command through the TCPGUI interface. There is a special command for adding a password:

X-PWADD e-mail-address password

The LSV_send_command function generally requires a password, which you donít necessarily have when youíre in the process of adding one. In this case, you can send the command anonymously through TCPGUI by using the anonymous e-mail address "@" as the "originator" in the call to LSV_send_command (but not in the X-PWADD command, obviously).

When LISTSERV receives the X-PWADD command, it sends e-mail to the given e-mail-address requesting confirmation. E-mail confirmation is the only way for LISTSERV to determine that the e-mail address provided is truly the correct address. Therefore, an application should never count on the password being immediately available. A message to the user, letting them know that they can continue after they have successfully confirmed the password registration, may be advisable.

6.4.3. Bulk operations

As noted above, the TCPGUI interface can only handle single-line commands. Therefore bulk operations, such as the bulk add and delete commands cannot be sent through TCPGUI, and can only be sent through the mail. The only ways to send bulk adds and deletes from an application are:

Turn them into individual add or delete commands, and send each of these through the TCPGUI interface. If there are many subscribers to add or delete, this can extremely slow, and is therefore not recommended.

Write a mail file containing the bulk add or delete job and use a local mail application to send it to LISTSERV.

Open up a connection with the SMTP port on the LISTSERV host and use SMTP commands (documented in RFC821) to send a mail file (documented in RFC822) containing the bulk add or delete job. This is essentially the same thing as the previous bullet, except that in the latter case, you used a third-party application to send the file, whereas with this method you must write your own.

6.4.4. Commands that respond over e-mail

LISTSERV will accept almost any one-line command through the TCPGUI interface. The answer you receive through the TCPGUI interface, however, may not always be what you expected. Commands whose responses tend to be long will generally be sent through e-mail. LISTSERV will always send the response to the following commands back through e-mail:

  • INFO
  • INDEX
  • LISTS DETAILED
  • LISTS GLOBAL
  • LISTS SUMMARY
  • GETPOST
  • GET for anything other than a list header

For these other commands, LISTSERV will send the response back through e-mail unless you use an option to make it come back through the TCPGUI interface:

  • GET listname -- requires the "(MSG" option

  • REVIEW -- requires the "MSG" option

6.4.5. Application-friendly commands

Some commands that can be sent through the TCPGUI interface and to which LISTSERV will send the response back through the TCPGUI interface nevertheless have responses that are human-friendly but not application-friendly. One such command is the QUERY command, which sends a response that looks like:

Subscription options for Francoise Becker , list MYLIST:

MAIL           You are sent individual postings as they are received
MIME           You prefer to receive messages in MIME format
SUBJECTHDR     Full (normal) mail headers with list name in message subject
REPRO          You receive a copy of your own postings
NOACK          No acknowledgement of successfully processed postings

Subscription date: 12 Mar 1997

The topics you subscribe to are: Mytopic, Other

To assist the application developer, the LISTSERV provides alternate commands for the following:

  • QUERY

  • A special option for QUERY: DEFSUB

  • SCAN

QUERY

To QUERY subscriber options from an application you should use:

QUERY ***GUI*** listname [FOR e-mail-address]

The response will look like the following:

***HDR*** e-mail-address
***NAME*** firstname lastname

***OPT*** option1
***OPT*** option2
...
***OPT*** optionN

***SUBDATE*** date
***TOPICS*** subscriber-topics
***TOPLIST*** list-topics
***HDR*** e-mail-address (next subscriber)
etc.

N matching entries found.

Where:

  • The "***HDR***" line denotes the beginning of the subscription settings for a particular subscriber (recall that the QUERY command could yield information for multiple subscriptions) and identifies the e-mail address of the subscription.

  • The "***NAME***" line provides the full name stored for that subscriber.

  • The "***OPT***" lines each show one option set for the subscription. The first option would always be MAIL or NOMAIL. All the other options are only those options that are NOT the default options in LISTSERV (as opposed to the default options set for the particular list -- these do not apply here).

  • The "***SUBDATE***" line contains the subscription date.

  • The "***TOPICS***" line lists the topics which are selected for this subscription.

  • The "***TOPLIST***" line lists all the topics that are available for the list, regardless of whether this particular subscription has them selected, except for "ALL" and "OTHER".

  • These lines are repeated for each matching entry found.

  • The last line gives a count of matching entries found.

QUERY DEFSUB

There is also a special QUERY command for obtaining default subscription options:

QUERY ***GUI*** ***DEFSUB*** listname

If this command is sent using an address that is subscribed to the given list, it works exactly the same as the "QUERY ***GUI***" command described above. If it is sent anonymously (see "Adding or replacing a password" above) or from an address which is not subscribed, then the first line in the response is:

***DEF***

And the remainder of the response is the same as the response to "QUERY ***GUI***" for a subscriber with the listís default subscription settings.

SCAN

To scan a list for a pattern, you should use

SCAN ***GUI*** listname pattern

The response will look like the following:

***MBX*** user1@host.domain
Firstname Lastname <user1@host.domain>
***MBX*** user2@host2.domain
"Full name w/ special characters" <user2@host2.domain>
etc.
***END***
SCAN: N matches.

6.4.6. Error handling

When the command you send produces an error the TCPGUI interface sends back the exact error that you would receive through the mail when that error is detected by LISTSERV (for example, if you use the wrong listname, or misspell a command). However, the TCPGUI interface does have some error messages specific to it, for when the error occurs within TCPGUI rather than LISTSERV. These are:

  • ***NOPW*** -- the e-mail address does not have a password registered with LISTSERV

  • ***BADPW*** -- the password provided in the TCPGUI command does not match the password registered for the given e-mail address.

6.5. LCMDX.C

/******************************************************************************
 *                                                                            *
 * LISTSERV V2 - send command to LISTSERV on remote node via TCPGUI interface *
 *                                                                            *
 *       Copyright L-Soft international 1996-97 - All rights reserved         *
 *                                                                            *
 * Syntax:                                                                    *
 *                                                                            *
 *  lcmdx hostname[:port] address password command                            *
 *                                                                            *
 * Connects to 'hostname' on port 'port' (default=2306) using the LISTSERV    *
 * TCPGUI protocol, then executes the LISTSERV command 'command' from the     *
 * origin 'address'. 'password' is the personal LISTSERV password associated  *
 * with the command origin ('address') - see the description of the PW ADD    *
 * command for more information on LISTSERV passwords. The reply from         *
 * LISTSERV is echoed to standard output (the command is executed             *
 * synchronously).                                                            *
 *                                                                            *
 ******************************************************************************/

#include <ctype.h>
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include <errno.h>
#include <string.h>
#include <netdb.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#ifdef INTUX
#include <net/errno.h>
#endif

#define DEFAULT_PORT    2306

#ifdef ultrix
        /* Use read() rather than recv() to bypass a bug in Ultrix */
#define recv(a, b, c, d) read(a, b, c)
#endif

static int receive(int ss, char *buf, int len)
{
        char *w, *e;
        int l;

        for (w = buf, e = buf + len; w < e;) {
                l = recv(ss, w, e - w, 0);
                if (l <= 0)
                        return(l);
                w += l;
        }
        return(len);
}

int LSV_send_command(char *hostname, unsigned short port, char *origin,
                     char *pw, char *command, FILE *writeto)
{
        char buf[256], *reply = 0, *cmd, *w, *r, *e;
        unsigned char *wb;
        int rc, ss, len, orglen, n;
        unsigned int ibuf[2];
        struct sockaddr_in sa_connect;
        struct hostent *H;

        /* Initialize */
        cmd = malloc(strlen(command) + strlen(pw) + 5);
        sprintf(cmd, "%s PW=%s", command, pw);
        orglen = strlen(origin);

        /* Create a socket */
        if ((ss = socket(AF_INET, SOCK_STREAM, 0)) < 0)
                goto Socket_Error;

        /* Prepare sa_connect structure */
        memset(&sa_connect, 0, sizeof(sa_connect));
        sa_connect.sin_family = AF_INET;
        sa_connect.sin_port = htons(port);
        if ((H = gethostbyname(hostname)) && H->h_addr_list[0])
                memcpy(&sa_connect.sin_addr, H->h_addr_list[0], 4);
        else
                goto Socket_Error;

        /* Connect to the TCPGUI port */
        if (connect(ss, (struct sockaddr *)&sa_connect,
                    sizeof(sa_connect)) < 0)
                goto Socket_Error;

        /* Send the protocol level request and the command header */
        wb = (unsigned char *)buf;
        len = strlen(cmd);
        n = len + orglen + 1;   /* Byte length                  */
        *wb++ = '1';            /* Protocol level: 1            */
        *wb++ = 'B';            /* Mode: binary                 */
        *wb++ = '\r';
        *wb++ = '\n';
        *wb++ = n / 256;        /* Request length byte 1        */
        *wb++ = n & 255;        /* Request length byte 2        */
        *wb++ = orglen;         /* Origin length: 1             */
        for (r = origin; *r;)
                *wb++ = (unsigned char)*r++;

        if (send(ss, buf, (char *)wb - buf, 0) < 0)
                goto Socket_Error;

        /* Await confirmation */
        for (w = buf;;) {
                n = recv(ss, w, buf + sizeof(buf) - w, 0);
                if (n <= 0)
                        goto Socket_Error;
                w += n;
                for (r = buf; r < w && *r != '\n'; r++);
                if (r != w)
                        break;
        }

        /* Anything other than 250 is an error */
        if (buf[0] != '2' || buf[1] != '5' || buf[2] != '0')
                goto Protocol_Error;

        /* Finish sending the command text */
        if (send(ss, cmd, len, 0) < 0)
                goto Socket_Error;

        /* Read the return code and reply length */
        if (receive(ss, (char *)ibuf, 8) <= 0)
                goto Socket_Error;

        /* Exit if the return code is not 0 */
        if (ntohl(ibuf[0]))
                goto Protocol_Error;

        /* Read the reply */
        len = ntohl(ibuf[1]);
        reply = malloc(len + 1);
        if (receive(ss, (char *)reply, len) <= 0)
                goto Socket_Error;

        /* Cut it into individual lines, and output it */
        for (r = reply, e = reply + len; r < e;) {
                for (w = r; w < e && *w != '\r'; w++);
                *w++ = '\0';
                fprintf(writeto, "%s\n", r);
                r = w;
                if (r < e && *r == '\n')
                        r++;
        }

        /* Close the socket and return */
        rc = 0;
        goto Done;

Protocol_Error:
        rc = 1000;
        goto Done;

Socket_Error:
        rc = errno;
        goto Done;

Done:
        free(cmd);
        if (reply)
                free(reply);
        if (ss >= 0)
                close(ss);
        return(rc);
}

 
#ifndef NO_MAIN
int main(int argc, char **argv)
{
        char cmd[8192], hostname[80], *w, *r;
        int rc, n;
        unsigned short port;

        /* Parse positional parameters */
        if (argc < 5) {
                printf("\
Syntax: lcmdx hostname[:port] address password command\n");
                return(EINVAL);
        }

        port = DEFAULT_PORT;
        for (r = argv[1], w = hostname; *r && *r != ':';)
                *w++ = *r++;
        *w = '\0';
        if (*r == ':')
                port = atoi(++r);

        for (n = 4, w = cmd; n < argc; n++) {
                if (w != cmd)   
                        *w++ = ' ';
                for (r = argv[n]; *r; *w++ = *r++);
        }
        *w = '\0';

        /* Execute the command */
        rc = LSV_send_command(hostname, port, argv[2], argv[3], cmd,
                                        stdout);
        if (rc == 1000)
                printf("\
>>> Protocol error while communicating with LISTSERV.");
        else if (rc != 0)
                printf("\
>>> Error - unable to initiate communication with LISTSERV (errno=%d).\n", rc);

        return(rc);
}
#endif

Revision History

19990305-001 POST_FILTER exit--the listserv.cmsut1 file cannot be edited 
             when the list exit is called. The message may only be 
             accepted or rejected.
19990623-001 4.5.4, added clarification of difference between empty string 
             and NULL values in database applications
19990623-001 Added 4.5.6, example of how to use the OPTIONS column values.
19990805-001 4.6.2, one of the examples had a wrapped DISTRIBUTE command 
             line. Inserted continuation card and noted reference to 2.3 
             which discusses JOB card syntax.
19990809-001 4.1, 4.1.3, and 4.2, clarified that LSMTP Classic 1.1b or 
             later is required for mail-merge.
19990809-002 Added 4.5.7, how to migrate existing user options from 
             "standard" LISTSERV list to DBMS-type list
19990820-001 4.3.3, clarified that the -l switches mentioned go in the 
             CFLAGS_`uname` Makefile macro and are Oracle-version-dependent
19990825-001 4.6.1, added a unix example URL.
19990825-002 Chapter 1, in order to reduce confusion between the SEARCH 
             command and DBMS features, reworded title and several other 
             reference to "database functions"
19990825-003 Revision 1 issued.
20000302-001 3.5.1, note about need to patch sendmail to make it work with 
             probes
20000503-001 4.3.1, clarified information about NT OCI kits.
20000522-001 5.1, under the bullet point for naming unix exits, changed 
             "exit programs must always be spelled in upper case" to "exit
             programs must always be named in upper case", hopefully to 
             avoid confusion.
20000522-002 5.1, under point #2 for preparing a list exit, added 2nd 
             paragraph explaining that you do not code file extensions 
             along with file names in LIST_EXITS. Also cautionary note 
             under point #1 to use only alphanumeric characters when naming
             exit programs.
20000522-003 Added 5.4.
20000624-001 In 4.2.1 under the first bullet point, expanded "Access" to 
             "The Microsoft Access DBMS product" to minimize potential 
             confusion.
20000816-001 "return(err)" at end of lcmdx.c should be "return(rc)"
20001024-001 3.4.1, ECHO= must follow any PRIME= in a JOB card or a syntax 
             error occurs.
20010321-001 Documented restrictions added to 4.1.3 (LSMTP required for MM)
             and 4.6.3 "Command tickets" (list owners cannot issue ticketed 
             commands).
20010321-002 4.2.1, added "Except as specifically indicated above" to 
             beginning of last paragraph.
20010322-001 Revision 2 issued.