PEP Documentation

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Launching M-Script Programs (Advanced)

This page does not attempt to teach you how to write M-Script programs. For that, please visit http://www.islandnet.com/mscript/.

What is an "M-Script Program"?

Why?

How does it work?

The rule is the easy part. Here's a sample PEP rule that launches (executes) an M-Script program called "archiver.ms2":

exec if subject contains "[Llamas]" "archiver"

The program itself must have a ".ms2" extension and must be located in your "ms2" directory, as per the M-Script documentation.

In the example above, we launch the M-Script program without passing the message itself to the program. The program will run, but it has no way of accessing the headers or the body of the message. Depending on what the program does, this may or may not be what you want.

If you want your program to have access to the message, you need to specify an additional parameter in your rule. This is the name of a file to which a copy of the message will be saved prior to launching your program:

exec if subject contains "[Llamas]" "archiver" "temp/message.txt"

If your program exits with a value of zero, PEP halts without delivering your message. This makes it effectively the same a s DELETE rule. If the program exits with a non-zero value, PEP continues processing the rest of your mailrule file.

NOTE:

• It is not a good idea to use a fixed filename because if two messages come in simultaneously one will clobber the other. Use the PEP_ID value to form part of the filename: temp/{PEP_ID}.txt

• The saved message will not be deleted after your program halts, so it's up to you to do this insude your program.

• Your program should always exit with an explicit return value of either zero or one. If it doesn't the value is undefined and you may get unexpected results.

Environment Variables

PEP_ID

This is a string that is guaranteed to be unique for each message PEP processes. It is usually used as the filename for passing that message to the program.

PEP_IP

This is the IP address of the machine that passed the message to our mail server/

PEP_RULE

This is a copy of the rule that caused the program to launch.

PEP_LINES

This a number that indicates how many lines long the message is.

PEP_BYTES

This is a number that indicates how large the message is in bytes.

PEP_TOCOUNT

This is a number that indicates how many addresses there are in the To: header of the message.

PEP_CCCOUNT

This is a number that indicates how many addresses there are in the Cc: header of the message.

An Example

We start with a rule like the following:

exec if subject contains "[VBS]" "counter"

Since we're simply counting occurances of such messages, we don't need to pass the actual messages to the program.

Next we create the file "counter.ms2" in our "ms2" directory. It would look something like this:

if exists( "vbs.count" )    in = open( "vbs.count", "r+" ) else    in = open( "vbs.count, "w" ) endif if in    while !lockf( in )    endif    count = read( in ) + 1    rewind( in )    write( in, count, "\n" )    close( in ) endif return 1

And that's it. Every time we get a message with "[VBS]" in the subject, the program runs and adds 1 to the value in the "vbs.count" file.

Note the last line which returns a value of one to PEP. This will cause PEP to continue testing the message against your mailrule file. Unless a subsequent rule deletes it, it will be delivered to your mailbox.