On Wed, Jan 21, 2009 at 1:28 AM, Timo Sirainen <tss@iki.fi> wrote:

On Tue, 2009-01-20 at 23:18 +0100, Maciej Uhlig wrote:

...

Timo Sirainen:

...

What exactly are they? I guess a global file that is served as a message for all users? Right. With POP3 it is served once - after first user login after the message was placed in bulletin database (just a plaintext file in a directory, for instance).

...

That's more difficult to implement with IMAP than with POP3. You know better, but... just place incoming (bulletin) mail in INBOX.

Well, okay, I was thinking about a way to not duplicate the message to everyone's mailbox. And I guess with virtual mailboxes there's the problem that users can't then delete the message (or it gets deleted for everyone).

So what you want is a mailing list for your users without actually going through MTA. Shouldn't be too difficult to implement as a plugin I guess. You'd mainly just need to somehow keep track of what messages have been delivered to the user. You could maybe even implement this as a shell script with http://wiki.dovecot.org/PostLoginScripting although of course then users who have long running imap sessions won't see the bulletins until they reconnect.

Just to chip in with my $2 cents... I used tpop3d for a long time before switching to Dovecot and we had Bulletins functionality using some perl hooks. Below is the perl script that Chris Lightfoot (R.I.P), provided for this:

<QUOTE>

#!/usr/local/bin/perl

use GDBM_File;

#Implementing POP3 server bulletins using tpop3d #$Id: README.bulletins,v 1.1 2003/08/01 12:11:38 chris Exp $

At many large sites it is useful to be able to distribute a `bulletin'

message

to all mail users. tpop3d can provide this functionality by having user

login

trigger delivery of any outstanding bulletin messages via the onlogin

handler mechanism, as for POP-before-SMTP.

This is new and untested functionality, but the basic idea is that you

specify

onlogin-child-wait: yes

in tpop3d.conf, then write an auth-perl or auth-other onlogin action to

handle

bulletin delivery. Here is a sketch of a perl subroutine that could be

used

for this:

onlogin_bulletins_handler REQUEST

Deliver any bulletins which are pending for the authenticated user

identified in the REQUEST. This subroutine is called by tpop3d, which

will set REQUEST->{local_part} and REQUEST->{domain} to the proper

values. Bulletins should be complete RFC822 messages stored in flat

text files under /etc/mail/bulletins, each with the extension .msg.

This function will use a GDBM database for each bulletin to record the

addresses of users to whom it has been delivered, so as to ensure that

each user receives only one copy of each bulletin. Bulletins are

delivered to user mailboxes using the local mail transport agent, though

this behaviour could be changed if required.

sub onlogin_bulletins_handler ($) {
my $req = shift;
my $resp = { };

#

Iterate over list of bulletins.

foreach my $bull (glob("/usr/local/etc/tpop3d/bulletins/*.msg")) {
my $recips = $bull;

# Obtain and tie delivery database, creating it if it does not

already exist.

$recips =~ s/msg$/db/;
my $r = $req->{local_part} . '@' . $req->{domain};
my %rr;
tie(%rr, 'GDBM_File', $recips, &GDBM_File::GDBM_WRCREAT, 0600);

# Attempt delivery if this user has not already been sent a copy

of this message.

if (!exists($rr{$r})) {

# Invoke sendmail. There are better ways of doing this, but

this is simplest. Note that it wouldn't usually be safe to

call sendmail in this way, but tpop3d has already

authenticated somebody using the given local-part and

domain, so they're presumably safe strings.

 system("sendmail -oi '$r' < $bull");
 if ($? == 0) {

# Sendmail exits with code 0 on success.

 $rr{$r} = 1;
  } else {

# Sendmail (or system(3)) failed. There's not a whole lot

we can do here, but we log a message and abort sending

any other bulletins to this user for the moment.

 untie(%rr);
 return { logmsg => "sendmail failed; error code $?" };
    }
 }
 untie(%rr);

}

Don't log anything in case of success; we might want to note how

many bulletins were delivered or something, of course.

return { }; }

</QUOTE>

The configuration end of tpop3d (tpop3d.conf) required the following:

Enable authentication via an embedded perl interpreter.

auth-perl-enable: true

auth-perl-start: perl code

Specify a line of perl code to be executed at startup.

auth-perl-start: do '/usr/local/etc/tpop3d/bulletins.pl';

auth-perl-finish: perl code

Specify a line of perl code to be executed when the authentication driver

#auth-perl-finish:

auth-perl-apop: subroutine name

Specify the name of a perl subroutine which will be called when

#auth-perl-apop:

auth-perl-pass: subroutine name

Specify the name of a perl subroutine which will be called when

#auth-perl-pass:

auth-perl-onlogin: subroutine name

Specify the name of a perl subroutine which will be called after

auth-perl-onlogin: onlogin_bulletins_handler

Perhaps someone can easily adapt that to Dovecot using PostLoginScripting<http://wiki.dovecot.org/PostLoginScripting> . In worst case scenario, one could run tpop3d for POP3 and Dovecot for IMAP to get the functionality.

PS: tpop3d was licensed under GNU GENERAL PUBLIC LICENSE.

-- Best regards, Odhiambo WASHINGTON, Nairobi,KE +254733744121/+254722743223

"The only time a woman really succeeds in changing a man is when he is a baby." - Natalie Wood