qpsmtpd/docs/advanced.pod

#
# This file is best read with ``perldoc advanced.pod''
#

### 
# Conventions:
#  plugin names:  F<myplugin>
#  constants:     I<LOGDEBUG>
#  smtp commands, answers: B<HELO>, B<250 Queued!>
#
# Notes: 
#  * due to restrictions of some POD parsers, no C<<$object->method()>>
#    are allowed, use C<$object-E<gt>method()> 
# 

=head1 Advanced Playground

=head2 Discarding messages

If you want to make the client think a message has been regularily accepted,
but in real you delete it or send it to F</dev/null>, ..., use something
like the following plugin and load it before your default queue plugin.

  sub hook_queue {
    my ($self, $transaction) = @_;
    if ($transaction->notes('discard_mail')) {
      my $msg_id = $transaction->header->get('Message-Id') || '';
      $msg_id =~ s/[\r\n].*//s;
      return(OK, "Queued! $msg_id");
    }
    return(DECLINED);
  }


=head2 Changing return values

This is an example how to use the C<isa_plugin> method.

The B<rcpt_ok_maxrelay> plugin wraps the B<rcpt_ok> plugin. The B<rcpt_ok>
plugin checks the F<rcpthosts> and F<morercpthosts> config files for
domains, which we accept mail for. If not found it tells the
client that relaying is not allowed. Clients which are marked as
C<relay clients> are excluded from this rule. This plugin counts the
number of unsuccessfull relaying attempts and drops the connection if
too many were made.

The optional parameter I<MAX_RELAY_ATTEMPTS> configures this plugin to drop
the connection after I<MAX_RELAY_ATTEMPTS> unsuccessful relaying attempts.
Set to C<0> to disable, default is C<5>.

Note: Do not load both (B<rcpt_ok> and B<rcpt_ok_maxrelay>). This plugin
should be configured to run I<last>, like B<rcpt_ok>.

 use Qpsmtpd::DSN;

 sub init {
   my ($self, $qp, @args) = @_;
   die "too many arguments"
     if @args > 1;
   $self->{_count_relay_max} = defined $args[0] ? $args[0] : 5;
   $self->isa_plugin("rcpt_ok");
 }

 sub hook_rcpt {
   my ($self, $transaction, $recipient) = @_;
   my ($rc, @msg) = $self->SUPER::hook_rcpt($transaction, $recipient);

   return $rc, @msg
      unless (($rc == DENY) and $self->{_count_relay_max});

   my $count = 
     ($self->connection->notes('count_relay_attempts') || 0) + 1;
   $self->connection->notes('count_relay_attempts', $count);

   return $rc, @msg unless ($count > $self->{_count_relay_max});
   return Qpsmtpd::DSN->relaying_denied(DENY_DISCONNECT, 
           "Too many relaying attempts"); 
 }

=head2 Results of other hooks

B<NOTE:> just copied from README.plugins

If we're in a transaction, the results of a callback are stored in

    $self->transaction->notes( $code->{name})->{"hook_$hook"}->{return}

If we're in a connection, store things in the connection notes instead.
B<FIXME>: does the above (regarding connection notes) work?

=cut

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