NAME

       Mail::Milter::Chain - Perl extension for chaining milter callbacks

SYNOPSIS

           use Mail::Milter::Chain;

           my $chain = new Mail::Milter::Chain({ connect => \&foo, ... }, ...);
           $chain->register({ connect => \&bar, ... });
           $chain->register({ connect => \&baz, ... });

           $chain->accept_break(1);

           use Sendmail::Milter;
           ...
           Sendmail::Milter::register('foo', $chain, SMFI_CURR_ACTS);

DESCRIPTION

       Mail::Milter::Chain allows multiple milter callback sets to be registered in a single
       milter server instance, simulating multiple milters running in separate servers.  This is
       typically much less resource intensive than running each milter in its own server process.

       Any contained milter returning SMFIS_REJECT, SMFIS_TEMPFAIL, or SMFIS_DISCARD will
       terminate the entire chain and return the respective code up to the containing chain or
       milter server.

       Normally, a milter returning SMFIS_ACCEPT will remove only that milter from the chain,
       allowing others to continue processing the message.  Alternatively, SMFIS_ACCEPT can be
       made to terminate the entire chain as is done for error results; see "accept_break()"
       below.

       A "Mail::Milter::Chain" is itself a milter callback hash reference, and can thus be passed
       directly to "Sendmail::Milter::register()" or another Mail::Milter::Chain container.
       IMPORTANT CAVEAT:  Once this object has been registered with a parent container (a milter
       or another chain), DO NOT call "register()" on this object any longer.  This will result
       in difficult to diagnose problems at callback time.

METHODS

       new([HASHREF, ...])
           Creates a Mail::Milter::Chain object.  For convenience, accepts one or more hash
           references corresponding to individual callback sets that will be registered with this
           chain.

       accept_break(FLAG)
           If FLAG is 0 (the default), SMFIS_ACCEPT will only remove the current milter from the
           list of callbacks, thus simulating a completely independent milter server.

           If FLAG is 1, SMFIS_ACCEPT will terminate the entire chain and propagate SMFIS_ACCEPT
           up to the parent chain or milter server.  This allows a milter to provide a sort of
           "whitelist" effect, where SMFIS_ACCEPT speaks for the entire chain rather than just
           one milter callback set.

           This method returns a reference to the object itself, allowing this method call to be
           chained.

       register(HASHREF)
           Registers a callback set with this chain.  Do not call after this chain has itself
           been registered with a parent container (chain or milter server).

AUTHOR

       Todd Vierling, <tv@duh.org> <tv@pobox.com>

SEE ALSO

       Mail::Milter, Sendmail::Milter