Mail::Milter::Chain(3)

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