NAME
Mail::DKIM::SignerPolicy - determines signing parameters for a message
VERSION
version 1.20240827
DESCRIPTION
A "signer policy" is an object, class, or function used by Mail::DKIM::Signer to determine what signatures to add to the current message. To take advantage of signer policies, create your own Perl class that extends the Mail::DKIM::SignerPolicy class. The only method you need to implement is the apply() method.
The apply() method takes as a parameter the Mail::DKIM::Signer object. Using this object, it can determine some properties of the message (e.g. what the From: address or Sender: address is). Then it sets various signer properties as desired. The apply() method should return a nonzero value if the message should be signed. If a false value is returned, then the message is "skipped" (i.e. not signed).
Here is an example of a policy that always returns the same values:
package MySignerPolicy;
use base 'Mail::DKIM::SignerPolicy';
sub apply
{
my $self = shift;
my $signer = shift;
$signer->algorithm('rsa-sha1');
$signer->method('relaxed');
$signer->domain('example.org');
$signer->selector('selector1');
$signer->key_file('private.key');
return 1;
}
To use this policy, simply specify the name of the class as the Policy parameter...
my $dkim = Mail::DKIM::Signer->new(
Policy => 'MySignerPolicy',
);
ADVANCED
You can also have the policy actually build the signature for the Signer to use. To do this, call the signer's add_signature() method from within your apply() callback. E.g.,
sub apply
{
my $self = shift;
my $signer = shift;
$signer->add_signature(
new Mail::DKIM::Signature(
Algorithm => $signer->algorithm,
Method => $signer->method,
Headers => $signer->headers,
Domain => $signer->domain,
Selector => $signer->selector,
));
return;
}
Again, if you do not want any signatures, return zero or undef. If you use add_signature() to create a signature, the default signature will not be created, even if you return nonzero.
AUTHORS
Jason Long <jason@long.name>
Marc Bradshaw <marc@marcbradshaw.net>
Bron Gondwana <brong@fastmailteam.com> (ARC)
THANKS
Work on ensuring that this module passes the ARC test suite was generously sponsored by Valimail (https://www.valimail.com/)
COPYRIGHT AND LICENSE
Copyright (C) 2013 by Messiah College
Copyright (C) 2010 by Jason Long
Copyright (C) 2017 by Standcore LLC
Copyright (C) 2020 by FastMail Pty Ltd
This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself, either Perl version 5.8.6 or, at your option, any later version of Perl 5 you may have available.