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.IX Title "Mail::DKIM::SignerPolicy 3pm"
.TH Mail::DKIM::SignerPolicy 3pm 2024-01-28 "perl v5.38.2" "User Contributed Perl Documentation"
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.SH NAME
Mail::DKIM::SignerPolicy \- determines signing parameters for a message
.SH VERSION
.IX Header "VERSION"
version 1.20240124
.SH DESCRIPTION
.IX Header "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 \fBapply()\fR method.
.PP
The \fBapply()\fR 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 \fBapply()\fR 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).
.PP
Here is an example of a policy that always returns the same values:
.PP
.Vb 2
\&  package MySignerPolicy;
\&  use base \*(AqMail::DKIM::SignerPolicy\*(Aq;
\&
\&  sub apply
\&  {
\&      my $self = shift;
\&      my $signer = shift;
\&  
\&      $signer\->algorithm(\*(Aqrsa\-sha1\*(Aq);
\&      $signer\->method(\*(Aqrelaxed\*(Aq);
\&      $signer\->domain(\*(Aqexample.org\*(Aq);
\&      $signer\->selector(\*(Aqselector1\*(Aq);
\&      $signer\->key_file(\*(Aqprivate.key\*(Aq);
\&  
\&      return 1;
\&  }
.Ve
.PP
To use this policy, simply specify the name of the class as the Policy
parameter...
.PP
.Vb 3
\&  my $dkim = Mail::DKIM::Signer\->new(
\&                  Policy => \*(AqMySignerPolicy\*(Aq,
\&             );
.Ve
.SH ADVANCED
.IX Header "ADVANCED"
You can also have the policy actually build the signature for the Signer
to use. To do this, call the signer's \fBadd_signature()\fR method from within
your \fBapply()\fR callback. E.g.,
.PP
.Vb 4
\&  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;
\&  }
.Ve
.PP
Again, if you do not want any signatures, return zero or undef. If you
use \fBadd_signature()\fR to create a signature, the default signature will
not be created, even if you return nonzero.
.SH AUTHORS
.IX Header "AUTHORS"
.IP \(bu 4
Jason Long <jason@long.name>
.IP \(bu 4
Marc Bradshaw <marc@marcbradshaw.net>
.IP \(bu 4
Bron Gondwana <brong@fastmailteam.com> (ARC)
.SH THANKS
.IX Header "THANKS"
Work on ensuring that this module passes the ARC test suite was
generously sponsored by Valimail (https://www.valimail.com/)
.SH "COPYRIGHT AND LICENSE"
.IX Header "COPYRIGHT AND LICENSE"
.IP \(bu 4
Copyright (C) 2013 by Messiah College
.IP \(bu 4
Copyright (C) 2010 by Jason Long
.IP \(bu 4
Copyright (C) 2017 by Standcore LLC
.IP \(bu 4
Copyright (C) 2020 by FastMail Pty Ltd
.PP
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.