NAME

       Courier::Filter::Module::Header - Message header filter module for the Courier::Filter
       framework

SYNOPSIS

           use Courier::Filter::Module::Header;

           my $module = Courier::Filter::Module::Header->new(
               fields      => \%patterns_by_field_name,
               response    => $response_text,

               logger      => $logger,
               inverse     => 0,
               trusting    => 0,
               testing     => 0,
               debugging   => 0
           );

           my $filter = Courier::Filter->new(
               ...
               modules     => [ $module ],
               ...
           );

DESCRIPTION

       This class is a filter module class for use with Courier::Filter.  It matches a message if
       one of the message's header fields matches the configured criteria.

   Constructor
       The following constructor is provided:

       new(%options): returns Courier::Filter::Module::Header
           Creates a new Header filter module.

           %options is a list of key/value pairs representing any of the following options:

           fields
               Required.  A reference to a hash containing the message header field names and
               patterns (as key/value pairs) that messages are to be matched against.  Field
               names are matched case-insensitively.  Patterns may either be simple strings (for
               exact, case-sensitive matches) or regular expression objects created by the "qr//"
               operator (for inexact, partial matches).

               So for instance, to match any message from the "debian-devel" mailing list with
               the subject containing something about 'duelling banjoes', you could set the
               "fields" option as follows:

                   fields      => {
                      'list-id'    => '<debian-devel.lists.debian.org>',
                       subject     => qr/duell?ing\s+banjoe?s?/i
                   }

           response
               A string that is to be returned literally as the match result in case of a match.
               Defaults to "Prohibited header value detected: <field>: <value>".

           All options of the Courier::Filter::Module constructor are also supported.  Please see
           "new()" in Courier::Filter::Module for their descriptions.

   Instance methods
       See "Instance methods" in Courier::Filter::Module for a description of the provided
       instance methods.

SEE ALSO

       Courier::Filter::Module::Envelope, Courier::Filter::Module, Courier::Filter::Overview.

       For AVAILABILITY, SUPPORT, and LICENSE information, see Courier::Filter::Overview.

AUTHOR

       Julian Mehnle <julian@mehnle.net>