Provided by: libmail-message-perl_3.006-1_all bug

NAME

       Mail::Message::Head::Partial - subset of header information of a message

INHERITANCE

        Mail::Message::Head::Partial
          is a Mail::Message::Head::Complete
          is a Mail::Message::Head
          is a Mail::Reporter

SYNOPSIS

        my $partial = $head->strip;
        $partial->isa('Mail::Message::Head')  # true
        $partial->isDelayed                      # false
        $partial->isPartial                      # true

        $partial->removeFields( qr/^X-/ );
        $partial->removeFieldsExcept( qw/To From/ );
        $partial->removeResentGroups;
        $partial->removeListGroup;
        $partial->removeSpamGroups;

DESCRIPTION

       Header information consumes a considerable amount of memory.  Most of this information is
       only useful during a short period of time in your program, or sometimes it is not used at
       all.  You then can decide to remove most of the header information.  However, be warned
       that it will be lost permanently: the header (and therefore the message) gets mutulated!

       Extends "DESCRIPTION" in Mail::Message::Head::Complete.

OVERLOADED

       Extends "OVERLOADED" in Mail::Message::Head::Complete.

       overload: ""
           Inherited, see "OVERLOADED" in Mail::Message::Head

       overload: bool
           Inherited, see "OVERLOADED" in Mail::Message::Head

METHODS

       Extends "METHODS" in Mail::Message::Head::Complete.

   Constructors
       Extends "Constructors" in Mail::Message::Head::Complete.

       Mail::Message::Head::Partial->build( [PAIR|$field], ... )
           Inherited, see "Constructors" in Mail::Message::Head::Complete

       $obj->clone( [@names|ARRAY|Regexps] )
           Inherited, see "Constructors" in Mail::Message::Head::Complete

       Mail::Message::Head::Partial->new(%options)
           Inherited, see "Constructors" in Mail::Message::Head

   The header
       Extends "The header" in Mail::Message::Head::Complete.

       $obj->isDelayed()
           Inherited, see "The header" in Mail::Message::Head

       $obj->isEmpty()
           Inherited, see "The header" in Mail::Message::Head

       $obj->isModified()
           Inherited, see "The header" in Mail::Message::Head

       $obj->knownNames()
           Inherited, see "The header" in Mail::Message::Head

       $obj->message( [$message] )
           Inherited, see "The header" in Mail::Message::Head

       $obj->modified( [BOOLEAN] )
           Inherited, see "The header" in Mail::Message::Head

       $obj->nrLines()
           Inherited, see "The header" in Mail::Message::Head::Complete

       $obj->orderedFields()
           Inherited, see "The header" in Mail::Message::Head

       $obj->size()
           Inherited, see "The header" in Mail::Message::Head::Complete

       $obj->wrap($integer)
           Inherited, see "The header" in Mail::Message::Head::Complete

   Access to the header
       Extends "Access to the header" in Mail::Message::Head::Complete.

       $obj->add( $field | $line | <$name, $body, [$attrs]> )
           Inherited, see "Access to the header" in Mail::Message::Head::Complete

       $obj->addListGroup($object)
           Inherited, see "Access to the header" in Mail::Message::Head::Complete

       $obj->addResentGroup($resent_group|$data)
           Inherited, see "Access to the header" in Mail::Message::Head::Complete

       $obj->addSpamGroup($object)
           Inherited, see "Access to the header" in Mail::Message::Head::Complete

       $obj->cleanupOrderedFields()
           The header maintains a list of fields which are ordered in sequence of definition.  It
           is required to maintain the header order to keep the related fields of resent groups
           together.  The fields are also included in a hash, sorted on their name for fast
           access.

           The references to field objects in the hash are real, those in the ordered list are
           weak.  So when field objects are removed from the hash, their references in the
           ordered list are automagically undef'd.

           When many fields are removed, for instance with removeFields() or
           removeFieldsExcept(), then it is useful to remove the list of undefs from the ordered
           list as well.  In those cases, this method is called automatically, however you may
           have your own reasons to call this method.

       $obj->count($name)
           Inherited, see "Access to the header" in Mail::Message::Head::Complete

       $obj->delete($name)
           Inherited, see "Access to the header" in Mail::Message::Head::Complete

       $obj->get( $name, [$index] )
           Inherited, see "Access to the header" in Mail::Message::Head

       $obj->grepNames( [@names|ARRAY|Regexps] )
           Inherited, see "Access to the header" in Mail::Message::Head::Complete

       $obj->listGroup()
           Inherited, see "Access to the header" in Mail::Message::Head::Complete

       $obj->names()
           Inherited, see "Access to the header" in Mail::Message::Head::Complete

       $obj->print( [$fh] )
           Inherited, see "Access to the header" in Mail::Message::Head::Complete

       $obj->printSelected($fh, <STRING|Regexp>, ...)
           Inherited, see "Access to the header" in Mail::Message::Head::Complete

       $obj->printUndisclosed( [$fh] )
           Inherited, see "Access to the header" in Mail::Message::Head::Complete

       $obj->removeContentInfo()
           Inherited, see "Access to the header" in Mail::Message::Head::Complete

       $obj->removeField($field)
           Inherited, see "Access to the header" in Mail::Message::Head::Complete

       $obj->removeFields( <STRING|Regexp>, ... )
           Remove the fields from the header which are exactly named 'STRING' (case insensitive)
           or match the regular expresssion.  Do not forget to add the 'i' modifier to the
           regexp, because fields are case insensitive.

           See also removeField() which is used to remove one field object from the header.  The
           reverse specification can be made with "removeFieldsExcept()".

           example:

            $head->removeFields('bcc', 'received');
            $head->removeFields( qr/^content-/i );

       $obj->removeFieldsExcept(STRING|Regexp, ...)
           Remove all fields from the header which are not equivalent to one of the specified
           STRINGs (case-insensitive) and which are not matching one of the REGular EXPressions.
           Do not forget to add the 'i' modifier to the Regexp, because fields are case
           insensitive.

           See also removeField() which is used to remove one field object from the header.  The
           reverse specification can be made with "removeFields()".

           example:

            $head->removeFieldsExcept('subject', qr/^content-/i );
            $head->removeFieldsExcept( qw/subject to from sender cc/ );

       $obj->removeListGroup()
           Removes all header lines which are used to administer mailing lists.  Which fields
           that are is explained in Mail::Message::Head::ListGroup.  Returned is the number of
           removed lines.

       $obj->removeResentGroups()
           Removes all header lines which are member of a resent group, which are explained in
           Mail::Message::Head::ResentGroup.  Returned is the number of removed lines.

           For removing single groups (for instance because you want to keep the last), use
           Mail::Message::Head::FieldGroup::delete().

       $obj->removeSpamGroups()
           Removes all header lines which were produced by spam detection and spam-fighting
           software.  Which fields that are is explained in Mail::Message::Head::SpamGroup.
           Returned is the number of removed lines.

       $obj->resentGroups()
           Inherited, see "Access to the header" in Mail::Message::Head::Complete

       $obj->reset($name, @fields)
           Inherited, see "Access to the header" in Mail::Message::Head::Complete

       $obj->set( $field | $line | <$name, $body, [$attrs]> )
           Inherited, see "Access to the header" in Mail::Message::Head::Complete

       $obj->spamDetected()
           Inherited, see "Access to the header" in Mail::Message::Head::Complete

       $obj->spamGroups( [$names] )
           Inherited, see "Access to the header" in Mail::Message::Head::Complete

       $obj->string()
           Inherited, see "Access to the header" in Mail::Message::Head::Complete

       $obj->study( $name, [$index] )
           Inherited, see "Access to the header" in Mail::Message::Head

   About the body
       Extends "About the body" in Mail::Message::Head::Complete.

       $obj->guessBodySize()
           Inherited, see "About the body" in Mail::Message::Head

       $obj->guessTimeStamp()
           Inherited, see "About the body" in Mail::Message::Head::Complete

       $obj->isMultipart()
           Inherited, see "About the body" in Mail::Message::Head

       $obj->recvstamp()
           Inherited, see "About the body" in Mail::Message::Head::Complete

       $obj->timestamp()
           Inherited, see "About the body" in Mail::Message::Head::Complete

   Internals
       Extends "Internals" in Mail::Message::Head::Complete.

       $obj->addNoRealize($field)
           Inherited, see "Internals" in Mail::Message::Head

       $obj->addOrderedFields($fields)
           Inherited, see "Internals" in Mail::Message::Head

       $obj->createFromLine()
           Inherited, see "Internals" in Mail::Message::Head::Complete

       $obj->createMessageId()
           Inherited, see "Internals" in Mail::Message::Head::Complete

       $obj->fileLocation()
           Inherited, see "Internals" in Mail::Message::Head

       $obj->load()
           Inherited, see "Internals" in Mail::Message::Head

       $obj->messageIdPrefix( [$prefix, [$hostname]|CODE] )
       Mail::Message::Head::Partial->messageIdPrefix( [$prefix, [$hostname]|CODE] )
           Inherited, see "Internals" in Mail::Message::Head::Complete

       $obj->moveLocation($distance)
           Inherited, see "Internals" in Mail::Message::Head

       $obj->read($parser)
           Inherited, see "Internals" in Mail::Message::Head

       $obj->setNoRealize($field)
           Inherited, see "Internals" in Mail::Message::Head

   Error handling
       Extends "Error handling" in Mail::Message::Head::Complete.

       $obj->AUTOLOAD()
           Inherited, see "Error handling" in Mail::Reporter

       $obj->addReport($object)
           Inherited, see "Error handling" in Mail::Reporter

       $obj->defaultTrace( [$level]|[$loglevel, $tracelevel]|[$level, $callback] )
       Mail::Message::Head::Partial->defaultTrace( [$level]|[$loglevel, $tracelevel]|[$level,
       $callback] )
           Inherited, see "Error handling" in Mail::Reporter

       $obj->errors()
           Inherited, see "Error handling" in Mail::Reporter

       $obj->log( [$level, [$strings]] )
       Mail::Message::Head::Partial->log( [$level, [$strings]] )
           Inherited, see "Error handling" in Mail::Reporter

       $obj->logPriority($level)
       Mail::Message::Head::Partial->logPriority($level)
           Inherited, see "Error handling" in Mail::Reporter

       $obj->logSettings()
           Inherited, see "Error handling" in Mail::Reporter

       $obj->notImplemented()
           Inherited, see "Error handling" in Mail::Reporter

       $obj->report( [$level] )
           Inherited, see "Error handling" in Mail::Reporter

       $obj->reportAll( [$level] )
           Inherited, see "Error handling" in Mail::Reporter

       $obj->trace( [$level] )
           Inherited, see "Error handling" in Mail::Reporter

       $obj->warnings()
           Inherited, see "Error handling" in Mail::Reporter

   Cleanup
       Extends "Cleanup" in Mail::Message::Head::Complete.

       $obj->DESTROY()
           Inherited, see "Cleanup" in Mail::Reporter

DETAILS

       Extends "DETAILS" in Mail::Message::Head::Complete.

   Ordered header fields
       Extends "Ordered header fields" in Mail::Message::Head::Complete.

   Head class implementation
       Extends "Head class implementation" in Mail::Message::Head::Complete.

   Subsets of header fields
       Extends "Subsets of header fields" in Mail::Message::Head::Complete.

   Reducing the header size
       A message header is very large in memory and quite large on disk, and therefore a good
       candidate for size reduction.  One way to reduce the size is by simply eliminating
       superfluous header fields.  Each field requires at least 100 bytes of run-time memory, so
       this may help!

       Before you start playing around with removeFields() and removeFieldsExcept(), you may take
       a look at two large groups of fields which can be removes as sets: the resent headers and
       the mailinglist headers.

       Resent headers describe the intermediate steps in the transmission process for the
       messages.  After successful delivery, they are rarely useful.

       When you are archiving a mailinglist, it is hardly ever useful to store a the list
       administration lines for each message as well.

       . see examples/reduce.pl in distribution

        foreach my $msg ($folder->messages)
        {  $msg->head->removeResentGroups;
           $msg->head->removeResentList;
        }

DIAGNOSTICS

       Warning: Cannot remove field $name from header: not found.
           You ask to remove a field which is not known in the header.  Using delete(), reset(),
           or set() to do the job will not result in warnings: those methods check the existence
           of the field first.

       Warning: Field objects have an implied name ($name)
       Error: Package $package does not implement $method.
           Fatal error: the specific package (or one of its superclasses) does not implement this
           method where it should. This message means that some other related classes do
           implement this method however the class at hand does not.  Probably you should
           investigate this and probably inform the author of the package.

SEE ALSO

       This module is part of Mail-Message distribution version 3.006, built on January 24, 2018.
       Website: http://perl.overmeer.net/CPAN/

LICENSE

       Copyrights 2001-2018 by [Mark Overmeer]. For other contributors see ChangeLog.

       This program is free software; you can redistribute it and/or modify it under the same
       terms as Perl itself.  See http://dev.perl.org/licenses/