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

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

 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;

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 messsage) gets mutulated!

overload: "" See OVERLOADED in Mail::Message::Head

overload: bool See OVERLOADED in Mail::Message::Head

$obj->build([PAIR|FIELD]-LIST) See Constructors in Mail::Message::Head::Complete

$obj->clone([FIELDS]) See Constructors in Mail::Message::Head::Complete

Mail::Message::Head::Partial->new(OPTIONS) See Constructors in Mail::Message::Head

$obj->isDelayed See The header in Mail::Message::Head

$obj->isEmpty See The header in Mail::Message::Head

$obj->isModified See The header in Mail::Message::Head

$obj->knownNames See The header in Mail::Message::Head

$obj->message([MESSAGE]) See The header in Mail::Message::Head

$obj->modified([BOOLEAN]) See The header in Mail::Message::Head

$obj->nrLines See The header in Mail::Message::Head::Complete

$obj->orderedFields See The header in Mail::Message::Head

$obj->size See The header in Mail::Message::Head::Complete

$obj->wrap(INTEGER) See The header in Mail::Message::Head::Complete

$obj->add(FIELD | LINE | (NAME,BODY[,ATTRS])) See Access to the header in Mail::Message::Head::Complete

$obj->addListGroup(OBJECT) See Access to the header in Mail::Message::Head::Complete

$obj->addResentGroup(RESENT-GROUP|DATA) See Access to the header in Mail::Message::Head::Complete

$obj->addSpamGroup(OBJECT) 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) See Access to the header in Mail::Message::Head::Complete

$obj->delete(NAME) See Access to the header in Mail::Message::Head::Complete

$obj->get(NAME [,INDEX]) See Access to the header in Mail::Message::Head

$obj->grepNames([NAMES|ARRAY-OF-NAMES|REGEXS]) See Access to the header in Mail::Message::Head::Complete

$obj->listGroup See Access to the header in Mail::Message::Head::Complete

$obj->names See Access to the header in Mail::Message::Head::Complete

$obj->print([FILEHANDLE]) See Access to the header in Mail::Message::Head::Complete

$obj->printSelected(FILEHANDLE, (STRING|REGEXP)s) See Access to the header in Mail::Message::Head::Complete

$obj->printUndisclosed([FILEHANDLE]) See Access to the header in Mail::Message::Head::Complete

$obj->removeContentInfo See Access to the header in Mail::Message::Head::Complete

$obj->removeField(FIELD) See Access to the header in Mail::Message::Head::Complete

$obj->removeFields(STRING|REGEXP, [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 CWremoveFieldsExcept(). Example:

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

$obj->removeFieldsExcept(STRING|REGEXP, [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 CWremoveFields(). 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 See Access to the header in Mail::Message::Head::Complete

$obj->reset(NAME, FIELDS) See Access to the header in Mail::Message::Head::Complete

$obj->set(FIELD | LINE | (NAME, BODY [,ATTRS])) See Access to the header in Mail::Message::Head::Complete

$obj->spamDetected See Access to the header in Mail::Message::Head::Complete

$obj->spamGroups([NAMES]) See Access to the header in Mail::Message::Head::Complete

$obj->string See Access to the header in Mail::Message::Head::Complete

$obj->study(NAME [,INDEX]) See Access to the header in Mail::Message::Head

$obj->guessBodySize See About the body in Mail::Message::Head

$obj->guessTimeStamp See About the body in Mail::Message::Head::Complete

$obj->isMultipart See About the body in Mail::Message::Head

$obj->recvstamp See About the body in Mail::Message::Head::Complete

$obj->timestamp See About the body in Mail::Message::Head::Complete

$obj->addNoRealize(FIELD) See Internals in Mail::Message::Head

$obj->addOrderedFields(FIELDS) See Internals in Mail::Message::Head

$obj->createFromLine See Internals in Mail::Message::Head::Complete

$obj->createMessageId See Internals in Mail::Message::Head::Complete

$obj->fileLocation See Internals in Mail::Message::Head

$obj->load See Internals in Mail::Message::Head

$obj->messageIdPrefix([PREFIX, [HOSTNAME]|CODE])

Mail::Message::Head::Partial->messageIdPrefix([PREFIX, [HOSTNAME]|CODE]) See Internals in Mail::Message::Head::Complete

$obj->moveLocation(DISTANCE) See Internals in Mail::Message::Head

$obj->read(PARSER) See Internals in Mail::Message::Head

$obj->setNoRealize(FIELD) See Internals in Mail::Message::Head

$obj->AUTOLOAD See Error handling in Mail::Reporter

$obj->addReport(OBJECT) See Error handling in Mail::Reporter

$obj->defaultTrace([LEVEL]|[LOGLEVEL, TRACELEVEL]|[LEVEL, CALLBACK])

Mail::Message::Head::Partial->defaultTrace([LEVEL]|[LOGLEVEL, TRACELEVEL]|[LEVEL, CALLBACK]) See Error handling in Mail::Reporter

$obj->errors See Error handling in Mail::Reporter

$obj->log([LEVEL [,STRINGS]])

Mail::Message::Head::Partial->log([LEVEL [,STRINGS]]) See Error handling in Mail::Reporter

$obj->logPriority(LEVEL)

Mail::Message::Head::Partial->logPriority(LEVEL) See Error handling in Mail::Reporter

$obj->logSettings See Error handling in Mail::Reporter

$obj->notImplemented See Error handling in Mail::Reporter

$obj->report([LEVEL]) See Error handling in Mail::Reporter

$obj->reportAll([LEVEL]) See Error handling in Mail::Reporter

$obj->trace([LEVEL]) See Error handling in Mail::Reporter

$obj->warnings See Error handling in Mail::Reporter

$obj->DESTROY See Cleanup in Mail::Reporter

$obj->inGlobalDestruction See Cleanup in Mail::Reporter

Warning: Cannot remove field CW$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 CW$package does not implement CW$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.

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.

Example: see examples/reduce.pl in distribution

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

See the MailBox website at <http://perl.overmeer.net/mailbox/> for more details.

Distribution version 2.063. Written by Mark Overmeer (mark@overmeer.net). See the ChangeLog for other contributors.

Copyright (c) 2001-2003 by the author(s). All rights reserved. This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.