=encoding utf8

=head1 NAME

Mail::Message::Part - a part of a message, but a message by itself

=head1 INHERITANCE

 Mail::Message::Part
   is a Mail::Message
   is a Mail::Reporter

=head1 SYNOPSIS

  my Mail::Message $message = ...;
  if($message->isMultipart) {
     my Mail::Message::Part $part;

     foreach $part ($message->body->parts) {
        $part->print(\*OUT);
        my $attached_head = $part->head;
        my $attached_body = $part->body;      # encoded as read
        my $attached_body = $part->decoded;   # transfer-encoding removed
     }
  }

=head1 DESCRIPTION

A C<Mail::Message::Part> object contains a message which is included in
the body of another message.  For instance I<attachments> are I<parts>.

READ L<Mail::Message|Mail::Message> FIRST.  A part is a special message: it has a
reference to its parent message, and will usually not be sub-classed
into mail folder specific variants.

Extends L<"DESCRIPTION" in Mail::Message|Mail::Message/"DESCRIPTION">.

=head1 METHODS

Extends L<"METHODS" in Mail::Message|Mail::Message/"METHODS">.

=head2 Constructors

Extends L<"Constructors" in Mail::Message|Mail::Message/"Constructors">.

=over 4

=item $obj-E<gt>B<clone>(%options)

Inherited, see L<Mail::Message/"Constructors">

=item $class-E<gt>B<new>(%options)

Create a message part.
Improves base, see L<Mail::Reporter/"Constructors">

 -Option    --Defined in     --Default
  body        Mail::Message    undef
  body_type   Mail::Message    Mail::Message::Body::Lines
  container                    <required>
  deleted     Mail::Message    false
  field_type  Mail::Message    undef
  head        Mail::Message    <empty header>
  head_type   Mail::Message    Mail::Message::Head::Complete
  labels      Mail::Message    +{}
  messageId   Mail::Message    undef
  modified    Mail::Message    false
  trusted     Mail::Message    false

=over 2

=item body => $object

=item body_type => $class

=item container => BODY

Reference to the parental L<Mail::Message::Body|Mail::Message::Body> object where this part
is a member of.  That object may be a L<Mail::Message::Body::Multipart|Mail::Message::Body::Multipart>
or a L<Mail::Message::Body::Nested|Mail::Message::Body::Nested>.

=item deleted => BOOLEAN

=item field_type => $class

=item head => $object

=item head_type => $class

=item labels => \@pairs|\%settings

=item messageId => $id

=item modified => BOOLEAN

=item trusted => BOOLEAN

=back

=back

=head2 Attributes

Extends L<"Attributes" in Mail::Message|Mail::Message/"Attributes">.

=head2 Constructing a message

Extends L<"Constructing a message" in Mail::Message|Mail::Message/"Constructing a message">.

=over 4

=item $obj-E<gt>B<bounce>( [<$rg_object|%options>] )

Inherited, see L<Mail::Message::Construct::Bounce/"Constructing a message">

=item $class-E<gt>B<build>( [$message|$part|$body], @fields, %options )

Inherited, see L<Mail::Message::Construct::Build/"Constructing a message">

=item $class-E<gt>B<buildFromBody>($body, $container, $headers)

Shape a message part around a C<$body>.  Bodies have information about their
content in them, which is used to construct a header for the message.
Next to that, more C<$headers> can be specified.  No headers are obligatory.
No extra headers are fabricated automatically.
Improves base, see L<Mail::Message::Construct::Build/"Constructing a message">

» example: 

  my $multi = Mail::Message::Body::Multipart->new;
  my $part  = Mail::Message::Part->buildFromBody($body, $multi);

=item $obj-E<gt>B<forward>(%options)

Inherited, see L<Mail::Message::Construct::Forward/"Constructing a message">

=item $obj-E<gt>B<forwardAttach>(%options)

Inherited, see L<Mail::Message::Construct::Forward/"Constructing a message">

=item $obj-E<gt>B<forwardEncapsulate>(%options)

Inherited, see L<Mail::Message::Construct::Forward/"Constructing a message">

=item $obj-E<gt>B<forwardInline>(%options)

Inherited, see L<Mail::Message::Construct::Forward/"Constructing a message">

=item $obj-E<gt>B<forwardNo>(%options)

Inherited, see L<Mail::Message::Construct::Forward/"Constructing a message">

=item $obj-E<gt>B<forwardPostlude>()

Inherited, see L<Mail::Message::Construct::Forward/"Constructing a message">

=item $obj-E<gt>B<forwardPrelude>()

Inherited, see L<Mail::Message::Construct::Forward/"Constructing a message">

=item $obj-E<gt>B<forwardSubject>(STRING)

Inherited, see L<Mail::Message::Construct::Forward/"Constructing a message">

=item $class-E<gt>B<read>($fh|$text|\$text|\@lines, %options)

Inherited, see L<Mail::Message::Construct::Read/"Constructing a message">

=item $obj-E<gt>B<rebuild>(%options)

Inherited, see L<Mail::Message::Construct::Rebuild/"Constructing a message">

=item $obj-E<gt>B<reply>(%options)

Inherited, see L<Mail::Message::Construct::Reply/"Constructing a message">

=item $obj-E<gt>B<replyPrelude>( [STRING|$field|$address|\@addrs|\@fields] )

Inherited, see L<Mail::Message::Construct::Reply/"Constructing a message">

=item $any-E<gt>B<replySubject>(STRING)

Inherited, see L<Mail::Message::Construct::Reply/"Constructing a message">

=back

=head2 The message

Extends L<"The message" in Mail::Message|Mail::Message/"The message">.

=over 4

=item $obj-E<gt>B<container>()

Inherited, see L<Mail::Message/"The message">

=item $obj-E<gt>B<endsOnNewline>()

Inherited, see L<Mail::Message/"The message">

=item $obj-E<gt>B<isDummy>()

Inherited, see L<Mail::Message/"The message">

=item $obj-E<gt>B<isPart>()

Inherited, see L<Mail::Message/"The message">

=item $obj-E<gt>B<messageId>()

Inherited, see L<Mail::Message/"The message">

=item $obj-E<gt>B<partNumber>()

Inherited, see L<Mail::Message/"The message">

=item $obj-E<gt>B<print>( [$fh] )

Inherited, see L<Mail::Message/"The message">

=item $obj-E<gt>B<printEscapedFrom>($fh)

Prints the message part, but all lines which start with 'From ' will get
a leading E<gt>.  See L<Mail::Message::Body::printEscapedFrom()|Mail::Message::Body/"Access to the payload">.

=item $obj-E<gt>B<send>( [$mailer], %options )

Inherited, see L<Mail::Message/"The message">

=item $obj-E<gt>B<size>()

Inherited, see L<Mail::Message/"The message">

=item $obj-E<gt>B<toplevel>()

Inherited, see L<Mail::Message/"The message">

=item $obj-E<gt>B<write>( [$fh] )

Inherited, see L<Mail::Message/"The message">

=back

=head2 The header

Extends L<"The header" in Mail::Message|Mail::Message/"The header">.

=over 4

=item $obj-E<gt>B<bcc>()

Inherited, see L<Mail::Message/"The header">

=item $obj-E<gt>B<cc>()

Inherited, see L<Mail::Message/"The header">

=item $obj-E<gt>B<date>()

Inherited, see L<Mail::Message/"The header">

=item $obj-E<gt>B<destinations>()

Inherited, see L<Mail::Message/"The header">

=item $obj-E<gt>B<from>()

Inherited, see L<Mail::Message/"The header">

=item $obj-E<gt>B<get>($fieldname)

Inherited, see L<Mail::Message/"The header">

=item $obj-E<gt>B<guessTimestamp>()

Inherited, see L<Mail::Message/"The header">

=item $obj-E<gt>B<head>( [$head] )

Inherited, see L<Mail::Message/"The header">

=item $obj-E<gt>B<nrLines>()

Inherited, see L<Mail::Message/"The header">

=item $obj-E<gt>B<sender>()

Inherited, see L<Mail::Message/"The header">

=item $obj-E<gt>B<study>($fieldname)

Inherited, see L<Mail::Message/"The header">

=item $obj-E<gt>B<subject>()

Inherited, see L<Mail::Message/"The header">

=item $obj-E<gt>B<timestamp>()

Inherited, see L<Mail::Message/"The header">

=item $obj-E<gt>B<to>()

Inherited, see L<Mail::Message/"The header">

=back

=head2 The body

Extends L<"The body" in Mail::Message|Mail::Message/"The body">.

=over 4

=item $obj-E<gt>B<body>( [$body] )

Inherited, see L<Mail::Message/"The body">

=item $obj-E<gt>B<contentType>()

Inherited, see L<Mail::Message/"The body">

=item $obj-E<gt>B<decoded>(%options)

Inherited, see L<Mail::Message/"The body">

=item $obj-E<gt>B<encode>(%options)

Inherited, see L<Mail::Message/"The body">

=item $obj-E<gt>B<isMultipart>()

Inherited, see L<Mail::Message/"The body">

=item $obj-E<gt>B<isNested>()

Inherited, see L<Mail::Message/"The body">

=item $obj-E<gt>B<parts>( [<'ALL'|'ACTIVE'|'DELETED'|'RECURSE'|$filter>] )

Inherited, see L<Mail::Message/"The body">

=back

=head2 Flags

Extends L<"Flags" in Mail::Message|Mail::Message/"Flags">.

=over 4

=item $obj-E<gt>B<delete>()

Inherited, see L<Mail::Message/"Flags">

=item $obj-E<gt>B<deleted>( [BOOLEAN] )

Inherited, see L<Mail::Message/"Flags">

=item $obj-E<gt>B<isDeleted>()

Inherited, see L<Mail::Message/"Flags">

=item $obj-E<gt>B<isModified>()

Inherited, see L<Mail::Message/"Flags">

=item $obj-E<gt>B<label>($label|PAIRS)

Inherited, see L<Mail::Message/"Flags">

=item $obj-E<gt>B<labels>()

Inherited, see L<Mail::Message/"Flags">

=item $obj-E<gt>B<labelsToStatus>()

Inherited, see L<Mail::Message/"Flags">

=item $obj-E<gt>B<modified>( [BOOLEAN] )

Inherited, see L<Mail::Message/"Flags">

=item $obj-E<gt>B<statusToLabels>()

Inherited, see L<Mail::Message/"Flags">

=back

=head2 The whole message as text

Extends L<"The whole message as text" in Mail::Message|Mail::Message/"The whole message as text">.

=over 4

=item $obj-E<gt>B<file>()

Inherited, see L<Mail::Message::Construct::Text/"The whole message as text">

=item $obj-E<gt>B<lines>()

Inherited, see L<Mail::Message::Construct::Text/"The whole message as text">

=item $obj-E<gt>B<printStructure>( [$fh|undef],[$indent] )

Inherited, see L<Mail::Message::Construct::Text/"The whole message as text">

=item $obj-E<gt>B<string>()

Inherited, see L<Mail::Message::Construct::Text/"The whole message as text">

=back

=head2 Internals

Extends L<"Internals" in Mail::Message|Mail::Message/"Internals">.

=over 4

=item $obj-E<gt>B<clonedFrom>()

Inherited, see L<Mail::Message/"Internals">

=item $class-E<gt>B<coerce>( <$body|$message>, $multipart, @headers )

Transforms a C<$body> or C<$message> to a real message part.  The C<$multipart>
refers to the parental body.

When ta C<$body> is specified, extra C<@headers> can be supplied as well.
Bodies are coerced into message parts by calling L<buildFromBody()|Mail::Message::Part/"METHODS">.
If you specify a C<$message> residing in a folder, this message will
automatically be cloned.
Improves base, see L<Mail::Message/"Internals">

=item $obj-E<gt>B<isDelayed>()

Inherited, see L<Mail::Message/"Internals">

=item $obj-E<gt>B<readBody>( $parser, $head, [$bodytype] )

Inherited, see L<Mail::Message/"Internals">

=item $obj-E<gt>B<readFromParser>( $parser, [$bodytype] )

Inherited, see L<Mail::Message/"Internals">

=item $obj-E<gt>B<readHead>( $parser, [$class] )

Inherited, see L<Mail::Message/"Internals">

=item $obj-E<gt>B<recursiveRebuildPart>($part, %options)

Inherited, see L<Mail::Message::Construct::Rebuild/"Internals">

=item $obj-E<gt>B<storeBody>($body)

Inherited, see L<Mail::Message/"Internals">

=item $obj-E<gt>B<takeMessageId>( [STRING] )

Inherited, see L<Mail::Message/"Internals">

=back

=head2 Error handling

Extends L<"Error handling" in Mail::Message|Mail::Message/"Error handling">.

=over 4

=item $obj-E<gt>B<AUTOLOAD>()

Inherited, see L<Mail::Message::Construct/"METHODS">

=item $obj-E<gt>B<notImplemented>()

Inherited, see L<Mail::Reporter/"Error handling">

=item $any-E<gt>B<shortSize>( [$value] )

Inherited, see L<Mail::Message/"Error handling">

=item $obj-E<gt>B<shortString>()

Inherited, see L<Mail::Message/"Error handling">

=back

=head2 Cleanup

Extends L<"Cleanup" in Mail::Message|Mail::Message/"Cleanup">.

=over 4

=item $obj-E<gt>B<DESTROY>()

Inherited, see L<Mail::Reporter/"Cleanup">

=item $obj-E<gt>B<destruct>()

Message parts can not be destructed per part: only whole messages can
be forcefully freed from memory.  Of course, you can L<delete()|Mail::Message/"Flags"> separate
parts, which only sets a flag not to write a part again.  Furthermore,
you may cosider L<rebuild()|Mail::Message::Construct::Rebuild/"Constructing a message"> to get rit of deleted parts.
Improves base, see L<Mail::Message/"Cleanup">

=back

=head1 DETAILS

Extends L<"DETAILS" in Mail::Message|Mail::Message/"DETAILS">.

=head1 DIAGNOSTICS

=over 4

=item Error: Cannot include forward source as $kind.

Unknown alternative for the L<forward(include)|Mail::Message::Construct::Forward/"Constructing a message">.  Valid choices are
C<NO>, C<INLINE>, C<ATTACH>, and C<ENCAPSULATE>.
Cast by C<forward()>

=item Error: No default mailer found to send message.

The message L<send()|Mail::Message/"The message"> mechanism had not enough information to automatically
find a mail transfer agent to sent this message.  Specify a mailer
explicitly using the C<via> options.
Cast by C<send()>

=item Error: cannot include reply source as $kind.

Unknown alternative for the C<include> option of L<reply()|Mail::Message::Construct::Reply/"Constructing a message">.  Valid
choices are C<NO>, C<INLINE>, and C<ATTACH>.
Cast by C<reply()>

=item Error: cannot read message from a $source}.

Cast by C<read()>

=item Error: class $package does not implement method $method.

Fatal error: the specific C<$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.
Cast by C<notImplemented()>

=item Error: method bounce requires To, Cc, or Bcc.

The message L<bounce()|Mail::Message::Construct::Bounce/"Constructing a message"> method forwards a received message off to someone
else without modification; you must specified it's new destination.
If you have the urge not to specify any destination, you probably
are looking for L<reply()|Mail::Message::Construct::Reply/"Constructing a message">. When you wish to modify the content, use
L<forward()|Mail::Message::Construct::Forward/"Constructing a message">.
Cast by C<bounce()>

=item Error: method forwardAttach requires a preamble.

Cast by C<forwardAttach()>

=item Error: method forwardEncapsulate requires a preamble.

Cast by C<forwardEncapsulate()>

=item Error: method forwardNo requires a To.

Cast by C<forwardNo()>

=item Error: method forwardNo requires a body.

Cast by C<forwardNo()>

=item Error: no container specified for part.

Cast by C<new()>

=item Error: no rebuild rule $name defined.

Cast by C<rebuild()>

=item Error: only build() Mail::Message's; they are not in a folder yet.

You may wish to construct a message to be stored in a some kind
of folder, but you need to do that in two steps.  First, create a
normal L<Mail::Message|Mail::Message>, and then add it to the folder.  During this
L<Mail::Box::addMessage()|Mail::Box/"The folder"> process, the message will get L<coerce()|Mail::Message::Part/"METHODS">-d
into the right message type, adding storage information and the like.
Cast by C<build()>

=item Error: select parts via '$what'?

Cast by C<parts()>

=item Warning: skipped unknown key '$key' in build.

Cast by C<build()>

=item Error: you cannot destruct message parts, only whole messages.

Message parts can not be destructed per part: only whole messages can
be forcefully freed from memory. Consider L<delete()|Mail::Message/"Flags"> or L<rebuild()|Mail::Message::Construct::Rebuild/"Constructing a message">.
Cast by C<destruct()>

=back

=head1 SEE ALSO

This module is part of Mail-Message version 4.03,
built on January 26, 2026. Website: F<http://perl.overmeer.net/CPAN/>

=head1 LICENSE

For contributors see file ChangeLog.

This software is copyright (c) 2001-2026 by Mark Overmeer.

This is free software; you can redistribute it and/or modify it under
the same terms as the Perl 5 programming language system itself.

