=encoding utf8

=head1 NAME

Mail::Message::Body::Multipart - body of a message with attachments

=head1 INHERITANCE

 Mail::Message::Body::Multipart
   is a Mail::Message::Body
   is a Mail::Reporter

   Mail::Message::Body also extends Mail::Reporter
   is a Mail::Reporter

=head1 SYNOPSIS

  See Mail::Message::Body

  if($body->isMultipart) {
     my @attachments = $body->parts;
     my $attachment3 = $body->part(2);
     my $before      = $body->preamble;
     my $after       = $body->epilogue;
     $body->part(1)->delete;
  }

=head1 DESCRIPTION

The body (content) of a message can be stored in various ways.  In this
manual-page you find the description of extra functionality you have
when a message contains attachments (parts).

The number of multipart alternatives is growing.  A full list is maintained
by IANA af L<https://www.iana.org/assignments/media-types/media-types.xhtml#multipart>

=over 4

=item * multipart/mixed

=item * multipart/alternative

=item * multipart/related

=item * multipart/report, RFC6522

=item * multipart/signed, RFC1847

=item * multipart/encrypted

=item * multipart/multilingual, RFC8255 (unused)

=back

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

=head1 OVERLOADED

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

=over 4

=item overload: B<""> stringification

Inherited, see L<Mail::Message::Body/"OVERLOADED">

=item overload: B<'=='> numerical comparison

Inherited, see L<Mail::Message::Body/"OVERLOADED">

=item overload: B<@{}> addressed as array

Inherited, see L<Mail::Message::Body/"OVERLOADED">

=item overload: B<bool> true/false

Inherited, see L<Mail::Message::Body/"OVERLOADED">

=back

=head1 METHODS

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

=head2 Constructors

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

=over 4

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

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

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

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

 -Option           --Defined in         --Default
  based_on           Mail::Message::Body  undef
  boundary                                undef
  charset            Mail::Message::Body  'PERL'
  checked            Mail::Message::Body  false
  content_id         Mail::Message::Body  undef
  data               Mail::Message::Body  undef
  description        Mail::Message::Body  undef
  disposition        Mail::Message::Body  undef
  eol                Mail::Message::Body  'NATIVE'
  epilogue                                ''
  file               Mail::Message::Body  undef
  filename           Mail::Message::Body  undef
  language           Mail::Message::Body  undef
  message            Mail::Message::Body  undef
  mime_type          Mail::Message::Body  'multipart/mixed'
  modified           Mail::Message::Body  false
  parts                                   undef
  preamble                                undef
  transfer_encoding  Mail::Message::Body  'none'

=over 2

=item based_on => $body

=item boundary => $separator

The C<$separator> string to be used between parts of the message.
This separator must be unique in case the message contains nested
multiparts (which are not unusual).  If C<undef>, a nice unique boundary
will be generated.

=item charset => $charset|'PERL'|<undef>

=item checked => BOOLEAN

=item content_id => STRING

=item data => \@lines|$text

=item description => STRING|$field

=item disposition => STRING|$field

=item eol => 'CR'|'LF'|'CRLF'|'NATIVE'

=item epilogue => $body|$text

The text which is included in the main body after the final boundary.  This
is usually empty, and has no meaning.

Provide a C<$body> object or plain C<$text> (which will automatically translated
into a C<text/plain> body).

=item file => $file|$handle|$io

=item filename => $file

=item language => STRING|\@lang|$field

=item message => $message

=item mime_type => STRING|$field|$mime

=item modified => BOOLEAN

=item parts => [$message, $body, ...]

Specifies an initial list of parts in this body.  These may be full
C<$message> objects, or C<$body> objects which will be transformed into messages
before use.  Each message is coerced into a L<Mail::Message::Part|Mail::Message::Part> object.

MIME::Entity and L<Mail::Internet|Mail::Internet> objects are acceptable in the
list, because they are coercible into L<Mail::Message::Part|Mail::Message::Part>'s.  Values
of C<undef> will be skipped silently.

=item preamble => $body|$text

The C<$text> which is included in the body before the first part.  It is
common use to include a text to warn the user that the message is a
multipart.  However, this was useful in earlier days: most mail
agents are very capable in warning the user themselves.

Provide a C<$body> object or plain C<$text> (which will automatically translated
into a C<text/plain> body).

=item transfer_encoding => STRING|$field

=back

» example: 

  my $intro = Mail::Message::Body->new(data => ['part one']);
  my $pgp   = Mail::Message::Body->new(data => ['part three']);

  my $body  = Mail::Message::Body::Multipart->new(
    boundary => time . '--it-s-mine',
    preamble => "This is a multi-part message in MIME format.\n\n",
    parts    => [ $intro, $folder->message(3)->decoded, $pgp ],
  );

=back

=head2 Attributes

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

=over 4

=item $obj-E<gt>B<charsetDetectAlgorithm>( [CODE|undef|METHOD] )

Inherited, see L<Mail::Message::Body::Encode/"Attributes">

=back

=head2 Constructing a body

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

=over 4

=item $obj-E<gt>B<attach>($messages|$bodies)

Attach a list of C<$messages> to this multipart.  A new body is returned.
When you specify C<$bodies>, they will first be translated into
real messages.  MIME::Entity and L<Mail::Internet|Mail::Internet> objects may be
specified too.  In any case, the parts will be coerced into
L<Mail::Message::Part|Mail::Message::Part>'s.
Improves base, see L<Mail::Message::Body::Construct/"Constructing a body">

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

Inherited, see L<Mail::Message::Body::Encode/"Constructing a body">

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

Inherited, see L<Mail::Message::Body::Encode/"Constructing a body">

=item $obj-E<gt>B<concatenate>(@components)

Inherited, see L<Mail::Message::Body::Construct/"Constructing a body">

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

Inherited, see L<Mail::Message::Body/"Constructing a body">

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

Inherited, see L<Mail::Message::Body::Encode/"Constructing a body">

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

Inherited, see L<Mail::Message::Body::Encode/"Constructing a body">

=item $obj-E<gt>B<eol>( ['CR'|'LF'|'CRLF'|'NATIVE'] )

Inherited, see L<Mail::Message::Body::Encode/"Constructing a body">

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

Execute the C<CODE> for each component of the message: the preamble, the
epilogue, and each of the parts.

Each component is a body and is passed as second argument to the C<CODE>.
The first argument is a reference to this multi-parted body.  The C<CODE>
returns a body object.  When any of the returned bodies differs from
the body which was passed, then a new multi-part body will be returned.
Reference to the not-changed bodies and the changed bodies will be
included in that new multi-part.

» example: 

  my $checked = $multi->foreachComponent(sub {$_[1]->check});

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

It is NOT possible to call some code for each line of a multipart,
because that would not only inflict damage to the body of each
message part, but also to the headers and the part separators.
Improves base, see L<Mail::Message::Body::Construct/"Constructing a body">

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

Removes all parts which contains data usually defined as being signature.
The L<MIME::Type|MIME::Type> module provides this knowledge.  A new multipart is
returned, containing the remaining parts.  No C<%options> are defined yet,
although some may be specified, because this method overrules the
C<stripSignature> method for normal bodies.
Improves base, see L<Mail::Message::Body::Construct/"Constructing a body">

 -Option     --Defined in                    --Default
  max_lines    Mail::Message::Body::Construct  10
  pattern      Mail::Message::Body::Construct  qr/^--\s?$/
  result_type  Mail::Message::Body::Construct  <same as current>

=over 2

=item max_lines => INTEGER|undef

=item pattern => REGEX|STRING|CODE

=item result_type => CLASS

=back

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

Inherited, see L<Mail::Message::Body::Encode/"Constructing a body">

=back

=head2 The body

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

=over 4

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

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

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

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

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

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

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

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

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

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

=back

=head2 About the payload

Extends L<"About the payload" in Mail::Message::Body|Mail::Message::Body/"About the payload">.

=over 4

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

Inherited, see L<Mail::Message::Body/"About the payload">

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

Inherited, see L<Mail::Message::Body/"About the payload">

=item $obj-E<gt>B<contentId>( [STRING|$field] )

Inherited, see L<Mail::Message::Body/"About the payload">

=item $obj-E<gt>B<description>( [STRING|$field] )

Inherited, see L<Mail::Message::Body/"About the payload">

=item $obj-E<gt>B<disposition>( [STRING|$field] )

Inherited, see L<Mail::Message::Body/"About the payload">

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

Inherited, see L<Mail::Message::Body::Encode/"About the payload">

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

Inherited, see L<Mail::Message::Body::Encode/"About the payload">

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

Inherited, see L<Mail::Message::Body::Encode/"About the payload">

=item $obj-E<gt>B<language>( [@langs|\@langs|$langs|$field] )

Inherited, see L<Mail::Message::Body/"About the payload">

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

Inherited, see L<Mail::Message::Body/"About the payload">

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

Inherited, see L<Mail::Message::Body/"About the payload">

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

Inherited, see L<Mail::Message::Body/"About the payload">

=item $obj-E<gt>B<transferEncoding>( [STRING|$field] )

Inherited, see L<Mail::Message::Body/"About the payload">

=item $obj-E<gt>B<type>( [STRING|$field] )

Inherited, see L<Mail::Message::Body/"About the payload">

=back

=head2 Access to the payload

Extends L<"Access to the payload" in Mail::Message::Body|Mail::Message::Body/"Access to the payload">.

=over 4

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

Returns the boundary which is used to separate the parts in this
body.  If none was read from file, then one will be assigned.  With
C<STRING> you explicitly set the boundary to be used.

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

Inherited, see L<Mail::Message::Body/"Access to the payload">

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

Returns the epilogue; the text after the last message part (after the
last real attachment).
The epilogue is stored in a BODY object, and its encoding is taken
from the general multipart header.

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

Inherited, see L<Mail::Message::Body/"Access to the payload">

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

Inherited, see L<Mail::Message::Body/"Access to the payload">

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

Returns only the part with the specified C<$index>.  You may use a negative
value here, which counts from the back in the list.  Parts which are
flagged to be deleted are included in the count.

» example: 

  $message->body->part(2)->print;
  $body->part(1)->delete;

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

Return all parts by default, or when C<ALL> is specified.  C<ACTIVE> returns
the parts which are not flagged for deletion, as opposite to C<DELETED>.
C<RECURSE> descents into all nested multiparts to collect all parts.

You may also specify a code reference which is called for each nested
part.  The first argument will be the message part.  When the code
returns C<true>, the part is incorporated in the return list.

» example: 

  print "Number of attachments: ",
     scalar $message->body->parts('ACTIVE');

  foreach my $part ($message->body->parts) {
     print "Type: ", $part->get('Content-Type');
  }

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

Returns the preamble; the text before the first message part (before the
first real attachment).
The preamble is stored in a BODY object, and its encoding is taken
from the multipart header.

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

Inherited, see L<Mail::Message::Body/"Access to the payload">

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

Inherited, see L<Mail::Message::Body/"Access to the payload">

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

Inherited, see L<Mail::Message::Body/"Access to the payload">

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

Inherited, see L<Mail::Message::Body/"Access to the payload">

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

Inherited, see L<Mail::Message::Body/"Access to the payload">

=back

=head2 Internals

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

=over 4

=item $any-E<gt>B<addTransferEncHandler>( $name, <$class|$object> )

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

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

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

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

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

=item $obj-E<gt>B<fileLocation>( [$begin, $end] )

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

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

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

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

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

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

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

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

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

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

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

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

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

=back

=head2 Error handling

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

=over 4

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

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

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

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

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

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

=back

=head2 Cleanup

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

=over 4

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

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

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

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

=back

=head1 DETAILS

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

=head1 DIAGNOSTICS

=over 4

=item Warning: Content-Transfer-Encoding '$te' requires explicit charset, defaulted to utf-8.

Cast by C<encode()>

=item Error: You cannot use foreachLine on a multipart.

L<foreachLine()|Mail::Message::Body::Multipart/"METHODS"> should be used on decoded message bodies only, because
it would attempt to modify part-headers and separators as well, which is
clearly not acceptable.
Cast by C<foreachLine()>

=item Error: cannot concatenate element $which

Cast by C<concatenate()>

=item Fault: cannot open $file to write body: $!

Cast by C<write()>

=item Warning: charset '$name' is not known.

The encoding or decoding of a message body encounters a character set which
is not understood by Perl's Encode module.
Cast by C<encode()>

=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: 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: data not convertible to a message (type is $type)

An object which is not coercable into a L<Mail::Message::Part|Mail::Message::Part> object was
passed to the initiation.
Cast by C<new()>

=item Fault: error closing $file after write body: $!

Cast by C<write()>

=item Warning: no decoder defined for transfer encoding '$encoding'.

The data (message body) is encoded in a way which is not currently understood,
therefore no decoding (or recoding) can take place.
Cast by C<encode()>

=item Warning: no encoder defined for transfer encoding '$encoding'.

The data (message body) has been decoded, but the required encoding is
unknown.  The decoded data is returned.
Cast by C<encode()>

=item Error: no filename parameter for write() body.

Cast by C<write()>

=item Error: part number needs multi-part or nested.

Cast by C<partNumberOf()>

=item Error: unknown criterium $what to select parts.

Valid choices for part selections are C<ALL>, C<ACTIVE>, C<DELETED>,
C<RECURSE> or a code reference.  However, some other argument was passed.
Cast by C<parts()>

=item Error: unknown line terminator '$eol'.

Cast by C<eol()>

=back

=head1 SEE ALSO

This module is part of Mail-Message version 4.01,
built on December 13, 2025. Website: F<http://perl.overmeer.net/CPAN/>

=head1 LICENSE

For contributors see file ChangeLog.

This software is copyright (c) 2001-2025 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.