
=head1 NAME


Mail::Message - general message object

=head1 CLASS INHERITANCE

Mail::Message
  has extra code in Mail::Message::Construct

Mail::Message
   is a Mail::Reporter

Mail::Message is extended by
   Mail::Box::Message
   Mail::Message::Dummy
   Mail::Message::Part

=head1 SYNOPSIS


 use Mail::Box::Manager;
 my $mgr    = Mail::Box::Manager->new;
 my $folder = $mgr->open(folder => $MAIL);
 my $msg    = $folder->message(2);    # $msg isa Mail::Message

 $msg->decoded->print($outfile);

 my Mail::Message $construct  = Mail::Message->new;
 my Mail::Message $construct  = Mail::Message->build(...);
 my Mail::Message::Head $head = $msg->head;
 my Mail::Message::Body $body = $msg->decoded;
 my $subject = $msg->get('subject');

=head1 DESCRIPTION


A Mail::Message object is a container for message information read from a
file.  Everything what is not folder related will be found here.

Complex message handling (like construction of replies) are handled by the
Mail::Message::Construct package which is autoloaded.  That package
adds functionality to the Mail::Message objects.

The main methods are get() (to get information from a message
header) and decoded() to get the intended content of a message.

=head1 METHODS

=head2 Initiation

=over 4

=item B<new> OPTIONS X<new>

 OPTION               DEFAULT
 body                 undef
 body_type            'Mail::Message::Body::Lines'
 field_type           undef
 head                 undef
 head_type            'Mail::Message::Head::Complete'
 head_wrap            72
 log                  'WARNINGS'
 messageId            undef
 modified             <false>
 trace                'WARNINGS'
 trusted              <false>

=over 4

=item B<body> =E<gt> OBJECT X<new(body)>

Instantiate the message with a body which has been created somewhere
before the message is constructed.  The OBJECT must be a sub-class
of Mail::Message::Body.

=item B<body_type> =E<gt> CLASS X<new(body_type)>

Default type of body to be created for readBody().

=item B<field_type> =E<gt> CLASS X<new(field_type)>

=item B<head> =E<gt> OBJECT X<new(head)>

Instantiate the message with a head which has been created somewhere
before the message is constructed.  The OBJECT must be a (sub-)class
of Mail::Message::Head.

=item B<head_type> =E<gt> CLASS X<new(head_type)>

Default type of head to be created for readHead().

=item B<head_wrap> =E<gt> INTEGER X<new(head_wrap)>

The soft maximum line width of header lines in the folder to write.

=item B<log> =E<gt> LEVEL

See Mail::Reporter::new(log)

=item B<messageId> =E<gt> STRING X<new(messageId)>

The id on which this message can be recognized.  If none specified and
not defined in the header --but one is needed-- there will be one assigned
to the message to be able to pass unique message-ids between objects.

=item B<modified> =E<gt> BOOLEAN X<new(modified)>

Flags this message as being modified, from the beginning on.  Usually,
modification is auto-detected, but there may be reasons to be extra
explicit.

=item B<trace> =E<gt> LEVEL

See Mail::Reporter::new(trace)

=item B<trusted> =E<gt> BOOLEAN X<new(trusted)>

Is this message from a trusted source?  If not, the content must be
checked before use.

=back

=back

=head2 Constructing a Message

=over 4

=item B<bounce> OPTIONS

See Mail::Message::Construct::bounce()

=item B<build> [MESSAGE|BODY], CONTENT

See Mail::Message::Construct::build()

=item B<buildFromBody> BODY, HEADERS

See Mail::Message::Construct::buildFromBody()

=item B<coerce> MESSAGE X<coerce>

(Class method) Coerce a MESSAGE into a Mail::Message.  In some
occasions, for instance where you add a message to a folder, this
coercion is automatically called to ensure that the correct message
type is stored.

The coerced message is returned on success, otherwise C<undef>.  The
coerced message may be a reblessed version of the original message
or a new object.

Valid MESSAGEs which can be coerced into Mail::Message objects
are of type

=over 4

=item * C<MIME::Entity>'s, using Mail::Message::Convert::MimeEntity

=item * C<Mail::Internet>'s, using Mail::Message::Convert::MimeEntity

=item * any extension of Mail::Message is left untouched

=back

Examples:

 my $message = Mail::Message->new(...);
 my $coerced = Mail::Box::Mbox::Message->coerce($message);
 # now $coerced is a Mail::Box::Mbox::Message

It is better to use (when the message will be stored in that folder):

 my $folder  = Mail::Box::Mbox->new;
 my $coerced = $folder->coerce($message);
 my $coerced = $folder->addMessage($message);

=item B<forward> OPTIONS

See Mail::Message::Construct::forward()

=item B<forwardPostlude> 

See Mail::Message::Construct::forwardPostlude()

=item B<forwardPrelude> 

See Mail::Message::Construct::forwardPrelude()

=item B<forwardSubject> STRING

See Mail::Message::Construct::forwardSubject()

=item B<read> FILEHANDLE|SCALAR|REF-SCALAR|ARRAY-OF-LINES, OPTIONS

See Mail::Message::Construct::read()

=item B<reply> OPTIONS

See Mail::Message::Construct::reply()

=item B<replyPrelude> [STRING|FIELD|ADDRESS]

See Mail::Message::Construct::replyPrelude()

=item B<replySubject> STRING

See Mail::Message::Construct::replySubject()

=back

=head2 The Message

=over 4

=item B<clone>  X<clone>

Create a copy of this message.  Returned is a Mail::Message object.
The head and body, the log and trace levels are taken.  Labels are
copied with the message, but the delete and modified flags are not.
 
BE WARNED: the clone of any kind of message (or a message part) will B<always
be a Mail::Message> object.  For example, a Mail::Box::Message's clone is
detached from the folder of its original.  When you use Mail::Box::addMessage()
with the cloned message at hand, then the clone will automatically
be coerced into the right message type to be added.

See also the copyTo() and moveTo() methods.

Examples:

 $copy = $msg->clone;

=item B<isDummy>  X<isDummy>

Dummy messages are used to fill holes in linked-list and such, where only
a message-id is known, but not the place of the header of body data.

This method is also available for Mail::Message::Dummy objects, where
this will return C<true>.  On any extension of Mail::Message, this will
return C<false>.

=item B<isPart>  X<isPart>

Returns true if the message is a part of another message.  This is
the case for Mail::Message::Part extensions of Mail::Message.
See parent() for examples.

=item B<messageId>  X<messageId>

Retrieve the message's id.  Every message has a unique message-id.  This id
is used mainly for recognizing discussion threads.

=item B<modified> [BOOLEAN] X<modified>

Returns (optionally after setting) whether this message is flagged as
being modified.  The modification flag is set C<true> when header lines
are changed, the header or body replaced by a new one, or when labels
are modified.

=item B<parent>  X<parent>

If the message is a part of another message, C<parent> returns the reference
to the containing message. C<parent> returns C<undef> if the message is not a
part, but rather the main message.

Examples:

 my Mail::Message $msg = ...
 return unless $msg->body->isMultipart;
 my $part   = $msg->body->part(2);

 return unless $part->body->isMultipart;
 my $nested = $part->body->part(3);

 $nested->parent;     # returns $part
 $nested->toplevel;   # returns $msg
 $msg->parent;        # returns undef
 $msg->toplevel;      # returns $msg
 $msg->isPart;        # returns false
 $part->isPart;       # returns true

=item B<print> [FILEHANDLE] X<print>

Print the message to the FILE-HANDLE, which defaults to the selected
filehandle.

Examples:

 $message->print(\*STDERR);
 $message->print;

 my $out = IO::File->new('out', 'w');
 $message->print($out);

=item B<send> [MAILER], OPTIONS X<send>

Transmit the message to anything outside this Perl program.  Writing

 my $mailer = Mail::Transport::SMTP->new(@smtpopts);
 $message->send($mailer, @sendopts);

is a short for

 my $mailer = Mail::Transport::SMTP->new(@smtpopts);
 $mailer->send($message, @sendopts);

However, when the MAILER is not specified, one will be auto-generated
via Mail::Transport::new().  This object will be re-used. For instance

 $message->send(@sendopts);

is equivalent to

 Mail::Transport->new->send($message, @sendopts);

The OPTIONS are mailer specific.

=item B<size>  X<size>

Returns the size of the whole message in bytes.

=item B<toplevel>  X<toplevel>

Returns a reference to the main message, which will be the current
message if the message is not part of
another message.  See parent() for examples.

=back

=head2 The Header

=over 4

=item B<get> FIELD X<get>

Returns the value which is stored in the header FIELD with the specified
name.  If the field has multiple appearances in the
header, the last instance is returned.

The field name is case insensitive.  Only the `body' of the field is
returned, not the comment (after ';').  If you need more complex handing
of fields, then call

Examples:

 print $msg->get('Content-Type'), "\n";

Is equivalent to:

 print $msg->head->get('Content-Type')->body, "\n";

=item B<head> [HEAD] X<head>

Return (optionally after setting) the HEAD of this message.
The head must be an (sub-)class of Mail::Message::Head.
When the head is added, status information is taken from it
and transformed into labels.  More labels can be added by the
LABELS hash.  They are added later.

Example:

 my $head = $msg->head(new Mail::Message::Head);

=back

=head2 Header Shortcuts

=over 4

=item B<bcc>  X<bcc>

Returns the addresses which are specified on the 'Resent-Bcc' header line, or,
if that line does not exists, on the 'Bcc' header line.  A list of
C<Mail::Address> objects is returned.

Bcc stands for I<Blind Carbon Copy>: destinations of the message which are
not listed in the messages actually sent.  So, this field will be empty
for received messages, but may be present in messages you construct yourself.

=item B<cc>  X<cc>

Returns the addresses which are specified on the 'Resent-Cc' header line, or,
if that line does not exists, on the 'Cc' header line.  A list of
C<Mail::Address> objects is returned.

=item B<date>  X<date>

Returns the last C<Date> header line as string.

Examples:

 my $date = $message->date;

=item B<destinations>  X<destinations>

Returns a list of C<Mail::Address> objects which contains the combined info
of active C<To>, C<Cc>, and C<Bcc> addresses.  Doubles are removed.

=item B<from>  X<from>

Returns the address of the sender.  This can only be one address.  Of this
is a bounced message, the C<Mail::Address> representation of the C<Resent-From>
line is returned.  Otherwise, the C<From> line is scanned.  If that line is
not present, the C<Sender> line is probed.  Otherwise, C<undef> is returned.

Example:

 my $from = $message->from;

=item B<guessTimestamp>  X<guessTimestamp>

Return an estimate on the time this message was sent.  The data is
derived from the header, where it can be derived from the C<date> and
C<received> lines.  For MBox-like folders you may get the date from
the from-line as well.

This method may return C<undef> if the header is not parsed or only
partially known.  If you require a time, then use the timestamp()
method, described below.

Examples:

 print "Receipt ", ($message->timestamp || 'unknown'), "\n";

=item B<nrLines>  X<nrLines>

Returns the number of lines used for the whole message.

=item B<subject>  X<subject>

Returns the message's subject, just as short-cut for writing

 $message->get('subject')

=item B<timestamp>  X<timestamp>

Get a timestamp, doesn't matter how much work it is.  If it is impossible
to get a time from the header-lines, the current time-of-living is taken.

=item B<to>  X<to>

Returns the addresses which are specified on the 'Resent-To' header line, or,
if that line does not exists, on the 'To' header line.  A list of
C<Mail::Address> objects is returned.

Examples:

 my @to = $message->to;

=back

=head2 The Body

=over 4

=item B<body> [BODY] X<body>

Return the body of this message.  BE WARNED that this returns
you an object which may be encoded: use decoded() to get a body
with usable data.

With options, a new BODY is set for this message.  The body must
be an (sub-)class of Mail::Message::Body.  In this case, information
from the specified body will be copied into the header.  The body
object will be encoded if needed, because messages written to file
or transmitted shall not contain binary data.  The converted body
is returned.

When BODY is C<undef>, the current message body will be dissected from
the message.  All relation will be cut.  The body is returned, and
can be connected to a different message.

Examples:

 my $body      = $msg->body;
 my @encoded   = $msg->body->lines;

 my $new       = Mail::Message::Body->new(mime_type => 'text/html');
 my $converted = $msg->body($new);

=item B<decoded> OPTIONS X<decoded>

Decodes the body of this message, and returns it as a body object.  If there
was no encoding, the body object as read from file is passed on, however,
some more work will be needed when a serious encoding is encountered.
The OPTIONS control how the conversion takes place.

 OPTION               DEFAULT
 keep                 <false>
 result_type          <type of body>

=over 4

=item B<keep> =E<gt> BOOLEAN X<decoded(keep)>

Controls whether the decoded result will be kept.  If not, the decoding
may be performed more than once.  However, it will consume extra
resources...

=item B<result_type> =E<gt> BODYTYPE X<decoded(result_type)>

Specifies which kind of body should be used for the final result, and
eventual intermediate conversion stages.  It is not sure that this
will be the type of the body returned.  BODYTYPE extends Mail::Message::Body.

=back

Examples:

 $message->decoded->print(\*OUT);
 $message->decoded->print;

 my $dec = $message->body($message->decoded);
 my $dec = $message->decoded(keep => 1);   # same

=item B<encode> OPTIONS X<encode>

Encode the message to a certain format.  Read the details in the
dedicated manual page Mail::Message::Body::Encode.  The OPTIONS which
can be specified here are those of the Mail::Message::Body::encode() method.

=item B<isMultipart>  X<isMultipart>

Check whether this message is a multipart message (has attachments).  To
find this out, we need at least the header of the message; there is no
need to read the body of the message to detect this.

=item B<parts> ['ALL'|'ACTIVE'|'DELETED'|'RECURSE'|FILTER] X<parts>

Returns the I<parts> of this message. Usually, the term I<part> is used
with I<multipart> messages: messages which are encapsulated in the body
of a message.  To abstract this concept: this method will return you
all header-body combinations which are stored within this message.
Objects returned are Mail::Message's and Mail::Message::Part's.

The option default to 'ALL', which will return the message itself for
single-parts, the nested content of a message/rfc822 object, respectively
the parts of a multipart without recursion.  In case of 'RECURSE', the
parts of multiparts will be collected recursively.  This option cannot
be combined with the other options, which you may want: it that case
you have to test yourself.

'ACTIVE' and 'DELETED' check for the deleted flag on messages and
message parts.  The FILTER is a code reference, which is called for
each message and message part (implies RECURSE).

Examples:

 my @parts = $msg->parts;           # $msg not multipart: returns ($msg)
 my $parts = $msg->parts('ACTIVE'); # returns ($msg)

 $msg->delete;
 my @parts = $msg->parts;           # returns ($msg)
 my $parts = $msg->parts('ACTIVE'); # returns ()

=back

=head2 Access to the Message

=over 4

=item B<file> 

See Mail::Message::Construct::file()

=item B<lines> 

See Mail::Message::Construct::lines()

=item B<string> 

See Mail::Message::Construct::string()

=back

=head2 Labels

=over 4

=item B<label> LABEL [,VALUE [LABEL, VALUE] ] X<label>

Return the value of the LABEL, optionally after setting it to VALUE.  If
the VALUE is C<undef> then the label is removed.  You may specify a list
of LABEL-VALUE pairs at once.  In the latter case, the first VALUE is returned.

Labels are used to store knowledge about handling of the message within
the folder.  Flags about whether a message was read, replied to, or
(in some cases) scheduled for deletion.

Some labels are taken from the header's C<Status> and C<X-Status> lines,
however folder types like MH define a separate label file.

Examples:

 print $message->label('seen');
 if($message->label('seen')) {...};
 $message->label(seen => 1);

=item B<labels>  X<labels>

Returns all known labels.  In SCALAR context, it returns the knowledge
as reference to a hash.  This is a reference to the original data, but
you shall *not* change that data directly: call C<label> for
changes!

In LIST context, you get a list of names which are defined.  Be warned
that they will not all evaluate to true, although most of them will.

=back

=head2 Reading and Writing [internals]

=over 4

=item B<DESTROY>  X<DESTROY>

When a message is to accessible anymore by any user's reference, Perl
will call DESTROY for final clean-up.  In this case, the head and
body are released, and de-registered for the folder.  You shall not call
this yourself!

=item B<isDelayed>  X<isDelayed>

Check whether the message is delayed (not yet read from file).  Returns
true or false, dependent on the body type.

=item B<labelsToStatus>  X<labelsToStatus>

When the labels were changes, there may be an effect for the
C<Status> and/or C<X-Status> header-lines.  Whether this update has
to take place depends on the type of folder.

=item B<readBody> PARSER, HEAD [, BODYTYPE] X<readBody>

Read a body of a message.  The PARSER is the access to the folder's
file, and the HEAD is already read.  Information from the HEAD is used
to create expectations about the message's length, but also to determine
the mime-type and encodings of the body data.

The BODYTYPE determines which kind of body will be made and defaults to
the value specified by the C<body_type> option at message creation
(see new()).  BODYTYPE may be the name of a body class, or a reference
to a routine which returns the body's class when passed the HEAD as only
argument.

=item B<readFromParser> PARSER, [BODYTYPE] X<readFromParser>

Read one message from file.  The PARSER is opened on the file.  First
readHeader() is called, and the head is stored in the message.  Then
readBody() is called, to produce a body.  Also the body is added to
the message without decodings being done.

The optional BODYTYPE may be a body class or a reference to a code
which returns a body-class based on the header.

=item B<readHead> PARSER [,CLASS] X<readHead>

Read a head into an object of the specified CLASS.  The CLASS defaults to
the C<head_type> option specified at creation of the message (see new()).
The PARSER is the access to the folder's file.

=item B<statusToLabels>  X<statusToLabels>

Update the labels according the status lines in the header.

=item B<storeBody> BODY X<storeBody>

Where the body() method can be used to set and get a body, with all
the necessary checks, this method is bluntly adding the specified body
to the message.  No conversions, not checking.

=item B<takeMessageId> [STRING] X<takeMessageId>

Take the message-id from the STRING, or create one when the C<undef>
is specified.  If not STRING nor C<undef> is given, the current header
of the message is requested for the value of the C<'Message-ID'> field.

Angles (if present) are removed from the id.

=back

=head2 Logging and Tracing

=over 4

=item B<errors> 

See Mail::Reporter::errors()

=item B<log> [LEVEL [,STRINGS]]

See Mail::Reporter::log()

=item B<printStructure> [INDENT]

See Mail::Message::Construct::printStructure()

=item B<report> [LEVEL]

See Mail::Reporter::report()

=item B<reportAll> [LEVEL]

See Mail::Reporter::reportAll()

=item B<trace> [LEVEL]

See Mail::Reporter::trace()

=item B<warnings> 

See Mail::Reporter::warnings()

=back

=head2 Other Methods

=over 4

=item B<AUTOLOAD> 

See Mail::Reporter::AUTOLOAD()

=item B<inGlobalDestruction> 

See Mail::Reporter::inGlobalDestruction()

=item B<logPriority> LEVEL

See Mail::Reporter::logPriority()

=item B<logSettings> 

See Mail::Reporter::logSettings()

=item B<notImplemented> 

See Mail::Reporter::notImplemented()

=back

=head1 SEE ALSO

A good start to read is Mail::Box-Overview.
More documentation and a mailinglist are available from the project's
website at L<http://perl.overmeer.net/mailbox/>.

=head1 AUTHOR

Mark Overmeer (L<mark@overmeer.net|mailto:mark@overmeer.net>) with the help of many.

=head1 VERSION

This code is beta, version 2.019.

Copyright (c) 2001-2002 Mark Overmeer. All rights reserved.
This program is free software; you can redistribute it and/or modify
it under the same terms as Perl itself.
