/ 
Mail-Box-2.022
River stage one • 8 direct dependents • 8 total dependents
/ Mail::Message::Body

NAME

Mail::Message::Body - the data of a body in a message

CLASS INHERITANCE

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

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

Mail::Message::Body is extended by Mail::Message::Body::File Mail::Message::Body::Lines Mail::Message::Body::Multipart Mail::Message::Body::Nested Mail::Message::Body::String

Mail::Message::Body is realized by Mail::Message::Body::Delayed

SYNOPSIS

my Mail::Message $msg = ...;
my $body  = $msg->body;
my @text  = $body->lines;
my $text  = $body->string;
my FileHandle $file = $body->file;
$body->print(\*FILE);

my $content_type = $body->type;
my $transfer_encoding = $body->transferEncoding;
my $encoded  = $body->encode(mime_type => 'text/html',
   charset => 'us-ascii', transfer_encoding => 'NONE');
my $decoded  = $body->decoded;

DESCRIPTION

The encoding and decoding functionality of a Mail::Message::Body is implemented in the Mail::Message::Body::Encode package. That package is automatically loaded when encoding and decoding of messages needs to take place.

The body of a message (a Mail::Message object) is stored in one of the body types. The functionality of each body type is equivalent, but there are performance differences. Each body type has its own documentation which contains details about its implementation.

A body can be contained in a message, but may also live without a message. In both cases it stores data, and the same questions can be asked: what type of data it is, how many bytes and lines, what encoding is used. Any body can be encoded and decoded, returning a new body object. However, bodies which are part of a message will always be in a shape that they can be written to a file or send to somewhere: they will be encoded if needed.

For example:

my $body    = Mail::Message::Body::String->new(mime_type => 'image/gif');
$body->print(\*OUT);    # this is binary image data...

my $encoded = $message->body($body);
$encoded->print(\*OUT); # ascii data, encoded image

Now encoded refers to the body of the $message which is the content of $body in a shape that it can be transmitted. Usually base64 encoding is used.

  • Mail::Message::Body::Lines

    Each line of the message body is stored as single scalar. This is a useful representation for a detailed look in the message body, which is usually line-organized.

  • Mail::Message::Body::String

    The whole message body is stored in one scalar. Small messages can be contained this way without performance penalties.

  • Mail::Message::Body::File

    The message body is stored in an external temporary file. This type of storage is especially useful when the body is large, the total folder is large, or memory is limited.

  • Mail::Message::Body::Delayed

    The message-body is not yet read, but the exact location of the body is known so the message can be read when needed.

  • Mail::Message::Body::Multipart

    The message body contains a set of sub-messages (which can contain multipart bodies themselves). Each sub-message is an instance of Mail::Message::Part, which is an extension of Mail::Message.

  • Mail::Message::Body::Nested

    Nested messages, like message/rfc822: they contain a message in the body. For most code, they simply behave like multiparts.

  • Mail::Message::Body::InFolder

    NOT IMPLEMENTED YET. The message is kept in the folder, and is only taken out when the content is changed.

  • Mail::Message::Body::External

    NOT IMPLEMENTED YET. The message is kept in a separate file, usually because the message body is large. The difference with the ::External object is that this external storage stays this way between closing and opening of a folder. The ::External object only uses a file when the folder is open.

Each body type has methods to produce the storage of the other types. As example, you can ask any body type for the message as a list of lines, but this call will be most efficient for the MM::Body::Lines type.

METHODS

Initiation

new OPTIONS

BE WARNED that, what you specify here are encodings and such which are already in place. The options will not trigger conversions. When you need conversions, first create a body with options which tell what you've got, and then call encode() for what you need.

OPTION               DEFAULT
based_on             undef
charset              'us-ascii'
checked              <false>
data                 undef
disposition          undef
eol                  'NATIVE'
file                 undef
log                  'WARNINGS'
message              undef
mime_type            'text/plain'
modified             <false>
trace                'WARNINGS'
transfer_encoding    'NONE'
based_on => BODY

The information about encodings must be taken from the specified BODY, unless specified differently.

charset => STRING

Defines the character-set which is used in the data. Only useful in combination with a mime_type which refers to text in any shape. This field is case-insensitive.

checked => BOOLEAN

Whether the added information has been check not to contain illegal octets with respect to the transfer encoding and mime type. If not checked, and then set as body for a message, it will be.

data => ARRAY-OF-LINES | STRING

The content of the body. The only way to set the content of a body is during the creation of the body. So if you want to modify the content of a message, you need to create a new body with the new content and add that to the body. The reason behind this, is that correct encodings and body information must be guaranteed. It avoids your hassle in calculating the number of lines in the body, and checking whether bad characters are enclosed in text.

Specify a reference to an ARRAY of lines, each terminated by a newline. Or one STRING which may contain multiple lines, separated and terminated by a newline.

disposition => STRING|FIELD

How this message can be decomposed. The data relates to the Content-Disposition field. Specify a STRING which will become the field content, or a real FIELD.

The content of this field is specified in RFC 1806. The body of the field can be inline, to indicate that the body is intended to be displayed automatically upon display of the message. Use attachment to indicate that they are separate from the main body of the mail message, and that their display should not be automatic, but contingent upon some further action of the user.

The filename attribute specifies a name to which is suggested to the reader of the message when it is extracted.

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

Convert the message into having the specified string as line terminator for all lines in the body. NATIVE is used to represent the \n on the current platform and will be translated in the applicable one.

BE WARNED that folders with a non-native encoding may appear on your platform, for instance in Windows folders handled from a UNIX system. The eol encoding has effect on the size of the body!

file => FILENAME|FILEHANDLE|IOHANDLE

Read the data from the specified file, file handle, or object of type IO::Handle.

log => LEVEL

See Mail::Reporter::new(log)

message => MESSAGE

The message where this body belongs to.

mime_type => STRING|FIELD|MIME

The type of data which is added. You may specify a content of a header line as STRING, or a FIELD object. You may also specify a MIME::Type object. In any case, it will be kept internally as a real field (a Mail::Message::Field object). This relates to the Content-Type header field.

A mime-type specification consists of two parts: a general class (text, image, application, etc) and a specific sub-class. Examples for specific classes with text are plain, html, and xml. This field is case-insensitive but case preserving. The default mime-type is text/plain,

modified => BOOLEAN

Whether the body is flagged modified, directly from its creation.

trace => LEVEL

See Mail::Reporter::new(trace)

transfer_encoding => STRING|FIELD

The encoding that the data has. If the data is to be encoded, than you will have to call encode() after the body is created. That will return a new encoded body. This field is case-insensitive and relates to the Content-Transfer-Encoding field in the header.

Examples:

my $body = Mail::Message::Body::String->new(file => \*IN,
   mime_type => 'text/html; charset="ISO-8859-1"');

my $body = Mail::Message::Body::Lines->new(data => ['first', $second],
   charset => 'ISO-10646', transfer_encoding => 'NONE');

my $body = Mail::Message::Body::Lines->new(data => \@lines,
   transfer_encoding => 'base64');

my $body = Mail::Message::Body::Lines->new(file => 'picture.gif',
   mime_type => 'image/gif');

The Body

clone

Return a copy of this body, usually to be included in a cloned message (see Mail::Message::clone()).

decoded OPTIONS

Returns a body (an object which is (a sub-)class of a Mail::Message::Body) which contains a simplified representation of textual data. The returned object may be the object where this is called on, but may also be a new body of any type.

my $dec = $body->decoded;

is equivalent with

my $dec = $body->encode(mime_type => 'text/plain', charset => 'us-ascii',
   transfer_encoding => 'NONE');

The $dec which is returned is a body. Ask with the mimeType() method what is produced. This body is not related to a header, so you can not ask $dec->get('Content-Type')!

OPTION               DEFAULT
result_type          <same as current>
result_type => CLASS
isDelayed

Returns a true or false value, depending on whether the body of this message has been read from file. This can only false for a Mail::Message::Body::Delayed.

isMultipart

Returns whether this message-body contains parts which are messages by themselves.

isNested

Only true for a message body which contains exactly one sub-message: the ::Nested body type.

message [MESSAGE]

Returns the message where this body belongs to, optionally setting it to a new MESSAGE first. If undef is passed, the body will be disconnected from the message.

modified [BOOL]

Returns whether the body is flagged as being modified, optionally after setting it to BOOL.

Print the body to the specified file (defaults to the selected handle)

About the Payload

charset

Returns the character set which is used in the text body as string. This is part of the result of what the type method returns.

checked [BOOLEAN]

Returns whether the body encoding has been checked or not (optionally after setting the flag to a new value).

disposition [STRING|FIELD]

Returns (optionally after setting) how the message can be disposed (unpacked). The argument can be a STRING (which is converted into a field), or a fully prepared header field. The related header field is Content-Disposition.

eol ['CR'|'LF'|'CRLF'|'NATIVE']

Returns the character (or characters) which are used to separate lines within this body.

isBinary

See Mail::Message::Body::Encode::isBinary()

isText

See Mail::Message::Body::Encode::isText()

mimeType

Returns a MIME::Type object which is related to this body's type. This differs from the type method, which results in a Mail::Message::Field.

Examples:

if($body->mimeType eq 'text/html') {...}
print $body->mimeType->simplified;
nrLines

Returns the number of lines in the message body. For multi-part messages, this includes the header lines and boundaries of all the parts.

size

The estimate total number of bytes in the message body. Message bodies are always simple ASCII. The decoded message, however, may contain UTF8 characters. See Mail::Message::decode().

transferEncoding [STRING|FIELD]

Returns the transfer-encoding of the data within this body. If it needs to be changed, call the encode() or decoded() method.

The optional STRING or FIELD enforces a new encoding to be set, without the actual required translations.

Examples:

my $transfer = $msg->decoded->transferEncoding;
$transfer->print;
   # --> Content-Encoding: base64
type

Returns the type of information the body contains. The type is taken from the header field Content-Type, but may have changed during encoding --or decoding-- of the body (see the encode method).

The returned is a reference to a Mail::Message::Field object, where you can ask for the body (main content of the field) and the comment (after a semicolon). To get to the body, you can better use mimeType().

Examples:

my $msg     = $folder->message(6);
$msg->get('Content-Type')->print;
   # --> Content-Type: text/plain; charset="us-ascii"

my $content = $msg->decoded;
my $type    = $content->type;

print "This is a $type message\n";
   # --> This is a text/plain; charset="us-ascii" message

print "This is a ", $type->body, "message\n";
   # --> This is a text/plain message

print "Comment: ", $type->comment, "\n";
   # --> Comment: charset="us-ascii"

Access to the Payload

file

Return the content of the body as a file handle. The returned stream may be a real file, or a simulated file in any form that Perl supports. While you may not be able to write to the file handle, you can read from it.

WARNING: Even if the file handle supports writing, do not write to the file handle. If you do some of the internal values maintained by the Mail::Message::Body may not be updated. Use only the data() method instead.

lines

Return the content of the body as a list of lines (in LIST context) or a reference to an array of lines (in SCALAR context). In scalar context the array of lines is cached to avoid needless copying and therefore provide much faster access for large messages.

To just get the number of lines in the body, use the nrLines() method, which is usually much more efficient.

BE WARNED: For some types of bodies the reference will refer to the original data. You must not change the referenced data! If you do some of the internal values maintained by the Mail::Message::Body may not be updated. Use the data() method instead.

Examples:

my @lines    = $body->lines;     # copies lines
my $line3    = ($body->lines)[3] # only one copy
print $lines[0];

my $linesref = $body->lines;     # reference to originals
my $line3    = $body->lines->[3] # only one copy (faster)
print $linesref->[0];

print $body->[0];                # by overloading
string

Return the content of the body as a scalar (a single string). This is a copy of the internally kept information.

Examples:

my $text = $body->string;
print "Body: $body\n";     # by overloading

Constructing a Body

addTransferEncHandler NAME, CLASS|OBJECT

See Mail::Message::Body::Encode::addTransferEncHandler()

attach MESSAGES, OPTIONS

See Mail::Message::Body::Construct::attach()

check

See Mail::Message::Body::Encode::check()

concatenate COMPONENTS

See Mail::Message::Body::Construct::concatenate()

encode OPTIONS

See Mail::Message::Body::Encode::encode()

encoded

See Mail::Message::Body::Encode::encoded()

foreachLine CODE

See Mail::Message::Body::Construct::foreachLine()

getTransferEncHandler TYPE

See Mail::Message::Body::Encode::getTransferEncHandler()

stripSignature OPTIONS

See Mail::Message::Body::Construct::stripSignature()

unify BODY

See Mail::Message::Body::Encode::unify()

Reading and Writing [internals]

AUTOLOAD
fileLocation [BEGIN,END]

The location of the body in the file. Returned a list containing begin and end. The begin is the offsets of the first byte if the folder used for this body. The end is the offset of the first byte of the next message.

load

Be sure that the body is loaded. This returns the loaded body.

moveLocation [DISTANCE]

Move the registration of the message to a new location over DISTANCE. This is called when the message is written to a new version of the same folder-file.

read PARSER, HEAD, BODYTYPE [,CHARS [,LINES]]

Read the body with the PARSER from file. The implementation of this method will differ between types of bodies. The BODYTYPE argument is a class name or a code reference of a routine which can produce a class name, and is used in multipart bodies to determine the type of the body for each part.

The CHARS argument is the estimated number of bytes in the body, or undef when this is not known. This data can sometimes be derived from the header (the Content-Length line) or file-size.

The second argument is the estimated number of LINES of the body. It is less useful than the CHARS but may be of help determining whether the message separator is trustworthy. This value may be found in the Lines field of the header.

Logging and Tracing

defaultTrace [LEVEL, [LEVEL]

See Mail::Reporter::defaultTrace()

errors

See Mail::Reporter::errors()

log [LEVEL [,STRINGS]]

See Mail::Reporter::log()

report [LEVEL]

See Mail::Reporter::report()

reportAll [LEVEL]

See Mail::Reporter::reportAll()

trace [LEVEL]

See Mail::Reporter::trace()

warnings

See Mail::Reporter::warnings()

Other Methods

DESTROY

See Mail::Reporter::DESTROY()

inGlobalDestruction

See Mail::Reporter::inGlobalDestruction()

logPriority LEVEL

See Mail::Reporter::logPriority()

logSettings

See Mail::Reporter::logSettings()

notImplemented

See Mail::Reporter::notImplemented()

SEE ALSO

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

AUTHOR

Mark Overmeer (mark@overmeer.net) with the help of many.

VERSION

This code is beta, version 2.022.

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.