MIME::Body - phpMan

NAME
    MIME::Body - the body of a MIME message

SYNOPSIS
    Before reading further, you should see MIME::Tools to make sure that you
    understand where this module fits into the grand scheme of things. Go
    on, do it now. I'll wait.

    Ready? Ok...

  Obtaining bodies
       ### Get the bodyhandle of a MIME::Entity object:
       $body = $entity->bodyhandle;

       ### Create a body which stores data in a disk file:
       $body = new MIME::Body::File "/path/to/file";

       ### Create a body which stores data in an in-core array:
       $body = new MIME::Body::InCore \@strings;

  Opening, closing, and using IO handles
       ### Write data to the body:
       $IO = $body->open("w")      || die "open body: $!";
       $IO->print($message);
       $IO->close                  || die "close I/O handle: $!";

       ### Read data from the body (in this case, line by line):
       $IO = $body->open("r")      || die "open body: $!";
       while (defined($_ = $IO->getline)) {
           ### do stuff
       }
       $IO->close                  || die "close I/O handle: $!";

  Other I/O
       ### Dump the ENCODED body data to a filehandle:
       $body->print(\*STDOUT);

       ### Slurp all the UNENCODED data in, and put it in a scalar:
       $string = $body->as_string;

       ### Slurp all the UNENCODED data in, and put it in an array of lines:
       @lines = $body->as_lines;

  Working directly with paths to underlying files
       ### Where's the data?
       if (defined($body->path)) {   ### data is on disk:
           print "data is stored externally, in ", $body->path;
       }
       else {                        ### data is in core:
           print "data is already in core, and is...\n", $body->as_string;
       }

       ### Get rid of anything on disk:
       $body->purge;

DESCRIPTION
    MIME messages can be very long (e.g., tar files, MPEGs, etc.) or very
    short (short textual notes, as in ordinary mail). Long messages are best
    stored in files, while short ones are perhaps best stored in core.

    This class is an attempt to define a common interface for objects which
    contain message data, regardless of how the data is physically stored.
    The lifespan of a "body" object usually looks like this:

    1.  Body object is created by a MIME::Parser during parsing. It's at
        this point that the actual MIME::Body subclass is chosen, and new()
        is invoked. (For example: if the body data is going to a file, then
        it is at this point that the class MIME::Body::File, and the
        filename, is chosen).

    2.  Data is written to the body (usually by the MIME parser) like this:
        The body is opened for writing, via "open("w")". This will trash any
        previous contents, and return an "I/O handle" opened for writing.
        Data is written to this I/O handle, via print(). Then the I/O handle
        is closed, via close().

    3.  Data is read from the body (usually by the user application) like
        this: The body is opened for reading by a user application, via
        "open("r")". This will return an "I/O handle" opened for reading.
        Data is read from the I/O handle, via read(), getline(), or
        getlines(). Then the I/O handle is closed, via close().

    4.  Body object is destructed.

    You can write your own subclasses, as long as they follow the interface
    described below. Implementers of subclasses should assume that steps 2
    and 3 may be repeated any number of times, and in different orders
    (e.g., 1-2-2-3-2-3-3-3-3-3-2-4).

    In any case, once a MIME::Body has been created, you ask to open it for
    reading or writing, which gets you an "i/o handle": you then use the
    same mechanisms for reading from or writing to that handle, no matter
    what class it is.

    Beware: unless you know for certain what kind of body you have, you
    should *not* assume that the body has an underlying filehandle.

PUBLIC INTERFACE
    new ARGS...
        *Class method, constructor.* Create a new body. Any ARGS are sent to
        init().

    init ARGS...
        *Instance method, abstract, initiallizer.* This is called
        automatically by "new()", with the arguments given to "new()". The
        arguments are optional, and entirely up to the subclass. The default
        method does nothing,

    as_lines
        *Instance method.* Return the contents of the body as an array of
        lines (each terminated by a newline, with the possible exception of
        the final one). Returns empty on failure (NB: indistinguishable from
        an empty body!).

        Note: the default method gets the data via repeated getline() calls;
        your subclass might wish to override this.

    as_string
        *Instance method.* Return the body data as a string (slurping it
        into core if necessary). Best not to do this unless you're *sure*
        that the body is reasonably small! Returns empty string for an empty
        body, and undef on failure.

        Note: the default method uses print(), which gets the data via
        repeated read() calls; your subclass might wish to override this.

    binmode [ONOFF]
        *Instance method.* With argument, flags whether or not open() should
        return an I/O handle which has binmode() activated. With no
        argument, just returns the current value.

    is_encoded [ONOFF]
        *Instance method.* If set to yes, no decoding is applied on output.
        This flag is set by MIME::Parser, if the parser runs in
        decode_bodies(0) mode, so the content is handled unmodified.

    dup *Instance method.* Duplicate the bodyhandle.

        *Beware:* external data in bodyhandles is *not* copied to new files!
        Changing the data in one body's data file, or purging that body,
        *will* affect its duplicate. Bodies with in-core data probably need
        not worry.

    open READWRITE
        *Instance method, abstract.* This should do whatever is necessary to
        open the body for either writing (if READWRITE is "w") or reading
        (if mode is "r").

        This method is expected to return an "I/O handle" object on success,
        and undef on error. An I/O handle can be any object that supports a
        small set of standard methods for reading/writing data. See the
        IO::Handle class for an example.

    path [PATH]
        *Instance method.* If you're storing the body data externally (e.g.,
        in a disk file), you'll want to give applications the ability to get
        at that data, for cleanup. This method should return the path to the
        data, or undef if there is none.

        Where appropriate, the path *should* be a simple string, like a
        filename. With argument, sets the PATH, which should be undef if
        there is none.

    print FILEHANDLE
        *Instance method.* Output the body data to the given filehandle, or
        to the currently-selected one if none is given.

    purge
        *Instance method, abstract.* Remove any data which resides external
        to the program (e.g., in disk files). Immediately after a purge(),
        the path() should return undef to indicate that the external data is
        no longer available.

SUBCLASSES
    The following built-in classes are provided:

       Body                 Stores body     When open()ed,
       class:               data in:        returns:
       --------------------------------------------------------
       MIME::Body::File     disk file       IO::Handle
       MIME::Body::Scalar   scalar          IO::Handle
       MIME::Body::InCore   scalar array    IO::Handle

  MIME::Body::File
    A body class that stores the data in a disk file. Invoke the constructor
    as:

        $body = new MIME::Body::File "/path/to/file";

    In this case, the "path()" method would return the given path, so you
    *could* say:

        if (defined($body->path)) {
            open BODY, $body->path or die "open: $!";
            while (<BODY>) {
                ### do stuff
            }
            close BODY;
        }

    But you're best off not doing this.

  MIME::Body::Scalar
    A body class that stores the data in-core, in a simple scalar. Invoke
    the constructor as:

        $body = new MIME::Body::Scalar \$string;

    A single scalar argument sets the body to that value, exactly as though
    you'd opened for the body for writing, written the value, and closed the
    body again:

        $body = new MIME::Body::Scalar "Line 1\nLine 2\nLine 3";

    A single array reference sets the body to the result of joining all the
    elements of that array together:

        $body = new MIME::Body::Scalar ["Line 1\n",
                                        "Line 2\n",
                                        "Line 3"];

  MIME::Body::InCore
    A body class that stores the data in-core. Invoke the constructor as:

        $body = new MIME::Body::InCore \$string;
        $body = new MIME::Body::InCore  $string;
        $body = new MIME::Body::InCore \@stringarray

    A simple scalar argument sets the body to that value, exactly as though
    you'd opened for the body for writing, written the value, and closed the
    body again:

        $body = new MIME::Body::InCore "Line 1\nLine 2\nLine 3";

    A single array reference sets the body to the concatenation of all
    scalars that it holds:

        $body = new MIME::Body::InCore ["Line 1\n",
                                        "Line 2\n",
                                        "Line 3"];

  Defining your own subclasses
    So you're not happy with files and scalar-arrays? No problem: just
    define your own MIME::Body subclass, and make a subclass of MIME::Parser
    or MIME::ParserBase which returns an instance of your body class
    whenever appropriate in the "new_body_for(head)" method.

    Your "body" class must inherit from MIME::Body (or some subclass of it),
    and it must either provide (or inherit the default for) the following
    methods...

    The default inherited method *should suffice* for all these:

        new
        binmode [ONOFF]
        path

    The default inherited method *may suffice* for these, but perhaps
    there's a better implementation for your subclass.

        init ARGS...
        as_lines
        as_string
        dup
        print
        purge

    The default inherited method *will probably not suffice* for these:

        open

NOTES
    One reason I didn't just use IO::Handle objects for message bodies was
    that I wanted a "body" object to be a form of completely encapsulated
    program-persistent storage; that is, I wanted users to be able to write
    code like this...

       ### Get body handle from this MIME message, and read its data:
       $body = $entity->bodyhandle;
       $IO = $body->open("r");
       while (defined($_ = $IO->getline)) {
           print STDOUT $_;
       }
       $IO->close;

    ...without requiring that they know anything more about how the $body
    object is actually storing its data (disk file, scalar variable, array
    variable, or whatever).

    Storing the body of each MIME message in a persistently-open IO::Handle
    was a possibility, but it seemed like a bad idea, considering that a
    single multipart MIME message could easily suck up all the available
    file descriptors on some systems. This risk increases if the user
    application is processing more than one MIME entity at a time.

SEE ALSO
    MIME::Tools

AUTHOR
    Eryq (eryq AT zeegee.com), ZeeGee Software Inc (http://www.zeegee.com).
    David F. Skoll (dfs AT roaringpenguin.com) http://www.roaringpenguin.com

    All rights reserved. This program is free software; you can redistribute
    it and/or modify it under the same terms as Perl itself.

    Thanks to Achim Bohnet for suggesting that MIME::Parser not be
    restricted to the use of FileHandles.

    #------------------------------ 1;