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MIME::Body(3)                        User Contributed Perl Documentation                       MIME::Body(3)



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 -------------------------------------------------------MIME::Body::File
          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@zeegee.com), ZeeGee Software Inc (http://www.zeegee.com).  David F. Skoll
       (dfs@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;



perl v5.16.2                                     2012-06-08                                    MIME::Body(3)