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MIME::Tools(3pm)               User Contributed Perl Documentation               MIME::Tools(3pm)

NAME
       MIME-tools - modules for parsing (and creating!) MIME entities

SYNOPSIS
       Here's some pretty basic code for parsing a MIME message, and outputting its decoded
       components to a given directory:

           use MIME::Parser;

           ### Create parser, and set some parsing options:
           my $parser = new MIME::Parser;
           $parser->output_under("$ENV{HOME}/mimemail");

           ### Parse input:
           $entity = $parser->parse(\*STDIN) or die "parse failed\n";

           ### Take a look at the top-level entity (and any parts it has):
           $entity->dump_skeleton;

       Here's some code which composes and sends a MIME message containing three parts: a text
       file, an attached GIF, and some more text:

           use MIME::Entity;

           ### Create the top-level, and set up the mail headers:
           $top = MIME::Entity->build(Type    =>"multipart/mixed",
                                      From    => "me\@myhost.com",
                                      To      => "you\@yourhost.com",
                                      Subject => "Hello, nurse!");

           ### Part #1: a simple text document:
           $top->attach(Path=>"./testin/short.txt");

           ### Part #2: a GIF file:
           $top->attach(Path        => "./docs/mime-sm.gif",
                        Type        => "image/gif",
                        Encoding    => "base64");

           ### Part #3: some literal text:
           $top->attach(Data=>$message);

           ### Send it:
           open MAIL, "| /usr/lib/sendmail -t -oi -oem" or die "open: $!";
           $top->print(\*MAIL);
           close MAIL;

       For more examples, look at the scripts in the examples directory of the MIME-tools
       distribution.

DESCRIPTION
       MIME-tools is a collection of Perl5 MIME:: modules for parsing, decoding, and generating
       single- or multipart (even nested multipart) MIME messages.  (Yes, kids, that means you
       can send messages with attached GIF files).

REQUIREMENTS
       You will need the following installed on your system:

               File::Path
               File::Spec
               IPC::Open2              (optional)
               MIME::Base64
               MIME::QuotedPrint
               Net::SMTP
               Mail::Internet, ...     from the MailTools distribution.

       See the Makefile.PL in your distribution for the most-comprehensive list of prerequisite
       modules and their version numbers.

A QUICK TOUR
   Overview of the classes
       Here are the classes you'll generally be dealing with directly:

           (START HERE)            results() .-----------------.
                 \                 .-------->| MIME::          |
                  .-----------.   /          | Parser::Results |
                  | MIME::    |--'           `-----------------'
                  | Parser    |--.           .-----------------.
                  `-----------'   \ filer()  | MIME::          |
                     | parse()     `-------->| Parser::Filer   |
                     | gives you             `-----------------'
                     | a...                                  | output_path()
                     |                                       | determines
                     |                                       | path() of...
                     |    head()       .--------.            |
                     |    returns...   | MIME:: | get()      |
                     V       .-------->| Head   | etc...     |
                  .--------./          `--------'            |
            .---> | MIME:: |                                 |
            `-----| Entity |           .--------.            |
          parts() `--------'\          | MIME:: |           /
          returns            `-------->| Body   |<---------'
          sub-entities    bodyhandle() `--------'
          (if any)        returns...       | open()
                                           | returns...
                                           |
                                           V
                                       .--------. read()
                                       | IO::   | getline()
                                       | Handle | print()
                                       `--------' etc...

       To illustrate, parsing works this way:

       o   The "parser" parses the MIME stream.  A parser is an instance of "MIME::Parser".  You
           hand it an input stream (like a filehandle) to parse a message from: if the parse is
           successful, the result is an "entity".

       o   A parsed message is represented by an "entity".  An entity is an instance of
           "MIME::Entity" (a subclass of "Mail::Internet").  If the message had "parts" (e.g.,
           attachments), then those parts are "entities" as well, contained inside the top-level
           entity.  Each entity has a "head" and a "body".

       o   The entity's "head" contains information about the message.  A "head" is an instance
           of "MIME::Head" (a subclass of "Mail::Header").  It contains information from the
           message header: content type, sender, subject line, etc.

       o   The entity's "body" knows where the message data is.  You can ask to "open" this data
           source for reading or writing, and you will get back an "I/O handle".

       o   You can open() a "body" and get an "I/O handle" to read/write message data.  This
           handle is an object that is basically like an IO::Handle...  it can be any class, so
           long as it supports a small, standard set of methods for reading from or writing to
           the underlying data source.

       A typical multipart message containing two parts -- a textual greeting and an "attached"
       GIF file -- would be a tree of MIME::Entity objects, each of which would have its own
       MIME::Head.  Like this:

           .--------.
           | MIME:: | Content-type: multipart/mixed
           | Entity | Subject: Happy Samhaine!
           `--------'
                |
                `----.
               parts |
                     |   .--------.
                     |---| MIME:: | Content-type: text/plain; charset=us-ascii
                     |   | Entity | Content-transfer-encoding: 7bit
                     |   `--------'
                     |   .--------.
                     |---| MIME:: | Content-type: image/gif
                         | Entity | Content-transfer-encoding: base64
                         `--------' Content-disposition: inline;
                                      filename="hs.gif"

   Parsing messages
       You usually start by creating an instance of MIME::Parser and setting up certain parsing
       parameters: what directory to save extracted files to, how to name the files, etc.

       You then give that instance a readable filehandle on which waits a MIME message.  If all
       goes well, you will get back a MIME::Entity object (a subclass of Mail::Internet), which
       consists of...

       o   A MIME::Head (a subclass of Mail::Header) which holds the MIME header data.

       o   A MIME::Body, which is a object that knows where the body data is.  You ask this
           object to "open" itself for reading, and it will hand you back an "I/O handle" for
           reading the data: this could be of any class, so long as it conforms to a subset of
           the IO::Handle interface.

       If the original message was a multipart document, the MIME::Entity object will have a non-
       empty list of "parts", each of which is in turn a MIME::Entity (which might also be a
       multipart entity, etc, etc...).

       Internally, the parser (in MIME::Parser) asks for instances of MIME::Decoder whenever it
       needs to decode an encoded file.  MIME::Decoder has a mapping from supported encodings
       (e.g., 'base64') to classes whose instances can decode them.  You can add to this mapping
       to try out new/experiment encodings.  You can also use MIME::Decoder by itself.

   Composing messages
       All message composition is done via the MIME::Entity class.  For single-part messages, you
       can use the MIME::Entity/build constructor to create MIME entities very easily.

       For multipart messages, you can start by creating a top-level "multipart" entity with
       MIME::Entity::build(), and then use the similar MIME::Entity::attach() method to attach
       parts to that message.  Please note: what most people think of as "a text message with an
       attached GIF file" is really a multipart message with 2 parts: the first being the text
       message, and the second being the GIF file.

       When building MIME a entity, you'll have to provide two very important pieces of
       information: the content type and the content transfer encoding.  The type is usually
       easy, as it is directly determined by the file format; e.g., an HTML file is "text/html".
       The encoding, however, is trickier... for example, some HTML files are "7bit"-compliant,
       but others might have very long lines and would need to be sent "quoted-printable" for
       reliability.

       See the section on encoding/decoding for more details, as well as "A MIME PRIMER" below.

   Sending email
       Since MIME::Entity inherits directly from Mail::Internet, you can use the normal
       Mail::Internet mechanisms to send email.  For example,

           $entity->smtpsend;

   Encoding/decoding support
       The MIME::Decoder class can be used to encode as well; this is done when printing MIME
       entities.  All the standard encodings are supported (see "A MIME PRIMER" below for
       details):

           Encoding:        | Normally used when message contents are:
           -------------------------------------------------------------------
           7bit             | 7-bit data with under 1000 chars/line, or multipart.
           8bit             | 8-bit data with under 1000 chars/line.
           binary           | 8-bit data with some long lines (or no line breaks).
           quoted-printable | Text files with some 8-bit chars (e.g., Latin-1 text).
           base64           | Binary files.

       Which encoding you choose for a given document depends largely on (1) what you know about
       the document's contents (text vs binary), and (2) whether you need the resulting message
       to have a reliable encoding for 7-bit Internet email transport.

       In general, only "quoted-printable" and "base64" guarantee reliable transport of all data;
       the other three "no-encoding" encodings simply pass the data through, and are only
       reliable if that data is 7bit ASCII with under 1000 characters per line, and has no
       conflicts with the multipart boundaries.

       I've considered making it so that the content-type and encoding can be automatically
       inferred from the file's path, but that seems to be asking for trouble... or at least, for
       Mail::Cap...

   Message-logging
       MIME-tools is a large and complex toolkit which tries to deal with a wide variety of
       external input.  It's sometimes helpful to see what's really going on behind the scenes.
       There are several kinds of messages logged by the toolkit itself:

       Debug messages
           These are printed directly to the STDERR, with a prefix of "MIME-tools: debug".

           Debug message are only logged if you have turned "debugging" on in the MIME::Tools
           configuration.

       Warning messages
           These are logged by the standard Perl warn() mechanism to indicate an unusual
           situation.  They all have a prefix of "MIME-tools: warning".

           Warning messages are only logged if $^W is set true and MIME::Tools is not configured
           to be "quiet".

       Error messages
           These are logged by the standard Perl warn() mechanism to indicate that something
           actually failed.  They all have a prefix of "MIME-tools: error".

           Error messages are only logged if $^W is set true and MIME::Tools is not configured to
           be "quiet".

       Usage messages
           Unlike "typical" warnings above, which warn about problems processing data, usage-
           warnings are for alerting developers of deprecated methods and suspicious invocations.

           Usage messages are currently only logged if $^W is set true and MIME::Tools is not
           configured to be "quiet".

       When a MIME::Parser (or one of its internal helper classes) wants to report a message, it
       generally does so by recording the message to the MIME::Parser::Results object immediately
       before invoking the appropriate function above.  That means each parsing run has its own
       trace-log which can be examined for problems.

   Configuring the toolkit
       If you want to tweak the way this toolkit works (for example, to turn on debugging), use
       the routines in the MIME::Tools module.

       debugging
           Turn debugging on or off.  Default is false (off).

                MIME::Tools->debugging(1);

       quiet
           Turn the reporting of warning/error messages on or off.  Default is true, meaning that
           these message are silenced.

                MIME::Tools->quiet(1);

       version
           Return the toolkit version.

                print MIME::Tools->version, "\n";

THINGS YOU SHOULD DO
   Take a look at the examples
       The MIME-Tools distribution comes with an "examples" directory.  The scripts in there are
       basically just tossed-together, but they'll give you some ideas of how to use the parser.

   Run with warnings enabled
       Always run your Perl script with "-w".  If you see a warning about a deprecated method,
       change your code ASAP.  This will ease upgrades tremendously.

   Avoid non-standard encodings
       Don't try to MIME-encode using the non-standard MIME encodings.  It's just not a good
       practice if you want people to be able to read your messages.

   Plan for thrown exceptions
       For example, if your mail-handling code absolutely must not die, then perform mail parsing
       like this:

           $entity = eval { $parser->parse(\*INPUT) };

       Parsing is a complex process, and some components may throw exceptions if seriously-bad
       things happen.  Since "seriously-bad" is in the eye of the beholder, you're better off
       catching possible exceptions instead of asking me to propagate "undef" up the stack.  Use
       of exceptions in reusable modules is one of those religious issues we're never all going
       to agree upon; thankfully, that's what "eval{}" is good for.

   Check the parser results for warnings/errors
       As of 5.3xx, the parser tries extremely hard to give you a MIME::Entity.  If there were
       any problems, it logs warnings/errors to the underlying "results" object (see
       MIME::Parser::Results).  Look at that object after each parse.  Print out the warnings and
       errors, especially if messages don't parse the way you thought they would.

   Don't plan on printing exactly what you parsed!
       Parsing is a (slightly) lossy operation.  Because of things like ambiguities in
       base64-encoding, the following is not going to spit out its input unchanged in all cases:

           $entity = $parser->parse(\*STDIN);
           $entity->print(\*STDOUT);

       If you're using MIME::Tools to process email, remember to save the data you parse if you
       want to send it on unchanged.  This is vital for things like PGP-signed email.

   Understand how international characters are represented
       The MIME standard allows for text strings in headers to contain characters from any
       character set, by using special sequences which look like this:

           =?ISO-8859-1?Q?Keld_J=F8rn_Simonsen?=

       To be consistent with the existing Mail::Field classes, MIME::Tools does not automatically
       unencode these strings, since doing so would lose the character-set information and
       interfere with the parsing of fields (see "decode_headers" in MIME::Parser for a full
       explanation).  That means you should be prepared to deal with these encoded strings.

       The most common question then is, how do I decode these encoded strings?  The answer
       depends on what you want to decode them to: ASCII, Latin1, UTF-8, etc.  Be aware that your
       "target" representation may not support all possible character sets you might encounter;
       for example, Latin1 (ISO-8859-1) has no way of representing Big5 (Chinese) characters.  A
       common practice is to represent "untranslateable" characters as "?"s, or to ignore them
       completely.

       To unencode the strings into some of the more-popular Western byte representations (e.g.,
       Latin1, Latin2, etc.), you can use the decoders in MIME::WordDecoder (see
       MIME::WordDecoder).  The simplest way is by using "unmime()", a function wrapped around
       your "default" decoder, as follows:

           use MIME::WordDecoder;
           ...
           $subject = unmime $entity->head->get('subject');

       One place this is done automatically is in extracting the recommended filename for a part
       while parsing.  That's why you should start by setting up the best "default" decoder if
       the default target of Latin1 isn't to your liking.

THINGS I DO THAT YOU SHOULD KNOW ABOUT
   Fuzzing of CRLF and newline on input
       RFC 2045 dictates that MIME streams have lines terminated by CRLF ("\r\n").  However, it
       is extremely likely that folks will want to parse MIME streams where each line ends in the
       local newline character "\n" instead.

       An attempt has been made to allow the parser to handle both CRLF and newline-terminated
       input.

   Fuzzing of CRLF and newline when decoding
       The "7bit" and "8bit" decoders will decode both a "\n" and a "\r\n" end-of-line sequence
       into a "\n".

       The "binary" decoder (default if no encoding specified) still outputs stuff verbatim... so
       a MIME message with CRLFs and no explicit encoding will be output as a text file that, on
       many systems, will have an annoying ^M at the end of each line... but this is as it should
       be.

   Fuzzing of CRLF and newline when encoding/composing
       TODO FIXME All encoders currently output the end-of-line sequence as a "\n", with the
       assumption that the local mail agent will perform the conversion from newline to CRLF when
       sending the mail.  However, there probably should be an option to output CRLF as per RFC
       2045

   Inability to handle multipart boundaries with embedded newlines
       Let's get something straight: this is an evil, EVIL practice.  If your mailer creates
       multipart boundary strings that contain newlines, give it two weeks notice and find
       another one.  If your mail robot receives MIME mail like this, regard it as syntactically
       incorrect, which it is.

   Ignoring non-header headers
       People like to hand the parser raw messages straight from POP3 or from a mailbox.  There
       is often predictable non-header information in front of the real headers; e.g., the
       initial "From" line in the following message:

           From - Wed Mar 22 02:13:18 2000
           Return-Path: <eryq AT zeegee.com>
           Subject: Hello

       The parser simply ignores such stuff quietly.  Perhaps it shouldn't, but most people seem
       to want that behavior.

   Fuzzing of empty multipart preambles
       Please note that there is currently an ambiguity in the way preambles are parsed in.  The
       following message fragments both are regarded as having an empty preamble (where "\n"
       indicates a newline character):

            Content-type: multipart/mixed; boundary="xyz"\n
            Subject: This message (#1) has an empty preamble\n
            \n
            --xyz\n
            ...

            Content-type: multipart/mixed; boundary="xyz"\n
            Subject: This message (#2) also has an empty preamble\n
            \n
            \n
            --xyz\n
            ...

       In both cases, the first completely-empty line (after the "Subject") marks the end of the
       header.

       But we should clearly ignore the second empty line in message #2, since it fills the role
       of "the newline which is only there to make sure that the boundary is at the beginning of
       a line".  Such newlines are never part of the content preceding the boundary; thus, there
       is no preamble "content" in message #2.

       However, it seems clear that message #1 also has no preamble "content", and is in fact
       merely a compact representation of an empty preamble.

   Use of a temp file during parsing
       Why not do everything in core?  Although the amount of core available on even a modest
       home system continues to grow, the size of attachments continues to grow with it.  I
       wanted to make sure that even users with small systems could deal with decoding multi-
       megabyte sounds and movie files.  That means not being core-bound.

       As of the released 5.3xx, MIME::Parser gets by with only one temp file open per parser.
       This temp file provides a sort of infinite scratch space for dealing with the current
       message part.  It's fast and lightweight, but you should know about it anyway.

   Why do I assume that MIME objects are email objects?
       Achim Bohnet once pointed out that MIME headers do nothing more than store a collection of
       attributes, and thus could be represented as objects which don't inherit from
       Mail::Header.

       I agree in principle, but RFC 2045 says otherwise.  RFC 2045 [MIME] headers are a
       syntactic subset of RFC-822 [email] headers.  Perhaps a better name for these modules
       would have been RFC1521:: instead of MIME::, but we're a little beyond that stage now.

       When I originally wrote these modules for the CPAN, I agonized for a long time about
       whether or not they really should subclass from Mail::Internet (then at version 1.17).
       Thanks to Graham Barr, who graciously evolved MailTools 1.06 to be more MIME-friendly,
       unification was achieved at MIME-tools release 2.0.  The benefits in reuse alone have been
       substantial.

A MIME PRIMER
       So you need to parse (or create) MIME, but you're not quite up on the specifics?  No
       problem...

   Glossary
       Here are some definitions adapted from RFC 1521 (predecessor of the current RFC 204[56789]
       defining MIME) explaining the terminology we use; each is accompanied by the equivalent in
       MIME:: module terms...

       attachment
           An "attachment" is common slang for any part of a multipart message -- except,
           perhaps, for the first part, which normally carries a user message describing the
           attachments that follow (e.g.: "Hey dude, here's that GIF file I promised you.").

           In our system, an attachment is just a MIME::Entity under the top-level entity,
           probably one of its parts.

       body
           The "body" of an entity is that portion of the entity which follows the header and
           which contains the real message content.  For example, if your MIME message has a GIF
           file attachment, then the body of that attachment is the base64-encoded GIF file
           itself.

           A body is represented by an instance of MIME::Body.  You get the body of an entity by
           sending it a bodyhandle() message.

       body part
           One of the parts of the body of a multipart /entity.  A body part has a /header and a
           /body, so it makes sense to speak about the body of a body part.

           Since a body part is just a kind of entity, it's represented by an instance of
           MIME::Entity.

       entity
           An "entity" means either a /message or a /body part.  All entities have a /header and
           a /body.

           An entity is represented by an instance of MIME::Entity.  There are instance methods
           for recovering the header (a MIME::Head) and the body (a MIME::Body).

       header
           This is the top portion of the MIME message, which contains the "Content-type",
           "Content-transfer-encoding", etc.  Every MIME entity has a header, represented by an
           instance of MIME::Head.  You get the header of an entity by sending it a head()
           message.

       message
           A "message" generally means the complete (or "top-level") message being transferred on
           a network.

           There currently is no explicit package for "messages"; under MIME::, messages are
           streams of data which may be read in from files or filehandles.  You can think of the
           MIME::Entity returned by the MIME::Parser as representing the full message.

   Content types
       This indicates what kind of data is in the MIME message, usually as majortype/minortype.
       The standard major types are shown below.  A more-comprehensive listing may be found in
       RFC-2046.

       application
           Data which does not fit in any of the other categories, particularly data to be
           processed by some type of application program.  "application/octet-stream",
           "application/gzip", "application/postscript"...

       audio
           Audio data.  "audio/basic"...

       image
           Graphics data.  "image/gif", "image/jpeg"...

       message
           A message, usually another mail or MIME message.  "message/rfc822"...

       multipart
           A message containing other messages.  "multipart/mixed", "multipart/alternative"...

       text
           Textual data, meant for humans to read.  "text/plain", "text/html"...

       video
           Video or video+audio data.  "video/mpeg"...

   Content transfer encodings
       This is how the message body is packaged up for safe transit.  There are the 5 major MIME
       encodings.  A more-comprehensive listing may be found in RFC-2045.

       7bit
           No encoding is done at all.  This label simply asserts that no 8-bit characters are
           present, and that lines do not exceed 1000 characters in length (including the CRLF).

       8bit
           No encoding is done at all.  This label simply asserts that the message might contain
           8-bit characters, and that lines do not exceed 1000 characters in length (including
           the CRLF).

       binary
           No encoding is done at all.  This label simply asserts that the message might contain
           8-bit characters, and that lines may exceed 1000 characters in length.  Such messages
           are the least likely to get through mail gateways.

       base64
           A standard encoding, which maps arbitrary binary data to the 7bit domain.  Like
           "uuencode", but very well-defined.  This is how you should send essentially binary
           information (tar files, GIFs, JPEGs, etc.).

       quoted-printable
           A standard encoding, which maps arbitrary line-oriented data to the 7bit domain.
           Useful for encoding messages which are textual in nature, yet which contain non-ASCII
           characters (e.g., Latin-1, Latin-2, or any other 8-bit alphabet).

SEE ALSO
       MIME::Parser, MIME::Head, MIME::Body, MIME::Entity, MIME::Decoder, Mail::Header,
       Mail::Internet

       At the time of this writing, the MIME-tools homepage was
       http://www.mimedefang.org/static/mime-tools.php.  Check there for updates and support.

       The MIME format is documented in RFCs 1521-1522, and more recently in RFCs 2045-2049.

       The MIME header format is an outgrowth of the mail header format documented in RFC 822.

SUPPORT
       Please file support requests via rt.cpan.org.

CHANGE LOG
       Released as MIME-parser (1.0): 28 April 1996.  Released as MIME-tools (2.0): Halloween
       1996.  Released as MIME-tools (4.0): Christmas 1997.  Released as MIME-tools (5.0):
       Mother's Day 2000.

       See ChangeLog file for full details.

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

       Copyright (c) 1998, 1999 by ZeeGee Software Inc (www.zeegee.com).  Copyright (c) 2004 by
       Roaring Penguin Software Inc (www.roaringpenguin.com)

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

       See the COPYING file in the distribution for details.

ACKNOWLEDGMENTS
       This kit would not have been possible but for the direct contributions of the following:

           Gisle Aas             The MIME encoding/decoding modules.
           Laurent Amon          Bug reports and suggestions.
           Graham Barr           The new MailTools.
           Achim Bohnet          Numerous good suggestions, including the I/O model.
           Kent Boortz           Initial code for RFC-1522-decoding of MIME headers.
           Andreas Koenig        Numerous good ideas, tons of beta testing,
                                   and help with CPAN-friendly packaging.
           Igor Starovoitov      Bug reports and suggestions.
           Jason L Tibbitts III  Bug reports, suggestions, patches.

       Not to mention the Accidental Beta Test Team, whose bug reports (and comments) have been
       invaluable in improving the whole:

           Phil Abercrombie
           Mike Blazer
           Brandon Browning
           Kurt Freytag
           Steve Kilbane
           Jake Morrison
           Rolf Nelson
           Joel Noble
           Michael W. Normandin
           Tim Pierce
           Andrew Pimlott
           Dragomir R. Radev
           Nickolay Saukh
           Russell Sutherland
           Larry Virden
           Zyx

       Please forgive me if I've accidentally left you out.  Better yet, email me, and I'll put
       you in.

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

       See the COPYING file for more details.

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