1 \input texinfo @c -*-texinfo-*-
3 @setfilename emacs-mime
4 @settitle Emacs MIME Manual
9 @c * Emacs MIME: (emacs-mime). The MIME de/composition library.
14 @setchapternewpage odd
18 This file documents the Emacs MIME interface functionality.
20 Copyright (C) 1998,99 Free Software Foundation, Inc.
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30 (this paragraph not being relevant to the printed manual).
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38 Permission is granted to copy and distribute translations of this manual
39 into another language, under the above conditions for modified versions.
45 @title Emacs MIME Manual
47 @author by Lars Magne Ingebrigtsen
50 @vskip 0pt plus 1filll
51 Copyright @copyright{} 1998,99 Free Software Foundation, Inc.
53 Permission is granted to make and distribute verbatim copies of
54 this manual provided the copyright notice and this permission notice
55 are preserved on all copies.
57 Permission is granted to copy and distribute modified versions of this
58 manual under the conditions for verbatim copying, provided that the
59 entire resulting derived work is distributed under the terms of a
60 permission notice identical to this one.
62 Permission is granted to copy and distribute translations of this manual
63 into another language, under the above conditions for modified versions.
73 This manual documents the libraries used to compose and display
76 This is not a manual meant for users; it's a manual directed at people
77 who want to write functions and commands that manipulate @sc{mime}
80 @sc{mime} is short for @dfn{Multipurpose Internet Mail Extensions}.
81 This standard is documented in a number of RFCs; mainly RFC2045 (Format
82 of Internet Message Bodies), RFC2046 (Media Types), RFC2047 (Message
83 Header Extensions for Non-ASCII Text), RFC2048 (Registration
84 Procedures), RFC2049 (Conformance Criteria and Examples). It is highly
85 recommended that anyone who intends writing @sc{mime}-compliant software
86 read at least RFC2045 and RFC2047.
89 * Interface Functions:: An abstraction over the basic functions.
90 * Basic Functions:: Utility and basic parsing functions.
91 * Decoding and Viewing:: A framework for decoding and viewing.
92 * Composing:: MML; a language for describing MIME parts.
93 * Standards:: A summary of RFCs and working documents used.
94 * Index:: Function and variable index.
98 @node Interface Functions
99 @chapter Interface Functions
100 @cindex interface functions
103 The @code{mail-parse} library is an abstraction over the actual
104 low-level libraries that are described in the next chapter.
106 Standards change, and so programs have to change to fit in the new
107 mold. For instance, RFC2045 describes a syntax for the
108 @code{Content-Type} header that only allows ASCII characters in the
109 parameter list. RFC2231 expands on RFC2045 syntax to provide a scheme
110 for continuation headers and non-ASCII characters.
112 The traditional way to deal with this is just to update the library
113 functions to parse the new syntax. However, this is sometimes the wrong
114 thing to do. In some instances it may be vital to be able to understand
115 both the old syntax as well as the new syntax, and if there is only one
116 library, one must choose between the old version of the library and the
117 new version of the library.
119 The Emacs MIME library takes a different tack. It defines a series of
120 low-level libraries (@file{rfc2047.el}, @file{rfc2231.el} and so on)
121 that parses strictly according to the corresponding standard. However,
122 normal programs would not use the functions provided by these libraries
123 directly, but instead use the functions provided by the
124 @code{mail-parse} library. The functions in this library are just
125 aliases to the corresponding functions in the latest low-level
126 libraries. Using this scheme, programs get a consistent interface they
127 can use, and library developers are free to create write code that
128 handles new standards.
130 The following functions are defined by this library:
133 @item mail-header-parse-content-type
134 @findex mail-header-parse-content-type
135 Parse a @code{Content-Type} header and return a list on the following
140 (attribute1 . value1)
141 (attribute2 . value2)
148 (mail-header-parse-content-type
149 "image/gif; name=\"b980912.gif\"")
150 @result{} ("image/gif" (name . "b980912.gif"))
153 @item mail-header-parse-content-disposition
154 @findex mail-header-parse-content-disposition
155 Parse a @code{Content-Disposition} header and return a list on the same
156 format as the function above.
158 @item mail-content-type-get
159 @findex mail-content-type-get
160 Takes two parameters---a list on the format above, and an attribute.
161 Returns the value of the attribute.
164 (mail-content-type-get
165 '("image/gif" (name . "b980912.gif")) 'name)
166 @result{} "b980912.gif"
169 @item mail-header-encode-parameter
170 @findex mail-header-encode-parameter
171 Takes a parameter string and returns an encoded version of the string.
172 This is used for parameters in headers like @code{Content-Type} and
173 @code{Content-Disposition}.
175 @item mail-header-remove-comments
176 @findex mail-header-remove-comments
177 Return a comment-free version of a header.
180 (mail-header-remove-comments
181 "Gnus/5.070027 (Pterodactyl Gnus v0.27) (Finnish Landrace)")
182 @result{} "Gnus/5.070027 "
185 @item mail-header-remove-whitespace
186 @findex mail-header-remove-whitespace
187 Remove linear white space from a header. Space inside quoted strings
188 and comments is preserved.
191 (mail-header-remove-whitespace
192 "image/gif; name=\"Name with spaces\"")
193 @result{} "image/gif;name=\"Name with spaces\""
196 @item mail-header-get-comment
197 @findex mail-header-get-comment
198 Return the last comment in a header.
201 (mail-header-get-comment
202 "Gnus/5.070027 (Pterodactyl Gnus v0.27) (Finnish Landrace)")
203 @result{} "Finnish Landrace"
206 @item mail-header-parse-address
207 @findex mail-header-parse-address
208 Parse an address and return a list containing the mailbox and the
212 (mail-header-parse-address
213 "Hrvoje Niksic <hniksic@@srce.hr>")
214 @result{} ("hniksic@@srce.hr" . "Hrvoje Niksic")
217 @item mail-header-parse-addresses
218 @findex mail-header-parse-addresses
219 Parse a string with list of addresses and return a list of elements like
220 the one described above.
223 (mail-header-parse-addresses
224 "Hrvoje Niksic <hniksic@@srce.hr>, Steinar Bang <sb@@metis.no>")
225 @result{} (("hniksic@@srce.hr" . "Hrvoje Niksic")
226 ("sb@@metis.no" . "Steinar Bang"))
229 @item mail-header-parse-date
230 @findex mail-header-parse-date
231 Parse a date string and return an Emacs time structure.
233 @item mail-narrow-to-head
234 @findex mail-narrow-to-head
235 Narrow the buffer to the header section of the buffer. Point is placed
236 at the beginning of the narrowed buffer.
238 @item mail-header-narrow-to-field
239 @findex mail-header-narrow-to-field
240 Narrow the buffer to the header under point.
242 @item mail-encode-encoded-word-region
243 @findex mail-encode-encoded-word-region
244 Encode the non-ASCII words in the region. For instance,
245 @samp{Naïve} is encoded as @samp{=?iso-8859-1?q?Na=EFve?=}.
247 @item mail-encode-encoded-word-buffer
248 @findex mail-encode-encoded-word-buffer
249 Encode the non-ASCII words in the current buffer. This function is
250 meant to be called narrowed to the headers of a message.
252 @item mail-encode-encoded-word-string
253 @findex mail-encode-encoded-word-string
254 Encode the words that need encoding in a string, and return the result.
257 (mail-encode-encoded-word-string
258 "This is naïve, baby")
259 @result{} "This is =?iso-8859-1?q?na=EFve,?= baby"
262 @item mail-decode-encoded-word-region
263 @findex mail-decode-encoded-word-region
264 Decode the encoded words in the region.
266 @item mail-decode-encoded-word-string
267 @findex mail-decode-encoded-word-string
268 Decode the encoded words in the string and return the result.
271 (mail-decode-encoded-word-string
272 "This is =?iso-8859-1?q?na=EFve,?= baby")
273 @result{} "This is naïve, baby"
278 Currently, @code{mail-parse} is an abstraction over @code{ietf-drums},
279 @code{rfc2047}, @code{rfc2045} and @code{rfc2231}. These are documented
280 in the subsequent sections.
284 @node Basic Functions
285 @chapter Basic Functions
287 This chapter describes the basic, ground-level functions for parsing and
288 handling. Covered here is parsing @code{From} lines, removing comments
289 from header lines, decoding encoded words, parsing date headers and so
290 on. High-level functionality is dealt with in the next chapter
291 (@pxref{Decoding and Viewing}).
294 * rfc2045:: Encoding @code{Content-Type} headers.
295 * rfc2231:: Parsing @code{Content-Type} headers.
296 * ietf-drums:: Handling mail headers defined by RFC822bis.
297 * rfc2047:: En/decoding encoded words in headers.
298 * time-date:: Functions for parsing dates and manipulating time.
299 * qp:: Quoted-Printable en/decoding.
300 * base64:: Base64 en/decoding.
301 * binhex:: Binhex decoding.
302 * uudecode:: Uuencode decoding.
303 * rfc1843:: Decoding HZ-encoded text.
304 * mailcap:: How parts are displayed is specified by the @file{.mailcap} file
311 RFC2045 is the ``main'' @sc{mime} document, and as such, one would
312 imagine that there would be a lot to implement. But there isn't, since
313 most of the implementation details are delegated to the subsequent
316 So @file{rfc2045.el} has only a single function:
319 @item rfc2045-encode-string
320 @findex rfc2045-encode-string
321 Takes a parameter and a value and returns a @samp{PARAM=VALUE} string.
322 @var{value} will be quoted if there are non-safe characters in it.
329 RFC2231 defines a syntax for the @code{Content-Type} and
330 @code{Content-Disposition} headers. Its snappy name is @dfn{MIME
331 Parameter Value and Encoded Word Extensions: Character Sets, Languages,
334 In short, these headers look something like this:
337 Content-Type: application/x-stuff;
338 title*0*=us-ascii'en'This%20is%20even%20more%20;
339 title*1*=%2A%2A%2Afun%2A%2A%2A%20;
343 They usually aren't this bad, though.
345 The following functions are defined by this library:
348 @item rfc2231-parse-string
349 @findex rfc2231-parse-string
350 Parse a @code{Content-Type} header and return a list describing its
354 (rfc2231-parse-string
355 "application/x-stuff;
356 title*0*=us-ascii'en'This%20is%20even%20more%20;
357 title*1*=%2A%2A%2Afun%2A%2A%2A%20;
358 title*2=\"isn't it!\"")
359 @result{} ("application/x-stuff"
360 (title . "This is even more ***fun*** isn't it!"))
363 @item rfc2231-get-value
364 @findex rfc2231-get-value
365 Takes one of the lists on the format above and returns
366 the value of the specified attribute.
368 @item rfc2231-encode-string
369 @findex rfc2231-encode-string
370 Encode a parameter in headers likes @code{Content-Type} and
371 @code{Content-Disposition}.
379 @dfn{drums} is an IETF working group that is working on the replacement
382 The functions provided by this library include:
385 @item ietf-drums-remove-comments
386 @findex ietf-drums-remove-comments
387 Remove the comments from the argument and return the results.
389 @item ietf-drums-remove-whitespace
390 @findex ietf-drums-remove-whitespace
391 Remove linear white space from the string and return the results.
392 Spaces inside quoted strings and comments are left untouched.
394 @item ietf-drums-get-comment
395 @findex ietf-drums-get-comment
396 Return the last most comment from the string.
398 @item ietf-drums-parse-address
399 @findex ietf-drums-parse-address
400 Parse an address string and return a list that contains the mailbox and
403 @item ietf-drums-parse-addresses
404 @findex ietf-drums-parse-addresses
405 Parse a string that contains any number of comma-separated addresses and
406 return a list that contains mailbox/plain text pairs.
408 @item ietf-drums-parse-date
409 @findex ietf-drums-parse-date
410 Parse a date string and return an Emacs time structure.
412 @item ietf-drums-narrow-to-header
413 @findex ietf-drums-narrow-to-header
414 Narrow the buffer to the header section of the current buffer.
422 RFC2047 (Message Header Extensions for Non-ASCII Text) specifies how
423 non-ASCII text in headers are to be encoded. This is actually rather
424 complicated, so a number of variables are necessary to tweak what this
427 The following variables are tweakable:
430 @item rfc2047-default-charset
431 @vindex rfc2047-default-charset
432 Characters in this charset should not be decoded by this library.
433 This defaults to @code{iso-8859-1}.
435 @item rfc2047-header-encoding-list
436 @vindex rfc2047-header-encoding-list
437 This is an alist of header / encoding-type pairs. Its main purpose is
438 to prevent encoding of certain headers.
440 The keys can either be header regexps, or @code{t}.
442 The values can be either @code{nil}, in which case the header(s) in
443 question won't be encoded, or @code{mime}, which means that they will be
446 @item rfc2047-charset-encoding-alist
447 @vindex rfc2047-charset-encoding-alist
448 RFC2047 specifies two forms of encoding---@code{Q} (a
449 Quoted-Printable-like encoding) and @code{B} (base64). This alist
450 specifies which charset should use which encoding.
452 @item rfc2047-encoding-function-alist
453 @vindex rfc2047-encoding-function-alist
454 This is an alist of encoding / function pairs. The encodings are
455 @code{Q}, @code{B} and @code{nil}.
457 @item rfc2047-q-encoding-alist
458 @vindex rfc2047-q-encoding-alist
459 The @code{Q} encoding isn't quite the same for all headers. Some
460 headers allow a narrower range of characters, and that is what this
461 variable is for. It's an alist of header regexps / allowable character
464 @item rfc2047-encoded-word-regexp
465 @vindex rfc2047-encoded-word-regexp
466 When decoding words, this library looks for matches to this regexp.
470 Those were the variables, and these are this functions:
473 @item rfc2047-narrow-to-field
474 @findex rfc2047-narrow-to-field
475 Narrow the buffer to the header on the current line.
477 @item rfc2047-encode-message-header
478 @findex rfc2047-encode-message-header
479 Should be called narrowed to the header of a message. Encodes according
480 to @code{rfc2047-header-encoding-alist}.
482 @item rfc2047-encode-region
483 @findex rfc2047-encode-region
484 Encodes all encodable words in the region specified.
486 @item rfc2047-encode-string
487 @findex rfc2047-encode-string
488 Encode a string and return the results.
490 @item rfc2047-decode-region
491 @findex rfc2047-decode-region
492 Decode the encoded words in the region.
494 @item rfc2047-decode-string
495 @findex rfc2047-decode-string
496 Decode a string and return the results.
504 While not really a part of the @sc{mime} library, it is convenient to
505 document this library here. It deals with parsing @code{Date} headers
506 and manipulating time. (Not by using tesseracts, though, I'm sorry to
509 These functions convert between five formats: A date string, an Emacs
510 time structure, a decoded time list, a second number, and a day number.
512 The functions have quite self-explanatory names, so the following just
513 gives an overview of which functions are available.
516 (parse-time-string "Sat Sep 12 12:21:54 1998 +0200")
517 @result{} (54 21 12 12 9 1998 6 nil 7200)
519 (date-to-time "Sat Sep 12 12:21:54 1998 +0200")
520 @result{} (13818 19266)
522 (time-to-seconds '(13818 19266))
523 @result{} 905595714.0
525 (seconds-to-time 905595714.0)
526 @result{} (13818 19266 0)
528 (time-to-day '(13818 19266))
531 (days-to-time 729644)
532 @result{} (961933 65536)
534 (time-since '(13818 19266))
537 (time-less-p '(13818 19266) '(13818 19145))
540 (subtract-time '(13818 19266) '(13818 19145))
543 (days-between "Sat Sep 12 12:21:54 1998 +0200"
544 "Sat Sep 07 12:21:54 1998 +0200")
547 (date-leap-year-p 2000)
550 (time-to-day-in-year '(13818 19266))
555 And finally, we have @code{safe-date-to-time}, which does the same as
556 @code{date-to-time}, but returns a zero time if the date is
557 syntactically malformed.
564 This library deals with decoding and encoding Quoted-Printable text.
566 Very briefly explained, qp encoding means translating all 8-bit
567 characters (and lots of control characters) into things that look like
568 @samp{=EF}; that is, an equal sign followed by the byte encoded as a hex
571 The following functions are defined by the library:
574 @item quoted-printable-decode-region
575 @findex quoted-printable-decode-region
576 QP-decode all the encoded text in the specified region.
578 @item quoted-printable-decode-string
579 @findex quoted-printable-decode-string
580 Decode the QP-encoded text in a string and return the results.
582 @item quoted-printable-encode-region
583 @findex quoted-printable-encode-region
584 QP-encode all the encodable characters in the specified region. The third
585 optional parameter @var{fold} specifies whether to fold long lines.
586 (Long here means 72.)
588 @item quoted-printable-encode-string
589 @findex quoted-printable-encode-string
590 QP-encode all the encodable characters in a string and return the
600 Base64 is an encoding that encodes three bytes into four characters,
601 thereby increasing the size by about 33%. The alphabet used for
602 encoding is very resistant to mangling during transit.
604 The following functions are defined by this library:
607 @item base64-encode-region
608 @findex base64-encode-region
609 base64 encode the selected region. Return the length of the encoded
610 text. Optional third argument @var{no-line-break} means do not break
611 long lines into shorter lines.
613 @item base64-encode-string
614 @findex base64-encode-string
615 base64 encode a string and return the result.
617 @item base64-decode-region
618 @findex base64-decode-region
619 base64 decode the selected region. Return the length of the decoded
620 text. If the region can't be decoded, return @code{nil} and don't
623 @item base64-decode-string
624 @findex base64-decode-string
625 base64 decode a string and return the result. If the string can't be
626 decoded, @code{nil} is returned.
637 @code{binhex} is an encoding that originated in Macintosh environments.
638 The following function is supplied to deal with these:
641 @item binhex-decode-region
642 @findex binhex-decode-region
643 Decode the encoded text in the region. If given a third parameter, only
644 decode the @code{binhex} header and return the filename.
654 @code{uuencode} is probably still the most popular encoding of binaries
655 used on Usenet, although @code{base64} rules the mail world.
657 The following function is supplied by this package:
660 @item uudecode-decode-region
661 @findex uudecode-decode-region
662 Decode the text in the region.
672 RFC1843 deals with mixing Chinese and ASCII characters in messages. In
673 essence, RFC1843 switches between ASCII and Chinese by doing this:
676 This sentence is in ASCII.
677 The next sentence is in GB.~@{<:Ky2;S@{#,NpJ)l6HK!#~@}Bye.
680 Simple enough, and widely used in China.
682 The following functions are available to handle this encoding:
685 @item rfc1843-decode-region
686 Decode HZ-encoded text in the region.
688 @item rfc1843-decode-string
689 Decode a HZ-encoded string and return the result.
697 The @file{~/.mailcap} file is parsed by most @sc{mime}-aware message
698 handlers and describes how elements are supposed to be displayed.
699 Here's an example file:
703 audio/wav; wavplayer %s
706 This says that all image files should be displayed with @samp{xv}, and
707 that realaudio files should be played by @samp{rvplayer}.
709 The @code{mailcap} library parses this file, and provides functions for
713 @item mailcap-mime-data
714 @vindex mailcap-mime-data
715 This variable is an alist of alists containing backup viewing rules.
722 @item mailcap-parse-mailcaps
723 @findex mailcap-parse-mailcaps
724 Parse the @code{~/.mailcap} file.
726 @item mailcap-mime-info
727 Takes a @sc{mime} type as its argument and returns the matching viewer.
734 @node Decoding and Viewing
735 @chapter Decoding and Viewing
737 This chapter deals with decoding and viewing @sc{mime} messages on a
740 The main idea is to first analyze a @sc{mime} article, and then allow
741 other programs to do things based on the list of @dfn{handles} that are
742 returned as a result of this analysis.
745 * Dissection:: Analyzing a @sc{mime} message.
746 * Handles:: Handle manipulations.
747 * Display:: Displaying handles.
748 * Customization:: Variables that affect display.
755 The @code{mm-dissect-buffer} is the function responsible for dissecting
756 a @sc{mime} article. If given a multipart message, it will recursively
757 descend the message, following the structure, and return a tree of
758 @sc{mime} handles that describes the structure of the message.
764 A @sc{mime} handle is a list that fully describes a @sc{mime}
767 The following macros can be used to access elements in a handle:
770 @item mm-handle-buffer
771 @findex mm-handle-buffer
772 Return the buffer that holds the contents of the undecoded @sc{mime}
776 @findex mm-handle-type
777 Return the parsed @code{Content-Type} of the part.
779 @item mm-handle-encoding
780 @findex mm-handle-encoding
781 Return the @code{Content-Transfer-Encoding} of the part.
783 @item mm-handle-undisplayer
784 @findex mm-handle-undisplayer
785 Return the object that can be used to remove the displayed part (if it
788 @item mm-handle-set-undisplayer
789 @findex mm-handle-set-undisplayer
790 Set the undisplayer object.
792 @item mm-handle-disposition
793 @findex mm-handle-disposition
794 Return the parsed @code{Content-Disposition} of the part.
796 @item mm-handle-disposition
797 @findex mm-handle-disposition
798 Return the description of the part.
800 @item mm-get-content-id
801 Returns the handle(s) referred to by @code{Content-ID}.
809 Functions for displaying, removing and saving.
812 @item mm-display-part
813 @findex mm-display-part
817 @findex mm-remove-part
818 Remove the part (if it has been displayed).
821 @findex mm-inlinable-p
822 Say whether a @sc{mime} type can be displayed inline.
824 @item mm-automatic-display-p
825 @findex mm-automatic-display-p
826 Say whether a @sc{mime} type should be displayed automatically.
828 @item mm-destroy-part
829 @findex mm-destroy-part
830 Free all resources occupied by a part.
834 Offer to save the part in a file.
838 Offer to pipe the part to some process.
840 @item mm-interactively-view-part
841 @findex mm-interactively-view-part
842 Prompt for a mailcap method to use to view the part.
848 @section Customization
852 @item mm-inline-media-tests
853 This is an alist where the key is a @sc{mime} type, the second element
854 is a function to display the part @dfn{inline} (i.e., inside Emacs), and
855 the third element is a form to be @code{eval}ed to say whether the part
856 can be displayed inline.
858 This variable specifies whether a part @emph{can} be displayed inline,
859 and, if so, how to do it. It does not say whether parts are
860 @emph{actually} displayed inline.
862 @item mm-inlined-types
863 This, on the other hand, says what types are to be displayed inline, if
864 they satisfy the conditions set by the variable above. It's a list of
865 @sc{mime} media types.
867 @item mm-automatic-display
868 This is a list of types that are to be displayed ``automatically'', but
869 only if the above variable allows it. That is, only inlinable parts can
870 be displayed automatically.
872 @item mm-attachment-override-types
873 Some @sc{mime} agents create parts that have a content-disposition of
874 @samp{attachment}. This variable allows overriding that disposition and
875 displaying the part inline. (Note that the disposition is only
876 overridden if we are able to, and want to, display the part inline.)
878 @item mm-discouraged-alternatives
879 List of @sc{mime} types that are discouraged when viewing
880 @samp{multipart/alternative}. Viewing agents are supposed to view the
881 last possible part of a message, as that is supposed to be the richest.
882 However, users may prefer other types instead, and this list says what
883 types are most unwanted. If, for instance, @samp{text/html} parts are
884 very unwanted, and @samp{text/richtech} parts are somewhat unwanted,
885 then the value of this variable should be set to:
888 ("text/html" "text/richtext")
891 @item mm-inline-large-images-p
892 When displaying inline images that are larger than the window, XEmacs
893 does not enable scrolling, which means that you cannot see the whole
894 image. To prevent this, the library tries to determine the image size
895 before displaying it inline, and if it doesn't fit the window, the
896 library will display it externally (e.g. with @samp{ImageMagick} or
897 @samp{xv}). Setting this variable to @code{t} disables this check and
898 makes the library display all inline images as inline, regardless of
909 @cindex MIME Composing
911 @cindex MIME Meta Language
913 Creating a @sc{mime} message is boring and non-trivial. Therefore, a
914 library called @code{mml} has been defined that parses a language called
915 MML (@sc{mime} Meta Language) and generates @sc{mime} messages.
917 @findex mml-generate-mime
918 The main interface function is @code{mml-generate-mime}. It will
919 examine the contents of the current (narrowed-to) buffer and return a
920 string containing the @sc{mime} message.
923 * Simple MML Example:: An example MML document.
924 * MML Definition:: All valid MML elements.
925 * Advanced MML Example:: Another example MML document.
926 * Conversion:: Going from @sc{mime} to MML and vice versa.
930 @node Simple MML Example
931 @section Simple MML Example
933 Here's a simple @samp{multipart/alternative}:
936 <#multipart type=alternative>
937 This is a plain text part.
938 <#part type=text/enriched>
939 <center>This is a centered enriched part</center>
943 After running this through @code{mml-generate-mime}, we get this:
946 Content-Type: multipart/alternative; boundary="=-=-="
952 This is a plain text part.
955 Content-Type: text/enriched
958 <center>This is a centered enriched part</center>
965 @section MML Definition
967 The MML language is very simple. It looks a bit like an SGML
968 application, but it's not.
970 The main concept of MML is the @dfn{part}. Each part can be of a
971 different type or use a different charset. The way to delineate a part
972 is with a @samp{<#part ...>} tag. Multipart parts can be introduced
973 with the @samp{<#multipart ...>} tag. Parts are ended by the
974 @samp{<#/part>} or @samp{<#/multipart>} tags. Parts started with the
975 @samp{<#part ...>} tags are also closed by the next open tag.
977 There's also the @samp{<#external ...>} tag. These introduce
978 @samp{external/message-body} parts.
980 Each tag can contain zero or more parameters on the form
981 @samp{parameter=value}. The values may be enclosed in quotation marks,
982 but that's not necessary unless the value contains white space. So
983 @samp{filename=/home/user/#hello$^yes} is perfectly valid.
985 The following parameters have meaning in MML; parameters that have no
986 meaning are ignored. The MML parameter names are the same as the
987 @sc{mime} parameter names; the things in the parentheses say which
988 header it will be used in.
992 The @sc{mime} type of the part (@code{Content-Type}).
995 Use the contents of the file in the body of the part
996 (@code{Content-Disposition}).
999 The contents of the body of the part are to be encoded in the character
1000 set speficied (@code{Content-Type}).
1003 Might be used to suggest a file name if the part is to be saved
1004 to a file (@code{Content-Type}).
1007 Valid values are @samp{inline} and @samp{attachment}
1008 (@code{Content-Disposition}).
1011 Valid values are @samp{7bit}, @samp{8bit}, @samp{quoted-printable} and
1012 @samp{base64} (@code{Content-Transfer-Encoding}).
1015 A description of the part (@code{Content-Description}).
1018 RFC822 date when the part was created (@code{Content-Disposition}).
1020 @item modification-date
1021 RFC822 date when the part was modified (@code{Content-Disposition}).
1024 RFC822 date when the part was read (@code{Content-Disposition}).
1027 The size (in octets) of the part (@code{Content-Disposition}).
1031 Parameters for @samp{application/octet-stream}:
1035 Type of the part; informal---meant for human readers
1036 (@code{Content-Type}).
1039 Parameters for @samp{message/external-body}:
1043 A word indicating the supported access mechanism by which the file may
1044 be obtained. Values include @samp{ftp}, @samp{anon-ftp}, @samp{tftp},
1045 @samp{localfile}, and @samp{mailserver}. (@code{Content-Type}.)
1048 The RFC822 date after which the file may no longer be fetched.
1049 (@code{Content-Type}.)
1052 The size (in octets) of the file. (@code{Content-Type}.)
1055 Valid values are @samp{read} and @samp{read-write}
1056 (@code{Content-Type}).
1061 @node Advanced MML Example
1062 @section Advanced MML Example
1064 Here's a complex multipart message. It's a @samp{multipart/mixed} that
1065 contains many parts, one of which is a @samp{multipart/alternative}.
1068 <#multipart type=mixed>
1069 <#part type=image/jpeg filename=~/rms.jpg disposition=inline>
1070 <#multipart type=alternative>
1071 This is a plain text part.
1072 <#part type=text/enriched name=enriched.txt>
1073 <center>This is a centered enriched part</center>
1075 This is a new plain text part.
1076 <#part disposition=attachment>
1077 This plain text part is an attachment.
1081 And this is the resulting @sc{mime} message:
1084 Content-Type: multipart/mixed; boundary="=-=-="
1092 Content-Type: image/jpeg;
1093 filename="~/rms.jpg"
1094 Content-Disposition: inline;
1095 filename="~/rms.jpg"
1096 Content-Transfer-Encoding: base64
1098 /9j/4AAQSkZJRgABAQAAAQABAAD/2wBDAAgGBgcGBQgHBwcJCQgKDBQNDAsLDBkSEw8UHRof
1099 Hh0aHBwgJC4nICIsIxwcKDcpLDAxNDQ0Hyc5PTgyPC4zNDL/wAALCAAwADABAREA/8QAHwAA
1100 AQUBAQEBAQEAAAAAAAAAAAECAwQFBgcICQoL/8QAtRAAAgEDAwIEAwUFBAQAAAF9AQIDAAQR
1101 BRIhMUEGE1FhByJxFDKBkaEII0KxwRVS0fAkM2JyggkKFhcYGRolJicoKSo0NTY3ODk6Q0RF
1102 RkdISUpTVFVWV1hZWmNkZWZnaGlqc3R1dnd4eXqDhIWGh4iJipKTlJWWl5iZmqKjpKWmp6ip
1103 qrKztLW2t7i5usLDxMXGx8jJytLT1NXW19jZ2uHi4+Tl5ufo6erx8vP09fb3+Pn6/9oACAEB
1104 AAA/AO/rifFHjldNuGsrDa0qcSSHkA+gHrXKw+LtWLrMb+RgTyhbr+HSug07xNqV9fQtZrNI
1105 AyiaE/NuBPOOOP0rvRNE880KOC8TbXXGCv1FPqjrF4LDR7u5L7SkTFT/ALWOP1xXgTuXfc7E
1106 sx6nua6rwp4IvvEM8chCxWxOdzn7wz6V9AaB4S07w9p5itow0rDLSY5Pt9K43xO66P4xs71m
1107 2QXiGCbA4yOVJ9+1aYORkdK434lyNH4ahCnG66VT9Nj15JFbPdX0MS43M4VQf5/yr2vSpLnw
1108 5ZW8dlCZ8KFXjOPX0/mK6rSPEGt3Angu44fNEReHYNvIH3TzXDeKNO8RX+kSX2ouZkicTIOc
1109 L+g7E810ulFjpVtv3bwgB3HJyK5L4quY/C9sVxk3ij/xx6850u7t1mtp/wDlpEw3An3Jr3Dw
1110 34gsbWza4nBlhC5LDsaW6+IFgupQyCF3iHH7gA7c9R9ay7zx6t7aX9jHC4smhfBkGCvHGfrm
1111 tLQ7hbnRrV1GPkAP1x1/Hr+Ncr8Vzjwrbf8AX6v/AKA9eQRyYlQk8Yx9K6XTNbkgia2ciSIn
1112 7p5Ga9Atte0LTLKO6it4i7dVRFJDcZ4PvXN+JvEMF9bILVGXJLSZ4zkjivRPDaeX4b08HOTC
1113 pOffmua+KkbS+GLVUGT9tT/0B68eeIpIFYjB70+OOVXyoOM9+M1eaWeCLzHPyHGO/NVWvJJm
1114 jQ8KGH1NfQWhXSXmh2c8eArRLwO3HSv/2Q==
1117 Content-Type: multipart/alternative; boundary="==-=-="
1123 This is a plain text part.
1126 Content-Type: text/enriched;
1130 <center>This is a centered enriched part</center>
1136 This is a new plain text part.
1139 Content-Disposition: attachment
1142 This plain text part is an attachment.
1152 A (multipart) @sc{mime} message can be converted to MML with the
1153 @code{mime-to-mml} function. It works on the message in the current
1154 buffer, and substitutes MML markup for @sc{mime} boundaries.
1155 Non-textual parts do not have their contents in the buffer, but instead
1156 have the contents in separate buffers that are referred to from the MML
1160 An MML message can be converted back to @sc{mime} by the
1161 @code{mml-to-mime} function.
1163 These functions are in certain senses ``lossy''---you will not get back
1164 an identical message if you run @sc{mime-to-mml} and then
1165 @sc{mml-to-mime}. Not only will trivial things like the order of the
1166 headers differ, but the contents of the headers may also be different.
1167 For instance, the original message may use base64 encoding on text,
1168 while @sc{mml-to-mime} may decide to use quoted-printable encoding, and
1171 In essence, however, these two functions should be the inverse of each
1172 other. The resulting contents of the message should remain equivalent,
1179 The Emacs @sc{mime} library implements handling of various elements
1180 according to a (somewhat) large number of RFCs, drafts and standards
1181 documents. This chapter lists the relevant ones. They can all be
1182 fetched from @samp{http://www.stud.ifi.uio.no/~larsi/notes/}.
1187 Standard for the Format of ARPA Internet Text Messages.
1190 Standard for Interchange of USENET Messages
1193 Format of Internet Message Bodies
1199 Message Header Extensions for Non-ASCII Text
1202 Registration Procedures
1205 Conformance Criteria and Examples
1208 MIME Parameter Value and Encoded Word Extensions: Character Sets,
1209 Languages, and Continuations
1212 HZ - A Data Format for Exchanging Files of Arbitrarily Mixed Chinese and
1215 @item draft-ietf-drums-msg-fmt-05.txt
1216 Draft for the successor of RFC822
1219 The MIME Multipart/Related Content-type
1222 The Multipart/Report Content Type for the Reporting of Mail System
1223 Administrative Messages
1226 Communicating Presentation Information in Internet Messages: The
1227 Content-Disposition Header Field