3 @setfilename emacs-mime
4 @settitle Emacs MIME Manual
10 * Emacs MIME: (emacs-mime). The MIME de/composition library.
15 @setchapternewpage odd
19 This file documents the Emacs MIME interface functionality.
21 Copyright (C) 1998, 1999, 2000, 2001, 2002, 2003
22 Free Software Foundation, Inc.
24 Permission is granted to copy, distribute and/or modify this document
25 under the terms of the GNU Free Documentation License, Version 1.1 or
26 any later version published by the Free Software Foundation; with no
27 Invariant Sections, with the Front-Cover texts being ``A GNU
28 Manual'', and with the Back-Cover Texts as in (a) below. A copy of the
29 license is included in the section entitled ``GNU Free Documentation
30 License'' in the Emacs manual.
32 (a) The FSF's Back-Cover Text is: ``You have freedom to copy and modify
33 this GNU Manual, like GNU software. Copies published by the Free
34 Software Foundation raise funds for GNU development.''
36 This document is part of a collection distributed under the GNU Free
37 Documentation License. If you want to distribute this document
38 separately from the collection, you can do so by adding a copy of the
39 license to the document, as described in section 6 of the license.
45 @title Emacs MIME Manual
47 @author by Lars Magne Ingebrigtsen
50 @vskip 0pt plus 1filll
51 Copyright @copyright{} 1998, 1999, 2000, 2001, 2002, 2003 Free Software
54 Permission is granted to copy, distribute and/or modify this document
55 under the terms of the GNU Free Documentation License, Version 1.1 or
56 any later version published by the Free Software Foundation; with the
57 Invariant Sections being none, with the Front-Cover texts being ``A GNU
58 Manual'', and with the Back-Cover Texts as in (a) below. A copy of the
59 license is included in the section entitled ``GNU Free Documentation
60 License'' in the Emacs manual.
62 (a) The FSF's Back-Cover Text is: ``You have freedom to copy and modify
63 this GNU Manual, like GNU software. Copies published by the Free
64 Software Foundation raise funds for GNU development.''
66 This document is part of a collection distributed under the GNU Free
67 Documentation License. If you want to distribute this document
68 separately from the collection, you can do so by adding a copy of the
69 license to the document, as described in section 6 of the license.
78 This manual documents the libraries used to compose and display
79 @acronym{MIME} messages.
81 This manual is directed at users who want to modify the behaviour of
82 the @acronym{MIME} encoding/decoding process or want a more detailed
83 picture of how the Emacs @acronym{MIME} library works, and people who want
84 to write functions and commands that manipulate @acronym{MIME} elements.
86 @acronym{MIME} is short for @dfn{Multipurpose Internet Mail Extensions}.
87 This standard is documented in a number of RFCs; mainly RFC2045 (Format
88 of Internet Message Bodies), RFC2046 (Media Types), RFC2047 (Message
89 Header Extensions for Non-@acronym{ASCII} Text), RFC2048 (Registration
90 Procedures), RFC2049 (Conformance Criteria and Examples). It is highly
91 recommended that anyone who intends writing @acronym{MIME}-compliant software
92 read at least RFC2045 and RFC2047.
95 * Decoding and Viewing:: A framework for decoding and viewing.
96 * Composing:: MML; a language for describing @acronym{MIME} parts.
97 * Interface Functions:: An abstraction over the basic functions.
98 * Basic Functions:: Utility and basic parsing functions.
99 * Standards:: A summary of RFCs and working documents used.
100 * Index:: Function and variable index.
104 @node Decoding and Viewing
105 @chapter Decoding and Viewing
107 This chapter deals with decoding and viewing @acronym{MIME} messages on a
110 The main idea is to first analyze a @acronym{MIME} article, and then allow
111 other programs to do things based on the list of @dfn{handles} that are
112 returned as a result of this analysis.
115 * Dissection:: Analyzing a @acronym{MIME} message.
116 * Non-MIME:: Analyzing a non-@acronym{MIME} message.
117 * Handles:: Handle manipulations.
118 * Display:: Displaying handles.
119 * Display Customization:: Variables that affect display.
120 * Files and Directories:: Saving and naming attachments.
121 * New Viewers:: How to write your own viewers.
128 The @code{mm-dissect-buffer} is the function responsible for dissecting
129 a @acronym{MIME} article. If given a multipart message, it will recursively
130 descend the message, following the structure, and return a tree of
131 @acronym{MIME} handles that describes the structure of the message.
135 @vindex mm-uu-configure-list
137 Gnus also understands some non-@acronym{MIME} attachments, such as
138 postscript, uuencode, binhex, yenc, shar, forward, gnatsweb, pgp,
139 diff. Each of these features can be disabled by add an item into
140 @code{mm-uu-configure-list}. For example,
144 (add-to-list 'mm-uu-configure-list '(pgp-signed . disabled))
170 Non-@acronym{MIME} forwarded message.
178 @acronym{PGP} signed clear text.
181 @findex pgp-encrypted
182 @acronym{PGP} encrypted clear text.
186 @acronym{PGP} public keys.
189 @findex emacs-sources
190 @vindex mm-uu-emacs-sources-regexp
191 Emacs source code. This item works only in the groups matching
192 @code{mm-uu-emacs-sources-regexp}.
196 @vindex mm-uu-diff-groups-regexp
197 Patches. This is intended for groups where diffs of committed files
198 are automatically sent to. It only works in groups matching
199 @code{mm-uu-diff-groups-regexp}.
206 A @acronym{MIME} handle is a list that fully describes a @acronym{MIME}
209 The following macros can be used to access elements in a handle:
212 @item mm-handle-buffer
213 @findex mm-handle-buffer
214 Return the buffer that holds the contents of the undecoded @acronym{MIME}
218 @findex mm-handle-type
219 Return the parsed @code{Content-Type} of the part.
221 @item mm-handle-encoding
222 @findex mm-handle-encoding
223 Return the @code{Content-Transfer-Encoding} of the part.
225 @item mm-handle-undisplayer
226 @findex mm-handle-undisplayer
227 Return the object that can be used to remove the displayed part (if it
230 @item mm-handle-set-undisplayer
231 @findex mm-handle-set-undisplayer
232 Set the undisplayer object.
234 @item mm-handle-disposition
235 @findex mm-handle-disposition
236 Return the parsed @code{Content-Disposition} of the part.
238 @item mm-handle-disposition
239 @findex mm-handle-disposition
240 Return the description of the part.
242 @item mm-get-content-id
243 Returns the handle(s) referred to by @code{Content-ID}.
251 Functions for displaying, removing and saving.
254 @item mm-display-part
255 @findex mm-display-part
259 @findex mm-remove-part
260 Remove the part (if it has been displayed).
263 @findex mm-inlinable-p
264 Say whether a @acronym{MIME} type can be displayed inline.
266 @item mm-automatic-display-p
267 @findex mm-automatic-display-p
268 Say whether a @acronym{MIME} type should be displayed automatically.
270 @item mm-destroy-part
271 @findex mm-destroy-part
272 Free all resources occupied by a part.
276 Offer to save the part in a file.
280 Offer to pipe the part to some process.
282 @item mm-interactively-view-part
283 @findex mm-interactively-view-part
284 Prompt for a mailcap method to use to view the part.
289 @node Display Customization
290 @section Display Customization
294 @item mm-inline-media-tests
295 @vindex mm-inline-media-tests
296 This is an alist where the key is a @acronym{MIME} type, the second element
297 is a function to display the part @dfn{inline} (i.e., inside Emacs), and
298 the third element is a form to be @code{eval}ed to say whether the part
299 can be displayed inline.
301 This variable specifies whether a part @emph{can} be displayed inline,
302 and, if so, how to do it. It does not say whether parts are
303 @emph{actually} displayed inline.
305 @item mm-inlined-types
306 @vindex mm-inlined-types
307 This, on the other hand, says what types are to be displayed inline, if
308 they satisfy the conditions set by the variable above. It's a list of
309 @acronym{MIME} media types.
311 @item mm-automatic-display
312 @vindex mm-automatic-display
313 This is a list of types that are to be displayed ``automatically'', but
314 only if the above variable allows it. That is, only inlinable parts can
315 be displayed automatically.
317 @item mm-automatic-external-display
318 @vindex mm-automatic-external-display
319 This is a list of types that will be displayed automatically in an
322 @item mm-keep-viewer-alive-types
323 @vindex mm-keep-viewer-alive-types
324 This is a list of media types for which the external viewer will not
325 be killed when selecting a different article.
327 @item mm-attachment-override-types
328 @vindex mm-attachment-override-types
329 Some @acronym{MIME} agents create parts that have a content-disposition of
330 @samp{attachment}. This variable allows overriding that disposition and
331 displaying the part inline. (Note that the disposition is only
332 overridden if we are able to, and want to, display the part inline.)
334 @item mm-discouraged-alternatives
335 @vindex mm-discouraged-alternatives
336 List of @acronym{MIME} types that are discouraged when viewing
337 @samp{multipart/alternative}. Viewing agents are supposed to view the
338 last possible part of a message, as that is supposed to be the richest.
339 However, users may prefer other types instead, and this list says what
340 types are most unwanted. If, for instance, @samp{text/html} parts are
341 very unwanted, and @samp{text/richtext} parts are somewhat unwanted,
342 you could say something like:
345 (setq mm-discouraged-alternatives
346 '("text/html" "text/richtext")
348 (remove "text/html" mm-automatic-display))
351 @item mm-inline-large-images
352 @vindex mm-inline-large-images
353 When displaying inline images that are larger than the window, XEmacs
354 does not enable scrolling, which means that you cannot see the whole
355 image. To prevent this, the library tries to determine the image size
356 before displaying it inline, and if it doesn't fit the window, the
357 library will display it externally (e.g. with @samp{ImageMagick} or
358 @samp{xv}). Setting this variable to @code{t} disables this check and
359 makes the library display all inline images as inline, regardless of
362 @item mm-inline-override-types
363 @vindex mm-inline-override-types
364 @code{mm-inlined-types} may include regular expressions, for example to
365 specify that all @samp{text/.*} parts be displayed inline. If a user
366 prefers to have a type that matches such a regular expression be treated
367 as an attachment, that can be accomplished by setting this variable to a
368 list containing that type. For example assuming @code{mm-inlined-types}
369 includes @samp{text/.*}, then including @samp{text/html} in this
370 variable will cause @samp{text/html} parts to be treated as attachments.
372 @item mm-text-html-renderer
373 @vindex mm-text-html-renderer
374 This selects the function used to render @acronym{HTML}. The predefined
375 renderers are selected by the symbols @code{w3},
376 @code{w3m}@footnote{See @uref{http://emacs-w3m.namazu.org/} for more
377 information about emacs-w3m}, @code{links}, @code{lynx},
378 @code{w3m-standalone} or @code{html2text}. If @code{nil} use an
379 external viewer. You can also specify a function, which will be
380 called with a @acronym{MIME} handle as the argument.
382 @item mm-inline-text-html-with-images
383 @vindex mm-inline-text-html-with-images
384 Some @acronym{HTML} mails might have the trick of spammers using
385 @samp{<img>} tags. It is likely to be intended to verify whether you
386 have read the mail. You can prevent your personal informations from
387 leaking by setting this option to @code{nil} (which is the default).
388 It is currently ignored by Emacs/w3. For emacs-w3m, you may use the
389 command @kbd{t} on the image anchor to show an image even if it is
390 @code{nil}.@footnote{The command @kbd{T} will load all images. If you
391 have set the option @code{w3m-key-binding} to @code{info}, use @kbd{i}
394 @item mm-w3m-safe-url-regexp
395 @vindex mm-w3m-safe-url-regexp
396 A regular expression that matches safe URL names, i.e. URLs that are
397 unlikely to leak personal information when rendering @acronym{HTML}
398 email (the default value is @samp{\\`cid:}). If @code{nil} consider
401 @item mm-inline-text-html-with-w3m-keymap
402 @vindex mm-inline-text-html-with-w3m-keymap
403 You can use emacs-w3m command keys in the inlined text/html part by
404 setting this option to non-@code{nil}. The default value is @code{t}.
406 @item mm-external-terminal-program
407 @vindex mm-external-terminal-program
408 The program used to start an external terminal.
412 @node Files and Directories
413 @section Files and Directories
417 @item mm-default-directory
418 @vindex mm-default-directory
419 The default directory for saving attachments. If @code{nil} use
420 @code{default-directory}.
422 @item mm-tmp-directory
423 @vindex mm-tmp-directory
424 Directory for storing temporary files.
426 @item mm-file-name-rewrite-functions
427 @vindex mm-file-name-rewrite-functions
428 A list of functions used for rewriting file names of @acronym{MIME}
429 parts. Each function is applied successively to the file name.
430 Ready-made functions include
433 @item mm-file-name-delete-control
434 @findex mm-file-name-delete-control
435 Delete all control characters.
437 @item mm-file-name-delete-gotchas
438 @findex mm-file-name-delete-gotchas
439 Delete characters that could have unintended consequences when used
440 with flawed shell scripts, i.e. @samp{|}, @samp{>} and @samp{<}; and
441 @samp{-}, @samp{.} as the first character.
443 @item mm-file-name-delete-whitespace
444 @findex mm-file-name-delete-whitespace
445 Remove all whitespace.
447 @item mm-file-name-trim-whitespace
448 @findex mm-file-name-trim-whitespace
449 Remove leading and trailing whitespace.
451 @item mm-file-name-collapse-whitespace
452 @findex mm-file-name-collapse-whitespace
453 Collapse multiple whitespace characters.
455 @item mm-file-name-replace-whitespace
456 @findex mm-file-name-replace-whitespace
457 @vindex mm-file-name-replace-whitespace
458 Replace whitespace with underscores. Set the variable
459 @code{mm-file-name-replace-whitespace} to any other string if you do
460 not like underscores.
463 The standard Emacs functions @code{capitalize}, @code{downcase},
464 @code{upcase} and @code{upcase-initials} might also prove useful.
466 @item mm-path-name-rewrite-functions
467 @vindex mm-path-name-rewrite-functions
468 List of functions used for rewriting the full file names of @acronym{MIME}
469 parts. This is used when viewing parts externally, and is meant for
470 transforming the absolute name so that non-compliant programs can find
471 the file where it's saved.
478 Here's an example viewer for displaying @code{text/enriched} inline:
481 (defun mm-display-enriched-inline (handle)
484 (mm-insert-part handle)
485 (save-window-excursion
486 (enriched-decode (point-min) (point-max))
487 (setq text (buffer-string))))
488 (mm-insert-inline handle text)))
491 We see that the function takes a @acronym{MIME} handle as its parameter. It
492 then goes to a temporary buffer, inserts the text of the part, does some
493 work on the text, stores the result, goes back to the buffer it was
494 called from and inserts the result.
496 The two important helper functions here are @code{mm-insert-part} and
497 @code{mm-insert-inline}. The first function inserts the text of the
498 handle in the current buffer. It handles charset and/or content
499 transfer decoding. The second function just inserts whatever text you
500 tell it to insert, but it also sets things up so that the text can be
501 ``undisplayed'' in a convenient manner.
507 @cindex MIME Composing
509 @cindex MIME Meta Language
511 Creating a @acronym{MIME} message is boring and non-trivial. Therefore, a
512 library called @code{mml} has been defined that parses a language called
513 MML (@acronym{MIME} Meta Language) and generates @acronym{MIME} messages.
515 @findex mml-generate-mime
516 The main interface function is @code{mml-generate-mime}. It will
517 examine the contents of the current (narrowed-to) buffer and return a
518 string containing the @acronym{MIME} message.
521 * Simple MML Example:: An example MML document.
522 * MML Definition:: All valid MML elements.
523 * Advanced MML Example:: Another example MML document.
524 * Encoding Customization:: Variables that affect encoding.
525 * Charset Translation:: How charsets are mapped from @sc{mule} to @acronym{MIME}.
526 * Conversion:: Going from @acronym{MIME} to MML and vice versa.
527 * Flowed text:: Soft and hard newlines.
531 @node Simple MML Example
532 @section Simple MML Example
534 Here's a simple @samp{multipart/alternative}:
537 <#multipart type=alternative>
538 This is a plain text part.
539 <#part type=text/enriched>
540 <center>This is a centered enriched part</center>
544 After running this through @code{mml-generate-mime}, we get this:
547 Content-Type: multipart/alternative; boundary="=-=-="
553 This is a plain text part.
556 Content-Type: text/enriched
559 <center>This is a centered enriched part</center>
566 @section MML Definition
568 The MML language is very simple. It looks a bit like an SGML
569 application, but it's not.
571 The main concept of MML is the @dfn{part}. Each part can be of a
572 different type or use a different charset. The way to delineate a part
573 is with a @samp{<#part ...>} tag. Multipart parts can be introduced
574 with the @samp{<#multipart ...>} tag. Parts are ended by the
575 @samp{<#/part>} or @samp{<#/multipart>} tags. Parts started with the
576 @samp{<#part ...>} tags are also closed by the next open tag.
578 There's also the @samp{<#external ...>} tag. These introduce
579 @samp{external/message-body} parts.
581 Each tag can contain zero or more parameters on the form
582 @samp{parameter=value}. The values may be enclosed in quotation marks,
583 but that's not necessary unless the value contains white space. So
584 @samp{filename=/home/user/#hello$^yes} is perfectly valid.
586 The following parameters have meaning in MML; parameters that have no
587 meaning are ignored. The MML parameter names are the same as the
588 @acronym{MIME} parameter names; the things in the parentheses say which
589 header it will be used in.
593 The @acronym{MIME} type of the part (@code{Content-Type}).
596 Use the contents of the file in the body of the part
597 (@code{Content-Disposition}).
600 The contents of the body of the part are to be encoded in the character
601 set specified (@code{Content-Type}). @xref{Charset Translation}.
604 Might be used to suggest a file name if the part is to be saved
605 to a file (@code{Content-Type}).
608 Valid values are @samp{inline} and @samp{attachment}
609 (@code{Content-Disposition}).
612 Valid values are @samp{7bit}, @samp{8bit}, @samp{quoted-printable} and
613 @samp{base64} (@code{Content-Transfer-Encoding}). @xref{Charset
617 A description of the part (@code{Content-Description}).
620 RFC822 date when the part was created (@code{Content-Disposition}).
622 @item modification-date
623 RFC822 date when the part was modified (@code{Content-Disposition}).
626 RFC822 date when the part was read (@code{Content-Disposition}).
629 Who to encrypt/sign the part to. This field is used to override any
630 auto-detection based on the To/CC headers.
633 Identity used to sign the part. This field is used to override the
637 The size (in octets) of the part (@code{Content-Disposition}).
640 What technology to sign this MML part with (@code{smime}, @code{pgp}
644 What technology to encrypt this MML part with (@code{smime},
645 @code{pgp} or @code{pgpmime})
649 Parameters for @samp{application/octet-stream}:
653 Type of the part; informal---meant for human readers
654 (@code{Content-Type}).
657 Parameters for @samp{message/external-body}:
661 A word indicating the supported access mechanism by which the file may
662 be obtained. Values include @samp{ftp}, @samp{anon-ftp}, @samp{tftp},
663 @samp{localfile}, and @samp{mailserver}. (@code{Content-Type}.)
666 The RFC822 date after which the file may no longer be fetched.
667 (@code{Content-Type}.)
670 The size (in octets) of the file. (@code{Content-Type}.)
673 Valid values are @samp{read} and @samp{read-write}
674 (@code{Content-Type}).
678 Parameters for @samp{sign=smime}:
683 File containing key and certificate for signer.
687 Parameters for @samp{encrypt=smime}:
692 File containing certificate for recipient.
697 @node Advanced MML Example
698 @section Advanced MML Example
700 Here's a complex multipart message. It's a @samp{multipart/mixed} that
701 contains many parts, one of which is a @samp{multipart/alternative}.
704 <#multipart type=mixed>
705 <#part type=image/jpeg filename=~/rms.jpg disposition=inline>
706 <#multipart type=alternative>
707 This is a plain text part.
708 <#part type=text/enriched name=enriched.txt>
709 <center>This is a centered enriched part</center>
711 This is a new plain text part.
712 <#part disposition=attachment>
713 This plain text part is an attachment.
717 And this is the resulting @acronym{MIME} message:
720 Content-Type: multipart/mixed; boundary="=-=-="
728 Content-Type: image/jpeg;
730 Content-Disposition: inline;
732 Content-Transfer-Encoding: base64
734 /9j/4AAQSkZJRgABAQAAAQABAAD/2wBDAAgGBgcGBQgHBwcJCQgKDBQNDAsLDBkSEw8UHRof
735 Hh0aHBwgJC4nICIsIxwcKDcpLDAxNDQ0Hyc5PTgyPC4zNDL/wAALCAAwADABAREA/8QAHwAA
736 AQUBAQEBAQEAAAAAAAAAAAECAwQFBgcICQoL/8QAtRAAAgEDAwIEAwUFBAQAAAF9AQIDAAQR
737 BRIhMUEGE1FhByJxFDKBkaEII0KxwRVS0fAkM2JyggkKFhcYGRolJicoKSo0NTY3ODk6Q0RF
738 RkdISUpTVFVWV1hZWmNkZWZnaGlqc3R1dnd4eXqDhIWGh4iJipKTlJWWl5iZmqKjpKWmp6ip
739 qrKztLW2t7i5usLDxMXGx8jJytLT1NXW19jZ2uHi4+Tl5ufo6erx8vP09fb3+Pn6/9oACAEB
740 AAA/AO/rifFHjldNuGsrDa0qcSSHkA+gHrXKw+LtWLrMb+RgTyhbr+HSug07xNqV9fQtZrNI
741 AyiaE/NuBPOOOP0rvRNE880KOC8TbXXGCv1FPqjrF4LDR7u5L7SkTFT/ALWOP1xXgTuXfc7E
742 sx6nua6rwp4IvvEM8chCxWxOdzn7wz6V9AaB4S07w9p5itow0rDLSY5Pt9K43xO66P4xs71m
743 2QXiGCbA4yOVJ9+1aYORkdK434lyNH4ahCnG66VT9Nj15JFbPdX0MS43M4VQf5/yr2vSpLnw
744 5ZW8dlCZ8KFXjOPX0/mK6rSPEGt3Angu44fNEReHYNvIH3TzXDeKNO8RX+kSX2ouZkicTIOc
745 L+g7E810ulFjpVtv3bwgB3HJyK5L4quY/C9sVxk3ij/xx6850u7t1mtp/wDlpEw3An3Jr3Dw
746 34gsbWza4nBlhC5LDsaW6+IFgupQyCF3iHH7gA7c9R9ay7zx6t7aX9jHC4smhfBkGCvHGfrm
747 tLQ7hbnRrV1GPkAP1x1/Hr+Ncr8Vzjwrbf8AX6v/AKA9eQRyYlQk8Yx9K6XTNbkgia2ciSIn
748 7p5Ga9Atte0LTLKO6it4i7dVRFJDcZ4PvXN+JvEMF9bILVGXJLSZ4zkjivRPDaeX4b08HOTC
749 pOffmua+KkbS+GLVUGT9tT/0B68eeIpIFYjB70+OOVXyoOM9+M1eaWeCLzHPyHGO/NVWvJJm
750 jQ8KGH1NfQWhXSXmh2c8eArRLwO3HSv/2Q==
753 Content-Type: multipart/alternative; boundary="==-=-="
759 This is a plain text part.
762 Content-Type: text/enriched;
766 <center>This is a centered enriched part</center>
772 This is a new plain text part.
775 Content-Disposition: attachment
778 This plain text part is an attachment.
783 @node Encoding Customization
784 @section Encoding Customization
788 @item mm-body-charset-encoding-alist
789 @vindex mm-body-charset-encoding-alist
790 Mapping from @acronym{MIME} charset to encoding to use. This variable is
791 usually used except, e.g., when other requirements force a specific
792 encoding (digitally signed messages require 7bit encodings). The
796 ((iso-2022-jp . 7bit)
797 (iso-2022-jp-2 . 7bit)
803 As an example, if you do not want to have ISO-8859-1 characters
804 quoted-printable encoded, you may add @code{(iso-8859-1 . 8bit)} to
805 this variable. You can override this setting on a per-message basis
806 by using the @code{encoding} MML tag (@pxref{MML Definition}).
808 @item mm-coding-system-priorities
809 @vindex mm-coding-system-priorities
810 Prioritize coding systems to use for outgoing messages. The default
811 is @code{nil}, which means to use the defaults in Emacs. It is a list of
812 coding system symbols (aliases of coding systems does not work, use
813 @kbd{M-x describe-coding-system} to make sure you are not specifying
814 an alias in this variable). For example, if you have configured Emacs
815 to prefer UTF-8, but wish that outgoing messages should be sent in
816 ISO-8859-1 if possible, you can set this variable to
817 @code{(iso-latin-1)}. You can override this setting on a per-message
818 basis by using the @code{charset} MML tag (@pxref{MML Definition}).
820 @item mm-content-transfer-encoding-defaults
821 @vindex mm-content-transfer-encoding-defaults
822 Mapping from @acronym{MIME} types to encoding to use. This variable is usually
823 used except, e.g., when other requirements force a safer encoding
824 (digitally signed messages require 7bit encoding). Besides the normal
825 @acronym{MIME} encodings, @code{qp-or-base64} may be used to indicate that for
826 each case the most efficient of quoted-printable and base64 should be
827 used. You can override this setting on a per-message basis by using
828 the @code{encoding} MML tag (@pxref{MML Definition}).
830 @item mm-use-ultra-safe-encoding
831 @vindex mm-use-ultra-safe-encoding
832 When this is non-@code{nil}, it means that textual parts are encoded as
833 quoted-printable if they contain lines longer than 76 characters or
834 starting with "From " in the body. Non-7bit encodings (8bit, binary)
835 are generally disallowed. This reduce the probability that a non-8bit
836 clean MTA or MDA changes the message. This should never be set
837 directly, but bound by other functions when necessary (e.g., when
838 encoding messages that are to be digitally signed).
842 @node Charset Translation
843 @section Charset Translation
846 During translation from MML to @acronym{MIME}, for each @acronym{MIME} part which
847 has been composed inside Emacs, an appropriate charset has to be chosen.
849 @vindex mail-parse-charset
850 If you are running a non-@sc{mule} Emacs, this process is simple: If the
851 part contains any non-@acronym{ASCII} (8-bit) characters, the @acronym{MIME} charset
852 given by @code{mail-parse-charset} (a symbol) is used. (Never set this
853 variable directly, though. If you want to change the default charset,
854 please consult the documentation of the package which you use to process
855 @acronym{MIME} messages.
856 @xref{Various Message Variables, , Various Message Variables, message,
857 Message Manual}, for example.)
858 If there are only @acronym{ASCII} characters, the @acronym{MIME} charset US-ASCII is
864 @vindex mm-mime-mule-charset-alist
865 Things are slightly more complicated when running Emacs with @sc{mule}
866 support. In this case, a list of the @sc{mule} charsets used in the
867 part is obtained, and the @sc{mule} charsets are translated to @acronym{MIME}
868 charsets by consulting the variable @code{mm-mime-mule-charset-alist}.
869 If this results in a single @acronym{MIME} charset, this is used to encode
870 the part. But if the resulting list of @acronym{MIME} charsets contains more
871 than one element, two things can happen: If it is possible to encode the
872 part via UTF-8, this charset is used. (For this, Emacs must support
873 the @code{utf-8} coding system, and the part must consist entirely of
874 characters which have Unicode counterparts.) If UTF-8 is not available
875 for some reason, the part is split into several ones, so that each one
876 can be encoded with a single @acronym{MIME} charset. The part can only be
877 split at line boundaries, though---if more than one @acronym{MIME} charset is
878 required to encode a single line, it is not possible to encode the part.
880 When running Emacs with @sc{mule} support, the preferences for which
881 coding system to use is inherited from Emacs itself. This means that
882 if Emacs is set up to prefer UTF-8, it will be used when encoding
883 messages. You can modify this by altering the
884 @code{mm-coding-system-priorities} variable though (@pxref{Encoding
887 The charset to be used can be overridden by setting the @code{charset}
888 MML tag (@pxref{MML Definition}) when composing the message.
890 The encoding of characters (quoted-printable, 8bit etc) is orthogonal
891 to the discussion here, and is controlled by the variables
892 @code{mm-body-charset-encoding-alist} and
893 @code{mm-content-transfer-encoding-defaults} (@pxref{Encoding
900 A (multipart) @acronym{MIME} message can be converted to MML with the
901 @code{mime-to-mml} function. It works on the message in the current
902 buffer, and substitutes MML markup for @acronym{MIME} boundaries.
903 Non-textual parts do not have their contents in the buffer, but instead
904 have the contents in separate buffers that are referred to from the MML
908 An MML message can be converted back to @acronym{MIME} by the
909 @code{mml-to-mime} function.
911 These functions are in certain senses ``lossy''---you will not get back
912 an identical message if you run @code{mime-to-mml} and then
913 @code{mml-to-mime}. Not only will trivial things like the order of the
914 headers differ, but the contents of the headers may also be different.
915 For instance, the original message may use base64 encoding on text,
916 while @code{mml-to-mime} may decide to use quoted-printable encoding, and
919 In essence, however, these two functions should be the inverse of each
920 other. The resulting contents of the message should remain equivalent,
926 @cindex format=flowed
928 The Emacs @acronym{MIME} library will respect the @code{use-hard-newlines}
929 variable (@pxref{Hard and Soft Newlines, ,Hard and Soft Newlines,
930 emacs, Emacs Manual}) when encoding a message, and the
931 ``format=flowed'' Content-Type parameter when decoding a message.
933 On encoding text, lines terminated by soft newline characters are
934 filled together and wrapped after the column decided by
935 @code{fill-flowed-encode-column}. This variable controls how the text
936 will look in a client that does not support flowed text, the default
937 is to wrap after 66 characters. If hard newline characters are not
938 present in the buffer, no flow encoding occurs.
940 On decoding flowed text, lines with soft newline characters are filled
941 together and wrapped after the column decided by
942 @code{fill-flowed-display-column}. The default is to wrap after
948 @node Interface Functions
949 @chapter Interface Functions
950 @cindex interface functions
953 The @code{mail-parse} library is an abstraction over the actual
954 low-level libraries that are described in the next chapter.
956 Standards change, and so programs have to change to fit in the new
957 mold. For instance, RFC2045 describes a syntax for the
958 @code{Content-Type} header that only allows @acronym{ASCII} characters in the
959 parameter list. RFC2231 expands on RFC2045 syntax to provide a scheme
960 for continuation headers and non-@acronym{ASCII} characters.
962 The traditional way to deal with this is just to update the library
963 functions to parse the new syntax. However, this is sometimes the wrong
964 thing to do. In some instances it may be vital to be able to understand
965 both the old syntax as well as the new syntax, and if there is only one
966 library, one must choose between the old version of the library and the
967 new version of the library.
969 The Emacs @acronym{MIME} library takes a different tack. It defines a
970 series of low-level libraries (@file{rfc2047.el}, @file{rfc2231.el}
971 and so on) that parses strictly according to the corresponding
972 standard. However, normal programs would not use the functions
973 provided by these libraries directly, but instead use the functions
974 provided by the @code{mail-parse} library. The functions in this
975 library are just aliases to the corresponding functions in the latest
976 low-level libraries. Using this scheme, programs get a consistent
977 interface they can use, and library developers are free to create
978 write code that handles new standards.
980 The following functions are defined by this library:
983 @item mail-header-parse-content-type
984 @findex mail-header-parse-content-type
985 Parse a @code{Content-Type} header and return a list on the following
990 (attribute1 . value1)
991 (attribute2 . value2)
998 (mail-header-parse-content-type
999 "image/gif; name=\"b980912.gif\"")
1000 @result{} ("image/gif" (name . "b980912.gif"))
1003 @item mail-header-parse-content-disposition
1004 @findex mail-header-parse-content-disposition
1005 Parse a @code{Content-Disposition} header and return a list on the same
1006 format as the function above.
1008 @item mail-content-type-get
1009 @findex mail-content-type-get
1010 Takes two parameters---a list on the format above, and an attribute.
1011 Returns the value of the attribute.
1014 (mail-content-type-get
1015 '("image/gif" (name . "b980912.gif")) 'name)
1016 @result{} "b980912.gif"
1019 @item mail-header-encode-parameter
1020 @findex mail-header-encode-parameter
1021 Takes a parameter string and returns an encoded version of the string.
1022 This is used for parameters in headers like @code{Content-Type} and
1023 @code{Content-Disposition}.
1025 @item mail-header-remove-comments
1026 @findex mail-header-remove-comments
1027 Return a comment-free version of a header.
1030 (mail-header-remove-comments
1031 "Gnus/5.070027 (Pterodactyl Gnus v0.27) (Finnish Landrace)")
1032 @result{} "Gnus/5.070027 "
1035 @item mail-header-remove-whitespace
1036 @findex mail-header-remove-whitespace
1037 Remove linear white space from a header. Space inside quoted strings
1038 and comments is preserved.
1041 (mail-header-remove-whitespace
1042 "image/gif; name=\"Name with spaces\"")
1043 @result{} "image/gif;name=\"Name with spaces\""
1046 @item mail-header-get-comment
1047 @findex mail-header-get-comment
1048 Return the last comment in a header.
1051 (mail-header-get-comment
1052 "Gnus/5.070027 (Pterodactyl Gnus v0.27) (Finnish Landrace)")
1053 @result{} "Finnish Landrace"
1056 @item mail-header-parse-address
1057 @findex mail-header-parse-address
1058 Parse an address and return a list containing the mailbox and the
1062 (mail-header-parse-address
1063 "Hrvoje Niksic <hniksic@@srce.hr>")
1064 @result{} ("hniksic@@srce.hr" . "Hrvoje Niksic")
1067 @item mail-header-parse-addresses
1068 @findex mail-header-parse-addresses
1069 Parse a string with list of addresses and return a list of elements like
1070 the one described above.
1073 (mail-header-parse-addresses
1074 "Hrvoje Niksic <hniksic@@srce.hr>, Steinar Bang <sb@@metis.no>")
1075 @result{} (("hniksic@@srce.hr" . "Hrvoje Niksic")
1076 ("sb@@metis.no" . "Steinar Bang"))
1079 @item mail-header-parse-date
1080 @findex mail-header-parse-date
1081 Parse a date string and return an Emacs time structure.
1083 @item mail-narrow-to-head
1084 @findex mail-narrow-to-head
1085 Narrow the buffer to the header section of the buffer. Point is placed
1086 at the beginning of the narrowed buffer.
1088 @item mail-header-narrow-to-field
1089 @findex mail-header-narrow-to-field
1090 Narrow the buffer to the header under point. Understands continuation
1093 @item mail-header-fold-field
1094 @findex mail-header-fold-field
1095 Fold the header under point.
1097 @item mail-header-unfold-field
1098 @findex mail-header-unfold-field
1099 Unfold the header under point.
1101 @item mail-header-field-value
1102 @findex mail-header-field-value
1103 Return the value of the field under point.
1105 @item mail-encode-encoded-word-region
1106 @findex mail-encode-encoded-word-region
1107 Encode the non-@acronym{ASCII} words in the region. For instance,
1108 @samp{Naïve} is encoded as @samp{=?iso-8859-1?q?Na=EFve?=}.
1110 @item mail-encode-encoded-word-buffer
1111 @findex mail-encode-encoded-word-buffer
1112 Encode the non-@acronym{ASCII} words in the current buffer. This function is
1113 meant to be called narrowed to the headers of a message.
1115 @item mail-encode-encoded-word-string
1116 @findex mail-encode-encoded-word-string
1117 Encode the words that need encoding in a string, and return the result.
1120 (mail-encode-encoded-word-string
1121 "This is naïve, baby")
1122 @result{} "This is =?iso-8859-1?q?na=EFve,?= baby"
1125 @item mail-decode-encoded-word-region
1126 @findex mail-decode-encoded-word-region
1127 Decode the encoded words in the region.
1129 @item mail-decode-encoded-word-string
1130 @findex mail-decode-encoded-word-string
1131 Decode the encoded words in the string and return the result.
1134 (mail-decode-encoded-word-string
1135 "This is =?iso-8859-1?q?na=EFve,?= baby")
1136 @result{} "This is naïve, baby"
1141 Currently, @code{mail-parse} is an abstraction over @code{ietf-drums},
1142 @code{rfc2047}, @code{rfc2045} and @code{rfc2231}. These are documented
1143 in the subsequent sections.
1147 @node Basic Functions
1148 @chapter Basic Functions
1150 This chapter describes the basic, ground-level functions for parsing and
1151 handling. Covered here is parsing @code{From} lines, removing comments
1152 from header lines, decoding encoded words, parsing date headers and so
1153 on. High-level functionality is dealt with in the next chapter
1154 (@pxref{Decoding and Viewing}).
1157 * rfc2045:: Encoding @code{Content-Type} headers.
1158 * rfc2231:: Parsing @code{Content-Type} headers.
1159 * ietf-drums:: Handling mail headers defined by RFC822bis.
1160 * rfc2047:: En/decoding encoded words in headers.
1161 * time-date:: Functions for parsing dates and manipulating time.
1162 * qp:: Quoted-Printable en/decoding.
1163 * base64:: Base64 en/decoding.
1164 * binhex:: Binhex decoding.
1165 * uudecode:: Uuencode decoding.
1166 * yenc:: Yenc decoding.
1167 * rfc1843:: Decoding HZ-encoded text.
1168 * mailcap:: How parts are displayed is specified by the @file{.mailcap} file
1175 RFC2045 is the ``main'' @acronym{MIME} document, and as such, one would
1176 imagine that there would be a lot to implement. But there isn't, since
1177 most of the implementation details are delegated to the subsequent
1180 So @file{rfc2045.el} has only a single function:
1183 @item rfc2045-encode-string
1184 @findex rfc2045-encode-string
1185 Takes a parameter and a value and returns a @samp{PARAM=VALUE} string.
1186 @var{value} will be quoted if there are non-safe characters in it.
1193 RFC2231 defines a syntax for the @code{Content-Type} and
1194 @code{Content-Disposition} headers. Its snappy name is @dfn{MIME
1195 Parameter Value and Encoded Word Extensions: Character Sets, Languages,
1198 In short, these headers look something like this:
1201 Content-Type: application/x-stuff;
1202 title*0*=us-ascii'en'This%20is%20even%20more%20;
1203 title*1*=%2A%2A%2Afun%2A%2A%2A%20;
1207 They usually aren't this bad, though.
1209 The following functions are defined by this library:
1212 @item rfc2231-parse-string
1213 @findex rfc2231-parse-string
1214 Parse a @code{Content-Type} header and return a list describing its
1218 (rfc2231-parse-string
1219 "application/x-stuff;
1220 title*0*=us-ascii'en'This%20is%20even%20more%20;
1221 title*1*=%2A%2A%2Afun%2A%2A%2A%20;
1222 title*2=\"isn't it!\"")
1223 @result{} ("application/x-stuff"
1224 (title . "This is even more ***fun*** isn't it!"))
1227 @item rfc2231-get-value
1228 @findex rfc2231-get-value
1229 Takes one of the lists on the format above and returns
1230 the value of the specified attribute.
1232 @item rfc2231-encode-string
1233 @findex rfc2231-encode-string
1234 Encode a parameter in headers likes @code{Content-Type} and
1235 @code{Content-Disposition}.
1243 @dfn{drums} is an IETF working group that is working on the replacement
1246 The functions provided by this library include:
1249 @item ietf-drums-remove-comments
1250 @findex ietf-drums-remove-comments
1251 Remove the comments from the argument and return the results.
1253 @item ietf-drums-remove-whitespace
1254 @findex ietf-drums-remove-whitespace
1255 Remove linear white space from the string and return the results.
1256 Spaces inside quoted strings and comments are left untouched.
1258 @item ietf-drums-get-comment
1259 @findex ietf-drums-get-comment
1260 Return the last most comment from the string.
1262 @item ietf-drums-parse-address
1263 @findex ietf-drums-parse-address
1264 Parse an address string and return a list that contains the mailbox and
1265 the plain text name.
1267 @item ietf-drums-parse-addresses
1268 @findex ietf-drums-parse-addresses
1269 Parse a string that contains any number of comma-separated addresses and
1270 return a list that contains mailbox/plain text pairs.
1272 @item ietf-drums-parse-date
1273 @findex ietf-drums-parse-date
1274 Parse a date string and return an Emacs time structure.
1276 @item ietf-drums-narrow-to-header
1277 @findex ietf-drums-narrow-to-header
1278 Narrow the buffer to the header section of the current buffer.
1286 RFC2047 (Message Header Extensions for Non-@acronym{ASCII} Text) specifies how
1287 non-@acronym{ASCII} text in headers are to be encoded. This is actually rather
1288 complicated, so a number of variables are necessary to tweak what this
1291 The following variables are tweakable:
1294 @item rfc2047-default-charset
1295 @vindex rfc2047-default-charset
1296 Characters in this charset should not be decoded by this library.
1297 This defaults to @code{iso-8859-1}.
1299 @item rfc2047-header-encoding-alist
1300 @vindex rfc2047-header-encoding-alist
1301 This is an alist of header / encoding-type pairs. Its main purpose is
1302 to prevent encoding of certain headers.
1304 The keys can either be header regexps, or @code{t}.
1306 The values can be either @code{nil}, in which case the header(s) in
1307 question won't be encoded, or @code{mime}, which means that they will be
1310 @item rfc2047-charset-encoding-alist
1311 @vindex rfc2047-charset-encoding-alist
1312 RFC2047 specifies two forms of encoding---@code{Q} (a
1313 Quoted-Printable-like encoding) and @code{B} (base64). This alist
1314 specifies which charset should use which encoding.
1316 @item rfc2047-encoding-function-alist
1317 @vindex rfc2047-encoding-function-alist
1318 This is an alist of encoding / function pairs. The encodings are
1319 @code{Q}, @code{B} and @code{nil}.
1321 @item rfc2047-q-encoding-alist
1322 @vindex rfc2047-q-encoding-alist
1323 The @code{Q} encoding isn't quite the same for all headers. Some
1324 headers allow a narrower range of characters, and that is what this
1325 variable is for. It's an alist of header regexps / allowable character
1328 @item rfc2047-encoded-word-regexp
1329 @vindex rfc2047-encoded-word-regexp
1330 When decoding words, this library looks for matches to this regexp.
1334 Those were the variables, and these are this functions:
1337 @item rfc2047-narrow-to-field
1338 @findex rfc2047-narrow-to-field
1339 Narrow the buffer to the header on the current line.
1341 @item rfc2047-encode-message-header
1342 @findex rfc2047-encode-message-header
1343 Should be called narrowed to the header of a message. Encodes according
1344 to @code{rfc2047-header-encoding-alist}.
1346 @item rfc2047-encode-region
1347 @findex rfc2047-encode-region
1348 Encodes all encodable words in the region specified.
1350 @item rfc2047-encode-string
1351 @findex rfc2047-encode-string
1352 Encode a string and return the results.
1354 @item rfc2047-decode-region
1355 @findex rfc2047-decode-region
1356 Decode the encoded words in the region.
1358 @item rfc2047-decode-string
1359 @findex rfc2047-decode-string
1360 Decode a string and return the results.
1368 While not really a part of the @acronym{MIME} library, it is convenient to
1369 document this library here. It deals with parsing @code{Date} headers
1370 and manipulating time. (Not by using tesseracts, though, I'm sorry to
1373 These functions convert between five formats: A date string, an Emacs
1374 time structure, a decoded time list, a second number, and a day number.
1376 Here's a bunch of time/date/second/day examples:
1379 (parse-time-string "Sat Sep 12 12:21:54 1998 +0200")
1380 @result{} (54 21 12 12 9 1998 6 nil 7200)
1382 (date-to-time "Sat Sep 12 12:21:54 1998 +0200")
1383 @result{} (13818 19266)
1385 (time-to-seconds '(13818 19266))
1386 @result{} 905595714.0
1388 (seconds-to-time 905595714.0)
1389 @result{} (13818 19266 0)
1391 (time-to-days '(13818 19266))
1394 (days-to-time 729644)
1395 @result{} (961933 65536)
1397 (time-since '(13818 19266))
1400 (time-less-p '(13818 19266) '(13818 19145))
1403 (subtract-time '(13818 19266) '(13818 19145))
1406 (days-between "Sat Sep 12 12:21:54 1998 +0200"
1407 "Sat Sep 07 12:21:54 1998 +0200")
1410 (date-leap-year-p 2000)
1413 (time-to-day-in-year '(13818 19266))
1416 (time-to-number-of-days
1418 (date-to-time "Mon, 01 Jan 2001 02:22:26 GMT")))
1419 @result{} 4.146122685185185
1422 And finally, we have @code{safe-date-to-time}, which does the same as
1423 @code{date-to-time}, but returns a zero time if the date is
1424 syntactically malformed.
1426 The five data representations used are the following:
1430 An RFC822 (or similar) date string. For instance: @code{"Sat Sep 12
1431 12:21:54 1998 +0200"}.
1434 An internal Emacs time. For instance: @code{(13818 26466)}.
1437 A floating point representation of the internal Emacs time. For
1438 instance: @code{905595714.0}.
1441 An integer number representing the number of days since 00000101. For
1442 instance: @code{729644}.
1445 A list of decoded time. For instance: @code{(54 21 12 12 9 1998 6 t
1449 All the examples above represent the same moment.
1451 These are the functions available:
1455 Take a date and return a time.
1457 @item time-to-seconds
1458 Take a time and return seconds.
1460 @item seconds-to-time
1461 Take seconds and return a time.
1464 Take a time and return days.
1467 Take days and return a time.
1470 Take a date and return days.
1472 @item time-to-number-of-days
1473 Take a time and return the number of days that represents.
1475 @item safe-date-to-time
1476 Take a date and return a time. If the date is not syntactically valid,
1477 return a ``zero'' date.
1480 Take two times and say whether the first time is less (i. e., earlier)
1481 than the second time.
1484 Take a time and return a time saying how long it was since that time.
1487 Take two times and subtract the second from the first. I. e., return
1488 the time between the two times.
1491 Take two days and return the number of days between those two days.
1493 @item date-leap-year-p
1494 Take a year number and say whether it's a leap year.
1496 @item time-to-day-in-year
1497 Take a time and return the day number within the year that the time is
1506 This library deals with decoding and encoding Quoted-Printable text.
1508 Very briefly explained, qp encoding means translating all 8-bit
1509 characters (and lots of control characters) into things that look like
1510 @samp{=EF}; that is, an equal sign followed by the byte encoded as a hex
1513 The following functions are defined by the library:
1516 @item quoted-printable-decode-region
1517 @findex quoted-printable-decode-region
1518 QP-decode all the encoded text in the specified region.
1520 @item quoted-printable-decode-string
1521 @findex quoted-printable-decode-string
1522 Decode the QP-encoded text in a string and return the results.
1524 @item quoted-printable-encode-region
1525 @findex quoted-printable-encode-region
1526 QP-encode all the encodable characters in the specified region. The third
1527 optional parameter @var{fold} specifies whether to fold long lines.
1528 (Long here means 72.)
1530 @item quoted-printable-encode-string
1531 @findex quoted-printable-encode-string
1532 QP-encode all the encodable characters in a string and return the
1542 Base64 is an encoding that encodes three bytes into four characters,
1543 thereby increasing the size by about 33%. The alphabet used for
1544 encoding is very resistant to mangling during transit.
1546 The following functions are defined by this library:
1549 @item base64-encode-region
1550 @findex base64-encode-region
1551 base64 encode the selected region. Return the length of the encoded
1552 text. Optional third argument @var{no-line-break} means do not break
1553 long lines into shorter lines.
1555 @item base64-encode-string
1556 @findex base64-encode-string
1557 base64 encode a string and return the result.
1559 @item base64-decode-region
1560 @findex base64-decode-region
1561 base64 decode the selected region. Return the length of the decoded
1562 text. If the region can't be decoded, return @code{nil} and don't
1565 @item base64-decode-string
1566 @findex base64-decode-string
1567 base64 decode a string and return the result. If the string can't be
1568 decoded, @code{nil} is returned.
1579 @code{binhex} is an encoding that originated in Macintosh environments.
1580 The following function is supplied to deal with these:
1583 @item binhex-decode-region
1584 @findex binhex-decode-region
1585 Decode the encoded text in the region. If given a third parameter, only
1586 decode the @code{binhex} header and return the filename.
1595 @code{uuencode} is probably still the most popular encoding of binaries
1596 used on Usenet, although @code{base64} rules the mail world.
1598 The following function is supplied by this package:
1601 @item uudecode-decode-region
1602 @findex uudecode-decode-region
1603 Decode the text in the region.
1611 @code{yenc} is used for encoding binaries on Usenet. The following
1612 function is supplied by this package:
1615 @item yenc-decode-region
1616 @findex yenc-decode-region
1617 Decode the encoded text in the region.
1628 RFC1843 deals with mixing Chinese and @acronym{ASCII} characters in messages. In
1629 essence, RFC1843 switches between @acronym{ASCII} and Chinese by doing this:
1632 This sentence is in @acronym{ASCII}.
1633 The next sentence is in GB.~@{<:Ky2;S@{#,NpJ)l6HK!#~@}Bye.
1636 Simple enough, and widely used in China.
1638 The following functions are available to handle this encoding:
1641 @item rfc1843-decode-region
1642 Decode HZ-encoded text in the region.
1644 @item rfc1843-decode-string
1645 Decode a HZ-encoded string and return the result.
1653 The @file{~/.mailcap} file is parsed by most @acronym{MIME}-aware message
1654 handlers and describes how elements are supposed to be displayed.
1655 Here's an example file:
1659 audio/wav; wavplayer %s
1660 application/msword; catdoc %s ; copiousoutput ; nametemplate=%s.doc
1663 This says that all image files should be displayed with @code{gimp},
1664 that WAVE audio files should be played by @code{wavplayer}, and that
1665 MS-WORD files should be inlined by @code{catdoc}.
1667 The @code{mailcap} library parses this file, and provides functions for
1671 @item mailcap-mime-data
1672 @vindex mailcap-mime-data
1673 This variable is an alist of alists containing backup viewing rules.
1677 Interface functions:
1680 @item mailcap-parse-mailcaps
1681 @findex mailcap-parse-mailcaps
1682 Parse the @file{~/.mailcap} file.
1684 @item mailcap-mime-info
1685 Takes a @acronym{MIME} type as its argument and returns the matching viewer.
1695 The Emacs @acronym{MIME} library implements handling of various elements
1696 according to a (somewhat) large number of RFCs, drafts and standards
1697 documents. This chapter lists the relevant ones. They can all be
1698 fetched from @uref{http://quimby.gnus.org/notes/}.
1703 Standard for the Format of ARPA Internet Text Messages.
1706 Standard for Interchange of USENET Messages
1709 Format of Internet Message Bodies
1715 Message Header Extensions for Non-@acronym{ASCII} Text
1718 Registration Procedures
1721 Conformance Criteria and Examples
1724 @acronym{MIME} Parameter Value and Encoded Word Extensions: Character Sets,
1725 Languages, and Continuations
1728 HZ - A Data Format for Exchanging Files of Arbitrarily Mixed Chinese and
1729 @acronym{ASCII} characters
1731 @item draft-ietf-drums-msg-fmt-05.txt
1732 Draft for the successor of RFC822
1735 The @acronym{MIME} Multipart/Related Content-type
1738 The Multipart/Report Content Type for the Reporting of Mail System
1739 Administrative Messages
1742 Communicating Presentation Information in Internet Messages: The
1743 Content-Disposition Header Field
1746 Documentation of the text/plain format parameter for flowed text.
1762 @c coding: iso-8859-1