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
81 This manual is directed at users who want to modify the behaviour of
82 the @sc{mime} encoding/decoding process or want a more detailed
83 picture of how the Emacs @sc{mime} library works, and people who want
84 to write functions and commands that manipulate @sc{mime} elements.
86 @sc{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-ASCII Text), RFC2048 (Registration
90 Procedures), RFC2049 (Conformance Criteria and Examples). It is highly
91 recommended that anyone who intends writing @sc{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 @sc{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 @sc{mime} messages on a
110 The main idea is to first analyze a @sc{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 @sc{mime} message.
116 * Non-MIME:: Analyzing a non-@sc{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 @sc{mime} article. If given a multipart message, it will recursively
130 descend the message, following the structure, and return a tree of
131 @sc{mime} handles that describes the structure of the message.
135 @vindex mm-uu-configure-list
137 Gnus also understands some non-@sc{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-@sc{mime} forwarded message.
178 PGP signed clear text.
181 @findex pgp-encrypted
182 PGP encrypted clear text.
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 @sc{mime} handle is a list that fully describes a @sc{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 @sc{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 @sc{mime} type can be displayed inline.
266 @item mm-automatic-display-p
267 @findex mm-automatic-display-p
268 Say whether a @sc{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 @sc{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 @sc{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 @sc{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 @sc{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 @sc{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 @sc{mime} handle as the argument.
382 @item mm-inline-text-html-with-images
383 @vindex mm-inline-text-html-with-images
384 Some @sc{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 @sc{html} email
398 (the default value is @samp{\\`cid:}). If @code{nil} consider all
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 @sc{mime}
429 parts. Each function is applied successively to the file name.
430 Ready-made functions include
433 @item mm-file-name-delete-whitespace
434 @findex mm-file-name-delete-whitespace
435 Remove all whitespace.
437 @item mm-file-name-trim-whitespace
438 @findex mm-file-name-trim-whitespace
439 Remove leading and trailing whitespace.
441 @item mm-file-name-collapse-whitespace
442 @findex mm-file-name-collapse-whitespace
443 Collapse multiple whitespace characters.
445 @item mm-file-name-replace-whitespace
446 @findex mm-file-name-replace-whitespace
447 @vindex mm-file-name-replace-whitespace
448 Replace whitespace with underscores. Set the variable
449 @code{mm-file-name-replace-whitespace} to any other string if you do
450 not like underscores.
454 The standard Emacs functions @code{capitalize}, @code{downcase},
455 @code{upcase} and @code{upcase-initials} might also prove useful.
457 @item mm-path-name-rewrite-functions
458 @vindex mm-path-name-rewrite-functions
459 List of functions used for rewriting the full file names of @sc{mime}
460 parts. This is used when viewing parts externally, and is meant for
461 transforming the absolute name so that non-compliant programs can find
462 the file where it's saved.
469 Here's an example viewer for displaying @code{text/enriched} inline:
472 (defun mm-display-enriched-inline (handle)
475 (mm-insert-part handle)
476 (save-window-excursion
477 (enriched-decode (point-min) (point-max))
478 (setq text (buffer-string))))
479 (mm-insert-inline handle text)))
482 We see that the function takes a @sc{mime} handle as its parameter. It
483 then goes to a temporary buffer, inserts the text of the part, does some
484 work on the text, stores the result, goes back to the buffer it was
485 called from and inserts the result.
487 The two important helper functions here are @code{mm-insert-part} and
488 @code{mm-insert-inline}. The first function inserts the text of the
489 handle in the current buffer. It handles charset and/or content
490 transfer decoding. The second function just inserts whatever text you
491 tell it to insert, but it also sets things up so that the text can be
492 ``undisplayed'' in a convenient manner.
498 @cindex MIME Composing
500 @cindex MIME Meta Language
502 Creating a @sc{mime} message is boring and non-trivial. Therefore, a
503 library called @code{mml} has been defined that parses a language called
504 MML (@sc{mime} Meta Language) and generates @sc{mime} messages.
506 @findex mml-generate-mime
507 The main interface function is @code{mml-generate-mime}. It will
508 examine the contents of the current (narrowed-to) buffer and return a
509 string containing the @sc{mime} message.
512 * Simple MML Example:: An example MML document.
513 * MML Definition:: All valid MML elements.
514 * Advanced MML Example:: Another example MML document.
515 * Encoding Customization:: Variables that affect encoding.
516 * Charset Translation:: How charsets are mapped from @sc{mule} to @sc{mime}.
517 * Conversion:: Going from @sc{mime} to MML and vice versa.
518 * Flowed text:: Soft and hard newlines.
522 @node Simple MML Example
523 @section Simple MML Example
525 Here's a simple @samp{multipart/alternative}:
528 <#multipart type=alternative>
529 This is a plain text part.
530 <#part type=text/enriched>
531 <center>This is a centered enriched part</center>
535 After running this through @code{mml-generate-mime}, we get this:
538 Content-Type: multipart/alternative; boundary="=-=-="
544 This is a plain text part.
547 Content-Type: text/enriched
550 <center>This is a centered enriched part</center>
557 @section MML Definition
559 The MML language is very simple. It looks a bit like an SGML
560 application, but it's not.
562 The main concept of MML is the @dfn{part}. Each part can be of a
563 different type or use a different charset. The way to delineate a part
564 is with a @samp{<#part ...>} tag. Multipart parts can be introduced
565 with the @samp{<#multipart ...>} tag. Parts are ended by the
566 @samp{<#/part>} or @samp{<#/multipart>} tags. Parts started with the
567 @samp{<#part ...>} tags are also closed by the next open tag.
569 There's also the @samp{<#external ...>} tag. These introduce
570 @samp{external/message-body} parts.
572 Each tag can contain zero or more parameters on the form
573 @samp{parameter=value}. The values may be enclosed in quotation marks,
574 but that's not necessary unless the value contains white space. So
575 @samp{filename=/home/user/#hello$^yes} is perfectly valid.
577 The following parameters have meaning in MML; parameters that have no
578 meaning are ignored. The MML parameter names are the same as the
579 @sc{mime} parameter names; the things in the parentheses say which
580 header it will be used in.
584 The @sc{mime} type of the part (@code{Content-Type}).
587 Use the contents of the file in the body of the part
588 (@code{Content-Disposition}).
591 The contents of the body of the part are to be encoded in the character
592 set speficied (@code{Content-Type}). @xref{Charset Translation}.
595 Might be used to suggest a file name if the part is to be saved
596 to a file (@code{Content-Type}).
599 Valid values are @samp{inline} and @samp{attachment}
600 (@code{Content-Disposition}).
603 Valid values are @samp{7bit}, @samp{8bit}, @samp{quoted-printable} and
604 @samp{base64} (@code{Content-Transfer-Encoding}). @xref{Charset
608 A description of the part (@code{Content-Description}).
611 RFC822 date when the part was created (@code{Content-Disposition}).
613 @item modification-date
614 RFC822 date when the part was modified (@code{Content-Disposition}).
617 RFC822 date when the part was read (@code{Content-Disposition}).
620 Who to encrypt/sign the part to. This field is used to override any
621 auto-detection based on the To/CC headers.
624 The size (in octets) of the part (@code{Content-Disposition}).
627 What technology to sign this MML part with (@code{smime}, @code{pgp}
631 What technology to encrypt this MML part with (@code{smime},
632 @code{pgp} or @code{pgpmime})
636 Parameters for @samp{application/octet-stream}:
640 Type of the part; informal---meant for human readers
641 (@code{Content-Type}).
644 Parameters for @samp{message/external-body}:
648 A word indicating the supported access mechanism by which the file may
649 be obtained. Values include @samp{ftp}, @samp{anon-ftp}, @samp{tftp},
650 @samp{localfile}, and @samp{mailserver}. (@code{Content-Type}.)
653 The RFC822 date after which the file may no longer be fetched.
654 (@code{Content-Type}.)
657 The size (in octets) of the file. (@code{Content-Type}.)
660 Valid values are @samp{read} and @samp{read-write}
661 (@code{Content-Type}).
665 Parameters for @samp{sign=smime}:
670 File containing key and certificate for signer.
674 Parameters for @samp{encrypt=smime}:
679 File containing certificate for recipient.
684 @node Advanced MML Example
685 @section Advanced MML Example
687 Here's a complex multipart message. It's a @samp{multipart/mixed} that
688 contains many parts, one of which is a @samp{multipart/alternative}.
691 <#multipart type=mixed>
692 <#part type=image/jpeg filename=~/rms.jpg disposition=inline>
693 <#multipart type=alternative>
694 This is a plain text part.
695 <#part type=text/enriched name=enriched.txt>
696 <center>This is a centered enriched part</center>
698 This is a new plain text part.
699 <#part disposition=attachment>
700 This plain text part is an attachment.
704 And this is the resulting @sc{mime} message:
707 Content-Type: multipart/mixed; boundary="=-=-="
715 Content-Type: image/jpeg;
717 Content-Disposition: inline;
719 Content-Transfer-Encoding: base64
721 /9j/4AAQSkZJRgABAQAAAQABAAD/2wBDAAgGBgcGBQgHBwcJCQgKDBQNDAsLDBkSEw8UHRof
722 Hh0aHBwgJC4nICIsIxwcKDcpLDAxNDQ0Hyc5PTgyPC4zNDL/wAALCAAwADABAREA/8QAHwAA
723 AQUBAQEBAQEAAAAAAAAAAAECAwQFBgcICQoL/8QAtRAAAgEDAwIEAwUFBAQAAAF9AQIDAAQR
724 BRIhMUEGE1FhByJxFDKBkaEII0KxwRVS0fAkM2JyggkKFhcYGRolJicoKSo0NTY3ODk6Q0RF
725 RkdISUpTVFVWV1hZWmNkZWZnaGlqc3R1dnd4eXqDhIWGh4iJipKTlJWWl5iZmqKjpKWmp6ip
726 qrKztLW2t7i5usLDxMXGx8jJytLT1NXW19jZ2uHi4+Tl5ufo6erx8vP09fb3+Pn6/9oACAEB
727 AAA/AO/rifFHjldNuGsrDa0qcSSHkA+gHrXKw+LtWLrMb+RgTyhbr+HSug07xNqV9fQtZrNI
728 AyiaE/NuBPOOOP0rvRNE880KOC8TbXXGCv1FPqjrF4LDR7u5L7SkTFT/ALWOP1xXgTuXfc7E
729 sx6nua6rwp4IvvEM8chCxWxOdzn7wz6V9AaB4S07w9p5itow0rDLSY5Pt9K43xO66P4xs71m
730 2QXiGCbA4yOVJ9+1aYORkdK434lyNH4ahCnG66VT9Nj15JFbPdX0MS43M4VQf5/yr2vSpLnw
731 5ZW8dlCZ8KFXjOPX0/mK6rSPEGt3Angu44fNEReHYNvIH3TzXDeKNO8RX+kSX2ouZkicTIOc
732 L+g7E810ulFjpVtv3bwgB3HJyK5L4quY/C9sVxk3ij/xx6850u7t1mtp/wDlpEw3An3Jr3Dw
733 34gsbWza4nBlhC5LDsaW6+IFgupQyCF3iHH7gA7c9R9ay7zx6t7aX9jHC4smhfBkGCvHGfrm
734 tLQ7hbnRrV1GPkAP1x1/Hr+Ncr8Vzjwrbf8AX6v/AKA9eQRyYlQk8Yx9K6XTNbkgia2ciSIn
735 7p5Ga9Atte0LTLKO6it4i7dVRFJDcZ4PvXN+JvEMF9bILVGXJLSZ4zkjivRPDaeX4b08HOTC
736 pOffmua+KkbS+GLVUGT9tT/0B68eeIpIFYjB70+OOVXyoOM9+M1eaWeCLzHPyHGO/NVWvJJm
737 jQ8KGH1NfQWhXSXmh2c8eArRLwO3HSv/2Q==
740 Content-Type: multipart/alternative; boundary="==-=-="
746 This is a plain text part.
749 Content-Type: text/enriched;
753 <center>This is a centered enriched part</center>
759 This is a new plain text part.
762 Content-Disposition: attachment
765 This plain text part is an attachment.
770 @node Encoding Customization
771 @section Encoding Customization
775 @item mm-body-charset-encoding-alist
776 @vindex mm-body-charset-encoding-alist
777 Mapping from @sc{mime} charset to encoding to use. This variable is
778 usually used except, e.g., when other requirements force a specific
779 encoding (digitally signed messages require 7bit encodings). The
780 default is @code{((iso-2022-jp . 7bit) (iso-2022-jp-2 . 7bit))}. As
781 an example, if you do not want to have ISO-8859-1 characters
782 quoted-printable encoded, you may add @code{(iso-8859-1 . 8bit)} to
783 this variable. You can override this setting on a per-message basis
784 by using the @code{encoding} MML tag (@pxref{MML Definition}).
786 @item mm-coding-system-priorities
787 @vindex mm-coding-system-priorities
788 Prioritize coding systems to use for outgoing messages. The default
789 is @code{nil}, which means to use the defaults in Emacs. It is a list of
790 coding system symbols (aliases of coding systems does not work, use
791 @kbd{M-x describe-coding-system} to make sure you are not specifying
792 an alias in this variable). For example, if you have configured Emacs
793 to use prefer UTF-8, but wish that outgoing messages should be sent in
794 ISO-8859-1 if possible, you can set this variable to
795 @code{(iso-latin-1)}. You can override this setting on a per-message
796 basis by using the @code{charset} MML tag (@pxref{MML Definition}).
798 @item mm-content-transfer-encoding-defaults
799 @vindex mm-content-transfer-encoding-defaults
800 Mapping from @sc{mime} types to encoding to use. This variable is usually
801 used except, e.g., when other requirements force a safer encoding
802 (digitally signed messages require 7bit encoding). Besides the normal
803 @sc{mime} encodings, @code{qp-or-base64} may be used to indicate that for
804 each case the most efficient of quoted-printable and base64 should be
805 used. You can override this setting on a per-message basis by using
806 the @code{encoding} MML tag (@pxref{MML Definition}).
808 @item mm-use-ultra-safe-encoding
809 @vindex mm-use-ultra-safe-encoding
810 When this is non-@code{nil}, it means that textual parts are encoded as
811 quoted-printable if they contain lines longer than 76 characters or
812 starting with "From " in the body. Non-7bit encodings (8bit, binary)
813 are generally disallowed. This reduce the probability that a non-8bit
814 clean MTA or MDA changes the message. This should never be set
815 directly, but bound by other functions when necessary (e.g., when
816 encoding messages that are to be digitally signed).
820 @node Charset Translation
821 @section Charset Translation
824 During translation from MML to @sc{mime}, for each @sc{mime} part which
825 has been composed inside Emacs, an appropriate charset has to be chosen.
827 @vindex mail-parse-charset
828 If you are running a non-@sc{mule} Emacs, this process is simple: If the
829 part contains any non-ASCII (8-bit) characters, the @sc{mime} charset
830 given by @code{mail-parse-charset} (a symbol) is used. (Never set this
831 variable directly, though. If you want to change the default charset,
832 please consult the documentation of the package which you use to process
834 @xref{Various Message Variables, , Various Message Variables, message,
835 Message Manual}, for example.)
836 If there are only ASCII characters, the @sc{mime} charset US-ASCII is
842 @vindex mm-mime-mule-charset-alist
843 Things are slightly more complicated when running Emacs with @sc{mule}
844 support. In this case, a list of the @sc{mule} charsets used in the
845 part is obtained, and the @sc{mule} charsets are translated to @sc{mime}
846 charsets by consulting the variable @code{mm-mime-mule-charset-alist}.
847 If this results in a single @sc{mime} charset, this is used to encode
848 the part. But if the resulting list of @sc{mime} charsets contains more
849 than one element, two things can happen: If it is possible to encode the
850 part via UTF-8, this charset is used. (For this, Emacs must support
851 the @code{utf-8} coding system, and the part must consist entirely of
852 characters which have Unicode counterparts.) If UTF-8 is not available
853 for some reason, the part is split into several ones, so that each one
854 can be encoded with a single @sc{mime} charset. The part can only be
855 split at line boundaries, though---if more than one @sc{mime} charset is
856 required to encode a single line, it is not possible to encode the part.
858 When running Emacs with @sc{mule} support, the preferences for which
859 coding system to use is inherited from Emacs itself. This means that
860 if Emacs is set up to prefer UTF-8, it will be used when encoding
861 messages. You can modify this by altering the
862 @code{mm-coding-system-priorities} variable though (@pxref{Encoding
865 The charset to be used can be overriden by setting the @code{charset}
866 MML tag (@pxref{MML Definition}) when composing the message.
868 The encoding of characters (quoted-printable, 8bit etc) is orthogonal
869 to the discussion here, and is controlled by the variables
870 @code{mm-body-charset-encoding-alist} and
871 @code{mm-content-transfer-encoding-defaults} (@pxref{Encoding
878 A (multipart) @sc{mime} message can be converted to MML with the
879 @code{mime-to-mml} function. It works on the message in the current
880 buffer, and substitutes MML markup for @sc{mime} boundaries.
881 Non-textual parts do not have their contents in the buffer, but instead
882 have the contents in separate buffers that are referred to from the MML
886 An MML message can be converted back to @sc{mime} by the
887 @code{mml-to-mime} function.
889 These functions are in certain senses ``lossy''---you will not get back
890 an identical message if you run @sc{mime-to-mml} and then
891 @sc{mml-to-mime}. Not only will trivial things like the order of the
892 headers differ, but the contents of the headers may also be different.
893 For instance, the original message may use base64 encoding on text,
894 while @sc{mml-to-mime} may decide to use quoted-printable encoding, and
897 In essence, however, these two functions should be the inverse of each
898 other. The resulting contents of the message should remain equivalent,
904 @cindex format=flowed
906 The Emacs @sc{mime} library will respect the @code{use-hard-newlines}
907 variable (@pxref{Hard and Soft Newlines, ,Hard and Soft Newlines,
908 emacs, Emacs Manual}) when encoding a message, and the
909 ``format=flowed'' Content-Type parameter when decoding a message.
911 On encoding text, lines terminated by soft newline characters are
912 filled together and wrapped after the column decided by
913 @code{fill-flowed-encode-column}. This variable controls how the text
914 will look in a client that does not support flowed text, the default
915 is to wrap after 66 characters. If hard newline characters are not
916 present in the buffer, no flow encoding occurs.
918 On decoding flowed text, lines with soft newline characters are filled
919 together and wrapped after the column decided by
920 @code{fill-flowed-display-column}. The default is to wrap after
926 @node Interface Functions
927 @chapter Interface Functions
928 @cindex interface functions
931 The @code{mail-parse} library is an abstraction over the actual
932 low-level libraries that are described in the next chapter.
934 Standards change, and so programs have to change to fit in the new
935 mold. For instance, RFC2045 describes a syntax for the
936 @code{Content-Type} header that only allows ASCII characters in the
937 parameter list. RFC2231 expands on RFC2045 syntax to provide a scheme
938 for continuation headers and non-ASCII characters.
940 The traditional way to deal with this is just to update the library
941 functions to parse the new syntax. However, this is sometimes the wrong
942 thing to do. In some instances it may be vital to be able to understand
943 both the old syntax as well as the new syntax, and if there is only one
944 library, one must choose between the old version of the library and the
945 new version of the library.
947 The Emacs @sc{mime} library takes a different tack. It defines a
948 series of low-level libraries (@file{rfc2047.el}, @file{rfc2231.el}
949 and so on) that parses strictly according to the corresponding
950 standard. However, normal programs would not use the functions
951 provided by these libraries directly, but instead use the functions
952 provided by the @code{mail-parse} library. The functions in this
953 library are just aliases to the corresponding functions in the latest
954 low-level libraries. Using this scheme, programs get a consistent
955 interface they can use, and library developers are free to create
956 write code that handles new standards.
958 The following functions are defined by this library:
961 @item mail-header-parse-content-type
962 @findex mail-header-parse-content-type
963 Parse a @code{Content-Type} header and return a list on the following
968 (attribute1 . value1)
969 (attribute2 . value2)
976 (mail-header-parse-content-type
977 "image/gif; name=\"b980912.gif\"")
978 @result{} ("image/gif" (name . "b980912.gif"))
981 @item mail-header-parse-content-disposition
982 @findex mail-header-parse-content-disposition
983 Parse a @code{Content-Disposition} header and return a list on the same
984 format as the function above.
986 @item mail-content-type-get
987 @findex mail-content-type-get
988 Takes two parameters---a list on the format above, and an attribute.
989 Returns the value of the attribute.
992 (mail-content-type-get
993 '("image/gif" (name . "b980912.gif")) 'name)
994 @result{} "b980912.gif"
997 @item mail-header-encode-parameter
998 @findex mail-header-encode-parameter
999 Takes a parameter string and returns an encoded version of the string.
1000 This is used for parameters in headers like @code{Content-Type} and
1001 @code{Content-Disposition}.
1003 @item mail-header-remove-comments
1004 @findex mail-header-remove-comments
1005 Return a comment-free version of a header.
1008 (mail-header-remove-comments
1009 "Gnus/5.070027 (Pterodactyl Gnus v0.27) (Finnish Landrace)")
1010 @result{} "Gnus/5.070027 "
1013 @item mail-header-remove-whitespace
1014 @findex mail-header-remove-whitespace
1015 Remove linear white space from a header. Space inside quoted strings
1016 and comments is preserved.
1019 (mail-header-remove-whitespace
1020 "image/gif; name=\"Name with spaces\"")
1021 @result{} "image/gif;name=\"Name with spaces\""
1024 @item mail-header-get-comment
1025 @findex mail-header-get-comment
1026 Return the last comment in a header.
1029 (mail-header-get-comment
1030 "Gnus/5.070027 (Pterodactyl Gnus v0.27) (Finnish Landrace)")
1031 @result{} "Finnish Landrace"
1034 @item mail-header-parse-address
1035 @findex mail-header-parse-address
1036 Parse an address and return a list containing the mailbox and the
1040 (mail-header-parse-address
1041 "Hrvoje Niksic <hniksic@@srce.hr>")
1042 @result{} ("hniksic@@srce.hr" . "Hrvoje Niksic")
1045 @item mail-header-parse-addresses
1046 @findex mail-header-parse-addresses
1047 Parse a string with list of addresses and return a list of elements like
1048 the one described above.
1051 (mail-header-parse-addresses
1052 "Hrvoje Niksic <hniksic@@srce.hr>, Steinar Bang <sb@@metis.no>")
1053 @result{} (("hniksic@@srce.hr" . "Hrvoje Niksic")
1054 ("sb@@metis.no" . "Steinar Bang"))
1057 @item mail-header-parse-date
1058 @findex mail-header-parse-date
1059 Parse a date string and return an Emacs time structure.
1061 @item mail-narrow-to-head
1062 @findex mail-narrow-to-head
1063 Narrow the buffer to the header section of the buffer. Point is placed
1064 at the beginning of the narrowed buffer.
1066 @item mail-header-narrow-to-field
1067 @findex mail-header-narrow-to-field
1068 Narrow the buffer to the header under point. Understands continuation
1071 @item mail-header-fold-field
1072 @findex mail-header-fold-field
1073 Fold the header under point.
1075 @item mail-header-unfold-field
1076 @findex mail-header-unfold-field
1077 Unfold the header under point.
1079 @item mail-header-field-value
1080 @findex mail-header-field-value
1081 Return the value of the field under point.
1083 @item mail-encode-encoded-word-region
1084 @findex mail-encode-encoded-word-region
1085 Encode the non-ASCII words in the region. For instance,
1086 @samp{Naïve} is encoded as @samp{=?iso-8859-1?q?Na=EFve?=}.
1088 @item mail-encode-encoded-word-buffer
1089 @findex mail-encode-encoded-word-buffer
1090 Encode the non-ASCII words in the current buffer. This function is
1091 meant to be called narrowed to the headers of a message.
1093 @item mail-encode-encoded-word-string
1094 @findex mail-encode-encoded-word-string
1095 Encode the words that need encoding in a string, and return the result.
1098 (mail-encode-encoded-word-string
1099 "This is naïve, baby")
1100 @result{} "This is =?iso-8859-1?q?na=EFve,?= baby"
1103 @item mail-decode-encoded-word-region
1104 @findex mail-decode-encoded-word-region
1105 Decode the encoded words in the region.
1107 @item mail-decode-encoded-word-string
1108 @findex mail-decode-encoded-word-string
1109 Decode the encoded words in the string and return the result.
1112 (mail-decode-encoded-word-string
1113 "This is =?iso-8859-1?q?na=EFve,?= baby")
1114 @result{} "This is naïve, baby"
1119 Currently, @code{mail-parse} is an abstraction over @code{ietf-drums},
1120 @code{rfc2047}, @code{rfc2045} and @code{rfc2231}. These are documented
1121 in the subsequent sections.
1125 @node Basic Functions
1126 @chapter Basic Functions
1128 This chapter describes the basic, ground-level functions for parsing and
1129 handling. Covered here is parsing @code{From} lines, removing comments
1130 from header lines, decoding encoded words, parsing date headers and so
1131 on. High-level functionality is dealt with in the next chapter
1132 (@pxref{Decoding and Viewing}).
1135 * rfc2045:: Encoding @code{Content-Type} headers.
1136 * rfc2231:: Parsing @code{Content-Type} headers.
1137 * ietf-drums:: Handling mail headers defined by RFC822bis.
1138 * rfc2047:: En/decoding encoded words in headers.
1139 * time-date:: Functions for parsing dates and manipulating time.
1140 * qp:: Quoted-Printable en/decoding.
1141 * base64:: Base64 en/decoding.
1142 * binhex:: Binhex decoding.
1143 * uudecode:: Uuencode decoding.
1144 * yenc:: Yenc decoding.
1145 * rfc1843:: Decoding HZ-encoded text.
1146 * mailcap:: How parts are displayed is specified by the @file{.mailcap} file
1153 RFC2045 is the ``main'' @sc{mime} document, and as such, one would
1154 imagine that there would be a lot to implement. But there isn't, since
1155 most of the implementation details are delegated to the subsequent
1158 So @file{rfc2045.el} has only a single function:
1161 @item rfc2045-encode-string
1162 @findex rfc2045-encode-string
1163 Takes a parameter and a value and returns a @samp{PARAM=VALUE} string.
1164 @var{value} will be quoted if there are non-safe characters in it.
1171 RFC2231 defines a syntax for the @code{Content-Type} and
1172 @code{Content-Disposition} headers. Its snappy name is @dfn{MIME
1173 Parameter Value and Encoded Word Extensions: Character Sets, Languages,
1176 In short, these headers look something like this:
1179 Content-Type: application/x-stuff;
1180 title*0*=us-ascii'en'This%20is%20even%20more%20;
1181 title*1*=%2A%2A%2Afun%2A%2A%2A%20;
1185 They usually aren't this bad, though.
1187 The following functions are defined by this library:
1190 @item rfc2231-parse-string
1191 @findex rfc2231-parse-string
1192 Parse a @code{Content-Type} header and return a list describing its
1196 (rfc2231-parse-string
1197 "application/x-stuff;
1198 title*0*=us-ascii'en'This%20is%20even%20more%20;
1199 title*1*=%2A%2A%2Afun%2A%2A%2A%20;
1200 title*2=\"isn't it!\"")
1201 @result{} ("application/x-stuff"
1202 (title . "This is even more ***fun*** isn't it!"))
1205 @item rfc2231-get-value
1206 @findex rfc2231-get-value
1207 Takes one of the lists on the format above and returns
1208 the value of the specified attribute.
1210 @item rfc2231-encode-string
1211 @findex rfc2231-encode-string
1212 Encode a parameter in headers likes @code{Content-Type} and
1213 @code{Content-Disposition}.
1221 @dfn{drums} is an IETF working group that is working on the replacement
1224 The functions provided by this library include:
1227 @item ietf-drums-remove-comments
1228 @findex ietf-drums-remove-comments
1229 Remove the comments from the argument and return the results.
1231 @item ietf-drums-remove-whitespace
1232 @findex ietf-drums-remove-whitespace
1233 Remove linear white space from the string and return the results.
1234 Spaces inside quoted strings and comments are left untouched.
1236 @item ietf-drums-get-comment
1237 @findex ietf-drums-get-comment
1238 Return the last most comment from the string.
1240 @item ietf-drums-parse-address
1241 @findex ietf-drums-parse-address
1242 Parse an address string and return a list that contains the mailbox and
1243 the plain text name.
1245 @item ietf-drums-parse-addresses
1246 @findex ietf-drums-parse-addresses
1247 Parse a string that contains any number of comma-separated addresses and
1248 return a list that contains mailbox/plain text pairs.
1250 @item ietf-drums-parse-date
1251 @findex ietf-drums-parse-date
1252 Parse a date string and return an Emacs time structure.
1254 @item ietf-drums-narrow-to-header
1255 @findex ietf-drums-narrow-to-header
1256 Narrow the buffer to the header section of the current buffer.
1264 RFC2047 (Message Header Extensions for Non-ASCII Text) specifies how
1265 non-ASCII text in headers are to be encoded. This is actually rather
1266 complicated, so a number of variables are necessary to tweak what this
1269 The following variables are tweakable:
1272 @item rfc2047-default-charset
1273 @vindex rfc2047-default-charset
1274 Characters in this charset should not be decoded by this library.
1275 This defaults to @code{iso-8859-1}.
1277 @item rfc2047-header-encoding-alist
1278 @vindex rfc2047-header-encoding-alist
1279 This is an alist of header / encoding-type pairs. Its main purpose is
1280 to prevent encoding of certain headers.
1282 The keys can either be header regexps, or @code{t}.
1284 The values can be either @code{nil}, in which case the header(s) in
1285 question won't be encoded, or @code{mime}, which means that they will be
1288 @item rfc2047-charset-encoding-alist
1289 @vindex rfc2047-charset-encoding-alist
1290 RFC2047 specifies two forms of encoding---@code{Q} (a
1291 Quoted-Printable-like encoding) and @code{B} (base64). This alist
1292 specifies which charset should use which encoding.
1294 @item rfc2047-encoding-function-alist
1295 @vindex rfc2047-encoding-function-alist
1296 This is an alist of encoding / function pairs. The encodings are
1297 @code{Q}, @code{B} and @code{nil}.
1299 @item rfc2047-q-encoding-alist
1300 @vindex rfc2047-q-encoding-alist
1301 The @code{Q} encoding isn't quite the same for all headers. Some
1302 headers allow a narrower range of characters, and that is what this
1303 variable is for. It's an alist of header regexps / allowable character
1306 @item rfc2047-encoded-word-regexp
1307 @vindex rfc2047-encoded-word-regexp
1308 When decoding words, this library looks for matches to this regexp.
1312 Those were the variables, and these are this functions:
1315 @item rfc2047-narrow-to-field
1316 @findex rfc2047-narrow-to-field
1317 Narrow the buffer to the header on the current line.
1319 @item rfc2047-encode-message-header
1320 @findex rfc2047-encode-message-header
1321 Should be called narrowed to the header of a message. Encodes according
1322 to @code{rfc2047-header-encoding-alist}.
1324 @item rfc2047-encode-region
1325 @findex rfc2047-encode-region
1326 Encodes all encodable words in the region specified.
1328 @item rfc2047-encode-string
1329 @findex rfc2047-encode-string
1330 Encode a string and return the results.
1332 @item rfc2047-decode-region
1333 @findex rfc2047-decode-region
1334 Decode the encoded words in the region.
1336 @item rfc2047-decode-string
1337 @findex rfc2047-decode-string
1338 Decode a string and return the results.
1346 While not really a part of the @sc{mime} library, it is convenient to
1347 document this library here. It deals with parsing @code{Date} headers
1348 and manipulating time. (Not by using tesseracts, though, I'm sorry to
1351 These functions convert between five formats: A date string, an Emacs
1352 time structure, a decoded time list, a second number, and a day number.
1354 Here's a bunch of time/date/second/day examples:
1357 (parse-time-string "Sat Sep 12 12:21:54 1998 +0200")
1358 @result{} (54 21 12 12 9 1998 6 nil 7200)
1360 (date-to-time "Sat Sep 12 12:21:54 1998 +0200")
1361 @result{} (13818 19266)
1363 (time-to-seconds '(13818 19266))
1364 @result{} 905595714.0
1366 (seconds-to-time 905595714.0)
1367 @result{} (13818 19266 0)
1369 (time-to-days '(13818 19266))
1372 (days-to-time 729644)
1373 @result{} (961933 65536)
1375 (time-since '(13818 19266))
1378 (time-less-p '(13818 19266) '(13818 19145))
1381 (subtract-time '(13818 19266) '(13818 19145))
1384 (days-between "Sat Sep 12 12:21:54 1998 +0200"
1385 "Sat Sep 07 12:21:54 1998 +0200")
1388 (date-leap-year-p 2000)
1391 (time-to-day-in-year '(13818 19266))
1394 (time-to-number-of-days
1396 (date-to-time "Mon, 01 Jan 2001 02:22:26 GMT")))
1397 @result{} 4.146122685185185
1400 And finally, we have @code{safe-date-to-time}, which does the same as
1401 @code{date-to-time}, but returns a zero time if the date is
1402 syntactically malformed.
1404 The five data representations used are the following:
1408 An RFC822 (or similar) date string. For instance: @code{"Sat Sep 12
1409 12:21:54 1998 +0200"}.
1412 An internal Emacs time. For instance: @code{(13818 26466)}.
1415 A floating point representation of the internal Emacs time. For
1416 instance: @code{905595714.0}.
1419 An integer number representing the number of days since 00000101. For
1420 instance: @code{729644}.
1423 A list of decoded time. For instance: @code{(54 21 12 12 9 1998 6 t
1427 All the examples above represent the same moment.
1429 These are the functions available:
1433 Take a date and return a time.
1435 @item time-to-seconds
1436 Take a time and return seconds.
1438 @item seconds-to-time
1439 Take seconds and return a time.
1442 Take a time and return days.
1445 Take days and return a time.
1448 Take a date and return days.
1450 @item time-to-number-of-days
1451 Take a time and return the number of days that represents.
1453 @item safe-date-to-time
1454 Take a date and return a time. If the date is not syntactically valid,
1455 return a ``zero'' date.
1458 Take two times and say whether the first time is less (i. e., earlier)
1459 than the second time.
1462 Take a time and return a time saying how long it was since that time.
1465 Take two times and subtract the second from the first. I. e., return
1466 the time between the two times.
1469 Take two days and return the number of days between those two days.
1471 @item date-leap-year-p
1472 Take a year number and say whether it's a leap year.
1474 @item time-to-day-in-year
1475 Take a time and return the day number within the year that the time is
1484 This library deals with decoding and encoding Quoted-Printable text.
1486 Very briefly explained, qp encoding means translating all 8-bit
1487 characters (and lots of control characters) into things that look like
1488 @samp{=EF}; that is, an equal sign followed by the byte encoded as a hex
1491 The following functions are defined by the library:
1494 @item quoted-printable-decode-region
1495 @findex quoted-printable-decode-region
1496 QP-decode all the encoded text in the specified region.
1498 @item quoted-printable-decode-string
1499 @findex quoted-printable-decode-string
1500 Decode the QP-encoded text in a string and return the results.
1502 @item quoted-printable-encode-region
1503 @findex quoted-printable-encode-region
1504 QP-encode all the encodable characters in the specified region. The third
1505 optional parameter @var{fold} specifies whether to fold long lines.
1506 (Long here means 72.)
1508 @item quoted-printable-encode-string
1509 @findex quoted-printable-encode-string
1510 QP-encode all the encodable characters in a string and return the
1520 Base64 is an encoding that encodes three bytes into four characters,
1521 thereby increasing the size by about 33%. The alphabet used for
1522 encoding is very resistant to mangling during transit.
1524 The following functions are defined by this library:
1527 @item base64-encode-region
1528 @findex base64-encode-region
1529 base64 encode the selected region. Return the length of the encoded
1530 text. Optional third argument @var{no-line-break} means do not break
1531 long lines into shorter lines.
1533 @item base64-encode-string
1534 @findex base64-encode-string
1535 base64 encode a string and return the result.
1537 @item base64-decode-region
1538 @findex base64-decode-region
1539 base64 decode the selected region. Return the length of the decoded
1540 text. If the region can't be decoded, return @code{nil} and don't
1543 @item base64-decode-string
1544 @findex base64-decode-string
1545 base64 decode a string and return the result. If the string can't be
1546 decoded, @code{nil} is returned.
1557 @code{binhex} is an encoding that originated in Macintosh environments.
1558 The following function is supplied to deal with these:
1561 @item binhex-decode-region
1562 @findex binhex-decode-region
1563 Decode the encoded text in the region. If given a third parameter, only
1564 decode the @code{binhex} header and return the filename.
1573 @code{uuencode} is probably still the most popular encoding of binaries
1574 used on Usenet, although @code{base64} rules the mail world.
1576 The following function is supplied by this package:
1579 @item uudecode-decode-region
1580 @findex uudecode-decode-region
1581 Decode the text in the region.
1589 @code{yenc} is used for encoding binaries on Usenet. The following
1590 function is supplied by this package:
1593 @item yenc-decode-region
1594 @findex yenc-decode-region
1595 Decode the encoded text in the region.
1606 RFC1843 deals with mixing Chinese and ASCII characters in messages. In
1607 essence, RFC1843 switches between ASCII and Chinese by doing this:
1610 This sentence is in ASCII.
1611 The next sentence is in GB.~@{<:Ky2;S@{#,NpJ)l6HK!#~@}Bye.
1614 Simple enough, and widely used in China.
1616 The following functions are available to handle this encoding:
1619 @item rfc1843-decode-region
1620 Decode HZ-encoded text in the region.
1622 @item rfc1843-decode-string
1623 Decode a HZ-encoded string and return the result.
1631 The @file{~/.mailcap} file is parsed by most @sc{mime}-aware message
1632 handlers and describes how elements are supposed to be displayed.
1633 Here's an example file:
1637 audio/wav; wavplayer %s
1638 application/msword; catdoc %s ; copiousoutput ; nametemplate=%s.doc
1641 This says that all image files should be displayed with @code{gimp},
1642 that WAVE audio files should be played by @code{wavplayer}, and that
1643 MS-WORD files should be inlined by @code{catdoc}.
1645 The @code{mailcap} library parses this file, and provides functions for
1649 @item mailcap-mime-data
1650 @vindex mailcap-mime-data
1651 This variable is an alist of alists containing backup viewing rules.
1655 Interface functions:
1658 @item mailcap-parse-mailcaps
1659 @findex mailcap-parse-mailcaps
1660 Parse the @file{~/.mailcap} file.
1662 @item mailcap-mime-info
1663 Takes a @sc{mime} type as its argument and returns the matching viewer.
1673 The Emacs @sc{mime} library implements handling of various elements
1674 according to a (somewhat) large number of RFCs, drafts and standards
1675 documents. This chapter lists the relevant ones. They can all be
1676 fetched from @uref{http://quimby.gnus.org/notes/}.
1681 Standard for the Format of ARPA Internet Text Messages.
1684 Standard for Interchange of USENET Messages
1687 Format of Internet Message Bodies
1693 Message Header Extensions for Non-ASCII Text
1696 Registration Procedures
1699 Conformance Criteria and Examples
1702 @sc{mime} Parameter Value and Encoded Word Extensions: Character Sets,
1703 Languages, and Continuations
1706 HZ - A Data Format for Exchanging Files of Arbitrarily Mixed Chinese and
1709 @item draft-ietf-drums-msg-fmt-05.txt
1710 Draft for the successor of RFC822
1713 The @sc{mime} Multipart/Related Content-type
1716 The Multipart/Report Content Type for the Reporting of Mail System
1717 Administrative Messages
1720 Communicating Presentation Information in Internet Messages: The
1721 Content-Disposition Header Field
1724 Documentation of the text/plain format parameter for flowed text.
1740 @c coding: iso-8859-1