3 @setfilename emacs-mime
4 @settitle Emacs MIME Manual
10 This file documents the Emacs MIME interface functionality.
12 Copyright @copyright{} 1998-2011 Free Software Foundation, Inc.
15 Permission is granted to copy, distribute and/or modify this document
16 under the terms of the GNU Free Documentation License, Version 1.3 or
17 any later version published by the Free Software Foundation; with no
18 Invariant Sections, with the Front-Cover texts being ``A GNU Manual'',
19 and with the Back-Cover Texts as in (a) below. A copy of the license
20 is included in the section entitled ``GNU Free Documentation License''.
22 (a) The FSF's Back-Cover Text is: ``You have the freedom to copy and
23 modify this GNU manual. Buying copies from the FSF supports it in
24 developing GNU and promoting software freedom.''
28 @c Node ``Interface Functions'' uses Latin-1 characters
29 @documentencoding ISO-8859-1
33 * Emacs MIME: (emacs-mime). Emacs MIME de/composition library.
38 @setchapternewpage odd
41 @title Emacs MIME Manual
43 @author by Lars Magne Ingebrigtsen
45 @vskip 0pt plus 1filll
54 This manual documents the libraries used to compose and display
55 @acronym{MIME} messages.
57 This manual is directed at users who want to modify the behavior of
58 the @acronym{MIME} encoding/decoding process or want a more detailed
59 picture of how the Emacs @acronym{MIME} library works, and people who want
60 to write functions and commands that manipulate @acronym{MIME} elements.
62 @acronym{MIME} is short for @dfn{Multipurpose Internet Mail Extensions}.
63 This standard is documented in a number of RFCs; mainly RFC2045 (Format
64 of Internet Message Bodies), RFC2046 (Media Types), RFC2047 (Message
65 Header Extensions for Non-@acronym{ASCII} Text), RFC2048 (Registration
66 Procedures), RFC2049 (Conformance Criteria and Examples). It is highly
67 recommended that anyone who intends writing @acronym{MIME}-compliant software
68 read at least RFC2045 and RFC2047.
75 * Decoding and Viewing:: A framework for decoding and viewing.
76 * Composing:: @acronym{MML}; a language for describing @acronym{MIME} parts.
77 * Interface Functions:: An abstraction over the basic functions.
78 * Basic Functions:: Utility and basic parsing functions.
79 * Standards:: A summary of RFCs and working documents used.
80 * GNU Free Documentation License:: The license for this documentation.
81 * Index:: Function and variable index.
85 @node Decoding and Viewing
86 @chapter Decoding and Viewing
88 This chapter deals with decoding and viewing @acronym{MIME} messages on a
91 The main idea is to first analyze a @acronym{MIME} article, and then allow
92 other programs to do things based on the list of @dfn{handles} that are
93 returned as a result of this analysis.
96 * Dissection:: Analyzing a @acronym{MIME} message.
97 * Non-MIME:: Analyzing a non-@acronym{MIME} message.
98 * Handles:: Handle manipulations.
99 * Display:: Displaying handles.
100 * Display Customization:: Variables that affect display.
101 * Files and Directories:: Saving and naming attachments.
102 * New Viewers:: How to write your own viewers.
109 The @code{mm-dissect-buffer} is the function responsible for dissecting
110 a @acronym{MIME} article. If given a multipart message, it will recursively
111 descend the message, following the structure, and return a tree of
112 @acronym{MIME} handles that describes the structure of the message.
116 @vindex mm-uu-configure-list
118 Gnus also understands some non-@acronym{MIME} attachments, such as
119 postscript, uuencode, binhex, yenc, shar, forward, gnatsweb, pgp,
120 diff. Each of these features can be disabled by add an item into
121 @code{mm-uu-configure-list}. For example,
125 (add-to-list 'mm-uu-configure-list '(pgp-signed . disabled))
151 Non-@acronym{MIME} forwarded message.
159 @acronym{PGP} signed clear text.
162 @findex pgp-encrypted
163 @acronym{PGP} encrypted clear text.
167 @acronym{PGP} public keys.
170 @findex emacs-sources
171 @vindex mm-uu-emacs-sources-regexp
172 Emacs source code. This item works only in the groups matching
173 @code{mm-uu-emacs-sources-regexp}.
177 @vindex mm-uu-diff-groups-regexp
178 Patches. This is intended for groups where diffs of committed files
179 are automatically sent to. It only works in groups matching
180 @code{mm-uu-diff-groups-regexp}.
183 @cindex verbatim-marks
184 Slrn-style verbatim marks.
188 LaTeX documents. It only works in groups matching
189 @code{mm-uu-tex-groups-regexp}.
193 @cindex text/x-verbatim
194 @c Is @vindex suitable for a face?
195 @vindex mm-uu-extract
196 Some inlined non-@acronym{MIME} attachments are displayed using the face
197 @code{mm-uu-extract}. By default, no @acronym{MIME} button for these
198 parts is displayed. You can force displaying a button using @kbd{K b}
199 (@code{gnus-summary-display-buttonized}) or add @code{text/x-verbatim}
200 to @code{gnus-buttonized-mime-types}, @xref{MIME Commands, ,MIME
201 Commands, gnus, Gnus Manual}.
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-get-content-id
239 Returns the handle(s) referred to by @code{Content-ID}.
247 Functions for displaying, removing and saving.
250 @item mm-display-part
251 @findex mm-display-part
255 @findex mm-remove-part
256 Remove the part (if it has been displayed).
259 @findex mm-inlinable-p
260 Say whether a @acronym{MIME} type can be displayed inline.
262 @item mm-automatic-display-p
263 @findex mm-automatic-display-p
264 Say whether a @acronym{MIME} type should be displayed automatically.
266 @item mm-destroy-part
267 @findex mm-destroy-part
268 Free all resources occupied by a part.
272 Offer to save the part in a file.
276 Offer to pipe the part to some process.
278 @item mm-interactively-view-part
279 @findex mm-interactively-view-part
280 Prompt for a mailcap method to use to view the part.
285 @node Display Customization
286 @section Display Customization
290 @item mm-inline-media-tests
291 @vindex mm-inline-media-tests
292 This is an alist where the key is a @acronym{MIME} type, the second element
293 is a function to display the part @dfn{inline} (i.e., inside Emacs), and
294 the third element is a form to be @code{eval}ed to say whether the part
295 can be displayed inline.
297 This variable specifies whether a part @emph{can} be displayed inline,
298 and, if so, how to do it. It does not say whether parts are
299 @emph{actually} displayed inline.
301 @item mm-inlined-types
302 @vindex mm-inlined-types
303 This, on the other hand, says what types are to be displayed inline, if
304 they satisfy the conditions set by the variable above. It's a list of
305 @acronym{MIME} media types.
307 @item mm-automatic-display
308 @vindex mm-automatic-display
309 This is a list of types that are to be displayed ``automatically'', but
310 only if the above variable allows it. That is, only inlinable parts can
311 be displayed automatically.
313 @item mm-automatic-external-display
314 @vindex mm-automatic-external-display
315 This is a list of types that will be displayed automatically in an
318 @item mm-keep-viewer-alive-types
319 @vindex mm-keep-viewer-alive-types
320 This is a list of media types for which the external viewer will not
321 be killed when selecting a different article.
323 @item mm-attachment-override-types
324 @vindex mm-attachment-override-types
325 Some @acronym{MIME} agents create parts that have a content-disposition of
326 @samp{attachment}. This variable allows overriding that disposition and
327 displaying the part inline. (Note that the disposition is only
328 overridden if we are able to, and want to, display the part inline.)
330 @item mm-discouraged-alternatives
331 @vindex mm-discouraged-alternatives
332 List of @acronym{MIME} types that are discouraged when viewing
333 @samp{multipart/alternative}. Viewing agents are supposed to view the
334 last possible part of a message, as that is supposed to be the richest.
335 However, users may prefer other types instead, and this list says what
336 types are most unwanted. If, for instance, @samp{text/html} parts are
337 very unwanted, and @samp{text/richtext} parts are somewhat unwanted,
338 you could say something like:
341 (setq mm-discouraged-alternatives
342 '("text/html" "text/richtext")
344 (remove "text/html" mm-automatic-display))
347 Adding @code{"image/.*"} might also be useful. Spammers use images as
348 the preferred part of @samp{multipart/alternative} messages, so you might
349 not notice there are other parts. See also
350 @code{gnus-buttonized-mime-types}, @ref{MIME Commands, ,MIME Commands,
351 gnus, Gnus Manual}. After adding @code{"multipart/alternative"} to
352 @code{gnus-buttonized-mime-types} you can choose manually which
353 alternative you'd like to view. For example, you can set those
357 (setq gnus-buttonized-mime-types
358 '("multipart/alternative" "multipart/signed")
359 mm-discouraged-alternatives
360 '("text/html" "image/.*"))
363 In this case, Gnus will display radio buttons for such a kind of spam
367 1. (*) multipart/alternative ( ) image/gif
369 2. (*) text/plain ( ) text/html
372 @item mm-inline-large-images
373 @vindex mm-inline-large-images
374 When displaying inline images that are larger than the window, Emacs
375 does not enable scrolling, which means that you cannot see the whole
376 image. To prevent this, the library tries to determine the image size
377 before displaying it inline, and if it doesn't fit the window, the
378 library will display it externally (e.g. with @samp{ImageMagick} or
379 @samp{xv}). Setting this variable to @code{t} disables this check and
380 makes the library display all inline images as inline, regardless of
381 their size. If you set this variable to @code{resize}, the image will
382 be displayed resized to fit in the window, if Emacs has the ability to
385 @item mm-inline-large-images-proportion
386 @vindex mm-inline-images-max-proportion
387 The proportion used when resizing large images.
389 @item mm-inline-override-types
390 @vindex mm-inline-override-types
391 @code{mm-inlined-types} may include regular expressions, for example to
392 specify that all @samp{text/.*} parts be displayed inline. If a user
393 prefers to have a type that matches such a regular expression be treated
394 as an attachment, that can be accomplished by setting this variable to a
395 list containing that type. For example assuming @code{mm-inlined-types}
396 includes @samp{text/.*}, then including @samp{text/html} in this
397 variable will cause @samp{text/html} parts to be treated as attachments.
399 @item mm-text-html-renderer
400 @vindex mm-text-html-renderer
401 This selects the function used to render @acronym{HTML}. The predefined
402 renderers are selected by the symbols @code{gnus-article-html}, @code{w3},
403 @code{w3m}@footnote{See @uref{http://emacs-w3m.namazu.org/} for more
404 information about emacs-w3m}, @code{links}, @code{lynx},
405 @code{w3m-standalone} or @code{html2text}. If @code{nil} use an
406 external viewer. You can also specify a function, which will be
407 called with a @acronym{MIME} handle as the argument.
409 @item mm-inline-text-html-with-images
410 @vindex mm-inline-text-html-with-images
411 Some @acronym{HTML} mails might have the trick of spammers using
412 @samp{<img>} tags. It is likely to be intended to verify whether you
413 have read the mail. You can prevent your personal informations from
414 leaking by setting this option to @code{nil} (which is the default).
415 It is currently ignored by Emacs/w3. For emacs-w3m, you may use the
416 command @kbd{t} on the image anchor to show an image even if it is
417 @code{nil}.@footnote{The command @kbd{T} will load all images. If you
418 have set the option @code{w3m-key-binding} to @code{info}, use @kbd{i}
421 @item mm-w3m-safe-url-regexp
422 @vindex mm-w3m-safe-url-regexp
423 A regular expression that matches safe URL names, i.e. URLs that are
424 unlikely to leak personal information when rendering @acronym{HTML}
425 email (the default value is @samp{\\`cid:}). If @code{nil} consider
426 all URLs safe. In Gnus, this will be overridden according to the value
427 of the variable @code{gnus-safe-html-newsgroups}, @xref{Various
428 Various, ,Various Various, gnus, Gnus Manual}.
430 @item mm-inline-text-html-with-w3m-keymap
431 @vindex mm-inline-text-html-with-w3m-keymap
432 You can use emacs-w3m command keys in the inlined text/html part by
433 setting this option to non-@code{nil}. The default value is @code{t}.
435 @item mm-external-terminal-program
436 @vindex mm-external-terminal-program
437 The program used to start an external terminal.
439 @item mm-enable-external
440 @vindex mm-enable-external
441 Indicate whether external @acronym{MIME} handlers should be used.
443 If @code{t}, all defined external @acronym{MIME} handlers are used. If
444 @code{nil}, files are saved to disk (@code{mailcap-save-binary-file}).
445 If it is the symbol @code{ask}, you are prompted before the external
446 @acronym{MIME} handler is invoked.
448 When you launch an attachment through mailcap (@pxref{mailcap}) an
449 attempt is made to use a safe viewer with the safest options---this isn't
450 the case if you save it to disk and launch it in a different way
451 (command line or double-clicking). Anyhow, if you want to be sure not
452 to launch any external programs, set this variable to @code{nil} or
457 @node Files and Directories
458 @section Files and Directories
462 @item mm-default-directory
463 @vindex mm-default-directory
464 The default directory for saving attachments. If @code{nil} use
465 @code{default-directory}.
467 @item mm-tmp-directory
468 @vindex mm-tmp-directory
469 Directory for storing temporary files.
471 @item mm-file-name-rewrite-functions
472 @vindex mm-file-name-rewrite-functions
473 A list of functions used for rewriting file names of @acronym{MIME}
474 parts. Each function is applied successively to the file name.
475 Ready-made functions include
478 @item mm-file-name-delete-control
479 @findex mm-file-name-delete-control
480 Delete all control characters.
482 @item mm-file-name-delete-gotchas
483 @findex mm-file-name-delete-gotchas
484 Delete characters that could have unintended consequences when used
485 with flawed shell scripts, i.e. @samp{|}, @samp{>} and @samp{<}; and
486 @samp{-}, @samp{.} as the first character.
488 @item mm-file-name-delete-whitespace
489 @findex mm-file-name-delete-whitespace
490 Remove all whitespace.
492 @item mm-file-name-trim-whitespace
493 @findex mm-file-name-trim-whitespace
494 Remove leading and trailing whitespace.
496 @item mm-file-name-collapse-whitespace
497 @findex mm-file-name-collapse-whitespace
498 Collapse multiple whitespace characters.
500 @item mm-file-name-replace-whitespace
501 @findex mm-file-name-replace-whitespace
502 @vindex mm-file-name-replace-whitespace
503 Replace whitespace with underscores. Set the variable
504 @code{mm-file-name-replace-whitespace} to any other string if you do
505 not like underscores.
508 The standard Emacs functions @code{capitalize}, @code{downcase},
509 @code{upcase} and @code{upcase-initials} might also prove useful.
511 @item mm-path-name-rewrite-functions
512 @vindex mm-path-name-rewrite-functions
513 List of functions used for rewriting the full file names of @acronym{MIME}
514 parts. This is used when viewing parts externally, and is meant for
515 transforming the absolute name so that non-compliant programs can find
516 the file where it's saved.
523 Here's an example viewer for displaying @code{text/enriched} inline:
526 (defun mm-display-enriched-inline (handle)
529 (mm-insert-part handle)
530 (save-window-excursion
531 (enriched-decode (point-min) (point-max))
532 (setq text (buffer-string))))
533 (mm-insert-inline handle text)))
536 We see that the function takes a @acronym{MIME} handle as its parameter. It
537 then goes to a temporary buffer, inserts the text of the part, does some
538 work on the text, stores the result, goes back to the buffer it was
539 called from and inserts the result.
541 The two important helper functions here are @code{mm-insert-part} and
542 @code{mm-insert-inline}. The first function inserts the text of the
543 handle in the current buffer. It handles charset and/or content
544 transfer decoding. The second function just inserts whatever text you
545 tell it to insert, but it also sets things up so that the text can be
546 ``undisplayed'' in a convenient manner.
552 @cindex MIME Composing
554 @cindex MIME Meta Language
556 Creating a @acronym{MIME} message is boring and non-trivial. Therefore,
557 a library called @code{mml} has been defined that parses a language
558 called @acronym{MML} (@acronym{MIME} Meta Language) and generates
559 @acronym{MIME} messages.
561 @findex mml-generate-mime
562 The main interface function is @code{mml-generate-mime}. It will
563 examine the contents of the current (narrowed-to) buffer and return a
564 string containing the @acronym{MIME} message.
567 * Simple MML Example:: An example @acronym{MML} document.
568 * MML Definition:: All valid @acronym{MML} elements.
569 * Advanced MML Example:: Another example @acronym{MML} document.
570 * Encoding Customization:: Variables that affect encoding.
571 * Charset Translation:: How charsets are mapped from @sc{mule} to @acronym{MIME}.
572 * Conversion:: Going from @acronym{MIME} to @acronym{MML} and vice versa.
573 * Flowed text:: Soft and hard newlines.
577 @node Simple MML Example
578 @section Simple MML Example
580 Here's a simple @samp{multipart/alternative}:
583 <#multipart type=alternative>
584 This is a plain text part.
585 <#part type=text/enriched>
586 <center>This is a centered enriched part</center>
590 After running this through @code{mml-generate-mime}, we get this:
593 Content-Type: multipart/alternative; boundary="=-=-="
599 This is a plain text part.
602 Content-Type: text/enriched
605 <center>This is a centered enriched part</center>
612 @section MML Definition
614 The @acronym{MML} language is very simple. It looks a bit like an SGML
615 application, but it's not.
617 The main concept of @acronym{MML} is the @dfn{part}. Each part can be of a
618 different type or use a different charset. The way to delineate a part
619 is with a @samp{<#part ...>} tag. Multipart parts can be introduced
620 with the @samp{<#multipart ...>} tag. Parts are ended by the
621 @samp{<#/part>} or @samp{<#/multipart>} tags. Parts started with the
622 @samp{<#part ...>} tags are also closed by the next open tag.
624 There's also the @samp{<#external ...>} tag. These introduce
625 @samp{external/message-body} parts.
627 Each tag can contain zero or more parameters on the form
628 @samp{parameter=value}. The values may be enclosed in quotation marks,
629 but that's not necessary unless the value contains white space. So
630 @samp{filename=/home/user/#hello$^yes} is perfectly valid.
632 The following parameters have meaning in @acronym{MML}; parameters that have no
633 meaning are ignored. The @acronym{MML} parameter names are the same as the
634 @acronym{MIME} parameter names; the things in the parentheses say which
635 header it will be used in.
639 The @acronym{MIME} type of the part (@code{Content-Type}).
642 Use the contents of the file in the body of the part
643 (@code{Content-Disposition}).
646 The contents of the body of the part are to be encoded in the character
647 set specified (@code{Content-Type}). @xref{Charset Translation}.
650 Might be used to suggest a file name if the part is to be saved
651 to a file (@code{Content-Type}).
654 Valid values are @samp{inline} and @samp{attachment}
655 (@code{Content-Disposition}).
658 Valid values are @samp{7bit}, @samp{8bit}, @samp{quoted-printable} and
659 @samp{base64} (@code{Content-Transfer-Encoding}). @xref{Charset
663 A description of the part (@code{Content-Description}).
666 RFC822 date when the part was created (@code{Content-Disposition}).
668 @item modification-date
669 RFC822 date when the part was modified (@code{Content-Disposition}).
672 RFC822 date when the part was read (@code{Content-Disposition}).
675 Who to encrypt/sign the part to. This field is used to override any
676 auto-detection based on the To/CC headers.
679 Identity used to sign the part. This field is used to override the
683 The size (in octets) of the part (@code{Content-Disposition}).
686 What technology to sign this @acronym{MML} part with (@code{smime}, @code{pgp}
690 What technology to encrypt this @acronym{MML} part with (@code{smime},
691 @code{pgp} or @code{pgpmime})
695 Parameters for @samp{text/plain}:
699 Formatting parameter for the text, valid values include @samp{fixed}
700 (the default) and @samp{flowed}. Normally you do not specify this
701 manually, since it requires the textual body to be formatted in a
702 special way described in RFC 2646. @xref{Flowed text}.
705 Parameters for @samp{application/octet-stream}:
709 Type of the part; informal---meant for human readers
710 (@code{Content-Type}).
713 Parameters for @samp{message/external-body}:
717 A word indicating the supported access mechanism by which the file may
718 be obtained. Values include @samp{ftp}, @samp{anon-ftp}, @samp{tftp},
719 @samp{localfile}, and @samp{mailserver}. (@code{Content-Type}.)
722 The RFC822 date after which the file may no longer be fetched.
723 (@code{Content-Type}.)
726 The size (in octets) of the file. (@code{Content-Type}.)
729 Valid values are @samp{read} and @samp{read-write}
730 (@code{Content-Type}).
734 Parameters for @samp{sign=smime}:
739 File containing key and certificate for signer.
743 Parameters for @samp{encrypt=smime}:
748 File containing certificate for recipient.
753 @node Advanced MML Example
754 @section Advanced MML Example
756 Here's a complex multipart message. It's a @samp{multipart/mixed} that
757 contains many parts, one of which is a @samp{multipart/alternative}.
760 <#multipart type=mixed>
761 <#part type=image/jpeg filename=~/rms.jpg disposition=inline>
762 <#multipart type=alternative>
763 This is a plain text part.
764 <#part type=text/enriched name=enriched.txt>
765 <center>This is a centered enriched part</center>
767 This is a new plain text part.
768 <#part disposition=attachment>
769 This plain text part is an attachment.
773 And this is the resulting @acronym{MIME} message:
776 Content-Type: multipart/mixed; boundary="=-=-="
784 Content-Type: image/jpeg;
786 Content-Disposition: inline;
788 Content-Transfer-Encoding: base64
790 /9j/4AAQSkZJRgABAQAAAQABAAD/2wBDAAgGBgcGBQgHBwcJCQgKDBQNDAsLDBkSEw8UHRof
791 Hh0aHBwgJC4nICIsIxwcKDcpLDAxNDQ0Hyc5PTgyPC4zNDL/wAALCAAwADABAREA/8QAHwAA
792 AQUBAQEBAQEAAAAAAAAAAAECAwQFBgcICQoL/8QAtRAAAgEDAwIEAwUFBAQAAAF9AQIDAAQR
793 BRIhMUEGE1FhByJxFDKBkaEII0KxwRVS0fAkM2JyggkKFhcYGRolJicoKSo0NTY3ODk6Q0RF
794 RkdISUpTVFVWV1hZWmNkZWZnaGlqc3R1dnd4eXqDhIWGh4iJipKTlJWWl5iZmqKjpKWmp6ip
795 qrKztLW2t7i5usLDxMXGx8jJytLT1NXW19jZ2uHi4+Tl5ufo6erx8vP09fb3+Pn6/9oACAEB
796 AAA/AO/rifFHjldNuGsrDa0qcSSHkA+gHrXKw+LtWLrMb+RgTyhbr+HSug07xNqV9fQtZrNI
797 AyiaE/NuBPOOOP0rvRNE880KOC8TbXXGCv1FPqjrF4LDR7u5L7SkTFT/ALWOP1xXgTuXfc7E
798 sx6nua6rwp4IvvEM8chCxWxOdzn7wz6V9AaB4S07w9p5itow0rDLSY5Pt9K43xO66P4xs71m
799 2QXiGCbA4yOVJ9+1aYORkdK434lyNH4ahCnG66VT9Nj15JFbPdX0MS43M4VQf5/yr2vSpLnw
800 5ZW8dlCZ8KFXjOPX0/mK6rSPEGt3Angu44fNEReHYNvIH3TzXDeKNO8RX+kSX2ouZkicTIOc
801 L+g7E810ulFjpVtv3bwgB3HJyK5L4quY/C9sVxk3ij/xx6850u7t1mtp/wDlpEw3An3Jr3Dw
802 34gsbWza4nBlhC5LDsaW6+IFgupQyCF3iHH7gA7c9R9ay7zx6t7aX9jHC4smhfBkGCvHGfrm
803 tLQ7hbnRrV1GPkAP1x1/Hr+Ncr8Vzjwrbf8AX6v/AKA9eQRyYlQk8Yx9K6XTNbkgia2ciSIn
804 7p5Ga9Atte0LTLKO6it4i7dVRFJDcZ4PvXN+JvEMF9bILVGXJLSZ4zkjivRPDaeX4b08HOTC
805 pOffmua+KkbS+GLVUGT9tT/0B68eeIpIFYjB70+OOVXyoOM9+M1eaWeCLzHPyHGO/NVWvJJm
806 jQ8KGH1NfQWhXSXmh2c8eArRLwO3HSv/2Q==
809 Content-Type: multipart/alternative; boundary="==-=-="
815 This is a plain text part.
818 Content-Type: text/enriched;
822 <center>This is a centered enriched part</center>
828 This is a new plain text part.
831 Content-Disposition: attachment
834 This plain text part is an attachment.
839 @node Encoding Customization
840 @section Encoding Customization
844 @item mm-body-charset-encoding-alist
845 @vindex mm-body-charset-encoding-alist
846 Mapping from @acronym{MIME} charset to encoding to use. This variable is
847 usually used except, e.g., when other requirements force a specific
848 encoding (digitally signed messages require 7bit encodings). The
852 ((iso-2022-jp . 7bit)
853 (iso-2022-jp-2 . 7bit)
859 As an example, if you do not want to have ISO-8859-1 characters
860 quoted-printable encoded, you may add @code{(iso-8859-1 . 8bit)} to
861 this variable. You can override this setting on a per-message basis
862 by using the @code{encoding} @acronym{MML} tag (@pxref{MML Definition}).
864 @item mm-coding-system-priorities
865 @vindex mm-coding-system-priorities
866 Prioritize coding systems to use for outgoing messages. The default
867 is @code{nil}, which means to use the defaults in Emacs, but is
868 @code{(iso-8859-1 iso-2022-jp iso-2022-jp-2 shift_jis utf-8)} when
869 running Emacs in the Japanese language environment. It is a list of
870 coding system symbols (aliases of coding systems are also allowed, use
871 @kbd{M-x describe-coding-system} to make sure you are specifying correct
872 coding system names). For example, if you have configured Emacs
873 to prefer UTF-8, but wish that outgoing messages should be sent in
874 ISO-8859-1 if possible, you can set this variable to
875 @code{(iso-8859-1)}. You can override this setting on a per-message
876 basis by using the @code{charset} @acronym{MML} tag (@pxref{MML Definition}).
878 As different hierarchies prefer different charsets, you may want to set
879 @code{mm-coding-system-priorities} according to the hierarchy in Gnus.
882 @c Corrections about preferred charsets are welcome. de, fr and fj
883 @c should be correct, I don't know about the rest (so these are only
886 (add-to-list 'gnus-newsgroup-variables 'mm-coding-system-priorities)
887 (setq gnus-parameters
889 ;; Some charsets are just examples!
890 '(("^cn\\." ;; Chinese
891 (mm-coding-system-priorities
892 '(iso-8859-1 cn-big5 chinese-iso-7bit utf-8)))
893 ("^cz\\.\\|^pl\\." ;; Central and Eastern European
894 (mm-coding-system-priorities '(iso-8859-2 utf-8)))
895 ("^de\\." ;; German language
896 (mm-coding-system-priorities '(iso-8859-1 iso-8859-15 utf-8)))
898 (mm-coding-system-priorities '(iso-8859-15 iso-8859-1 utf-8)))
899 ("^fj\\." ;; Japanese
900 (mm-coding-system-priorities
901 '(iso-8859-1 iso-2022-jp iso-2022-jp-2 shift_jis utf-8)))
902 ("^ru\\." ;; Cyrillic
903 (mm-coding-system-priorities
904 '(koi8-r iso-8859-5 iso-8859-1 utf-8))))
908 @item mm-content-transfer-encoding-defaults
909 @vindex mm-content-transfer-encoding-defaults
910 Mapping from @acronym{MIME} types to encoding to use. This variable is usually
911 used except, e.g., when other requirements force a safer encoding
912 (digitally signed messages require 7bit encoding). Besides the normal
913 @acronym{MIME} encodings, @code{qp-or-base64} may be used to indicate that for
914 each case the most efficient of quoted-printable and base64 should be
917 @code{qp-or-base64} has another effect. It will fold long lines so that
918 MIME parts may not be broken by MTA. So do @code{quoted-printable} and
921 Note that it affects body encoding only when a part is a raw forwarded
922 message (which will be made by @code{gnus-summary-mail-forward} with the
923 arg 2 for example) or is neither the @samp{text/*} type nor the
924 @samp{message/*} type. Even though in those cases, you can override
925 this setting on a per-message basis by using the @code{encoding}
926 @acronym{MML} tag (@pxref{MML Definition}).
928 @item mm-use-ultra-safe-encoding
929 @vindex mm-use-ultra-safe-encoding
930 When this is non-@code{nil}, it means that textual parts are encoded as
931 quoted-printable if they contain lines longer than 76 characters or
932 starting with "From " in the body. Non-7bit encodings (8bit, binary)
933 are generally disallowed. This reduce the probability that a non-8bit
934 clean MTA or MDA changes the message. This should never be set
935 directly, but bound by other functions when necessary (e.g., when
936 encoding messages that are to be digitally signed).
940 @node Charset Translation
941 @section Charset Translation
944 During translation from @acronym{MML} to @acronym{MIME}, for each
945 @acronym{MIME} part which has been composed inside Emacs, an appropriate
946 charset has to be chosen.
948 @vindex mail-parse-charset
949 If you are running a non-@sc{mule} Emacs, this process is simple: If the
950 part contains any non-@acronym{ASCII} (8-bit) characters, the @acronym{MIME} charset
951 given by @code{mail-parse-charset} (a symbol) is used. (Never set this
952 variable directly, though. If you want to change the default charset,
953 please consult the documentation of the package which you use to process
954 @acronym{MIME} messages.
955 @xref{Various Message Variables, , Various Message Variables, message,
956 Message Manual}, for example.)
957 If there are only @acronym{ASCII} characters, the @acronym{MIME} charset US-ASCII is
963 @vindex mm-mime-mule-charset-alist
964 Things are slightly more complicated when running Emacs with @sc{mule}
965 support. In this case, a list of the @sc{mule} charsets used in the
966 part is obtained, and the @sc{mule} charsets are translated to
967 @acronym{MIME} charsets by consulting the table provided by Emacs itself
968 or the variable @code{mm-mime-mule-charset-alist} for XEmacs.
969 If this results in a single @acronym{MIME} charset, this is used to encode
970 the part. But if the resulting list of @acronym{MIME} charsets contains more
971 than one element, two things can happen: If it is possible to encode the
972 part via UTF-8, this charset is used. (For this, Emacs must support
973 the @code{utf-8} coding system, and the part must consist entirely of
974 characters which have Unicode counterparts.) If UTF-8 is not available
975 for some reason, the part is split into several ones, so that each one
976 can be encoded with a single @acronym{MIME} charset. The part can only be
977 split at line boundaries, though---if more than one @acronym{MIME} charset is
978 required to encode a single line, it is not possible to encode the part.
980 When running Emacs with @sc{mule} support, the preferences for which
981 coding system to use is inherited from Emacs itself. This means that
982 if Emacs is set up to prefer UTF-8, it will be used when encoding
983 messages. You can modify this by altering the
984 @code{mm-coding-system-priorities} variable though (@pxref{Encoding
987 The charset to be used can be overridden by setting the @code{charset}
988 @acronym{MML} tag (@pxref{MML Definition}) when composing the message.
990 The encoding of characters (quoted-printable, 8bit etc) is orthogonal
991 to the discussion here, and is controlled by the variables
992 @code{mm-body-charset-encoding-alist} and
993 @code{mm-content-transfer-encoding-defaults} (@pxref{Encoding
1000 A (multipart) @acronym{MIME} message can be converted to @acronym{MML}
1001 with the @code{mime-to-mml} function. It works on the message in the
1002 current buffer, and substitutes @acronym{MML} markup for @acronym{MIME}
1003 boundaries. Non-textual parts do not have their contents in the buffer,
1004 but instead have the contents in separate buffers that are referred to
1005 from the @acronym{MML} tags.
1008 An @acronym{MML} message can be converted back to @acronym{MIME} by the
1009 @code{mml-to-mime} function.
1011 These functions are in certain senses ``lossy''---you will not get back
1012 an identical message if you run @code{mime-to-mml} and then
1013 @code{mml-to-mime}. Not only will trivial things like the order of the
1014 headers differ, but the contents of the headers may also be different.
1015 For instance, the original message may use base64 encoding on text,
1016 while @code{mml-to-mime} may decide to use quoted-printable encoding, and
1019 In essence, however, these two functions should be the inverse of each
1020 other. The resulting contents of the message should remain equivalent,
1025 @section Flowed text
1026 @cindex format=flowed
1028 The Emacs @acronym{MIME} library will respect the @code{use-hard-newlines}
1029 variable (@pxref{Hard and Soft Newlines, ,Hard and Soft Newlines,
1030 emacs, Emacs Manual}) when encoding a message, and the
1031 ``format=flowed'' Content-Type parameter when decoding a message.
1033 On encoding text, regardless of @code{use-hard-newlines}, lines
1034 terminated by soft newline characters are filled together and wrapped
1035 after the column decided by @code{fill-flowed-encode-column}.
1036 Quotation marks (matching @samp{^>* ?}) are respected. The variable
1037 controls how the text will look in a client that does not support
1038 flowed text, the default is to wrap after 66 characters. If hard
1039 newline characters are not present in the buffer, no flow encoding
1042 You can customize the value of the @code{mml-enable-flowed} variable
1043 to enable or disable the flowed encoding usage when newline
1044 characteres are present in the buffer.
1046 On decoding flowed text, lines with soft newline characters are filled
1047 together and wrapped after the column decided by
1048 @code{fill-flowed-display-column}. The default is to wrap after
1052 @item mm-fill-flowed
1053 @vindex mm-fill-flowed
1054 If non-@code{nil} a format=flowed article will be displayed flowed.
1058 @node Interface Functions
1059 @chapter Interface Functions
1060 @cindex interface functions
1063 The @code{mail-parse} library is an abstraction over the actual
1064 low-level libraries that are described in the next chapter.
1066 Standards change, and so programs have to change to fit in the new
1067 mold. For instance, RFC2045 describes a syntax for the
1068 @code{Content-Type} header that only allows @acronym{ASCII} characters in the
1069 parameter list. RFC2231 expands on RFC2045 syntax to provide a scheme
1070 for continuation headers and non-@acronym{ASCII} characters.
1072 The traditional way to deal with this is just to update the library
1073 functions to parse the new syntax. However, this is sometimes the wrong
1074 thing to do. In some instances it may be vital to be able to understand
1075 both the old syntax as well as the new syntax, and if there is only one
1076 library, one must choose between the old version of the library and the
1077 new version of the library.
1079 The Emacs @acronym{MIME} library takes a different tack. It defines a
1080 series of low-level libraries (@file{rfc2047.el}, @file{rfc2231.el}
1081 and so on) that parses strictly according to the corresponding
1082 standard. However, normal programs would not use the functions
1083 provided by these libraries directly, but instead use the functions
1084 provided by the @code{mail-parse} library. The functions in this
1085 library are just aliases to the corresponding functions in the latest
1086 low-level libraries. Using this scheme, programs get a consistent
1087 interface they can use, and library developers are free to create
1088 write code that handles new standards.
1090 The following functions are defined by this library:
1093 @item mail-header-parse-content-type
1094 @findex mail-header-parse-content-type
1095 Parse a @code{Content-Type} header and return a list on the following
1100 (attribute1 . value1)
1101 (attribute2 . value2)
1108 (mail-header-parse-content-type
1109 "image/gif; name=\"b980912.gif\"")
1110 @result{} ("image/gif" (name . "b980912.gif"))
1113 @item mail-header-parse-content-disposition
1114 @findex mail-header-parse-content-disposition
1115 Parse a @code{Content-Disposition} header and return a list on the same
1116 format as the function above.
1118 @item mail-content-type-get
1119 @findex mail-content-type-get
1120 Takes two parameters---a list on the format above, and an attribute.
1121 Returns the value of the attribute.
1124 (mail-content-type-get
1125 '("image/gif" (name . "b980912.gif")) 'name)
1126 @result{} "b980912.gif"
1129 @item mail-header-encode-parameter
1130 @findex mail-header-encode-parameter
1131 Takes a parameter string and returns an encoded version of the string.
1132 This is used for parameters in headers like @code{Content-Type} and
1133 @code{Content-Disposition}.
1135 @item mail-header-remove-comments
1136 @findex mail-header-remove-comments
1137 Return a comment-free version of a header.
1140 (mail-header-remove-comments
1141 "Gnus/5.070027 (Pterodactyl Gnus v0.27) (Finnish Landrace)")
1142 @result{} "Gnus/5.070027 "
1145 @item mail-header-remove-whitespace
1146 @findex mail-header-remove-whitespace
1147 Remove linear white space from a header. Space inside quoted strings
1148 and comments is preserved.
1151 (mail-header-remove-whitespace
1152 "image/gif; name=\"Name with spaces\"")
1153 @result{} "image/gif;name=\"Name with spaces\""
1156 @item mail-header-get-comment
1157 @findex mail-header-get-comment
1158 Return the last comment in a header.
1161 (mail-header-get-comment
1162 "Gnus/5.070027 (Pterodactyl Gnus v0.27) (Finnish Landrace)")
1163 @result{} "Finnish Landrace"
1166 @item mail-header-parse-address
1167 @findex mail-header-parse-address
1168 Parse an address and return a list containing the mailbox and the
1172 (mail-header-parse-address
1173 "Hrvoje Niksic <hniksic@@srce.hr>")
1174 @result{} ("hniksic@@srce.hr" . "Hrvoje Niksic")
1177 @item mail-header-parse-addresses
1178 @findex mail-header-parse-addresses
1179 Parse a string with list of addresses and return a list of elements like
1180 the one described above.
1183 (mail-header-parse-addresses
1184 "Hrvoje Niksic <hniksic@@srce.hr>, Steinar Bang <sb@@metis.no>")
1185 @result{} (("hniksic@@srce.hr" . "Hrvoje Niksic")
1186 ("sb@@metis.no" . "Steinar Bang"))
1189 @item mail-header-parse-date
1190 @findex mail-header-parse-date
1191 Parse a date string and return an Emacs time structure.
1193 @item mail-narrow-to-head
1194 @findex mail-narrow-to-head
1195 Narrow the buffer to the header section of the buffer. Point is placed
1196 at the beginning of the narrowed buffer.
1198 @item mail-header-narrow-to-field
1199 @findex mail-header-narrow-to-field
1200 Narrow the buffer to the header under point. Understands continuation
1203 @item mail-header-fold-field
1204 @findex mail-header-fold-field
1205 Fold the header under point.
1207 @item mail-header-unfold-field
1208 @findex mail-header-unfold-field
1209 Unfold the header under point.
1211 @item mail-header-field-value
1212 @findex mail-header-field-value
1213 Return the value of the field under point.
1215 @item mail-encode-encoded-word-region
1216 @findex mail-encode-encoded-word-region
1217 Encode the non-@acronym{ASCII} words in the region. For instance,
1218 @samp{Na@"{@dotless{i}}ve} is encoded as @samp{=?iso-8859-1?q?Na=EFve?=}.
1220 @item mail-encode-encoded-word-buffer
1221 @findex mail-encode-encoded-word-buffer
1222 Encode the non-@acronym{ASCII} words in the current buffer. This function is
1223 meant to be called narrowed to the headers of a message.
1225 @item mail-encode-encoded-word-string
1226 @findex mail-encode-encoded-word-string
1227 Encode the words that need encoding in a string, and return the result.
1230 (mail-encode-encoded-word-string
1231 "This is na@"{@dotless{i}}ve, baby")
1232 @result{} "This is =?iso-8859-1?q?na=EFve,?= baby"
1235 @item mail-decode-encoded-word-region
1236 @findex mail-decode-encoded-word-region
1237 Decode the encoded words in the region.
1239 @item mail-decode-encoded-word-string
1240 @findex mail-decode-encoded-word-string
1241 Decode the encoded words in the string and return the result.
1244 (mail-decode-encoded-word-string
1245 "This is =?iso-8859-1?q?na=EFve,?= baby")
1246 @result{} "This is na@"{@dotless{i}}ve, baby"
1251 Currently, @code{mail-parse} is an abstraction over @code{ietf-drums},
1252 @code{rfc2047}, @code{rfc2045} and @code{rfc2231}. These are documented
1253 in the subsequent sections.
1257 @node Basic Functions
1258 @chapter Basic Functions
1260 This chapter describes the basic, ground-level functions for parsing and
1261 handling. Covered here is parsing @code{From} lines, removing comments
1262 from header lines, decoding encoded words, parsing date headers and so
1263 on. High-level functionality is dealt with in the first chapter
1264 (@pxref{Decoding and Viewing}).
1267 * rfc2045:: Encoding @code{Content-Type} headers.
1268 * rfc2231:: Parsing @code{Content-Type} headers.
1269 * ietf-drums:: Handling mail headers defined by RFC822bis.
1270 * rfc2047:: En/decoding encoded words in headers.
1271 * time-date:: Functions for parsing dates and manipulating time.
1272 * qp:: Quoted-Printable en/decoding.
1273 * base64:: Base64 en/decoding.
1274 * binhex:: Binhex decoding.
1275 * uudecode:: Uuencode decoding.
1276 * yenc:: Yenc decoding.
1277 * rfc1843:: Decoding HZ-encoded text.
1278 * mailcap:: How parts are displayed is specified by the @file{.mailcap} file
1285 RFC2045 is the ``main'' @acronym{MIME} document, and as such, one would
1286 imagine that there would be a lot to implement. But there isn't, since
1287 most of the implementation details are delegated to the subsequent
1290 So @file{rfc2045.el} has only a single function:
1293 @item rfc2045-encode-string
1294 @findex rfc2045-encode-string
1295 Takes a parameter and a value and returns a @samp{PARAM=VALUE} string.
1296 @var{value} will be quoted if there are non-safe characters in it.
1303 RFC2231 defines a syntax for the @code{Content-Type} and
1304 @code{Content-Disposition} headers. Its snappy name is @dfn{MIME
1305 Parameter Value and Encoded Word Extensions: Character Sets, Languages,
1308 In short, these headers look something like this:
1311 Content-Type: application/x-stuff;
1312 title*0*=us-ascii'en'This%20is%20even%20more%20;
1313 title*1*=%2A%2A%2Afun%2A%2A%2A%20;
1317 They usually aren't this bad, though.
1319 The following functions are defined by this library:
1322 @item rfc2231-parse-string
1323 @findex rfc2231-parse-string
1324 Parse a @code{Content-Type} header and return a list describing its
1328 (rfc2231-parse-string
1329 "application/x-stuff;
1330 title*0*=us-ascii'en'This%20is%20even%20more%20;
1331 title*1*=%2A%2A%2Afun%2A%2A%2A%20;
1332 title*2=\"isn't it!\"")
1333 @result{} ("application/x-stuff"
1334 (title . "This is even more ***fun*** isn't it!"))
1337 @item rfc2231-get-value
1338 @findex rfc2231-get-value
1339 Takes one of the lists on the format above and returns
1340 the value of the specified attribute.
1342 @item rfc2231-encode-string
1343 @findex rfc2231-encode-string
1344 Encode a parameter in headers likes @code{Content-Type} and
1345 @code{Content-Disposition}.
1353 @dfn{drums} is an IETF working group that is working on the replacement
1356 The functions provided by this library include:
1359 @item ietf-drums-remove-comments
1360 @findex ietf-drums-remove-comments
1361 Remove the comments from the argument and return the results.
1363 @item ietf-drums-remove-whitespace
1364 @findex ietf-drums-remove-whitespace
1365 Remove linear white space from the string and return the results.
1366 Spaces inside quoted strings and comments are left untouched.
1368 @item ietf-drums-get-comment
1369 @findex ietf-drums-get-comment
1370 Return the last most comment from the string.
1372 @item ietf-drums-parse-address
1373 @findex ietf-drums-parse-address
1374 Parse an address string and return a list that contains the mailbox and
1375 the plain text name.
1377 @item ietf-drums-parse-addresses
1378 @findex ietf-drums-parse-addresses
1379 Parse a string that contains any number of comma-separated addresses and
1380 return a list that contains mailbox/plain text pairs.
1382 @item ietf-drums-parse-date
1383 @findex ietf-drums-parse-date
1384 Parse a date string and return an Emacs time structure.
1386 @item ietf-drums-narrow-to-header
1387 @findex ietf-drums-narrow-to-header
1388 Narrow the buffer to the header section of the current buffer.
1396 RFC2047 (Message Header Extensions for Non-@acronym{ASCII} Text) specifies how
1397 non-@acronym{ASCII} text in headers are to be encoded. This is actually rather
1398 complicated, so a number of variables are necessary to tweak what this
1401 The following variables are tweakable:
1404 @item rfc2047-header-encoding-alist
1405 @vindex rfc2047-header-encoding-alist
1406 This is an alist of header / encoding-type pairs. Its main purpose is
1407 to prevent encoding of certain headers.
1409 The keys can either be header regexps, or @code{t}.
1411 The values can be @code{nil}, in which case the header(s) in question
1412 won't be encoded, @code{mime}, which means that they will be encoded, or
1413 @code{address-mime}, which means the header(s) will be encoded carefully
1414 assuming they contain addresses.
1416 @item rfc2047-charset-encoding-alist
1417 @vindex rfc2047-charset-encoding-alist
1418 RFC2047 specifies two forms of encoding---@code{Q} (a
1419 Quoted-Printable-like encoding) and @code{B} (base64). This alist
1420 specifies which charset should use which encoding.
1422 @item rfc2047-encode-function-alist
1423 @vindex rfc2047-encode-function-alist
1424 This is an alist of encoding / function pairs. The encodings are
1425 @code{Q}, @code{B} and @code{nil}.
1427 @item rfc2047-encoded-word-regexp
1428 @vindex rfc2047-encoded-word-regexp
1429 When decoding words, this library looks for matches to this regexp.
1431 @item rfc2047-encoded-word-regexp-loose
1432 @vindex rfc2047-encoded-word-regexp-loose
1433 This is a version from which the regexp for the Q encoding pattern of
1434 @code{rfc2047-encoded-word-regexp} is made loose.
1436 @item rfc2047-encode-encoded-words
1437 @vindex rfc2047-encode-encoded-words
1438 The boolean variable specifies whether encoded words
1439 (e.g. @samp{=?us-ascii?q?hello?=}) should be encoded again.
1440 @code{rfc2047-encoded-word-regexp} is used to look for such words.
1442 @item rfc2047-allow-irregular-q-encoded-words
1443 @vindex rfc2047-allow-irregular-q-encoded-words
1444 The boolean variable specifies whether irregular Q encoded words
1445 (e.g. @samp{=?us-ascii?q?hello??=}) should be decoded. If it is
1446 non-@code{nil}, @code{rfc2047-encoded-word-regexp-loose} is used instead
1447 of @code{rfc2047-encoded-word-regexp} to look for encoded words.
1451 Those were the variables, and these are this functions:
1454 @item rfc2047-narrow-to-field
1455 @findex rfc2047-narrow-to-field
1456 Narrow the buffer to the header on the current line.
1458 @item rfc2047-encode-message-header
1459 @findex rfc2047-encode-message-header
1460 Should be called narrowed to the header of a message. Encodes according
1461 to @code{rfc2047-header-encoding-alist}.
1463 @item rfc2047-encode-region
1464 @findex rfc2047-encode-region
1465 Encodes all encodable words in the region specified.
1467 @item rfc2047-encode-string
1468 @findex rfc2047-encode-string
1469 Encode a string and return the results.
1471 @item rfc2047-decode-region
1472 @findex rfc2047-decode-region
1473 Decode the encoded words in the region.
1475 @item rfc2047-decode-string
1476 @findex rfc2047-decode-string
1477 Decode a string and return the results.
1479 @item rfc2047-encode-parameter
1480 @findex rfc2047-encode-parameter
1481 Encode a parameter in the RFC2047-like style. This is a substitution
1482 for the @code{rfc2231-encode-string} function, that is the standard but
1483 many mailers don't support it. @xref{rfc2231}.
1491 While not really a part of the @acronym{MIME} library, it is convenient to
1492 document this library here. It deals with parsing @code{Date} headers
1493 and manipulating time. (Not by using tesseracts, though, I'm sorry to
1496 These functions convert between five formats: A date string, an Emacs
1497 time structure, a decoded time list, a second number, and a day number.
1499 Here's a bunch of time/date/second/day examples:
1502 (parse-time-string "Sat Sep 12 12:21:54 1998 +0200")
1503 @result{} (54 21 12 12 9 1998 6 nil 7200)
1505 (date-to-time "Sat Sep 12 12:21:54 1998 +0200")
1506 @result{} (13818 19266)
1508 (time-to-seconds '(13818 19266))
1509 @result{} 905595714.0
1511 (seconds-to-time 905595714.0)
1512 @result{} (13818 19266 0)
1514 (time-to-days '(13818 19266))
1517 (days-to-time 729644)
1518 @result{} (961933 65536)
1520 (time-since '(13818 19266))
1523 (time-less-p '(13818 19266) '(13818 19145))
1526 (subtract-time '(13818 19266) '(13818 19145))
1529 (days-between "Sat Sep 12 12:21:54 1998 +0200"
1530 "Sat Sep 07 12:21:54 1998 +0200")
1533 (date-leap-year-p 2000)
1536 (time-to-day-in-year '(13818 19266))
1539 (time-to-number-of-days
1541 (date-to-time "Mon, 01 Jan 2001 02:22:26 GMT")))
1542 @result{} 4.146122685185185
1545 And finally, we have @code{safe-date-to-time}, which does the same as
1546 @code{date-to-time}, but returns a zero time if the date is
1547 syntactically malformed.
1549 The five data representations used are the following:
1553 An RFC822 (or similar) date string. For instance: @code{"Sat Sep 12
1554 12:21:54 1998 +0200"}.
1557 An internal Emacs time. For instance: @code{(13818 26466)}.
1560 A floating point representation of the internal Emacs time. For
1561 instance: @code{905595714.0}.
1564 An integer number representing the number of days since 00000101. For
1565 instance: @code{729644}.
1568 A list of decoded time. For instance: @code{(54 21 12 12 9 1998 6 t
1572 All the examples above represent the same moment.
1574 These are the functions available:
1578 Take a date and return a time.
1580 @item time-to-seconds
1581 Take a time and return seconds. Note that Emacs has a built-in
1582 function, @code{float-time}, that does this.
1584 @item seconds-to-time
1585 Take seconds and return a time.
1588 Take a time and return days.
1591 Take days and return a time.
1594 Take a date and return days.
1596 @item time-to-number-of-days
1597 Take a time and return the number of days that represents.
1599 @item safe-date-to-time
1600 Take a date and return a time. If the date is not syntactically valid,
1601 return a ``zero'' time.
1604 Take two times and say whether the first time is less (i. e., earlier)
1605 than the second time.
1608 Take a time and return a time saying how long it was since that time.
1611 Take two times and subtract the second from the first. I. e., return
1612 the time between the two times.
1615 Take two days and return the number of days between those two days.
1617 @item date-leap-year-p
1618 Take a year number and say whether it's a leap year.
1620 @item time-to-day-in-year
1621 Take a time and return the day number within the year that the time is
1630 This library deals with decoding and encoding Quoted-Printable text.
1632 Very briefly explained, qp encoding means translating all 8-bit
1633 characters (and lots of control characters) into things that look like
1634 @samp{=EF}; that is, an equal sign followed by the byte encoded as a hex
1637 The following functions are defined by the library:
1640 @item quoted-printable-decode-region
1641 @findex quoted-printable-decode-region
1642 QP-decode all the encoded text in the specified region.
1644 @item quoted-printable-decode-string
1645 @findex quoted-printable-decode-string
1646 Decode the QP-encoded text in a string and return the results.
1648 @item quoted-printable-encode-region
1649 @findex quoted-printable-encode-region
1650 QP-encode all the encodable characters in the specified region. The third
1651 optional parameter @var{fold} specifies whether to fold long lines.
1652 (Long here means 72.)
1654 @item quoted-printable-encode-string
1655 @findex quoted-printable-encode-string
1656 QP-encode all the encodable characters in a string and return the
1666 Base64 is an encoding that encodes three bytes into four characters,
1667 thereby increasing the size by about 33%. The alphabet used for
1668 encoding is very resistant to mangling during transit.
1670 The following functions are defined by this library:
1673 @item base64-encode-region
1674 @findex base64-encode-region
1675 base64 encode the selected region. Return the length of the encoded
1676 text. Optional third argument @var{no-line-break} means do not break
1677 long lines into shorter lines.
1679 @item base64-encode-string
1680 @findex base64-encode-string
1681 base64 encode a string and return the result.
1683 @item base64-decode-region
1684 @findex base64-decode-region
1685 base64 decode the selected region. Return the length of the decoded
1686 text. If the region can't be decoded, return @code{nil} and don't
1689 @item base64-decode-string
1690 @findex base64-decode-string
1691 base64 decode a string and return the result. If the string can't be
1692 decoded, @code{nil} is returned.
1703 @code{binhex} is an encoding that originated in Macintosh environments.
1704 The following function is supplied to deal with these:
1707 @item binhex-decode-region
1708 @findex binhex-decode-region
1709 Decode the encoded text in the region. If given a third parameter, only
1710 decode the @code{binhex} header and return the filename.
1719 @code{uuencode} is probably still the most popular encoding of binaries
1720 used on Usenet, although @code{base64} rules the mail world.
1722 The following function is supplied by this package:
1725 @item uudecode-decode-region
1726 @findex uudecode-decode-region
1727 Decode the text in the region.
1735 @code{yenc} is used for encoding binaries on Usenet. The following
1736 function is supplied by this package:
1739 @item yenc-decode-region
1740 @findex yenc-decode-region
1741 Decode the encoded text in the region.
1752 RFC1843 deals with mixing Chinese and @acronym{ASCII} characters in messages. In
1753 essence, RFC1843 switches between @acronym{ASCII} and Chinese by doing this:
1756 This sentence is in @acronym{ASCII}.
1757 The next sentence is in GB.~@{<:Ky2;S@{#,NpJ)l6HK!#~@}Bye.
1760 Simple enough, and widely used in China.
1762 The following functions are available to handle this encoding:
1765 @item rfc1843-decode-region
1766 Decode HZ-encoded text in the region.
1768 @item rfc1843-decode-string
1769 Decode a HZ-encoded string and return the result.
1777 The @file{~/.mailcap} file is parsed by most @acronym{MIME}-aware message
1778 handlers and describes how elements are supposed to be displayed.
1779 Here's an example file:
1783 audio/wav; wavplayer %s
1784 application/msword; catdoc %s ; copiousoutput ; nametemplate=%s.doc
1787 This says that all image files should be displayed with @code{gimp},
1788 that WAVE audio files should be played by @code{wavplayer}, and that
1789 MS-WORD files should be inlined by @code{catdoc}.
1791 The @code{mailcap} library parses this file, and provides functions for
1795 @item mailcap-mime-data
1796 @vindex mailcap-mime-data
1797 This variable is an alist of alists containing backup viewing rules.
1801 Interface functions:
1804 @item mailcap-parse-mailcaps
1805 @findex mailcap-parse-mailcaps
1806 Parse the @file{~/.mailcap} file.
1808 @item mailcap-mime-info
1809 Takes a @acronym{MIME} type as its argument and returns the matching viewer.
1819 The Emacs @acronym{MIME} library implements handling of various elements
1820 according to a (somewhat) large number of RFCs, drafts and standards
1821 documents. This chapter lists the relevant ones. They can all be
1822 fetched from @uref{http://quimby.gnus.org/notes/}.
1827 Standard for the Format of ARPA Internet Text Messages.
1830 Standard for Interchange of USENET Messages
1833 Format of Internet Message Bodies
1839 Message Header Extensions for Non-@acronym{ASCII} Text
1842 Registration Procedures
1845 Conformance Criteria and Examples
1848 @acronym{MIME} Parameter Value and Encoded Word Extensions: Character Sets,
1849 Languages, and Continuations
1852 HZ - A Data Format for Exchanging Files of Arbitrarily Mixed Chinese and
1853 @acronym{ASCII} characters
1855 @item draft-ietf-drums-msg-fmt-05.txt
1856 Draft for the successor of RFC822
1859 The @acronym{MIME} Multipart/Related Content-type
1862 The Multipart/Report Content Type for the Reporting of Mail System
1863 Administrative Messages
1866 Communicating Presentation Information in Internet Messages: The
1867 Content-Disposition Header Field
1870 Documentation of the text/plain format parameter for flowed text.
1874 @node GNU Free Documentation License
1875 @chapter GNU Free Documentation License
1876 @include doclicense.texi
1887 @c coding: iso-8859-1