X-Git-Url: http://git.chise.org/gitweb/?a=blobdiff_plain;f=texi%2Femacs-mime.texi;h=e1153116becf1f0877127cfb6653b01a949361b6;hb=36bd162f4f7cd40453b8683e796730836c352b2a;hp=f333fa5e7bb031254fa83447744e8a98d51a1140;hpb=e7b89fdbd5b964b512e70e7d89b4a0248e2e550e;p=elisp%2Fgnus.git- diff --git a/texi/emacs-mime.texi b/texi/emacs-mime.texi index f333fa5..e115311 100644 --- a/texi/emacs-mime.texi +++ b/texi/emacs-mime.texi @@ -1,43 +1,42 @@ -\input texinfo @c -*-texinfo-*- +\input texinfo -@setfilename message +@setfilename emacs-mime @settitle Emacs MIME Manual @synindex fn cp @synindex vr cp @synindex pg cp -@c @direntry -@c * Emacs MIME: (emacs-mime). The MIME de/composition library. -@c @end direntry +@dircategory Emacs +@direntry +* Emacs MIME: (emacs-mime). The MIME de/composition library. +@end direntry @iftex @finalout @end iftex @setchapternewpage odd -@ifinfo +@ifnottex This file documents the Emacs MIME interface functionality. -Copyright (C) 1996 Free Software Foundation, Inc. +Copyright (C) 1998, 1999, 2000, 2001 Free Software Foundation, Inc. -Permission is granted to make and distribute verbatim copies of -this manual provided the copyright notice and this permission notice -are preserved on all copies. +Permission is granted to copy, distribute and/or modify this document +under the terms of the GNU Free Documentation License, Version 1.1 or +any later version published by the Free Software Foundation; with no +Invariant Sections, with the Front-Cover texts being ``A GNU +Manual'', and with the Back-Cover Texts as in (a) below. A copy of the +license is included in the section entitled ``GNU Free Documentation +License'' in the Emacs manual. -@ignore -Permission is granted to process this file through Tex and print the -results, provided the printed document carries copying permission -notice identical to this one except for the removal of this paragraph -(this paragraph not being relevant to the printed manual). +(a) The FSF's Back-Cover Text is: ``You have freedom to copy and modify +this GNU Manual, like GNU software. Copies published by the Free +Software Foundation raise funds for GNU development.'' -@end ignore -Permission is granted to copy and distribute modified versions of this -manual under the conditions for verbatim copying, provided also that the -entire resulting derived work is distributed under the terms of a -permission notice identical to this one. - -Permission is granted to copy and distribute translations of this manual -into another language, under the above conditions for modified versions. -@end ifinfo +This document is part of a collection distributed under the GNU Free +Documentation License. If you want to distribute this document +separately from the collection, you can do so by adding a copy of the +license to the document, as described in section 6 of the license. +@end ifnottex @tex @@ -48,20 +47,24 @@ into another language, under the above conditions for modified versions. @page @vskip 0pt plus 1filll -Copyright @copyright{} 1998 Free Software Foundation, Inc. - -Permission is granted to make and distribute verbatim copies of -this manual provided the copyright notice and this permission notice -are preserved on all copies. - -Permission is granted to copy and distribute modified versions of this -manual under the conditions for verbatim copying, provided that the -entire resulting derived work is distributed under the terms of a -permission notice identical to this one. - -Permission is granted to copy and distribute translations of this manual -into another language, under the above conditions for modified versions. - +Copyright @copyright{} 1998, 1999, 2000 Free Software Foundation, Inc. + +Permission is granted to copy, distribute and/or modify this document +under the terms of the GNU Free Documentation License, Version 1.1 or +any later version published by the Free Software Foundation; with the +Invariant Sections being none, with the Front-Cover texts being ``A GNU +Manual'', and with the Back-Cover Texts as in (a) below. A copy of the +license is included in the section entitled ``GNU Free Documentation +License'' in the Emacs manual. + +(a) The FSF's Back-Cover Text is: ``You have freedom to copy and modify +this GNU Manual, like GNU software. Copies published by the Free +Software Foundation raise funds for GNU development.'' + +This document is part of a collection distributed under the GNU Free +Documentation License. If you want to distribute this document +separately from the collection, you can do so by adding a copy of the +license to the document, as described in section 6 of the license. @end titlepage @page @@ -86,40 +89,22 @@ recommended that anyone who intends writing @sc{mime}-compliant software read at least RFC2045 and RFC2047. @menu +* Interface Functions:: An abstraction over the basic functions. * Basic Functions:: Utility and basic parsing functions. * Decoding and Viewing:: A framework for decoding and viewing. +* Composing:: MML; a language for describing MIME parts. +* Standards:: A summary of RFCs and working documents used. * Index:: Function and variable index. @end menu -@node Basic Functions -@chapter Basic Functions +@node Interface Functions +@chapter Interface Functions +@cindex interface functions +@cindex mail-parse -This chapter describes the basic, ground-level functions for parsing and -handling. Covered here is parsing @code{From} lines, removing comments -from header lines, decoding encoded words, parsing date headers and so -on. High-level functionality is dealt with in the next chapter -(@pxref{Decoding and Viewing}). - -@menu -* mail-parse:: The generalized @sc{mime} and mail interface. -* rfc2231:: Parsing @code{Content-Type} headers. -* drums:: Handling mail headers defined by RFC822bis. -* rfc2047:: En/decoding encoded words in headers. -* time-date:: Functions for parsing dates and manipulating time. -* qp:: Quoted-Printable en/decoding. -* base64:: Base64 en/decoding. -* mailcap:: How parts are displayed is specified by the @file{.mailcap} file -@end menu - - -@node mail-parse -@section mail-parse - -It is perhaps misleading to place the @code{mail-parse} library in this -chapter. It is not a basic low-level library---rather, it is an -abstraction over the actual low-level libraries that are described in the -subsequent sections. +The @code{mail-parse} library is an abstraction over the actual +low-level libraries that are described in the next chapter. Standards change, and so programs have to change to fit in the new mold. For instance, RFC2045 describes a syntax for the @@ -165,7 +150,7 @@ Here's an example: @example (mail-header-parse-content-type "image/gif; name=\"b980912.gif\"") -=> ("image/gif" (name . "b980912.gif")) +@result{} ("image/gif" (name . "b980912.gif")) @end example @item mail-header-parse-content-disposition @@ -181,9 +166,15 @@ Returns the value of the attribute. @example (mail-content-type-get '("image/gif" (name . "b980912.gif")) 'name) -=> "b980912.gif" +@result{} "b980912.gif" @end example +@item mail-header-encode-parameter +@findex mail-header-encode-parameter +Takes a parameter string and returns an encoded version of the string. +This is used for parameters in headers like @code{Content-Type} and +@code{Content-Disposition}. + @item mail-header-remove-comments @findex mail-header-remove-comments Return a comment-free version of a header. @@ -191,7 +182,7 @@ Return a comment-free version of a header. @example (mail-header-remove-comments "Gnus/5.070027 (Pterodactyl Gnus v0.27) (Finnish Landrace)") -=> "Gnus/5.070027 " +@result{} "Gnus/5.070027 " @end example @item mail-header-remove-whitespace @@ -202,7 +193,7 @@ and comments is preserved. @example (mail-header-remove-whitespace "image/gif; name=\"Name with spaces\"") -=> "image/gif;name=\"Name with spaces\"" +@result{} "image/gif;name=\"Name with spaces\"" @end example @item mail-header-get-comment @@ -210,9 +201,9 @@ and comments is preserved. Return the last comment in a header. @example -(mail-header-get-comment +(mail-header-get-comment "Gnus/5.070027 (Pterodactyl Gnus v0.27) (Finnish Landrace)") -=> "Finnish Landrace" +@result{} "Finnish Landrace" @end example @item mail-header-parse-address @@ -223,7 +214,7 @@ plaintext name. @example (mail-header-parse-address "Hrvoje Niksic ") -=> ("hniksic@@srce.hr" . "Hrvoje Niksic") +@result{} ("hniksic@@srce.hr" . "Hrvoje Niksic") @end example @item mail-header-parse-addresses @@ -234,7 +225,7 @@ the one described above. @example (mail-header-parse-addresses "Hrvoje Niksic , Steinar Bang ") -=> (("hniksic@@srce.hr" . "Hrvoje Niksic") +@result{} (("hniksic@@srce.hr" . "Hrvoje Niksic") ("sb@@metis.no" . "Steinar Bang")) @end example @@ -268,7 +259,7 @@ Encode the words that need encoding in a string, and return the result. @example (mail-encode-encoded-word-string "This is naïve, baby") -=> "This is =?iso-8859-1?q?na=EFve,?= baby" +@result{} "This is =?iso-8859-1?q?na=EFve,?= baby" @end example @item mail-decode-encoded-word-region @@ -282,14 +273,57 @@ Decode the encoded words in the string and return the result. @example (mail-decode-encoded-word-string "This is =?iso-8859-1?q?na=EFve,?= baby") -=> "This is naïve, baby" +@result{} "This is naïve, baby" @end example @end table -Currently, @code{mail-parse} is an abstraction over @code{drums}, -@code{rfc2047} and @code{rfc2231}. These are documented in the -subsequent sections. +Currently, @code{mail-parse} is an abstraction over @code{ietf-drums}, +@code{rfc2047}, @code{rfc2045} and @code{rfc2231}. These are documented +in the subsequent sections. + + + +@node Basic Functions +@chapter Basic Functions + +This chapter describes the basic, ground-level functions for parsing and +handling. Covered here is parsing @code{From} lines, removing comments +from header lines, decoding encoded words, parsing date headers and so +on. High-level functionality is dealt with in the next chapter +(@pxref{Decoding and Viewing}). + +@menu +* rfc2045:: Encoding @code{Content-Type} headers. +* rfc2231:: Parsing @code{Content-Type} headers. +* ietf-drums:: Handling mail headers defined by RFC822bis. +* rfc2047:: En/decoding encoded words in headers. +* time-date:: Functions for parsing dates and manipulating time. +* qp:: Quoted-Printable en/decoding. +* base64:: Base64 en/decoding. +* binhex:: Binhex decoding. +* uudecode:: Uuencode decoding. +* rfc1843:: Decoding HZ-encoded text. +* mailcap:: How parts are displayed is specified by the @file{.mailcap} file +@end menu + + +@node rfc2045 +@section rfc2045 + +RFC2045 is the ``main'' @sc{mime} document, and as such, one would +imagine that there would be a lot to implement. But there isn't, since +most of the implementation details are delegated to the subsequent +RFCs. + +So @file{rfc2045.el} has only a single function: + +@table @code +@item rfc2045-encode-string +@findex rfc2045-encode-string +Takes a parameter and a value and returns a @samp{PARAM=VALUE} string. +@var{value} will be quoted if there are non-safe characters in it. +@end table @node rfc2231 @@ -321,24 +355,29 @@ elements. @example (rfc2231-parse-string - "application/x-stuff; + "application/x-stuff; title*0*=us-ascii'en'This%20is%20even%20more%20; title*1*=%2A%2A%2Afun%2A%2A%2A%20; title*2=\"isn't it!\"") -=> ("application/x-stuff" +@result{} ("application/x-stuff" (title . "This is even more ***fun*** isn't it!")) @end example @item rfc2231-get-value @findex rfc2231-get-value -Takes one of the lists on the format above and return +Takes one of the lists on the format above and returns the value of the specified attribute. +@item rfc2231-encode-string +@findex rfc2231-encode-string +Encode a parameter in headers likes @code{Content-Type} and +@code{Content-Disposition}. + @end table -@node drums -@section drums +@node ietf-drums +@section ietf-drums @dfn{drums} is an IETF working group that is working on the replacement for RFC822. @@ -346,35 +385,35 @@ for RFC822. The functions provided by this library include: @table @code -@item drums-remove-comments -@findex drums-remove-comments +@item ietf-drums-remove-comments +@findex ietf-drums-remove-comments Remove the comments from the argument and return the results. -@item drums-remove-whitespace -@findex drums-remove-whitespace +@item ietf-drums-remove-whitespace +@findex ietf-drums-remove-whitespace Remove linear white space from the string and return the results. Spaces inside quoted strings and comments are left untouched. -@item drums-get-comment -@findex drums-get-comment +@item ietf-drums-get-comment +@findex ietf-drums-get-comment Return the last most comment from the string. -@item drums-parse-address -@findex drums-parse-address +@item ietf-drums-parse-address +@findex ietf-drums-parse-address Parse an address string and return a list that contains the mailbox and the plain text name. -@item drums-parse-addresses -@findex drums-parse-addresses +@item ietf-drums-parse-addresses +@findex ietf-drums-parse-addresses Parse a string that contains any number of comma-separated addresses and return a list that contains mailbox/plain text pairs. -@item drums-parse-date -@findex drums-parse-date +@item ietf-drums-parse-date +@findex ietf-drums-parse-date Parse a date string and return an Emacs time structure. -@item drums-narrow-to-header -@findex drums-narrow-to-header +@item ietf-drums-narrow-to-header +@findex ietf-drums-narrow-to-header Narrow the buffer to the header section of the current buffer. @end table @@ -423,11 +462,11 @@ This is an alist of encoding / function pairs. The encodings are The @code{Q} encoding isn't quite the same for all headers. Some headers allow a narrower range of characters, and that is what this variable is for. It's an alist of header regexps / allowable character -ranges. +ranges. @item rfc2047-encoded-word-regexp @vindex rfc2047-encoded-word-regexp -When decoding words, this library looks for matches to this regexp. +When decoding words, this library looks for matches to this regexp. @end table @@ -470,56 +509,134 @@ document this library here. It deals with parsing @code{Date} headers and manipulating time. (Not by using tesseracts, though, I'm sorry to say.) -These functions converts between five formats: A date string, an Emacs +These functions convert between five formats: A date string, an Emacs time structure, a decoded time list, a second number, and a day number. -The functions have quite self-explanatory names, so the following just -gives an overview of which functions are available. +Here's a bunch of time/date/second/day examples: @example (parse-time-string "Sat Sep 12 12:21:54 1998 +0200") -=> (54 21 12 12 9 1998 6 nil 7200) +@result{} (54 21 12 12 9 1998 6 nil 7200) (date-to-time "Sat Sep 12 12:21:54 1998 +0200") -=> (13818 19266) +@result{} (13818 19266) (time-to-seconds '(13818 19266)) -=> 905595714.0 +@result{} 905595714.0 (seconds-to-time 905595714.0) -=> (13818 19266 0) +@result{} (13818 19266 0) -(time-to-day '(13818 19266)) -=> 729644 +(time-to-days '(13818 19266)) +@result{} 729644 (days-to-time 729644) -=> (961933 65536) +@result{} (961933 65536) (time-since '(13818 19266)) -=> (0 430) +@result{} (0 430) (time-less-p '(13818 19266) '(13818 19145)) -=> nil +@result{} nil (subtract-time '(13818 19266) '(13818 19145)) -=> (0 121) +@result{} (0 121) (days-between "Sat Sep 12 12:21:54 1998 +0200" "Sat Sep 07 12:21:54 1998 +0200") -=> 5 +@result{} 5 (date-leap-year-p 2000) -=> t +@result{} t (time-to-day-in-year '(13818 19266)) -=> 255 +@result{} 255 +(time-to-number-of-days + (time-since + (date-to-time "Mon, 01 Jan 2001 02:22:26 GMT"))) +@result{} 4.146122685185185 @end example And finally, we have @code{safe-date-to-time}, which does the same as @code{date-to-time}, but returns a zero time if the date is syntactically malformed. +The five data representations used are the following: + +@table @var +@item date +An RFC822 (or similar) date string. For instance: @code{"Sat Sep 12 +12:21:54 1998 +0200"}. + +@item time +An internal Emacs time. For instance: @code{(13818 26466)}. + +@item seconds +A floating point representation of the internal Emacs time. For +instance: @code{905595714.0}. + +@item days +An integer number representing the number of days since 00000101. For +instance: @code{729644}. + +@item decoded time +A list of decoded time. For instance: @code{(54 21 12 12 9 1998 6 t +7200)}. +@end table + +All the examples above represent the same moment. + +These are the functions available: + +@table @code +@item date-to-time +Take a date and return a time. + +@item time-to-seconds +Take a time and return seconds. + +@item seconds-to-time +Take seconds and return a time. + +@item time-to-days +Take a time and return days. + +@item days-to-time +Take days and return a time. + +@item date-to-day +Take a date and return days. + +@item time-to-number-of-days +Take a time and return the number of days that represents. + +@item safe-date-to-time +Take a date and return a time. If the date is not syntactically valid, +return a "zero" date. + +@item time-less-p +Take two times and say whether the first time is less (i. e., earlier) +than the second time. + +@item time-since +Take a time and return a time saying how long it was since that time. + +@item subtract-time +Take two times and subtract the second from the first. I. e., return +the time between the two times. + +@item days-between +Take two days and return the number of days between those two days. + +@item date-leap-year-p +Take a year number and say whether it's a leap year. + +@item time-to-day-in-year +Take a time and return the day number within the year that the time is +in. + +@end table @node qp @@ -559,6 +676,7 @@ results. @node base64 @section base64 +@cindex base64 Base64 is an encoding that encodes three bytes into four characters, thereby increasing the size by about 33%. The alphabet used for @@ -591,6 +709,69 @@ decoded, @code{nil} is returned. @end table +@node binhex +@section binhex +@cindex binhex +@cindex Apple +@cindex Macintosh + +@code{binhex} is an encoding that originated in Macintosh environments. +The following function is supplied to deal with these: + +@table @code +@item binhex-decode-region +@findex binhex-decode-region +Decode the encoded text in the region. If given a third parameter, only +decode the @code{binhex} header and return the filename. + +@end table + + +@node uudecode +@section uudecode +@cindex uuencode +@cindex uudecode + +@code{uuencode} is probably still the most popular encoding of binaries +used on Usenet, although @code{base64} rules the mail world. + +The following function is supplied by this package: + +@table @code +@item uudecode-decode-region +@findex uudecode-decode-region +Decode the text in the region. +@end table + + +@node rfc1843 +@section rfc1843 +@cindex rfc1843 +@cindex HZ +@cindex Chinese + +RFC1843 deals with mixing Chinese and ASCII characters in messages. In +essence, RFC1843 switches between ASCII and Chinese by doing this: + +@example +This sentence is in ASCII. +The next sentence is in GB.~@{<:Ky2;S@{#,NpJ)l6HK!#~@}Bye. +@end example + +Simple enough, and widely used in China. + +The following functions are available to handle this encoding: + +@table @code +@item rfc1843-decode-region +Decode HZ-encoded text in the region. + +@item rfc1843-decode-string +Decode a HZ-encoded string and return the result. + +@end table + + @node mailcap @section mailcap @@ -599,12 +780,12 @@ handlers and describes how elements are supposed to be displayed. Here's an example file: @example -image/*; xv -8 %s -audio/x-pn-realaudio; rvplayer %s +image/*; gimp -8 %s +audio/wav; wavplayer %s @end example -This says that all image files should be displayed with @samp{xv}, and -that realaudio files should be played by @samp{rvplayer}. +This says that all image files should be displayed with @code{gimp}, and +that WAVE audio files should be played by @code{wavplayer}. The @code{mailcap} library parses this file, and provides functions for matching types. @@ -639,12 +820,15 @@ higher level. The main idea is to first analyze a @sc{mime} article, and then allow other programs to do things based on the list of @dfn{handles} that are -returned as a result of this analyzation. +returned as a result of this analysis. @menu -* Dissection:: Analyzing a @sc{mime} message. -* Handles:: Handle manipulations. -* Display:: Displaying handles. +* Dissection:: Analyzing a @sc{mime} message. +* Non-MIME:: Analyzing a non-@sc{mime} message. +* Handles:: Handle manipulations. +* Display:: Displaying handles. +* Customization:: Variables that affect display. +* New Viewers:: How to write your own viewers. @end menu @@ -656,6 +840,62 @@ a @sc{mime} article. If given a multipart message, it will recursively descend the message, following the structure, and return a tree of @sc{mime} handles that describes the structure of the message. +@node Non-MIME +@section Non-MIME + +Gnus also understands some non-MIME attachments, such as postscript, +uuencode, binhex, shar, forward, gnatsweb, pgp. Each of these features +can be disabled by add an item into @code{mm-uu-configure-list}. +For example, + +@lisp +(require 'mm-uu) +(add-to-list 'mm-uu-configure-list '(pgp-signed . disabled)) +@end lisp + +@table @code +@item postscript +@findex postscript +Postscript file. + +@item uu +@findex uu +Uuencoded file. + +@item binhex +@findex binhex +Binhex encoded file. + +@item shar +@findex shar +Shar archive file. + +@item forward +@findex forward +Non-@sc{mime} forwarded message. + +@item gnatsweb +@findex gnatsweb +Gnatsweb attachment. + +@item pgp-signed +@findex pgp-signed +PGP signed clear text. + +@item pgp-encrypted +@findex pgp-encrypted +PGP encrypted clear text. + +@item pgp-key +@findex pgp-key +PGP public keys. + +@item emacs-sources +@findex emacs-sources +Emacs source code. This item works only in the groups matching +@code{mm-uu-emacs-sources-regexp}. + +@end table @node Handles @section Handles @@ -741,9 +981,493 @@ Offer to pipe the part to some process. Prompt for a mailcap method to use to view the part. @end table - - + +@node Customization +@section Customization + +@table @code + +@item mm-inline-media-tests +This is an alist where the key is a @sc{mime} type, the second element +is a function to display the part @dfn{inline} (i.e., inside Emacs), and +the third element is a form to be @code{eval}ed to say whether the part +can be displayed inline. + +This variable specifies whether a part @emph{can} be displayed inline, +and, if so, how to do it. It does not say whether parts are +@emph{actually} displayed inline. + +@item mm-inlined-types +This, on the other hand, says what types are to be displayed inline, if +they satisfy the conditions set by the variable above. It's a list of +@sc{mime} media types. + +@item mm-automatic-display +This is a list of types that are to be displayed ``automatically'', but +only if the above variable allows it. That is, only inlinable parts can +be displayed automatically. + +@item mm-attachment-override-types +Some @sc{mime} agents create parts that have a content-disposition of +@samp{attachment}. This variable allows overriding that disposition and +displaying the part inline. (Note that the disposition is only +overridden if we are able to, and want to, display the part inline.) + +@item mm-discouraged-alternatives +List of @sc{mime} types that are discouraged when viewing +@samp{multipart/alternative}. Viewing agents are supposed to view the +last possible part of a message, as that is supposed to be the richest. +However, users may prefer other types instead, and this list says what +types are most unwanted. If, for instance, @samp{text/html} parts are +very unwanted, and @samp{text/richtech} parts are somewhat unwanted, +then the value of this variable should be set to: + +@lisp +("text/html" "text/richtext") +@end lisp + +@item mm-inline-large-images-p +When displaying inline images that are larger than the window, XEmacs +does not enable scrolling, which means that you cannot see the whole +image. To prevent this, the library tries to determine the image size +before displaying it inline, and if it doesn't fit the window, the +library will display it externally (e.g. with @samp{ImageMagick} or +@samp{xv}). Setting this variable to @code{t} disables this check and +makes the library display all inline images as inline, regardless of +their size. + +@item mm-inline-override-p +@code{mm-inlined-types} may include regular expressions, for example to +specify that all @samp{text/.*} parts be displayed inline. If a user +prefers to have a type that matches such a regular expression be treated +as an attachment, that can be accomplished by setting this variable to a +list containing that type. For example assuming @code{mm-inlined-types} +includes @samp{text/.*}, then including @samp{text/html} in this +variable will cause @samp{text/html} parts to be treated as attachments. + +@end table + + +@node New Viewers +@section New Viewers + +Here's an example viewer for displaying @code{text/enriched} inline: + +@lisp +(defun mm-display-enriched-inline (handle) + (let (text) + (with-temp-buffer + (mm-insert-part handle) + (save-window-excursion + (enriched-decode (point-min) (point-max)) + (setq text (buffer-string)))) + (mm-insert-inline handle text))) +@end lisp + +We see that the function takes a @sc{mime} handle as its parameter. It +then goes to a temporary buffer, inserts the text of the part, does some +work on the text, stores the result, goes back to the buffer it was +called from and inserts the result. + +The two important helper functions here are @code{mm-insert-part} and +@code{mm-insert-inline}. The first function inserts the text of the +handle in the current buffer. It handles charset and/or content +transfer decoding. The second function just inserts whatever text you +tell it to insert, but it also sets things up so that the text can be +``undisplayed' in a convenient manner. + + +@node Composing +@chapter Composing +@cindex Composing +@cindex MIME Composing +@cindex MML +@cindex MIME Meta Language + +Creating a @sc{mime} message is boring and non-trivial. Therefore, a +library called @code{mml} has been defined that parses a language called +MML (@sc{mime} Meta Language) and generates @sc{mime} messages. + +@findex mml-generate-mime +The main interface function is @code{mml-generate-mime}. It will +examine the contents of the current (narrowed-to) buffer and return a +string containing the @sc{mime} message. + +@menu +* Simple MML Example:: An example MML document. +* MML Definition:: All valid MML elements. +* Advanced MML Example:: Another example MML document. +* Charset Translation:: How charsets are mapped from @sc{mule} to MIME. +* Conversion:: Going from @sc{mime} to MML and vice versa. +@end menu + + +@node Simple MML Example +@section Simple MML Example + +Here's a simple @samp{multipart/alternative}: + +@example +<#multipart type=alternative> +This is a plain text part. +<#part type=text/enriched> +
This is a centered enriched part
+<#/multipart> +@end example + +After running this through @code{mml-generate-mime}, we get this: + +@example +Content-Type: multipart/alternative; boundary="=-=-=" + + +--=-=-= + + +This is a plain text part. + +--=-=-= +Content-Type: text/enriched + + +
This is a centered enriched part
+ +--=-=-=-- +@end example + + +@node MML Definition +@section MML Definition + +The MML language is very simple. It looks a bit like an SGML +application, but it's not. + +The main concept of MML is the @dfn{part}. Each part can be of a +different type or use a different charset. The way to delineate a part +is with a @samp{<#part ...>} tag. Multipart parts can be introduced +with the @samp{<#multipart ...>} tag. Parts are ended by the +@samp{<#/part>} or @samp{<#/multipart>} tags. Parts started with the +@samp{<#part ...>} tags are also closed by the next open tag. + +There's also the @samp{<#external ...>} tag. These introduce +@samp{external/message-body} parts. + +Each tag can contain zero or more parameters on the form +@samp{parameter=value}. The values may be enclosed in quotation marks, +but that's not necessary unless the value contains white space. So +@samp{filename=/home/user/#hello$^yes} is perfectly valid. + +The following parameters have meaning in MML; parameters that have no +meaning are ignored. The MML parameter names are the same as the +@sc{mime} parameter names; the things in the parentheses say which +header it will be used in. + +@table @samp +@item type +The @sc{mime} type of the part (@code{Content-Type}). + +@item filename +Use the contents of the file in the body of the part +(@code{Content-Disposition}). + +@item charset +The contents of the body of the part are to be encoded in the character +set speficied (@code{Content-Type}). + +@item name +Might be used to suggest a file name if the part is to be saved +to a file (@code{Content-Type}). + +@item disposition +Valid values are @samp{inline} and @samp{attachment} +(@code{Content-Disposition}). + +@item encoding +Valid values are @samp{7bit}, @samp{8bit}, @samp{quoted-printable} and +@samp{base64} (@code{Content-Transfer-Encoding}). + +@item description +A description of the part (@code{Content-Description}). + +@item creation-date +RFC822 date when the part was created (@code{Content-Disposition}). + +@item modification-date +RFC822 date when the part was modified (@code{Content-Disposition}). + +@item read-date +RFC822 date when the part was read (@code{Content-Disposition}). + +@item size +The size (in octets) of the part (@code{Content-Disposition}). + +@item sign +What technology to sign this MML part with (@code{smime}, @code{pgp} +or @code{pgpmime}) + +@item encrypt +What technology to encrypt this MML part with (@code{smime}, +@code{pgp} or @code{pgpmime}) + +@end table + +Parameters for @samp{application/octet-stream}: + +@table @samp +@item type +Type of the part; informal---meant for human readers +(@code{Content-Type}). +@end table + +Parameters for @samp{message/external-body}: + +@table @samp +@item access-type +A word indicating the supported access mechanism by which the file may +be obtained. Values include @samp{ftp}, @samp{anon-ftp}, @samp{tftp}, +@samp{localfile}, and @samp{mailserver}. (@code{Content-Type}.) + +@item expiration +The RFC822 date after which the file may no longer be fetched. +(@code{Content-Type}.) + +@item size +The size (in octets) of the file. (@code{Content-Type}.) + +@item permission +Valid values are @samp{read} and @samp{read-write} +(@code{Content-Type}). + +@end table + +Parameters for @samp{sign=smime}: + +@table @samp + +@item keyfile +File containing key and certificate for signer. + +@end table + +Parameters for @samp{encrypt=smime}: + +@table @samp + +@item certfile +File containing certificate for recipient. + +@end table + + +@node Advanced MML Example +@section Advanced MML Example + +Here's a complex multipart message. It's a @samp{multipart/mixed} that +contains many parts, one of which is a @samp{multipart/alternative}. + +@example +<#multipart type=mixed> +<#part type=image/jpeg filename=~/rms.jpg disposition=inline> +<#multipart type=alternative> +This is a plain text part. +<#part type=text/enriched name=enriched.txt> +
This is a centered enriched part
+<#/multipart> +This is a new plain text part. +<#part disposition=attachment> +This plain text part is an attachment. +<#/multipart> +@end example + +And this is the resulting @sc{mime} message: + +@example +Content-Type: multipart/mixed; boundary="=-=-=" + + +--=-=-= + + + +--=-=-= +Content-Type: image/jpeg; + filename="~/rms.jpg" +Content-Disposition: inline; + filename="~/rms.jpg" +Content-Transfer-Encoding: base64 + +/9j/4AAQSkZJRgABAQAAAQABAAD/2wBDAAgGBgcGBQgHBwcJCQgKDBQNDAsLDBkSEw8UHRof +Hh0aHBwgJC4nICIsIxwcKDcpLDAxNDQ0Hyc5PTgyPC4zNDL/wAALCAAwADABAREA/8QAHwAA +AQUBAQEBAQEAAAAAAAAAAAECAwQFBgcICQoL/8QAtRAAAgEDAwIEAwUFBAQAAAF9AQIDAAQR +BRIhMUEGE1FhByJxFDKBkaEII0KxwRVS0fAkM2JyggkKFhcYGRolJicoKSo0NTY3ODk6Q0RF +RkdISUpTVFVWV1hZWmNkZWZnaGlqc3R1dnd4eXqDhIWGh4iJipKTlJWWl5iZmqKjpKWmp6ip +qrKztLW2t7i5usLDxMXGx8jJytLT1NXW19jZ2uHi4+Tl5ufo6erx8vP09fb3+Pn6/9oACAEB +AAA/AO/rifFHjldNuGsrDa0qcSSHkA+gHrXKw+LtWLrMb+RgTyhbr+HSug07xNqV9fQtZrNI +AyiaE/NuBPOOOP0rvRNE880KOC8TbXXGCv1FPqjrF4LDR7u5L7SkTFT/ALWOP1xXgTuXfc7E +sx6nua6rwp4IvvEM8chCxWxOdzn7wz6V9AaB4S07w9p5itow0rDLSY5Pt9K43xO66P4xs71m +2QXiGCbA4yOVJ9+1aYORkdK434lyNH4ahCnG66VT9Nj15JFbPdX0MS43M4VQf5/yr2vSpLnw +5ZW8dlCZ8KFXjOPX0/mK6rSPEGt3Angu44fNEReHYNvIH3TzXDeKNO8RX+kSX2ouZkicTIOc +L+g7E810ulFjpVtv3bwgB3HJyK5L4quY/C9sVxk3ij/xx6850u7t1mtp/wDlpEw3An3Jr3Dw +34gsbWza4nBlhC5LDsaW6+IFgupQyCF3iHH7gA7c9R9ay7zx6t7aX9jHC4smhfBkGCvHGfrm +tLQ7hbnRrV1GPkAP1x1/Hr+Ncr8Vzjwrbf8AX6v/AKA9eQRyYlQk8Yx9K6XTNbkgia2ciSIn +7p5Ga9Atte0LTLKO6it4i7dVRFJDcZ4PvXN+JvEMF9bILVGXJLSZ4zkjivRPDaeX4b08HOTC +pOffmua+KkbS+GLVUGT9tT/0B68eeIpIFYjB70+OOVXyoOM9+M1eaWeCLzHPyHGO/NVWvJJm +jQ8KGH1NfQWhXSXmh2c8eArRLwO3HSv/2Q== + +--=-=-= +Content-Type: multipart/alternative; boundary="==-=-=" + + +--==-=-= + + +This is a plain text part. + +--==-=-= +Content-Type: text/enriched; + name="enriched.txt" + + +
This is a centered enriched part
+ +--==-=-=-- + +--=-=-= + +This is a new plain text part. + +--=-=-= +Content-Disposition: attachment + + +This plain text part is an attachment. + +--=-=-=-- +@end example + +@node Charset Translation +@section Charset Translation +@cindex charsets + +During translation from MML to @sc{mime}, for each @sc{mime} part which +has been composed inside Emacs, an appropriate charset has to be chosen. + +@vindex mail-parse-charset +If you are running a non-@sc{mule} Emacs, this process is simple: If the +part contains any non-ASCII (8-bit) characters, the @sc{mime} charset +given by @code{mail-parse-charset} (a symbol) is used. (Never set this +variable directly, though. If you want to change the default charset, +please consult the documentation of the package which you use to process +@sc{mime} messages. +@xref{Various Message Variables, , Various Message Variables, message, + Message Manual}, for example.) +If there are only ASCII characters, the @sc{mime} charset US-ASCII is +used, of course. + +@cindex MULE +@cindex UTF-8 +@cindex Unicode +@vindex mm-mime-mule-charset-alist +Things are slightly more complicated when running Emacs with @sc{mule} +support. In this case, a list of the @sc{mule} charsets used in the +part is obtained, and the @sc{mule} charsets are translated to @sc{mime} +charsets by consulting the variable @code{mm-mime-mule-charset-alist}. +If this results in a single @sc{mime} charset, this is used to encode +the part. But if the resulting list of @sc{mime} charsets contains more +than one element, two things can happen: If it is possible to encode the +part via UTF-8, this charset is used. (For this, Emacs must support +the @code{utf-8} coding system, and the part must consist entirely of +characters which have Unicode counterparts.) If UTF-8 is not available +for some reason, the part is split into several ones, so that each one +can be encoded with a single @sc{mime} charset. The part can only be +split at line boundaries, though---if more than one @sc{mime} charset is +required to encode a single line, it is not possible to encode the part. + +@node Conversion +@section Conversion + +@findex mime-to-mml +A (multipart) @sc{mime} message can be converted to MML with the +@code{mime-to-mml} function. It works on the message in the current +buffer, and substitutes MML markup for @sc{mime} boundaries. +Non-textual parts do not have their contents in the buffer, but instead +have the contents in separate buffers that are referred to from the MML +tags. + +@findex mml-to-mime +An MML message can be converted back to @sc{mime} by the +@code{mml-to-mime} function. + +These functions are in certain senses ``lossy''---you will not get back +an identical message if you run @sc{mime-to-mml} and then +@sc{mml-to-mime}. Not only will trivial things like the order of the +headers differ, but the contents of the headers may also be different. +For instance, the original message may use base64 encoding on text, +while @sc{mml-to-mime} may decide to use quoted-printable encoding, and +so on. + +In essence, however, these two functions should be the inverse of each +other. The resulting contents of the message should remain equivalent, +if not identical. + + +@node Standards +@chapter Standards + +The Emacs @sc{mime} library implements handling of various elements +according to a (somewhat) large number of RFCs, drafts and standards +documents. This chapter lists the relevant ones. They can all be +fetched from @uref{http://quimby.gnus.org/notes/}. + +@table @dfn +@item RFC822 +@itemx STD11 +Standard for the Format of ARPA Internet Text Messages. + +@item RFC1036 +Standard for Interchange of USENET Messages + +@item RFC2045 +Format of Internet Message Bodies + +@item RFC2046 +Media Types + +@item RFC2047 +Message Header Extensions for Non-ASCII Text + +@item RFC2048 +Registration Procedures + +@item RFC2049 +Conformance Criteria and Examples + +@item RFC2231 +MIME Parameter Value and Encoded Word Extensions: Character Sets, +Languages, and Continuations + +@item RFC1843 +HZ - A Data Format for Exchanging Files of Arbitrarily Mixed Chinese and +ASCII characters + +@item draft-ietf-drums-msg-fmt-05.txt +Draft for the successor of RFC822 + +@item RFC2112 +The MIME Multipart/Related Content-type + +@item RFC1892 +The Multipart/Report Content Type for the Reporting of Mail System +Administrative Messages + +@item RFC2183 +Communicating Presentation Information in Internet Messages: The +Content-Disposition Header Field + +@end table + + @node Index @chapter Index @printindex cp @@ -752,4 +1476,8 @@ Prompt for a mailcap method to use to view the part. @contents @bye + +@c Local Variables: +@c mode: texinfo +@c coding: iso-8859-1 @c End: