-\input texinfo @c -*-texinfo-*-
+\input texinfo @c -*-texinfo-*- -*- coding: iso-latin-1 -*-
@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
@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
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)")
-@result{} "Finnish Landrace"
+@result{} "Finnish Landrace"
@end example
@item mail-header-parse-address
@end table
Currently, @code{mail-parse} is an abstraction over @code{ietf-drums},
-@code{rfc2047} and @code{rfc2231}. These are documented in the
-subsequent sections.
+@code{rfc2047}, @code{rfc2045} and @code{rfc2231}. These are documented
+in the subsequent sections.
@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!\"")
@item rfc2231-encode-string
@findex rfc2231-encode-string
Encode a parameter in headers likes @code{Content-Type} and
-@code{Content-Disposition}.
+@code{Content-Disposition}.
@end table
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
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")
(seconds-to-time 905595714.0)
@result{} (13818 19266 0)
-(time-to-day '(13818 19266))
+(time-to-days '(13818 19266))
@result{} 729644
(days-to-time 729644)
(time-to-day-in-year '(13818 19266))
@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
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.
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
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
@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 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
+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
* 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
set speficied (@code{Content-Type}).
@item name
-Might be used to suggest a file name if the part is to be saved
+Might be used to suggest a file name if the part is to be saved
to a file (@code{Content-Type}).
@item 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}:
@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}.
+contains many parts, one of which is a @samp{multipart/alternative}.
@example
<#multipart type=mixed>
--=-=-=--
@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
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 @samp{http://www.stud.ifi.uio.no/~larsi/notes/}.
+fetched from @uref{http://quimby.gnus.org/notes/}.
@table @dfn
@item RFC822
Content-Disposition Header Field
@end table
-
-
+
+
@node Index
@chapter Index
@printindex cp
projects / gnus / blobdiff