| 1 | \input texinfo |
| 2 | |
| 3 | @setfilename ../info/emacs-mime |
| 4 | @settitle Emacs MIME Manual |
| 5 | @synindex fn cp |
| 6 | @synindex vr cp |
| 7 | @synindex pg cp |
| 8 | |
| 9 | @copying |
| 10 | This file documents the Emacs MIME interface functionality. |
| 11 | |
| 12 | Copyright (C) 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005 |
| 13 | Free Software Foundation, Inc. |
| 14 | |
| 15 | @quotation |
| 16 | Permission is granted to copy, distribute and/or modify this document |
| 17 | under the terms of the GNU Free Documentation License, Version 1.2 or |
| 18 | any later version published by the Free Software Foundation; with no |
| 19 | Invariant Sections, with the Front-Cover texts being ``A GNU |
| 20 | Manual'', and with the Back-Cover Texts as in (a) below. A copy of the |
| 21 | license is included in the section entitled ``GNU Free Documentation |
| 22 | License'' in the Emacs manual. |
| 23 | |
| 24 | (a) The FSF's Back-Cover Text is: ``You have freedom to copy and modify |
| 25 | this GNU Manual, like GNU software. Copies published by the Free |
| 26 | Software Foundation raise funds for GNU development.'' |
| 27 | |
| 28 | This document is part of a collection distributed under the GNU Free |
| 29 | Documentation License. If you want to distribute this document |
| 30 | separately from the collection, you can do so by adding a copy of the |
| 31 | license to the document, as described in section 6 of the license. |
| 32 | @end quotation |
| 33 | @end copying |
| 34 | |
| 35 | @dircategory Emacs |
| 36 | @direntry |
| 37 | * Emacs MIME: (emacs-mime). Emacs MIME de/composition library. |
| 38 | @end direntry |
| 39 | @iftex |
| 40 | @finalout |
| 41 | @end iftex |
| 42 | @setchapternewpage odd |
| 43 | |
| 44 | @titlepage |
| 45 | @title Emacs MIME Manual |
| 46 | |
| 47 | @author by Lars Magne Ingebrigtsen |
| 48 | @page |
| 49 | @vskip 0pt plus 1filll |
| 50 | @insertcopying |
| 51 | @end titlepage |
| 52 | |
| 53 | @node Top |
| 54 | @top Emacs MIME |
| 55 | |
| 56 | This manual documents the libraries used to compose and display |
| 57 | @acronym{MIME} messages. |
| 58 | |
| 59 | This manual is directed at users who want to modify the behavior of |
| 60 | the @acronym{MIME} encoding/decoding process or want a more detailed |
| 61 | picture of how the Emacs @acronym{MIME} library works, and people who want |
| 62 | to write functions and commands that manipulate @acronym{MIME} elements. |
| 63 | |
| 64 | @acronym{MIME} is short for @dfn{Multipurpose Internet Mail Extensions}. |
| 65 | This standard is documented in a number of RFCs; mainly RFC2045 (Format |
| 66 | of Internet Message Bodies), RFC2046 (Media Types), RFC2047 (Message |
| 67 | Header Extensions for Non-@acronym{ASCII} Text), RFC2048 (Registration |
| 68 | Procedures), RFC2049 (Conformance Criteria and Examples). It is highly |
| 69 | recommended that anyone who intends writing @acronym{MIME}-compliant software |
| 70 | read at least RFC2045 and RFC2047. |
| 71 | |
| 72 | @menu |
| 73 | * Decoding and Viewing:: A framework for decoding and viewing. |
| 74 | * Composing:: @acronym{MML}; a language for describing @acronym{MIME} parts. |
| 75 | * Interface Functions:: An abstraction over the basic functions. |
| 76 | * Basic Functions:: Utility and basic parsing functions. |
| 77 | * Standards:: A summary of RFCs and working documents used. |
| 78 | * Index:: Function and variable index. |
| 79 | @end menu |
| 80 | |
| 81 | |
| 82 | @node Decoding and Viewing |
| 83 | @chapter Decoding and Viewing |
| 84 | |
| 85 | This chapter deals with decoding and viewing @acronym{MIME} messages on a |
| 86 | higher level. |
| 87 | |
| 88 | The main idea is to first analyze a @acronym{MIME} article, and then allow |
| 89 | other programs to do things based on the list of @dfn{handles} that are |
| 90 | returned as a result of this analysis. |
| 91 | |
| 92 | @menu |
| 93 | * Dissection:: Analyzing a @acronym{MIME} message. |
| 94 | * Non-MIME:: Analyzing a non-@acronym{MIME} message. |
| 95 | * Handles:: Handle manipulations. |
| 96 | * Display:: Displaying handles. |
| 97 | * Display Customization:: Variables that affect display. |
| 98 | * Files and Directories:: Saving and naming attachments. |
| 99 | * New Viewers:: How to write your own viewers. |
| 100 | @end menu |
| 101 | |
| 102 | |
| 103 | @node Dissection |
| 104 | @section Dissection |
| 105 | |
| 106 | The @code{mm-dissect-buffer} is the function responsible for dissecting |
| 107 | a @acronym{MIME} article. If given a multipart message, it will recursively |
| 108 | descend the message, following the structure, and return a tree of |
| 109 | @acronym{MIME} handles that describes the structure of the message. |
| 110 | |
| 111 | @node Non-MIME |
| 112 | @section Non-MIME |
| 113 | @vindex mm-uu-configure-list |
| 114 | |
| 115 | Gnus also understands some non-@acronym{MIME} attachments, such as |
| 116 | postscript, uuencode, binhex, yenc, shar, forward, gnatsweb, pgp, |
| 117 | diff. Each of these features can be disabled by add an item into |
| 118 | @code{mm-uu-configure-list}. For example, |
| 119 | |
| 120 | @lisp |
| 121 | (require 'mm-uu) |
| 122 | (add-to-list 'mm-uu-configure-list '(pgp-signed . disabled)) |
| 123 | @end lisp |
| 124 | |
| 125 | @table @code |
| 126 | @item postscript |
| 127 | @findex postscript |
| 128 | Postscript file. |
| 129 | |
| 130 | @item uu |
| 131 | @findex uu |
| 132 | Uuencoded file. |
| 133 | |
| 134 | @item binhex |
| 135 | @findex binhex |
| 136 | Binhex encoded file. |
| 137 | |
| 138 | @item yenc |
| 139 | @findex yenc |
| 140 | Yenc encoded file. |
| 141 | |
| 142 | @item shar |
| 143 | @findex shar |
| 144 | Shar archive file. |
| 145 | |
| 146 | @item forward |
| 147 | @findex forward |
| 148 | Non-@acronym{MIME} forwarded message. |
| 149 | |
| 150 | @item gnatsweb |
| 151 | @findex gnatsweb |
| 152 | Gnatsweb attachment. |
| 153 | |
| 154 | @item pgp-signed |
| 155 | @findex pgp-signed |
| 156 | @acronym{PGP} signed clear text. |
| 157 | |
| 158 | @item pgp-encrypted |
| 159 | @findex pgp-encrypted |
| 160 | @acronym{PGP} encrypted clear text. |
| 161 | |
| 162 | @item pgp-key |
| 163 | @findex pgp-key |
| 164 | @acronym{PGP} public keys. |
| 165 | |
| 166 | @item emacs-sources |
| 167 | @findex emacs-sources |
| 168 | @vindex mm-uu-emacs-sources-regexp |
| 169 | Emacs source code. This item works only in the groups matching |
| 170 | @code{mm-uu-emacs-sources-regexp}. |
| 171 | |
| 172 | @item diff |
| 173 | @vindex diff |
| 174 | @vindex mm-uu-diff-groups-regexp |
| 175 | Patches. This is intended for groups where diffs of committed files |
| 176 | are automatically sent to. It only works in groups matching |
| 177 | @code{mm-uu-diff-groups-regexp}. |
| 178 | |
| 179 | @end table |
| 180 | |
| 181 | @node Handles |
| 182 | @section Handles |
| 183 | |
| 184 | A @acronym{MIME} handle is a list that fully describes a @acronym{MIME} |
| 185 | component. |
| 186 | |
| 187 | The following macros can be used to access elements in a handle: |
| 188 | |
| 189 | @table @code |
| 190 | @item mm-handle-buffer |
| 191 | @findex mm-handle-buffer |
| 192 | Return the buffer that holds the contents of the undecoded @acronym{MIME} |
| 193 | part. |
| 194 | |
| 195 | @item mm-handle-type |
| 196 | @findex mm-handle-type |
| 197 | Return the parsed @code{Content-Type} of the part. |
| 198 | |
| 199 | @item mm-handle-encoding |
| 200 | @findex mm-handle-encoding |
| 201 | Return the @code{Content-Transfer-Encoding} of the part. |
| 202 | |
| 203 | @item mm-handle-undisplayer |
| 204 | @findex mm-handle-undisplayer |
| 205 | Return the object that can be used to remove the displayed part (if it |
| 206 | has been displayed). |
| 207 | |
| 208 | @item mm-handle-set-undisplayer |
| 209 | @findex mm-handle-set-undisplayer |
| 210 | Set the undisplayer object. |
| 211 | |
| 212 | @item mm-handle-disposition |
| 213 | @findex mm-handle-disposition |
| 214 | Return the parsed @code{Content-Disposition} of the part. |
| 215 | |
| 216 | @item mm-get-content-id |
| 217 | Returns the handle(s) referred to by @code{Content-ID}. |
| 218 | |
| 219 | @end table |
| 220 | |
| 221 | |
| 222 | @node Display |
| 223 | @section Display |
| 224 | |
| 225 | Functions for displaying, removing and saving. |
| 226 | |
| 227 | @table @code |
| 228 | @item mm-display-part |
| 229 | @findex mm-display-part |
| 230 | Display the part. |
| 231 | |
| 232 | @item mm-remove-part |
| 233 | @findex mm-remove-part |
| 234 | Remove the part (if it has been displayed). |
| 235 | |
| 236 | @item mm-inlinable-p |
| 237 | @findex mm-inlinable-p |
| 238 | Say whether a @acronym{MIME} type can be displayed inline. |
| 239 | |
| 240 | @item mm-automatic-display-p |
| 241 | @findex mm-automatic-display-p |
| 242 | Say whether a @acronym{MIME} type should be displayed automatically. |
| 243 | |
| 244 | @item mm-destroy-part |
| 245 | @findex mm-destroy-part |
| 246 | Free all resources occupied by a part. |
| 247 | |
| 248 | @item mm-save-part |
| 249 | @findex mm-save-part |
| 250 | Offer to save the part in a file. |
| 251 | |
| 252 | @item mm-pipe-part |
| 253 | @findex mm-pipe-part |
| 254 | Offer to pipe the part to some process. |
| 255 | |
| 256 | @item mm-interactively-view-part |
| 257 | @findex mm-interactively-view-part |
| 258 | Prompt for a mailcap method to use to view the part. |
| 259 | |
| 260 | @end table |
| 261 | |
| 262 | |
| 263 | @node Display Customization |
| 264 | @section Display Customization |
| 265 | |
| 266 | @table @code |
| 267 | |
| 268 | @item mm-inline-media-tests |
| 269 | @vindex mm-inline-media-tests |
| 270 | This is an alist where the key is a @acronym{MIME} type, the second element |
| 271 | is a function to display the part @dfn{inline} (i.e., inside Emacs), and |
| 272 | the third element is a form to be @code{eval}ed to say whether the part |
| 273 | can be displayed inline. |
| 274 | |
| 275 | This variable specifies whether a part @emph{can} be displayed inline, |
| 276 | and, if so, how to do it. It does not say whether parts are |
| 277 | @emph{actually} displayed inline. |
| 278 | |
| 279 | @item mm-inlined-types |
| 280 | @vindex mm-inlined-types |
| 281 | This, on the other hand, says what types are to be displayed inline, if |
| 282 | they satisfy the conditions set by the variable above. It's a list of |
| 283 | @acronym{MIME} media types. |
| 284 | |
| 285 | @item mm-automatic-display |
| 286 | @vindex mm-automatic-display |
| 287 | This is a list of types that are to be displayed ``automatically'', but |
| 288 | only if the above variable allows it. That is, only inlinable parts can |
| 289 | be displayed automatically. |
| 290 | |
| 291 | @item mm-automatic-external-display |
| 292 | @vindex mm-automatic-external-display |
| 293 | This is a list of types that will be displayed automatically in an |
| 294 | external viewer. |
| 295 | |
| 296 | @item mm-keep-viewer-alive-types |
| 297 | @vindex mm-keep-viewer-alive-types |
| 298 | This is a list of media types for which the external viewer will not |
| 299 | be killed when selecting a different article. |
| 300 | |
| 301 | @item mm-attachment-override-types |
| 302 | @vindex mm-attachment-override-types |
| 303 | Some @acronym{MIME} agents create parts that have a content-disposition of |
| 304 | @samp{attachment}. This variable allows overriding that disposition and |
| 305 | displaying the part inline. (Note that the disposition is only |
| 306 | overridden if we are able to, and want to, display the part inline.) |
| 307 | |
| 308 | @item mm-discouraged-alternatives |
| 309 | @vindex mm-discouraged-alternatives |
| 310 | List of @acronym{MIME} types that are discouraged when viewing |
| 311 | @samp{multipart/alternative}. Viewing agents are supposed to view the |
| 312 | last possible part of a message, as that is supposed to be the richest. |
| 313 | However, users may prefer other types instead, and this list says what |
| 314 | types are most unwanted. If, for instance, @samp{text/html} parts are |
| 315 | very unwanted, and @samp{text/richtext} parts are somewhat unwanted, |
| 316 | you could say something like: |
| 317 | |
| 318 | @lisp |
| 319 | (setq mm-discouraged-alternatives |
| 320 | '("text/html" "text/richtext") |
| 321 | mm-automatic-display |
| 322 | (remove "text/html" mm-automatic-display)) |
| 323 | @end lisp |
| 324 | |
| 325 | Adding @code{"image/.*"} might also be useful. Spammers use it as the |
| 326 | prefered part of @samp{multipart/alternative} messages. See also |
| 327 | @code{gnus-buttonized-mime-types} (@pxref{MIME Commands, ,MIME Commands, |
| 328 | gnus, Gnus Manual}), to which adding @code{"multipart/alternative"} |
| 329 | enables you to choose manually one of two types those mails include. |
| 330 | |
| 331 | @item mm-inline-large-images |
| 332 | @vindex mm-inline-large-images |
| 333 | When displaying inline images that are larger than the window, Emacs |
| 334 | does not enable scrolling, which means that you cannot see the whole |
| 335 | image. To prevent this, the library tries to determine the image size |
| 336 | before displaying it inline, and if it doesn't fit the window, the |
| 337 | library will display it externally (e.g. with @samp{ImageMagick} or |
| 338 | @samp{xv}). Setting this variable to @code{t} disables this check and |
| 339 | makes the library display all inline images as inline, regardless of |
| 340 | their size. |
| 341 | |
| 342 | @item mm-inline-override-types |
| 343 | @vindex mm-inline-override-types |
| 344 | @code{mm-inlined-types} may include regular expressions, for example to |
| 345 | specify that all @samp{text/.*} parts be displayed inline. If a user |
| 346 | prefers to have a type that matches such a regular expression be treated |
| 347 | as an attachment, that can be accomplished by setting this variable to a |
| 348 | list containing that type. For example assuming @code{mm-inlined-types} |
| 349 | includes @samp{text/.*}, then including @samp{text/html} in this |
| 350 | variable will cause @samp{text/html} parts to be treated as attachments. |
| 351 | |
| 352 | @item mm-text-html-renderer |
| 353 | @vindex mm-text-html-renderer |
| 354 | This selects the function used to render @acronym{HTML}. The predefined |
| 355 | renderers are selected by the symbols @code{w3}, |
| 356 | @code{w3m}@footnote{See @uref{http://emacs-w3m.namazu.org/} for more |
| 357 | information about emacs-w3m}, @code{links}, @code{lynx}, |
| 358 | @code{w3m-standalone} or @code{html2text}. If @code{nil} use an |
| 359 | external viewer. You can also specify a function, which will be |
| 360 | called with a @acronym{MIME} handle as the argument. |
| 361 | |
| 362 | @item mm-inline-text-html-with-images |
| 363 | @vindex mm-inline-text-html-with-images |
| 364 | Some @acronym{HTML} mails might have the trick of spammers using |
| 365 | @samp{<img>} tags. It is likely to be intended to verify whether you |
| 366 | have read the mail. You can prevent your personal informations from |
| 367 | leaking by setting this option to @code{nil} (which is the default). |
| 368 | It is currently ignored by Emacs/w3. For emacs-w3m, you may use the |
| 369 | command @kbd{t} on the image anchor to show an image even if it is |
| 370 | @code{nil}.@footnote{The command @kbd{T} will load all images. If you |
| 371 | have set the option @code{w3m-key-binding} to @code{info}, use @kbd{i} |
| 372 | or @kbd{I} instead.} |
| 373 | |
| 374 | @item mm-w3m-safe-url-regexp |
| 375 | @vindex mm-w3m-safe-url-regexp |
| 376 | A regular expression that matches safe URL names, i.e. URLs that are |
| 377 | unlikely to leak personal information when rendering @acronym{HTML} |
| 378 | email (the default value is @samp{\\`cid:}). If @code{nil} consider |
| 379 | all URLs safe. |
| 380 | |
| 381 | @item mm-inline-text-html-with-w3m-keymap |
| 382 | @vindex mm-inline-text-html-with-w3m-keymap |
| 383 | You can use emacs-w3m command keys in the inlined text/html part by |
| 384 | setting this option to non-@code{nil}. The default value is @code{t}. |
| 385 | |
| 386 | @item mm-external-terminal-program |
| 387 | @vindex mm-external-terminal-program |
| 388 | The program used to start an external terminal. |
| 389 | |
| 390 | @item mm-enable-external |
| 391 | @vindex mm-enable-external |
| 392 | Indicate whether external @acronym{MIME} handlers should be used. |
| 393 | |
| 394 | If @code{t}, all defined external @acronym{MIME} handlers are used. If |
| 395 | @code{nil}, files are saved to disk (@code{mailcap-save-binary-file}). |
| 396 | If it is the symbol @code{ask}, you are prompted before the external |
| 397 | @acronym{MIME} handler is invoked. |
| 398 | |
| 399 | When you launch an attachment through mailcap (@pxref{mailcap}) an |
| 400 | attempt is made to use a safe viewer with the safest options---this isn't |
| 401 | the case if you save it to disk and launch it in a different way |
| 402 | (command line or double-clicking). Anyhow, if you want to be sure not |
| 403 | to launch any external programs, set this variable to @code{nil} or |
| 404 | @code{ask}. |
| 405 | |
| 406 | @end table |
| 407 | |
| 408 | @node Files and Directories |
| 409 | @section Files and Directories |
| 410 | |
| 411 | @table @code |
| 412 | |
| 413 | @item mm-default-directory |
| 414 | @vindex mm-default-directory |
| 415 | The default directory for saving attachments. If @code{nil} use |
| 416 | @code{default-directory}. |
| 417 | |
| 418 | @item mm-tmp-directory |
| 419 | @vindex mm-tmp-directory |
| 420 | Directory for storing temporary files. |
| 421 | |
| 422 | @item mm-file-name-rewrite-functions |
| 423 | @vindex mm-file-name-rewrite-functions |
| 424 | A list of functions used for rewriting file names of @acronym{MIME} |
| 425 | parts. Each function is applied successively to the file name. |
| 426 | Ready-made functions include |
| 427 | |
| 428 | @table @code |
| 429 | @item mm-file-name-delete-control |
| 430 | @findex mm-file-name-delete-control |
| 431 | Delete all control characters. |
| 432 | |
| 433 | @item mm-file-name-delete-gotchas |
| 434 | @findex mm-file-name-delete-gotchas |
| 435 | Delete characters that could have unintended consequences when used |
| 436 | with flawed shell scripts, i.e. @samp{|}, @samp{>} and @samp{<}; and |
| 437 | @samp{-}, @samp{.} as the first character. |
| 438 | |
| 439 | @item mm-file-name-delete-whitespace |
| 440 | @findex mm-file-name-delete-whitespace |
| 441 | Remove all whitespace. |
| 442 | |
| 443 | @item mm-file-name-trim-whitespace |
| 444 | @findex mm-file-name-trim-whitespace |
| 445 | Remove leading and trailing whitespace. |
| 446 | |
| 447 | @item mm-file-name-collapse-whitespace |
| 448 | @findex mm-file-name-collapse-whitespace |
| 449 | Collapse multiple whitespace characters. |
| 450 | |
| 451 | @item mm-file-name-replace-whitespace |
| 452 | @findex mm-file-name-replace-whitespace |
| 453 | @vindex mm-file-name-replace-whitespace |
| 454 | Replace whitespace with underscores. Set the variable |
| 455 | @code{mm-file-name-replace-whitespace} to any other string if you do |
| 456 | not like underscores. |
| 457 | @end table |
| 458 | |
| 459 | The standard Emacs functions @code{capitalize}, @code{downcase}, |
| 460 | @code{upcase} and @code{upcase-initials} might also prove useful. |
| 461 | |
| 462 | @item mm-path-name-rewrite-functions |
| 463 | @vindex mm-path-name-rewrite-functions |
| 464 | List of functions used for rewriting the full file names of @acronym{MIME} |
| 465 | parts. This is used when viewing parts externally, and is meant for |
| 466 | transforming the absolute name so that non-compliant programs can find |
| 467 | the file where it's saved. |
| 468 | |
| 469 | @end table |
| 470 | |
| 471 | @node New Viewers |
| 472 | @section New Viewers |
| 473 | |
| 474 | Here's an example viewer for displaying @code{text/enriched} inline: |
| 475 | |
| 476 | @lisp |
| 477 | (defun mm-display-enriched-inline (handle) |
| 478 | (let (text) |
| 479 | (with-temp-buffer |
| 480 | (mm-insert-part handle) |
| 481 | (save-window-excursion |
| 482 | (enriched-decode (point-min) (point-max)) |
| 483 | (setq text (buffer-string)))) |
| 484 | (mm-insert-inline handle text))) |
| 485 | @end lisp |
| 486 | |
| 487 | We see that the function takes a @acronym{MIME} handle as its parameter. It |
| 488 | then goes to a temporary buffer, inserts the text of the part, does some |
| 489 | work on the text, stores the result, goes back to the buffer it was |
| 490 | called from and inserts the result. |
| 491 | |
| 492 | The two important helper functions here are @code{mm-insert-part} and |
| 493 | @code{mm-insert-inline}. The first function inserts the text of the |
| 494 | handle in the current buffer. It handles charset and/or content |
| 495 | transfer decoding. The second function just inserts whatever text you |
| 496 | tell it to insert, but it also sets things up so that the text can be |
| 497 | ``undisplayed'' in a convenient manner. |
| 498 | |
| 499 | |
| 500 | @node Composing |
| 501 | @chapter Composing |
| 502 | @cindex Composing |
| 503 | @cindex MIME Composing |
| 504 | @cindex MML |
| 505 | @cindex MIME Meta Language |
| 506 | |
| 507 | Creating a @acronym{MIME} message is boring and non-trivial. Therefore, |
| 508 | a library called @code{mml} has been defined that parses a language |
| 509 | called @acronym{MML} (@acronym{MIME} Meta Language) and generates |
| 510 | @acronym{MIME} messages. |
| 511 | |
| 512 | @findex mml-generate-mime |
| 513 | The main interface function is @code{mml-generate-mime}. It will |
| 514 | examine the contents of the current (narrowed-to) buffer and return a |
| 515 | string containing the @acronym{MIME} message. |
| 516 | |
| 517 | @menu |
| 518 | * Simple MML Example:: An example @acronym{MML} document. |
| 519 | * MML Definition:: All valid @acronym{MML} elements. |
| 520 | * Advanced MML Example:: Another example @acronym{MML} document. |
| 521 | * Encoding Customization:: Variables that affect encoding. |
| 522 | * Charset Translation:: How charsets are mapped from @sc{mule} to @acronym{MIME}. |
| 523 | * Conversion:: Going from @acronym{MIME} to @acronym{MML} and vice versa. |
| 524 | * Flowed text:: Soft and hard newlines. |
| 525 | @end menu |
| 526 | |
| 527 | |
| 528 | @node Simple MML Example |
| 529 | @section Simple MML Example |
| 530 | |
| 531 | Here's a simple @samp{multipart/alternative}: |
| 532 | |
| 533 | @example |
| 534 | <#multipart type=alternative> |
| 535 | This is a plain text part. |
| 536 | <#part type=text/enriched> |
| 537 | <center>This is a centered enriched part</center> |
| 538 | <#/multipart> |
| 539 | @end example |
| 540 | |
| 541 | After running this through @code{mml-generate-mime}, we get this: |
| 542 | |
| 543 | @example |
| 544 | Content-Type: multipart/alternative; boundary="=-=-=" |
| 545 | |
| 546 | |
| 547 | --=-=-= |
| 548 | |
| 549 | |
| 550 | This is a plain text part. |
| 551 | |
| 552 | --=-=-= |
| 553 | Content-Type: text/enriched |
| 554 | |
| 555 | |
| 556 | <center>This is a centered enriched part</center> |
| 557 | |
| 558 | --=-=-=-- |
| 559 | @end example |
| 560 | |
| 561 | |
| 562 | @node MML Definition |
| 563 | @section MML Definition |
| 564 | |
| 565 | The @acronym{MML} language is very simple. It looks a bit like an SGML |
| 566 | application, but it's not. |
| 567 | |
| 568 | The main concept of @acronym{MML} is the @dfn{part}. Each part can be of a |
| 569 | different type or use a different charset. The way to delineate a part |
| 570 | is with a @samp{<#part ...>} tag. Multipart parts can be introduced |
| 571 | with the @samp{<#multipart ...>} tag. Parts are ended by the |
| 572 | @samp{<#/part>} or @samp{<#/multipart>} tags. Parts started with the |
| 573 | @samp{<#part ...>} tags are also closed by the next open tag. |
| 574 | |
| 575 | There's also the @samp{<#external ...>} tag. These introduce |
| 576 | @samp{external/message-body} parts. |
| 577 | |
| 578 | Each tag can contain zero or more parameters on the form |
| 579 | @samp{parameter=value}. The values may be enclosed in quotation marks, |
| 580 | but that's not necessary unless the value contains white space. So |
| 581 | @samp{filename=/home/user/#hello$^yes} is perfectly valid. |
| 582 | |
| 583 | The following parameters have meaning in @acronym{MML}; parameters that have no |
| 584 | meaning are ignored. The @acronym{MML} parameter names are the same as the |
| 585 | @acronym{MIME} parameter names; the things in the parentheses say which |
| 586 | header it will be used in. |
| 587 | |
| 588 | @table @samp |
| 589 | @item type |
| 590 | The @acronym{MIME} type of the part (@code{Content-Type}). |
| 591 | |
| 592 | @item filename |
| 593 | Use the contents of the file in the body of the part |
| 594 | (@code{Content-Disposition}). |
| 595 | |
| 596 | @item charset |
| 597 | The contents of the body of the part are to be encoded in the character |
| 598 | set specified (@code{Content-Type}). @xref{Charset Translation}. |
| 599 | |
| 600 | @item name |
| 601 | Might be used to suggest a file name if the part is to be saved |
| 602 | to a file (@code{Content-Type}). |
| 603 | |
| 604 | @item disposition |
| 605 | Valid values are @samp{inline} and @samp{attachment} |
| 606 | (@code{Content-Disposition}). |
| 607 | |
| 608 | @item encoding |
| 609 | Valid values are @samp{7bit}, @samp{8bit}, @samp{quoted-printable} and |
| 610 | @samp{base64} (@code{Content-Transfer-Encoding}). @xref{Charset |
| 611 | Translation}. |
| 612 | |
| 613 | @item description |
| 614 | A description of the part (@code{Content-Description}). |
| 615 | |
| 616 | @item creation-date |
| 617 | RFC822 date when the part was created (@code{Content-Disposition}). |
| 618 | |
| 619 | @item modification-date |
| 620 | RFC822 date when the part was modified (@code{Content-Disposition}). |
| 621 | |
| 622 | @item read-date |
| 623 | RFC822 date when the part was read (@code{Content-Disposition}). |
| 624 | |
| 625 | @item recipients |
| 626 | Who to encrypt/sign the part to. This field is used to override any |
| 627 | auto-detection based on the To/CC headers. |
| 628 | |
| 629 | @item sender |
| 630 | Identity used to sign the part. This field is used to override the |
| 631 | default key used. |
| 632 | |
| 633 | @item size |
| 634 | The size (in octets) of the part (@code{Content-Disposition}). |
| 635 | |
| 636 | @item sign |
| 637 | What technology to sign this @acronym{MML} part with (@code{smime}, @code{pgp} |
| 638 | or @code{pgpmime}) |
| 639 | |
| 640 | @item encrypt |
| 641 | What technology to encrypt this @acronym{MML} part with (@code{smime}, |
| 642 | @code{pgp} or @code{pgpmime}) |
| 643 | |
| 644 | @end table |
| 645 | |
| 646 | Parameters for @samp{text/plain}: |
| 647 | |
| 648 | @table @samp |
| 649 | @item format |
| 650 | Formatting parameter for the text, valid values include @samp{fixed} |
| 651 | (the default) and @samp{flowed}. Normally you do not specify this |
| 652 | manually, since it requires the textual body to be formatted in a |
| 653 | special way described in RFC 2646. @xref{Flowed text}. |
| 654 | @end table |
| 655 | |
| 656 | Parameters for @samp{application/octet-stream}: |
| 657 | |
| 658 | @table @samp |
| 659 | @item type |
| 660 | Type of the part; informal---meant for human readers |
| 661 | (@code{Content-Type}). |
| 662 | @end table |
| 663 | |
| 664 | Parameters for @samp{message/external-body}: |
| 665 | |
| 666 | @table @samp |
| 667 | @item access-type |
| 668 | A word indicating the supported access mechanism by which the file may |
| 669 | be obtained. Values include @samp{ftp}, @samp{anon-ftp}, @samp{tftp}, |
| 670 | @samp{localfile}, and @samp{mailserver}. (@code{Content-Type}.) |
| 671 | |
| 672 | @item expiration |
| 673 | The RFC822 date after which the file may no longer be fetched. |
| 674 | (@code{Content-Type}.) |
| 675 | |
| 676 | @item size |
| 677 | The size (in octets) of the file. (@code{Content-Type}.) |
| 678 | |
| 679 | @item permission |
| 680 | Valid values are @samp{read} and @samp{read-write} |
| 681 | (@code{Content-Type}). |
| 682 | |
| 683 | @end table |
| 684 | |
| 685 | Parameters for @samp{sign=smime}: |
| 686 | |
| 687 | @table @samp |
| 688 | |
| 689 | @item keyfile |
| 690 | File containing key and certificate for signer. |
| 691 | |
| 692 | @end table |
| 693 | |
| 694 | Parameters for @samp{encrypt=smime}: |
| 695 | |
| 696 | @table @samp |
| 697 | |
| 698 | @item certfile |
| 699 | File containing certificate for recipient. |
| 700 | |
| 701 | @end table |
| 702 | |
| 703 | |
| 704 | @node Advanced MML Example |
| 705 | @section Advanced MML Example |
| 706 | |
| 707 | Here's a complex multipart message. It's a @samp{multipart/mixed} that |
| 708 | contains many parts, one of which is a @samp{multipart/alternative}. |
| 709 | |
| 710 | @example |
| 711 | <#multipart type=mixed> |
| 712 | <#part type=image/jpeg filename=~/rms.jpg disposition=inline> |
| 713 | <#multipart type=alternative> |
| 714 | This is a plain text part. |
| 715 | <#part type=text/enriched name=enriched.txt> |
| 716 | <center>This is a centered enriched part</center> |
| 717 | <#/multipart> |
| 718 | This is a new plain text part. |
| 719 | <#part disposition=attachment> |
| 720 | This plain text part is an attachment. |
| 721 | <#/multipart> |
| 722 | @end example |
| 723 | |
| 724 | And this is the resulting @acronym{MIME} message: |
| 725 | |
| 726 | @example |
| 727 | Content-Type: multipart/mixed; boundary="=-=-=" |
| 728 | |
| 729 | |
| 730 | --=-=-= |
| 731 | |
| 732 | |
| 733 | |
| 734 | --=-=-= |
| 735 | Content-Type: image/jpeg; |
| 736 | filename="~/rms.jpg" |
| 737 | Content-Disposition: inline; |
| 738 | filename="~/rms.jpg" |
| 739 | Content-Transfer-Encoding: base64 |
| 740 | |
| 741 | /9j/4AAQSkZJRgABAQAAAQABAAD/2wBDAAgGBgcGBQgHBwcJCQgKDBQNDAsLDBkSEw8UHRof |
| 742 | Hh0aHBwgJC4nICIsIxwcKDcpLDAxNDQ0Hyc5PTgyPC4zNDL/wAALCAAwADABAREA/8QAHwAA |
| 743 | AQUBAQEBAQEAAAAAAAAAAAECAwQFBgcICQoL/8QAtRAAAgEDAwIEAwUFBAQAAAF9AQIDAAQR |
| 744 | BRIhMUEGE1FhByJxFDKBkaEII0KxwRVS0fAkM2JyggkKFhcYGRolJicoKSo0NTY3ODk6Q0RF |
| 745 | RkdISUpTVFVWV1hZWmNkZWZnaGlqc3R1dnd4eXqDhIWGh4iJipKTlJWWl5iZmqKjpKWmp6ip |
| 746 | qrKztLW2t7i5usLDxMXGx8jJytLT1NXW19jZ2uHi4+Tl5ufo6erx8vP09fb3+Pn6/9oACAEB |
| 747 | AAA/AO/rifFHjldNuGsrDa0qcSSHkA+gHrXKw+LtWLrMb+RgTyhbr+HSug07xNqV9fQtZrNI |
| 748 | AyiaE/NuBPOOOP0rvRNE880KOC8TbXXGCv1FPqjrF4LDR7u5L7SkTFT/ALWOP1xXgTuXfc7E |
| 749 | sx6nua6rwp4IvvEM8chCxWxOdzn7wz6V9AaB4S07w9p5itow0rDLSY5Pt9K43xO66P4xs71m |
| 750 | 2QXiGCbA4yOVJ9+1aYORkdK434lyNH4ahCnG66VT9Nj15JFbPdX0MS43M4VQf5/yr2vSpLnw |
| 751 | 5ZW8dlCZ8KFXjOPX0/mK6rSPEGt3Angu44fNEReHYNvIH3TzXDeKNO8RX+kSX2ouZkicTIOc |
| 752 | L+g7E810ulFjpVtv3bwgB3HJyK5L4quY/C9sVxk3ij/xx6850u7t1mtp/wDlpEw3An3Jr3Dw |
| 753 | 34gsbWza4nBlhC5LDsaW6+IFgupQyCF3iHH7gA7c9R9ay7zx6t7aX9jHC4smhfBkGCvHGfrm |
| 754 | tLQ7hbnRrV1GPkAP1x1/Hr+Ncr8Vzjwrbf8AX6v/AKA9eQRyYlQk8Yx9K6XTNbkgia2ciSIn |
| 755 | 7p5Ga9Atte0LTLKO6it4i7dVRFJDcZ4PvXN+JvEMF9bILVGXJLSZ4zkjivRPDaeX4b08HOTC |
| 756 | pOffmua+KkbS+GLVUGT9tT/0B68eeIpIFYjB70+OOVXyoOM9+M1eaWeCLzHPyHGO/NVWvJJm |
| 757 | jQ8KGH1NfQWhXSXmh2c8eArRLwO3HSv/2Q== |
| 758 | |
| 759 | --=-=-= |
| 760 | Content-Type: multipart/alternative; boundary="==-=-=" |
| 761 | |
| 762 | |
| 763 | --==-=-= |
| 764 | |
| 765 | |
| 766 | This is a plain text part. |
| 767 | |
| 768 | --==-=-= |
| 769 | Content-Type: text/enriched; |
| 770 | name="enriched.txt" |
| 771 | |
| 772 | |
| 773 | <center>This is a centered enriched part</center> |
| 774 | |
| 775 | --==-=-=-- |
| 776 | |
| 777 | --=-=-= |
| 778 | |
| 779 | This is a new plain text part. |
| 780 | |
| 781 | --=-=-= |
| 782 | Content-Disposition: attachment |
| 783 | |
| 784 | |
| 785 | This plain text part is an attachment. |
| 786 | |
| 787 | --=-=-=-- |
| 788 | @end example |
| 789 | |
| 790 | @node Encoding Customization |
| 791 | @section Encoding Customization |
| 792 | |
| 793 | @table @code |
| 794 | |
| 795 | @item mm-body-charset-encoding-alist |
| 796 | @vindex mm-body-charset-encoding-alist |
| 797 | Mapping from @acronym{MIME} charset to encoding to use. This variable is |
| 798 | usually used except, e.g., when other requirements force a specific |
| 799 | encoding (digitally signed messages require 7bit encodings). The |
| 800 | default is |
| 801 | |
| 802 | @lisp |
| 803 | ((iso-2022-jp . 7bit) |
| 804 | (iso-2022-jp-2 . 7bit) |
| 805 | (utf-16 . base64) |
| 806 | (utf-16be . base64) |
| 807 | (utf-16le . base64)) |
| 808 | @end lisp |
| 809 | |
| 810 | As an example, if you do not want to have ISO-8859-1 characters |
| 811 | quoted-printable encoded, you may add @code{(iso-8859-1 . 8bit)} to |
| 812 | this variable. You can override this setting on a per-message basis |
| 813 | by using the @code{encoding} @acronym{MML} tag (@pxref{MML Definition}). |
| 814 | |
| 815 | @item mm-coding-system-priorities |
| 816 | @vindex mm-coding-system-priorities |
| 817 | Prioritize coding systems to use for outgoing messages. The default |
| 818 | is @code{nil}, which means to use the defaults in Emacs, but is |
| 819 | @code{(iso-8859-1 iso-2022-jp iso-2022-jp-2 shift_jis utf-8)} when |
| 820 | running Emacs in the Japanese language environment. It is a list of |
| 821 | coding system symbols (aliases of coding systems are also allowed, use |
| 822 | @kbd{M-x describe-coding-system} to make sure you are specifying correct |
| 823 | coding system names). For example, if you have configured Emacs |
| 824 | to prefer UTF-8, but wish that outgoing messages should be sent in |
| 825 | ISO-8859-1 if possible, you can set this variable to |
| 826 | @code{(iso-8859-1)}. You can override this setting on a per-message |
| 827 | basis by using the @code{charset} @acronym{MML} tag (@pxref{MML Definition}). |
| 828 | |
| 829 | @item mm-content-transfer-encoding-defaults |
| 830 | @vindex mm-content-transfer-encoding-defaults |
| 831 | Mapping from @acronym{MIME} types to encoding to use. This variable is usually |
| 832 | used except, e.g., when other requirements force a safer encoding |
| 833 | (digitally signed messages require 7bit encoding). Besides the normal |
| 834 | @acronym{MIME} encodings, @code{qp-or-base64} may be used to indicate that for |
| 835 | each case the most efficient of quoted-printable and base64 should be |
| 836 | used. |
| 837 | |
| 838 | @code{qp-or-base64} has another effect. It will fold long lines so that |
| 839 | MIME parts may not be broken by MTA. So do @code{quoted-printable} and |
| 840 | @code{base64}. |
| 841 | |
| 842 | Note that it affects body encoding only when a part is a raw forwarded |
| 843 | message (which will be made by @code{gnus-summary-mail-forward} with the |
| 844 | arg 2 for example) or is neither the @samp{text/*} type nor the |
| 845 | @samp{message/*} type. Even though in those cases, you can override |
| 846 | this setting on a per-message basis by using the @code{encoding} |
| 847 | @acronym{MML} tag (@pxref{MML Definition}). |
| 848 | |
| 849 | @item mm-use-ultra-safe-encoding |
| 850 | @vindex mm-use-ultra-safe-encoding |
| 851 | When this is non-@code{nil}, it means that textual parts are encoded as |
| 852 | quoted-printable if they contain lines longer than 76 characters or |
| 853 | starting with "From " in the body. Non-7bit encodings (8bit, binary) |
| 854 | are generally disallowed. This reduce the probability that a non-8bit |
| 855 | clean MTA or MDA changes the message. This should never be set |
| 856 | directly, but bound by other functions when necessary (e.g., when |
| 857 | encoding messages that are to be digitally signed). |
| 858 | |
| 859 | @end table |
| 860 | |
| 861 | @node Charset Translation |
| 862 | @section Charset Translation |
| 863 | @cindex charsets |
| 864 | |
| 865 | During translation from @acronym{MML} to @acronym{MIME}, for each |
| 866 | @acronym{MIME} part which has been composed inside Emacs, an appropriate |
| 867 | charset has to be chosen. |
| 868 | |
| 869 | @vindex mail-parse-charset |
| 870 | If you are running a non-@sc{mule} Emacs, this process is simple: If the |
| 871 | part contains any non-@acronym{ASCII} (8-bit) characters, the @acronym{MIME} charset |
| 872 | given by @code{mail-parse-charset} (a symbol) is used. (Never set this |
| 873 | variable directly, though. If you want to change the default charset, |
| 874 | please consult the documentation of the package which you use to process |
| 875 | @acronym{MIME} messages. |
| 876 | @xref{Various Message Variables, , Various Message Variables, message, |
| 877 | Message Manual}, for example.) |
| 878 | If there are only @acronym{ASCII} characters, the @acronym{MIME} charset US-ASCII is |
| 879 | used, of course. |
| 880 | |
| 881 | @cindex MULE |
| 882 | @cindex UTF-8 |
| 883 | @cindex Unicode |
| 884 | @vindex mm-mime-mule-charset-alist |
| 885 | Things are slightly more complicated when running Emacs with @sc{mule} |
| 886 | support. In this case, a list of the @sc{mule} charsets used in the |
| 887 | part is obtained, and the @sc{mule} charsets are translated to |
| 888 | @acronym{MIME} charsets by consulting the table provided by Emacs itself |
| 889 | or the variable @code{mm-mime-mule-charset-alist} for XEmacs. |
| 890 | If this results in a single @acronym{MIME} charset, this is used to encode |
| 891 | the part. But if the resulting list of @acronym{MIME} charsets contains more |
| 892 | than one element, two things can happen: If it is possible to encode the |
| 893 | part via UTF-8, this charset is used. (For this, Emacs must support |
| 894 | the @code{utf-8} coding system, and the part must consist entirely of |
| 895 | characters which have Unicode counterparts.) If UTF-8 is not available |
| 896 | for some reason, the part is split into several ones, so that each one |
| 897 | can be encoded with a single @acronym{MIME} charset. The part can only be |
| 898 | split at line boundaries, though---if more than one @acronym{MIME} charset is |
| 899 | required to encode a single line, it is not possible to encode the part. |
| 900 | |
| 901 | When running Emacs with @sc{mule} support, the preferences for which |
| 902 | coding system to use is inherited from Emacs itself. This means that |
| 903 | if Emacs is set up to prefer UTF-8, it will be used when encoding |
| 904 | messages. You can modify this by altering the |
| 905 | @code{mm-coding-system-priorities} variable though (@pxref{Encoding |
| 906 | Customization}). |
| 907 | |
| 908 | The charset to be used can be overridden by setting the @code{charset} |
| 909 | @acronym{MML} tag (@pxref{MML Definition}) when composing the message. |
| 910 | |
| 911 | The encoding of characters (quoted-printable, 8bit etc) is orthogonal |
| 912 | to the discussion here, and is controlled by the variables |
| 913 | @code{mm-body-charset-encoding-alist} and |
| 914 | @code{mm-content-transfer-encoding-defaults} (@pxref{Encoding |
| 915 | Customization}). |
| 916 | |
| 917 | @node Conversion |
| 918 | @section Conversion |
| 919 | |
| 920 | @findex mime-to-mml |
| 921 | A (multipart) @acronym{MIME} message can be converted to @acronym{MML} |
| 922 | with the @code{mime-to-mml} function. It works on the message in the |
| 923 | current buffer, and substitutes @acronym{MML} markup for @acronym{MIME} |
| 924 | boundaries. Non-textual parts do not have their contents in the buffer, |
| 925 | but instead have the contents in separate buffers that are referred to |
| 926 | from the @acronym{MML} tags. |
| 927 | |
| 928 | @findex mml-to-mime |
| 929 | An @acronym{MML} message can be converted back to @acronym{MIME} by the |
| 930 | @code{mml-to-mime} function. |
| 931 | |
| 932 | These functions are in certain senses ``lossy''---you will not get back |
| 933 | an identical message if you run @code{mime-to-mml} and then |
| 934 | @code{mml-to-mime}. Not only will trivial things like the order of the |
| 935 | headers differ, but the contents of the headers may also be different. |
| 936 | For instance, the original message may use base64 encoding on text, |
| 937 | while @code{mml-to-mime} may decide to use quoted-printable encoding, and |
| 938 | so on. |
| 939 | |
| 940 | In essence, however, these two functions should be the inverse of each |
| 941 | other. The resulting contents of the message should remain equivalent, |
| 942 | if not identical. |
| 943 | |
| 944 | |
| 945 | @node Flowed text |
| 946 | @section Flowed text |
| 947 | @cindex format=flowed |
| 948 | |
| 949 | The Emacs @acronym{MIME} library will respect the @code{use-hard-newlines} |
| 950 | variable (@pxref{Hard and Soft Newlines, ,Hard and Soft Newlines, |
| 951 | emacs, Emacs Manual}) when encoding a message, and the |
| 952 | ``format=flowed'' Content-Type parameter when decoding a message. |
| 953 | |
| 954 | On encoding text, regardless of @code{use-hard-newlines}, lines |
| 955 | terminated by soft newline characters are filled together and wrapped |
| 956 | after the column decided by @code{fill-flowed-encode-column}. |
| 957 | Quotation marks (matching @samp{^>* ?}) are respected. The variable |
| 958 | controls how the text will look in a client that does not support |
| 959 | flowed text, the default is to wrap after 66 characters. If hard |
| 960 | newline characters are not present in the buffer, no flow encoding |
| 961 | occurs. |
| 962 | |
| 963 | On decoding flowed text, lines with soft newline characters are filled |
| 964 | together and wrapped after the column decided by |
| 965 | @code{fill-flowed-display-column}. The default is to wrap after |
| 966 | @code{fill-column}. |
| 967 | |
| 968 | |
| 969 | |
| 970 | |
| 971 | @node Interface Functions |
| 972 | @chapter Interface Functions |
| 973 | @cindex interface functions |
| 974 | @cindex mail-parse |
| 975 | |
| 976 | The @code{mail-parse} library is an abstraction over the actual |
| 977 | low-level libraries that are described in the next chapter. |
| 978 | |
| 979 | Standards change, and so programs have to change to fit in the new |
| 980 | mold. For instance, RFC2045 describes a syntax for the |
| 981 | @code{Content-Type} header that only allows @acronym{ASCII} characters in the |
| 982 | parameter list. RFC2231 expands on RFC2045 syntax to provide a scheme |
| 983 | for continuation headers and non-@acronym{ASCII} characters. |
| 984 | |
| 985 | The traditional way to deal with this is just to update the library |
| 986 | functions to parse the new syntax. However, this is sometimes the wrong |
| 987 | thing to do. In some instances it may be vital to be able to understand |
| 988 | both the old syntax as well as the new syntax, and if there is only one |
| 989 | library, one must choose between the old version of the library and the |
| 990 | new version of the library. |
| 991 | |
| 992 | The Emacs @acronym{MIME} library takes a different tack. It defines a |
| 993 | series of low-level libraries (@file{rfc2047.el}, @file{rfc2231.el} |
| 994 | and so on) that parses strictly according to the corresponding |
| 995 | standard. However, normal programs would not use the functions |
| 996 | provided by these libraries directly, but instead use the functions |
| 997 | provided by the @code{mail-parse} library. The functions in this |
| 998 | library are just aliases to the corresponding functions in the latest |
| 999 | low-level libraries. Using this scheme, programs get a consistent |
| 1000 | interface they can use, and library developers are free to create |
| 1001 | write code that handles new standards. |
| 1002 | |
| 1003 | The following functions are defined by this library: |
| 1004 | |
| 1005 | @table @code |
| 1006 | @item mail-header-parse-content-type |
| 1007 | @findex mail-header-parse-content-type |
| 1008 | Parse a @code{Content-Type} header and return a list on the following |
| 1009 | format: |
| 1010 | |
| 1011 | @lisp |
| 1012 | ("type/subtype" |
| 1013 | (attribute1 . value1) |
| 1014 | (attribute2 . value2) |
| 1015 | ...) |
| 1016 | @end lisp |
| 1017 | |
| 1018 | Here's an example: |
| 1019 | |
| 1020 | @example |
| 1021 | (mail-header-parse-content-type |
| 1022 | "image/gif; name=\"b980912.gif\"") |
| 1023 | @result{} ("image/gif" (name . "b980912.gif")) |
| 1024 | @end example |
| 1025 | |
| 1026 | @item mail-header-parse-content-disposition |
| 1027 | @findex mail-header-parse-content-disposition |
| 1028 | Parse a @code{Content-Disposition} header and return a list on the same |
| 1029 | format as the function above. |
| 1030 | |
| 1031 | @item mail-content-type-get |
| 1032 | @findex mail-content-type-get |
| 1033 | Takes two parameters---a list on the format above, and an attribute. |
| 1034 | Returns the value of the attribute. |
| 1035 | |
| 1036 | @example |
| 1037 | (mail-content-type-get |
| 1038 | '("image/gif" (name . "b980912.gif")) 'name) |
| 1039 | @result{} "b980912.gif" |
| 1040 | @end example |
| 1041 | |
| 1042 | @item mail-header-encode-parameter |
| 1043 | @findex mail-header-encode-parameter |
| 1044 | Takes a parameter string and returns an encoded version of the string. |
| 1045 | This is used for parameters in headers like @code{Content-Type} and |
| 1046 | @code{Content-Disposition}. |
| 1047 | |
| 1048 | @item mail-header-remove-comments |
| 1049 | @findex mail-header-remove-comments |
| 1050 | Return a comment-free version of a header. |
| 1051 | |
| 1052 | @example |
| 1053 | (mail-header-remove-comments |
| 1054 | "Gnus/5.070027 (Pterodactyl Gnus v0.27) (Finnish Landrace)") |
| 1055 | @result{} "Gnus/5.070027 " |
| 1056 | @end example |
| 1057 | |
| 1058 | @item mail-header-remove-whitespace |
| 1059 | @findex mail-header-remove-whitespace |
| 1060 | Remove linear white space from a header. Space inside quoted strings |
| 1061 | and comments is preserved. |
| 1062 | |
| 1063 | @example |
| 1064 | (mail-header-remove-whitespace |
| 1065 | "image/gif; name=\"Name with spaces\"") |
| 1066 | @result{} "image/gif;name=\"Name with spaces\"" |
| 1067 | @end example |
| 1068 | |
| 1069 | @item mail-header-get-comment |
| 1070 | @findex mail-header-get-comment |
| 1071 | Return the last comment in a header. |
| 1072 | |
| 1073 | @example |
| 1074 | (mail-header-get-comment |
| 1075 | "Gnus/5.070027 (Pterodactyl Gnus v0.27) (Finnish Landrace)") |
| 1076 | @result{} "Finnish Landrace" |
| 1077 | @end example |
| 1078 | |
| 1079 | @item mail-header-parse-address |
| 1080 | @findex mail-header-parse-address |
| 1081 | Parse an address and return a list containing the mailbox and the |
| 1082 | plaintext name. |
| 1083 | |
| 1084 | @example |
| 1085 | (mail-header-parse-address |
| 1086 | "Hrvoje Niksic <hniksic@@srce.hr>") |
| 1087 | @result{} ("hniksic@@srce.hr" . "Hrvoje Niksic") |
| 1088 | @end example |
| 1089 | |
| 1090 | @item mail-header-parse-addresses |
| 1091 | @findex mail-header-parse-addresses |
| 1092 | Parse a string with list of addresses and return a list of elements like |
| 1093 | the one described above. |
| 1094 | |
| 1095 | @example |
| 1096 | (mail-header-parse-addresses |
| 1097 | "Hrvoje Niksic <hniksic@@srce.hr>, Steinar Bang <sb@@metis.no>") |
| 1098 | @result{} (("hniksic@@srce.hr" . "Hrvoje Niksic") |
| 1099 | ("sb@@metis.no" . "Steinar Bang")) |
| 1100 | @end example |
| 1101 | |
| 1102 | @item mail-header-parse-date |
| 1103 | @findex mail-header-parse-date |
| 1104 | Parse a date string and return an Emacs time structure. |
| 1105 | |
| 1106 | @item mail-narrow-to-head |
| 1107 | @findex mail-narrow-to-head |
| 1108 | Narrow the buffer to the header section of the buffer. Point is placed |
| 1109 | at the beginning of the narrowed buffer. |
| 1110 | |
| 1111 | @item mail-header-narrow-to-field |
| 1112 | @findex mail-header-narrow-to-field |
| 1113 | Narrow the buffer to the header under point. Understands continuation |
| 1114 | headers. |
| 1115 | |
| 1116 | @item mail-header-fold-field |
| 1117 | @findex mail-header-fold-field |
| 1118 | Fold the header under point. |
| 1119 | |
| 1120 | @item mail-header-unfold-field |
| 1121 | @findex mail-header-unfold-field |
| 1122 | Unfold the header under point. |
| 1123 | |
| 1124 | @item mail-header-field-value |
| 1125 | @findex mail-header-field-value |
| 1126 | Return the value of the field under point. |
| 1127 | |
| 1128 | @item mail-encode-encoded-word-region |
| 1129 | @findex mail-encode-encoded-word-region |
| 1130 | Encode the non-@acronym{ASCII} words in the region. For instance, |
| 1131 |