lisp/mail/rfc2368.el

   1 ;;; rfc2368.el --- support for rfc2368
   2
   3 ;; Author: Sen Nagata <sen@eccosys.com>
   4 ;; Keywords: mail
   5
   6 ;; Copyright (C) 1998, 2000 Free Software Foundation, Inc.
   7
   8 ;; This file is part of GNU Emacs.
   9
  10 ;; GNU Emacs is free software; you can redistribute it and/or modify
  11 ;; it under the terms of the GNU General Public License as published by
  12 ;; the Free Software Foundation; either version 2, or (at your option)
  13 ;; any later version.
  14
  15 ;; GNU Emacs is distributed in the hope that it will be useful,
  16 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  17 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18 ;; GNU General Public License for more details.
  19
  20 ;; You should have received a copy of the GNU General Public License
  21 ;; along with GNU Emacs; see the file COPYING.  If not, write to the
  22 ;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  23 ;; Boston, MA 02111-1307, USA.
  24
  25 ;;; Commentary:
  26 ;;
  27 ;; notes:
  28 ;;
  29 ;;   -repeat after me: "the colon is not part of the header name..."
  30 ;;   -if w3 becomes part of emacs, then it may make sense to have this
  31 ;;    file depend on w3 -- the maintainer of w3 says merging w/ Emacs
  32 ;;    is planned!
  33 ;;
  34 ;; historical note:
  35 ;;
  36 ;;   this is intended as a replacement for mailto.el
  37 ;;
  38 ;; acknowledgements:
  39 ;;
  40 ;;   the functions that deal w/ unhexifying in this file were basically
  41 ;; taken from w3 -- i hope to replace them w/ something else soon OR
  42 ;; perhaps if w3 becomes a part of emacs soon, use the functions from w3.
  43
  44 ;;; History:
  45 ;;
  46 ;; 0.3:
  47 ;;
  48 ;;  added the constant rfc2368-version
  49 ;;  implemented first potential fix for a bug in rfc2368-mailto-regexp
  50 ;;  implemented first potential fix for a bug in rfc2368-parse-mailto
  51 ;;  (both bugs reported by Kenichi OKADA)
  52 ;;
  53 ;; 0.2:
  54 ;;
  55 ;;  started to use checkdoc
  56 ;;
  57 ;; 0.1:
  58 ;;
  59 ;;  initial implementation
  60
  61 ;;; Code:
  62
  63 ;; only an approximation?
  64 ;; see rfc 1738
  65 (defconst rfc2368-mailto-regexp
  66   "^\\(mailto:\\)\\([^?]+\\)*\\(\\?\\(.*\\)\\)*"
  67   "Regular expression to match and aid in parsing a mailto url.")
  68
  69 ;; describes 'mailto:'
  70 (defconst rfc2368-mailto-scheme-index 1
  71   "Describes the 'mailto:' portion of the url.")
  72 ;; i'm going to call this part the 'prequery'
  73 (defconst rfc2368-mailto-prequery-index 2
  74   "Describes the portion of the url between 'mailto:' and '?'.")
  75 ;; i'm going to call this part the 'query'
  76 (defconst rfc2368-mailto-query-index 4
  77   "Describes the portion of the url after '?'.")
  78
  79 ;; for dealing w/ unhexifying strings, my preferred approach is to use
  80 ;; a 'string-replace-match-using-function' which can perform a
  81 ;; string-replace-match and compute the replacement text based on a
  82 ;; passed function -- however, emacs doesn't seem to have such a
  83 ;; function yet :-(
  84
  85 ;; for the moment a rip-off of url-unhex (w3/url.el)
  86 (defun rfc2368-unhexify-char (char)
  87   "Unhexify CHAR -- e.g. %20 -> <SPC>."
  88   (if (> char ?9)
  89       (if (>= char ?a)
  90           (+ 10 (- char ?a))
  91         (+ 10 (- char ?A)))
  92     (- char ?0)))
  93
  94 ;; for the moment a rip-off of url-unhex-string (w3/url.el) (slightly modified)
  95 (defun rfc2368-unhexify-string (string)
  96   "Unhexify STRING -- e.g. 'hello%20there' -> 'hello there'."
  97   (let ((case-fold-search t)
  98         (result ""))
  99     (while (string-match "%[0-9a-f][0-9a-f]" string)
 100       (let* ((start (match-beginning 0))
 101              (hex-code (+ (* 16
 102                              (rfc2368-unhexify-char (elt string (+ start 1))))
 103                           (rfc2368-unhexify-char (elt string (+ start 2))))))
 104         (setq result (concat
 105                       result (substring string 0 start)
 106                       (char-to-string hex-code))
 107               string (substring string (match-end 0)))))
 108     ;; it seems clearer to do things this way than to just return:
 109     ;; (concat result string)
 110     (setq result (concat result string))
 111     result))
 112
 113 (defun rfc2368-parse-mailto-url (mailto-url)
 114   "Parse MAILTO-URL, and return an alist of header-name, header-value pairs.
 115 MAILTO-URL should be a RFC 2368 (mailto) compliant url.  A cons cell w/ a
 116 key of 'Body' is a special case and is considered a header for this purpose.
 117 The returned alist is intended for use w/ the `compose-mail' interface.
 118 Note: make sure MAILTO-URL has been 'unhtmlized' (e.g. &amp; -> &), before
 119 calling this function."
 120   (let ((case-fold-search t)
 121         prequery query headers-alist)
 122
 123     (if (string-match rfc2368-mailto-regexp mailto-url)
 124         (progn
 125
 126           (setq prequery
 127                 (match-string rfc2368-mailto-prequery-index mailto-url))
 128
 129           (setq query
 130                 (match-string rfc2368-mailto-query-index mailto-url))
 131
 132           ;; build alist of header name-value pairs
 133           (if (not (null query))
 134               (setq headers-alist
 135                     (mapcar
 136                      (lambda (x)
 137                        (let* ((temp-list (split-string x "="))
 138                               (header-name (car temp-list))
 139                               (header-value (cadr temp-list)))
 140                          ;; return ("Header-Name" . "header-value")
 141                          (cons
 142                           (capitalize (rfc2368-unhexify-string header-name))
 143                           (rfc2368-unhexify-string header-value))))
 144                      (split-string query "&"))))
 145
 146           ;; deal w/ multiple 'To' recipients
 147           (if prequery
 148               (progn
 149                 (if (assoc "To" headers-alist)
 150                     (let* ((our-cons-cell
 151                             (assoc "To" headers-alist))
 152                            (our-cdr
 153                             (cdr our-cons-cell)))
 154                       (setcdr our-cons-cell (concat our-cdr ", " prequery)))
 155                   (setq headers-alist
 156                         (cons (cons "To" prequery) headers-alist)))))
 157
 158           headers-alist)
 159
 160       (error "Failed to match a mailto: url"))
 161     ))
 162
 163 (provide 'rfc2368)
 164
 165 ;;; rfc2368.el ends here