lisp/gnus/mm-url.el

   1 ;;; mm-url.el --- a wrapper of url functions/commands for Gnus
   2
   3 ;; Copyright (C) 2001-2017 Free Software Foundation, Inc.
   4
   5 ;; Author: Shenghuo Zhu <zsh@cs.rochester.edu>
   6
   7 ;; This file is part of GNU Emacs.
   8
   9 ;; GNU Emacs is free software: you can redistribute it and/or modify
  10 ;; it under the terms of the GNU General Public License as published by
  11 ;; the Free Software Foundation, either version 3 of the License, or
  12 ;; (at your option) any later version.
  13
  14 ;; GNU Emacs is distributed in the hope that it will be useful,
  15 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  16 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17 ;; GNU General Public License for more details.
  18
  19 ;; You should have received a copy of the GNU General Public License
  20 ;; along with GNU Emacs.  If not, see <https://www.gnu.org/licenses/>.
  21
  22 ;;; Commentary:
  23
  24 ;; Some code is stolen from w3 and url packages. Some are moved from
  25 ;; nnweb.
  26
  27 ;; TODO: Support POST, cookie.
  28
  29 ;;; Code:
  30
  31 (eval-when-compile (require 'cl))
  32
  33 (require 'mm-util)
  34 (require 'gnus)
  35
  36 (defvar url-current-object)
  37 (defvar url-package-name)
  38 (defvar url-package-version)
  39
  40 (defgroup mm-url nil
  41   "A wrapper of url package and external url command for Gnus."
  42   :group 'gnus)
  43
  44 (defcustom mm-url-use-external (not
  45                                 (condition-case nil
  46                                     (require 'url)
  47                                   (error nil)))
  48   "If non-nil, use external grab program `mm-url-program'."
  49   :version "22.1"
  50   :type 'boolean
  51   :group 'mm-url)
  52
  53 (defvar mm-url-predefined-programs
  54   '((wget "wget" "--user-agent=mm-url" "-q" "-O" "-")
  55     (w3m  "w3m" "-dump_source")
  56     (lynx "lynx" "-source")
  57     (curl "curl" "--silent" "--user-agent" "mm-url" "--location")))
  58
  59 (defcustom mm-url-program
  60   (cond
  61    ((executable-find "wget") 'wget)
  62    ((executable-find "w3m") 'w3m)
  63    ((executable-find "lynx") 'lynx)
  64    ((executable-find "curl") 'curl)
  65    (t "GET"))
  66   "The url grab program.
  67 Likely values are `wget', `w3m', `lynx' and `curl'."
  68   :version "22.1"
  69   :type '(choice
  70           (symbol :tag "wget" wget)
  71           (symbol :tag "w3m" w3m)
  72           (symbol :tag "lynx" lynx)
  73           (symbol :tag "curl" curl)
  74           (string :tag "other"))
  75   :group 'mm-url)
  76
  77 (defcustom mm-url-arguments nil
  78   "The arguments for `mm-url-program'."
  79   :version "22.1"
  80   :type '(repeat string)
  81   :group 'mm-url)
  82
  83 \f
  84 ;;; Internal variables
  85
  86 ;; Stolen from w3.
  87 (defvar mm-url-html-entities
  88   '(
  89     ;;(excl        .  33)
  90     (quot        .  34)
  91     ;;(num         .  35)
  92     ;;(dollar      .  36)
  93     ;;(percent     .  37)
  94     (amp         .  38)
  95     (rsquo       .  39)                 ; should be U+8217
  96     ;;(apos        .  39)
  97     ;;(lpar        .  40)
  98     ;;(rpar        .  41)
  99     ;;(ast         .  42)
 100     ;;(plus        .  43)
 101     ;;(comma       .  44)
 102     ;;(period      .  46)
 103     ;;(colon       .  58)
 104     ;;(semi        .  59)
 105     (lt          .  60)
 106     ;;(equals      .  61)
 107     (gt          .  62)
 108     ;;(quest       .  63)
 109     ;;(commat      .  64)
 110     ;;(lsqb        .  91)
 111     ;;(rsqb        .  93)
 112     (uarr        .  94)                 ; should be U+8593
 113     ;;(lowbar      .  95)
 114     (lsquo       .  96)                 ; should be U+8216
 115     (lcub        . 123)
 116     ;;(verbar      . 124)
 117     (rcub        . 125)
 118     (tilde       . 126)
 119     (nbsp        . 160)
 120     (iexcl       . 161)
 121     (cent        . 162)
 122     (pound       . 163)
 123     (curren      . 164)
 124     (yen         . 165)
 125     (brvbar      . 166)
 126     (sect        . 167)
 127     (uml         . 168)
 128     (copy        . 169)
 129     (ordf        . 170)
 130     (laquo       . 171)
 131     (not         . 172)
 132     (shy         . 173)
 133     (reg         . 174)
 134     (macr        . 175)
 135     (deg         . 176)
 136     (plusmn      . 177)
 137     (sup2        . 178)
 138     (sup3        . 179)
 139     (acute       . 180)
 140     (micro       . 181)
 141     (para        . 182)
 142     (middot      . 183)
 143     (cedil       . 184)
 144     (sup1        . 185)
 145     (ordm        . 186)
 146     (raquo       . 187)
 147     (frac14      . 188)
 148     (frac12      . 189)
 149     (frac34      . 190)
 150     (iquest      . 191)
 151     (Agrave      . 192)
 152     (Aacute      . 193)
 153     (Acirc       . 194)
 154     (Atilde      . 195)
 155     (Auml        . 196)
 156     (Aring       . 197)
 157     (AElig       . 198)
 158     (Ccedil      . 199)
 159     (Egrave      . 200)
 160     (Eacute      . 201)
 161     (Ecirc       . 202)
 162     (Euml        . 203)
 163     (Igrave      . 204)
 164     (Iacute      . 205)
 165     (Icirc       . 206)
 166     (Iuml        . 207)
 167     (ETH         . 208)
 168     (Ntilde      . 209)
 169     (Ograve      . 210)
 170     (Oacute      . 211)
 171     (Ocirc       . 212)
 172     (Otilde      . 213)
 173     (Ouml        . 214)
 174     (times       . 215)
 175     (Oslash      . 216)
 176     (Ugrave      . 217)
 177     (Uacute      . 218)
 178     (Ucirc       . 219)
 179     (Uuml        . 220)
 180     (Yacute      . 221)
 181     (THORN       . 222)
 182     (szlig       . 223)
 183     (agrave      . 224)
 184     (aacute      . 225)
 185     (acirc       . 226)
 186     (atilde      . 227)
 187     (auml        . 228)
 188     (aring       . 229)
 189     (aelig       . 230)
 190     (ccedil      . 231)
 191     (egrave      . 232)
 192     (eacute      . 233)
 193     (ecirc       . 234)
 194     (euml        . 235)
 195     (igrave      . 236)
 196     (iacute      . 237)
 197     (icirc       . 238)
 198     (iuml        . 239)
 199     (eth         . 240)
 200     (ntilde      . 241)
 201     (ograve      . 242)
 202     (oacute      . 243)
 203     (ocirc       . 244)
 204     (otilde      . 245)
 205     (ouml        . 246)
 206     (divide      . 247)
 207     (oslash      . 248)
 208     (ugrave      . 249)
 209     (uacute      . 250)
 210     (ucirc       . 251)
 211     (uuml        . 252)
 212     (yacute      . 253)
 213     (thorn       . 254)
 214     (yuml        . 255)
 215
 216     ;; Special handling of these
 217     (frac56      . "5/6")
 218     (frac16      . "1/6")
 219     (frac45      . "4/5")
 220     (frac35      . "3/5")
 221     (frac25      . "2/5")
 222     (frac15      . "1/5")
 223     (frac23      . "2/3")
 224     (frac13      . "1/3")
 225     (frac78      . "7/8")
 226     (frac58      . "5/8")
 227     (frac38      . "3/8")
 228     (frac18      . "1/8")
 229
 230     ;; The following 5 entities are not mentioned in the HTML 2.0
 231     ;; standard, nor in any other HTML proposed standard of which I
 232     ;; am aware.  I am not even sure they are ISO entity names.  ***
 233     ;; Hence, some arrangement should be made to give a bad HTML
 234     ;; message when they are seen.
 235     (ndash       .  45)
 236     (mdash       .  45)
 237     (emsp        .  32)
 238     (ensp        .  32)
 239     (sim         . 126)
 240     (le          . "<=")
 241     (agr         . "alpha")
 242     (rdquo       . "''")
 243     (ldquo       . "``")
 244     (trade       . "(TM)")
 245     ;; To be done
 246     ;; (shy      . ????) ; soft hyphen
 247     )
 248   "An assoc list of entity names and how to actually display them.")
 249
 250 (defconst mm-url-unreserved-chars
 251   '(
 252     ?a ?b ?c ?d ?e ?f ?g ?h ?i ?j ?k ?l ?m ?n ?o ?p ?q ?r ?s ?t ?u ?v ?w ?x ?y ?z
 253     ?A ?B ?C ?D ?E ?F ?G ?H ?I ?J ?K ?L ?M ?N ?O ?P ?Q ?R ?S ?T ?U ?V ?W ?X ?Y ?Z
 254     ?0 ?1 ?2 ?3 ?4 ?5 ?6 ?7 ?8 ?9
 255     ?- ?_ ?. ?! ?~ ?* ?' ?\( ?\))
 256   "A list of characters that are _NOT_ reserved in the URL spec.
 257 This is taken from RFC 2396.")
 258
 259 (defun mm-url-load-url ()
 260   "Load `url-insert-file-contents'."
 261   (unless (condition-case ()
 262               (progn
 263                 (require 'url-handlers)
 264                 (require 'url-parse)
 265                 (require 'url-vars))
 266             (error nil))
 267     (require 'url)))
 268
 269 ;;;###autoload
 270 (defun mm-url-insert-file-contents (url)
 271   "Insert file contents of URL.
 272 If `mm-url-use-external' is non-nil, use `mm-url-program'."
 273   (if mm-url-use-external
 274       (progn
 275         (if (string-match "^file:/+" url)
 276             (insert-file-contents (substring url (1- (match-end 0))))
 277           (mm-url-insert-file-contents-external url))
 278         (goto-char (point-min))
 279         (setq url-current-object (url-generic-parse-url url))
 280         (list url (buffer-size)))
 281     (mm-url-load-url)
 282     (let ((name buffer-file-name)
 283           result)
 284       (setq result (url-insert-file-contents url))
 285       (save-excursion
 286         (goto-char (point-min))
 287         (while (re-search-forward "\r 1000\r ?" nil t)
 288           (replace-match "")))
 289       (setq buffer-file-name name)
 290       (when (listp result)
 291         (setq url-current-object
 292               (url-generic-parse-url (car result))))
 293       result)))
 294
 295 ;;;###autoload
 296 (defun mm-url-insert-file-contents-external (url)
 297   "Insert file contents of URL using `mm-url-program'."
 298   (let (program args)
 299     (if (symbolp mm-url-program)
 300         (let ((item (cdr (assq mm-url-program mm-url-predefined-programs))))
 301           (setq program (car item)
 302                 args (append (cdr item) (list url))))
 303       (setq program mm-url-program
 304             args (append mm-url-arguments (list url))))
 305     (unless (eq 0 (apply 'call-process program nil t nil args))
 306       (error "Couldn't fetch %s" url))))
 307
 308 (defvar mm-url-timeout 30
 309   "The number of seconds before timing out an URL fetch.")
 310
 311 (defvar mm-url-retries 10
 312   "The number of retries after timing out when fetching an URL.")
 313
 314 (defun mm-url-insert (url &optional follow-refresh)
 315   "Insert the contents from an URL in the current buffer.
 316 If FOLLOW-REFRESH is non-nil, redirect refresh url in META."
 317   (let ((times mm-url-retries)
 318         (done nil)
 319         (first t)
 320         result)
 321     (while (and (not (zerop (decf times)))
 322                 (not done))
 323       (with-timeout (mm-url-timeout)
 324         (unless first
 325           (message "Trying again (%s)..." (- mm-url-retries times)))
 326         (setq first nil)
 327         (if follow-refresh
 328             (save-restriction
 329               (narrow-to-region (point) (point))
 330               (mm-url-insert-file-contents url)
 331               (goto-char (point-min))
 332               (when (re-search-forward
 333                      "<meta[ \t\r\n]*http-equiv=\"Refresh\"[^>]*URL=\\([^\"]+\\)\"" nil t)
 334                 (let ((url (match-string 1)))
 335                   (delete-region (point-min) (point-max))
 336                   (setq result (mm-url-insert url t)))))
 337           (setq result (mm-url-insert-file-contents url)))
 338         (setq done t)))
 339     result))
 340
 341 (defun mm-url-decode-entities ()
 342   "Decode all HTML entities."
 343   (goto-char (point-min))
 344   (while (re-search-forward "&\\(#[0-9]+\\|#x[0-9a-f]+\\|[a-z]+[0-9]*\\);"
 345                             nil t)
 346     (let* ((entity (match-string 1))
 347            (elem (if (eq (aref entity 0) ?\#)
 348                      (let ((c
 349                             ;; Hex number: &#x3212
 350                             (if (eq (aref entity 1) ?x)
 351                                 (string-to-number (substring entity 2)
 352                                                   16)
 353                               ;; Decimal number: &#23
 354                               (string-to-number (substring entity 1)))))
 355                        (setq c (or (cdr (assq c mm-extra-numeric-entities))
 356                                    (mm-ucs-to-char c)))
 357                        (if (characterp c) c ?#))
 358                    (or (cdr (assq (intern entity)
 359                                   mm-url-html-entities))
 360                        ?#))))
 361       (unless (stringp elem)
 362         (setq elem (char-to-string elem)))
 363       (replace-match elem t t))))
 364
 365 (defun mm-url-decode-entities-nbsp ()
 366   "Decode all HTML entities and &nbsp; to a space."
 367   (let ((mm-url-html-entities (cons '(nbsp . 32) mm-url-html-entities)))
 368     (mm-url-decode-entities)))
 369
 370 (defun mm-url-decode-entities-string (string)
 371   (with-temp-buffer
 372     (insert string)
 373     (mm-url-decode-entities)
 374     (buffer-string)))
 375
 376 (defun mm-url-form-encode-xwfu (chunk)
 377   "Escape characters in a string for application/x-www-form-urlencoded.
 378 Blasphemous crap because someone didn't think %20 was good enough for encoding
 379 spaces.  Die Die Die."
 380   ;; This will get rid of the 'attributes' specified by the file type,
 381   ;; which are useless for an application/x-www-form-urlencoded form.
 382   (if (consp chunk)
 383       (setq chunk (cdr chunk)))
 384
 385   (if chunk
 386       (mapconcat
 387        (lambda (char)
 388          (cond
 389           ((= char ?  ) "+")
 390           ((memq char mm-url-unreserved-chars) (char-to-string char))
 391           (t (upcase (format "%%%02x" char)))))
 392        (encode-coding-string chunk (car (find-coding-systems-string chunk)))
 393        "")))
 394
 395 (defun mm-url-encode-www-form-urlencoded (pairs)
 396   "Return PAIRS encoded for forms."
 397   (mapconcat
 398    (lambda (data)
 399      (concat (mm-url-form-encode-xwfu (car data)) "="
 400              (mm-url-form-encode-xwfu (cdr data))))
 401    pairs "&"))
 402
 403 (autoload 'mml-compute-boundary "mml")
 404
 405 (defun mm-url-encode-multipart-form-data (data &optional boundary)
 406   "Return DATA encoded in multipart/form-data.
 407 DATA is a list where the elements can have the following form:
 408   (\"NAME\" . \"VALUE\")
 409   (\"submit\")
 410   (\"file\" . ((\"name\" . \"NAME\")
 411              (\"filename\" . \"FILENAME\")
 412              (\"content-type\" . \"CONTENT-TYPE\")
 413              (\"filedata\" . \"FILEDATA\")))
 414 Lowercase strings above are literals and uppercase are not."
 415   ;; RFC1867
 416   ;; Get a good boundary.
 417   (unless boundary
 418     (setq boundary (mml-compute-boundary '())))
 419   (with-temp-buffer
 420     (set-buffer-multibyte nil)
 421     (dolist (elem data)
 422       (let ((name (car elem))
 423             (value (cdr elem)))
 424         (insert "--" boundary "\r\n")
 425         (cond
 426          ((equal name "file")
 427           (insert (format
 428                    "Content-Disposition: form-data; name=%S; filename=%S\r\n"
 429                    (or (cdr (assoc "name" value)) name)
 430                    (cdr (assoc "filename" value))))
 431           (insert "Content-Transfer-Encoding: binary\r\n")
 432           (insert (format "Content-Type: %s\r\n\r\n"
 433                           (or (cdr (assoc "content-type" value))
 434                               "text/plain")))
 435           (let ((filedata (cdr (assoc "filedata" value))))
 436             (cond
 437              ((stringp filedata)
 438               (insert filedata))
 439              ;; How can this possibly be useful?
 440              ((integerp filedata)
 441               (insert (number-to-string filedata))))))
 442          ((equal name "submit")
 443           (insert
 444            "Content-Disposition: form-data; name=\"submit\"\r\n\r\nSubmit\r\n"))
 445          (t
 446           (insert (format "Content-Disposition: form-data; name=%S\r\n\r\n"
 447                           name))
 448           (insert value)))
 449         (unless (bolp)
 450           (insert "\r\n"))))
 451     (insert "--" boundary "--\r\n")
 452     (buffer-string)))
 453
 454 (defun mm-url-remove-markup ()
 455   "Remove all HTML markup, leaving just plain text."
 456   (goto-char (point-min))
 457   (while (search-forward "<!--" nil t)
 458     (delete-region (match-beginning 0)
 459                    (or (search-forward "-->" nil t)
 460                        (point-max))))
 461   (goto-char (point-min))
 462   (while (re-search-forward "<[^>]+>" nil t)
 463     (replace-match "" t t)))
 464
 465 (provide 'mm-url)
 466
 467 ;;; mm-url.el ends here