lisp/gnus/gnus-nocem.el

   1 ;;; gnus-nocem.el --- NoCeM pseudo-cancellation treatment
   2
   3 ;; Copyright (C) 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004,
   4 ;;   2005, 2006, 2007, 2008 Free Software Foundation, Inc.
   5
   6 ;; Author: Lars Magne Ingebrigtsen <larsi@gnus.org>
   7 ;; Keywords: news
   8
   9 ;; This file is part of GNU Emacs.
  10
  11 ;; GNU Emacs is free software; you can redistribute it and/or modify
  12 ;; it under the terms of the GNU General Public License as published by
  13 ;; the Free Software Foundation; either version 3, or (at your option)
  14 ;; any later version.
  15
  16 ;; GNU Emacs is distributed in the hope that it will be useful,
  17 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  18 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19 ;; GNU General Public License for more details.
  20
  21 ;; You should have received a copy of the GNU General Public License
  22 ;; along with GNU Emacs; see the file COPYING.  If not, write to the
  23 ;; Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  24 ;; Boston, MA 02110-1301, USA.
  25
  26 ;;; Commentary:
  27
  28 ;;; Code:
  29
  30 (eval-when-compile (require 'cl))
  31
  32 (require 'gnus)
  33 (require 'nnmail)
  34 (require 'gnus-art)
  35 (require 'gnus-sum)
  36 (require 'gnus-range)
  37
  38 (defgroup gnus-nocem nil
  39   "NoCeM pseudo-cancellation treatment."
  40   :group 'gnus-score)
  41
  42 (defcustom gnus-nocem-groups
  43   '("news.lists.filters" "news.admin.net-abuse.bulletins"
  44     "alt.nocem.misc" "news.admin.net-abuse.announce")
  45   "*List of groups that will be searched for NoCeM messages."
  46   :group 'gnus-nocem
  47   :type '(repeat (string :tag "Group")))
  48
  49 (defcustom gnus-nocem-issuers
  50   '("AutoMoose-1"                       ; CancelMoose[tm]
  51     "clewis@ferret.ocunix"              ; Chris Lewis
  52     "cosmo.roadkill"
  53     "SpamHippo"
  54     "hweede@snafu.de")
  55   "*List of NoCeM issuers to pay attention to.
  56
  57 This can also be a list of `(ISSUER CONDITION ...)' elements.
  58
  59 See <URL:http://www.xs4all.nl/~rosalind/nocemreg/nocemreg.html> for an
  60 issuer registry."
  61   :group 'gnus-nocem
  62   :link '(url-link "http://www.xs4all.nl/~rosalind/nocemreg/nocemreg.html")
  63   :type '(repeat (choice string sexp)))
  64
  65 (defcustom gnus-nocem-directory
  66   (nnheader-concat gnus-article-save-directory "NoCeM/")
  67   "*Directory where NoCeM files will be stored."
  68   :group 'gnus-nocem
  69   :type 'directory)
  70
  71 (defcustom gnus-nocem-expiry-wait 15
  72   "*Number of days to keep NoCeM headers in the cache."
  73   :group 'gnus-nocem
  74   :type 'integer)
  75
  76 (defcustom gnus-nocem-verifyer 'pgg-verify
  77   "*Function called to verify that the NoCeM message is valid.
  78 One likely value is `pgg-verify'.  If the function in this variable
  79 isn't bound, the message will be used unconditionally."
  80   :group 'gnus-nocem
  81   :type '(radio (function-item pgg-verify)
  82                 (function-item mc-verify)
  83                 (function :tag "other")))
  84
  85 (defcustom gnus-nocem-liberal-fetch nil
  86   "*If t try to fetch all messages which have @@NCM in the subject.
  87 Otherwise don't fetch messages which have references or whose message-id
  88 matches a previously scanned and verified nocem message."
  89   :group 'gnus-nocem
  90   :type 'boolean)
  91
  92 (defcustom gnus-nocem-check-article-limit 500
  93   "*If non-nil, the maximum number of articles to check in any NoCeM group."
  94   :group 'gnus-nocem
  95   :version "21.1"
  96   :type '(choice (const :tag "unlimited" nil)
  97                  (integer 1000)))
  98
  99 (defcustom gnus-nocem-check-from t
 100   "Non-nil means check for valid issuers in message bodies.
 101 Otherwise don't bother fetching articles unless their author matches a
 102 valid issuer, which is much faster if you are selective about the issuers."
 103   :group 'gnus-nocem
 104   :version "21.1"
 105   :type 'boolean)
 106
 107 ;;; Internal variables
 108
 109 (defvar gnus-nocem-active nil)
 110 (defvar gnus-nocem-alist nil)
 111 (defvar gnus-nocem-touched-alist nil)
 112 (defvar gnus-nocem-hashtb nil)
 113 (defvar gnus-nocem-seen-message-ids nil)
 114
 115 ;;; Functions
 116
 117 (defun gnus-nocem-active-file ()
 118   (concat (file-name-as-directory gnus-nocem-directory) "active"))
 119
 120 (defun gnus-nocem-cache-file ()
 121   (concat (file-name-as-directory gnus-nocem-directory) "cache"))
 122
 123 ;;
 124 ;; faster lookups for group names:
 125 ;;
 126
 127 (defvar gnus-nocem-real-group-hashtb nil
 128   "Real-name mappings of subscribed groups.")
 129
 130 (defun gnus-fill-real-hashtb ()
 131   "Fill up a hash table with the real-name mappings from the user's active file."
 132   (if (hash-table-p gnus-nocem-real-group-hashtb)
 133       (clrhash gnus-nocem-real-group-hashtb)
 134     (setq gnus-nocem-real-group-hashtb (make-hash-table :test 'equal)))
 135   (mapcar (lambda (group)
 136             (setq group (gnus-group-real-name (car group)))
 137             (puthash group t gnus-nocem-real-group-hashtb))
 138           gnus-newsrc-alist))
 139
 140 ;;;###autoload
 141 (defun gnus-nocem-scan-groups ()
 142   "Scan all NoCeM groups for new NoCeM messages."
 143   (interactive)
 144   (let ((groups gnus-nocem-groups)
 145         (gnus-inhibit-demon t)
 146         group active gactive articles check-headers)
 147     (gnus-make-directory gnus-nocem-directory)
 148     ;; Load any previous NoCeM headers.
 149     (gnus-nocem-load-cache)
 150     ;; Get the group name mappings:
 151     (gnus-fill-real-hashtb)
 152     ;; Read the active file if it hasn't been read yet.
 153     (and (file-exists-p (gnus-nocem-active-file))
 154          (not gnus-nocem-active)
 155          (ignore-errors
 156            (load (gnus-nocem-active-file) t t t)))
 157     ;; Go through all groups and see whether new articles have
 158     ;; arrived.
 159     (while (setq group (pop groups))
 160       (if (not (setq gactive (gnus-activate-group group)))
 161           ()                            ; This group doesn't exist.
 162         (setq active (nth 1 (assoc group gnus-nocem-active)))
 163         (when (and (not (< (cdr gactive) (car gactive))) ; Empty group.
 164                    (or (not active)
 165                        (< (cdr active) (cdr gactive))))
 166           ;; Ok, there are new articles in this group, se we fetch the
 167           ;; headers.
 168           (save-excursion
 169             (let ((dependencies (make-vector 10 nil))
 170                   headers header)
 171               (with-temp-buffer
 172                 (setq headers
 173                       (if (eq 'nov
 174                               (gnus-retrieve-headers
 175                                (setq articles
 176                                      (gnus-uncompress-range
 177                                       (cons
 178                                        (if active (1+ (cdr active))
 179                                          (car gactive))
 180                                        (cdr gactive))))
 181                                group))
 182                           (gnus-get-newsgroup-headers-xover
 183                            articles nil dependencies)
 184                         (gnus-get-newsgroup-headers dependencies)))
 185                 (while (setq header (pop headers))
 186                   ;; We take a closer look on all articles that have
 187                   ;; "@@NCM" in the subject.  Unless we already read
 188                   ;; this cross posted message.  Nocem messages
 189                   ;; are not allowed to have references, so we can
 190                   ;; ignore scanning followups.
 191                   (and (string-match "@@NCM" (mail-header-subject header))
 192                        (and gnus-nocem-check-from
 193                             (let ((case-fold-search t))
 194                               (catch 'ok
 195                                 (mapc
 196                                  (lambda (author)
 197                                    (if (consp author)
 198                                        (setq author (car author)))
 199                                    (if (string-match
 200                                         author (mail-header-from header))
 201                                        (throw 'ok t)))
 202                                  gnus-nocem-issuers)
 203                                 nil)))
 204                        (or gnus-nocem-liberal-fetch
 205                            (and (or (string= "" (mail-header-references
 206                                                  header))
 207                                     (null (mail-header-references header)))
 208                                 (not (member (mail-header-message-id header)
 209                                              gnus-nocem-seen-message-ids))))
 210                        (push header check-headers)))
 211                 (setq check-headers (last (nreverse check-headers)
 212                                           gnus-nocem-check-article-limit))
 213                 (let ((i 0)
 214                       (len (length check-headers)))
 215                   (dolist (h check-headers)
 216                     (gnus-message
 217                      7 "Checking article %d in %s for NoCeM (%d of %d)..."
 218                      (mail-header-number h) group (incf i) len)
 219                     (gnus-nocem-check-article group h)))))))
 220         (setq gnus-nocem-active
 221               (cons (list group gactive)
 222                     (delq (assoc group gnus-nocem-active)
 223                           gnus-nocem-active)))))
 224     ;; Save the results, if any.
 225     (gnus-nocem-save-cache)
 226     (gnus-nocem-save-active)))
 227
 228 (defun gnus-nocem-check-article (group header)
 229   "Check whether the current article is an NCM article and that we want it."
 230   ;; Get the article.
 231   (let ((date (mail-header-date header))
 232         (gnus-newsgroup-name group)
 233         issuer b e type)
 234     (when (or (not date)
 235               (time-less-p
 236                (time-since (date-to-time date))
 237                (days-to-time gnus-nocem-expiry-wait)))
 238       (gnus-request-article-this-buffer (mail-header-number header) group)
 239       (goto-char (point-min))
 240       (when (re-search-forward
 241              "-----BEGIN PGP\\(?: SIGNED\\)? MESSAGE-----"
 242              nil t)
 243         (delete-region (point-min) (match-beginning 0)))
 244       (when (re-search-forward
 245              "-----END PGP \\(?:MESSAGE\\|SIGNATURE\\)-----\n?"
 246              nil t)
 247         (delete-region (match-end 0) (point-max)))
 248       (goto-char (point-min))
 249       ;; The article has to have proper NoCeM headers.
 250       (when (and (setq b (search-forward "\n@@BEGIN NCM HEADERS\n" nil t))
 251                  (setq e (search-forward "\n@@BEGIN NCM BODY\n" nil t)))
 252         ;; We get the name of the issuer.
 253         (narrow-to-region b e)
 254         (setq issuer (mail-fetch-field "issuer")
 255               type (mail-fetch-field "type"))
 256         (widen)
 257         (if (not (gnus-nocem-message-wanted-p issuer type))
 258             (message "invalid NoCeM issuer: %s" issuer)
 259           (and (gnus-nocem-verify-issuer issuer) ; She is who she says she is.
 260                (gnus-nocem-enter-article) ; We gobble the message.
 261                (push (mail-header-message-id header) ; But don't come back for
 262                      gnus-nocem-seen-message-ids))))))) ; second helpings.
 263
 264 (defun gnus-nocem-message-wanted-p (issuer type)
 265   (let ((issuers gnus-nocem-issuers)
 266         wanted conditions condition)
 267     (cond
 268      ;; Do the quick check first.
 269      ((member issuer issuers)
 270       t)
 271      ((setq conditions (cdr (assoc issuer issuers)))
 272       ;; Check whether we want this type.
 273       (while (setq condition (pop conditions))
 274         (cond
 275          ((stringp condition)
 276           (when (string-match condition type)
 277             (setq wanted t)))
 278          ((and (consp condition)
 279                (eq (car condition) 'not)
 280                (stringp (cadr condition)))
 281           (when (string-match (cadr condition) type)
 282             (setq wanted nil)))
 283          (t
 284           (error "Invalid NoCeM condition: %S" condition))))
 285       wanted))))
 286
 287 (defun gnus-nocem-verify-issuer (person)
 288   "Verify using PGP that the canceler is who she says she is."
 289   (if (functionp gnus-nocem-verifyer)
 290       (ignore-errors
 291         (funcall gnus-nocem-verifyer))
 292     ;; If we don't have Mailcrypt, then we use the message anyway.
 293     t))
 294
 295 (defun gnus-nocem-enter-article ()
 296   "Enter the current article into the NoCeM cache."
 297   (goto-char (point-min))
 298   (let ((b (search-forward "\n@@BEGIN NCM BODY\n" nil t))
 299         (e (search-forward "\n@@END NCM BODY\n" nil t))
 300         (buf (current-buffer))
 301         ncm id group)
 302     (when (and b e)
 303       (narrow-to-region b (1+ (match-beginning 0)))
 304       (goto-char (point-min))
 305       (while (search-forward "\t" nil t)
 306         (cond
 307          ((not (ignore-errors
 308                  (setq group (gnus-group-real-name (symbol-name (read buf))))
 309                  (gethash group gnus-nocem-real-group-hashtb)))
 310           ;; An error.
 311           )
 312          (t
 313           ;; Valid group.
 314           (beginning-of-line)
 315           (while (eq (char-after) ?\t)
 316             (forward-line -1))
 317           (setq id (buffer-substring (point) (1- (search-forward "\t"))))
 318           (unless (if (hash-table-p gnus-nocem-hashtb)
 319                       (gethash id gnus-nocem-hashtb)
 320                     (setq gnus-nocem-hashtb (make-hash-table :test 'equal))
 321                     nil)
 322             ;; only store if not already present
 323             (puthash id t gnus-nocem-hashtb)
 324             (push id ncm))
 325           (forward-line 1)
 326           (while (eq (char-after) ?\t)
 327             (forward-line 1)))))
 328       (when ncm
 329         (setq gnus-nocem-touched-alist t)
 330         (push (cons (let ((time (current-time))) (setcdr (cdr time) nil) time)
 331                     ncm)
 332               gnus-nocem-alist))
 333       t)))
 334
 335 ;;;###autoload
 336 (defun gnus-nocem-load-cache ()
 337   "Load the NoCeM cache."
 338   (interactive)
 339   (unless gnus-nocem-alist
 340     ;; The buffer doesn't exist, so we create it and load the NoCeM
 341     ;; cache.
 342     (when (file-exists-p (gnus-nocem-cache-file))
 343       (load (gnus-nocem-cache-file) t t t)
 344       (gnus-nocem-alist-to-hashtb))))
 345
 346 (defun gnus-nocem-save-cache ()
 347   "Save the NoCeM cache."
 348   (when (and gnus-nocem-alist
 349              gnus-nocem-touched-alist)
 350     (with-temp-file (gnus-nocem-cache-file)
 351       (gnus-prin1 `(setq gnus-nocem-alist ',gnus-nocem-alist)))
 352     (setq gnus-nocem-touched-alist nil)))
 353
 354 (defun gnus-nocem-save-active ()
 355   "Save the NoCeM active file."
 356   (with-temp-file (gnus-nocem-active-file)
 357     (gnus-prin1 `(setq gnus-nocem-active ',gnus-nocem-active))))
 358
 359 (defun gnus-nocem-alist-to-hashtb ()
 360   "Create a hashtable from the Message-IDs we have."
 361   (let* ((alist gnus-nocem-alist)
 362          (pprev (cons nil alist))
 363          (prev pprev)
 364          (expiry (days-to-time gnus-nocem-expiry-wait))
 365          entry)
 366     (if (hash-table-p gnus-nocem-hashtb)
 367         (clrhash gnus-nocem-hashtb)
 368       (setq gnus-nocem-hashtb (make-hash-table :test 'equal)))
 369     (while (setq entry (car alist))
 370       (if (not (time-less-p (time-since (car entry)) expiry))
 371           ;; This entry has expired, so we remove it.
 372           (setcdr prev (cdr alist))
 373         (setq prev alist)
 374         ;; This is ok, so we enter it into the hashtable.
 375         (setq entry (cdr entry))
 376         (while entry
 377           (puthash (car entry) t gnus-nocem-hashtb)
 378           (setq entry (cdr entry))))
 379       (setq alist (cdr alist)))))
 380
 381 (gnus-add-shutdown 'gnus-nocem-close 'gnus)
 382
 383 (defun gnus-nocem-close ()
 384   "Clear internal NoCeM variables."
 385   (setq gnus-nocem-alist nil
 386         gnus-nocem-hashtb nil
 387         gnus-nocem-active nil
 388         gnus-nocem-touched-alist nil
 389         gnus-nocem-seen-message-ids nil
 390         gnus-nocem-real-group-hashtb nil))
 391
 392 (defun gnus-nocem-unwanted-article-p (id)
 393   "Say whether article ID in the current group is wanted."
 394   (and gnus-nocem-hashtb
 395        (gethash id gnus-nocem-hashtb)))
 396
 397 (provide 'gnus-nocem)
 398
 399 ;; arch-tag: 0e0c74ea-2f8e-4f3e-8fff-09f767c1adef
 400 ;;; gnus-nocem.el ends here