[Orgmode] [PATCH] better links to Gnus articles

[Tassilo Horn]

Hi Carsten and Org-crew,

here's the promised refactoring of org-gnus.el:

 - Rename org-usenet-links-prefer-google to org-gnus-prefer-web-links
 - Make that option work for gmane
 - Only make weblinks if the article is in a newsgroup
 - Only make weblinks if the article has no X-No-Archive header

There is little drawback:

 - Gnus stored some headers in an array and makes them instantly
   available.  Unfortunately that doesn't apply to X-No-Archive, so I
   have to select and widen the article buffer and parse anew.

   But I guess that's not a real problem...

So here's the patch:

>From b252dea93a851e42c649b94db08ea0b115712a6a Mon Sep 17 00:00:00 2001
From: Tassilo Horn <address@hidden>
Date: Tue, 18 Nov 2008 21:59:04 +0100
Subject: [PATCH] - Rename org-usenet-links-prefer-google to 
org-gnus-prefer-web-links
 - Make that option work for gmane
 - Only make weblinks if the article is in a newsgroup
 - Only make weblinks if the article has no X-No-Archive header

---
 lisp/org-gnus.el |   77 +++++++++++++++++++++++++++++++++--------------------
 lisp/org.el      |    2 +-
 2 files changed, 49 insertions(+), 30 deletions(-)

diff --git a/lisp/org-gnus.el b/lisp/org-gnus.el
index 851425e..42f7798 100644
--- a/lisp/org-gnus.el
+++ b/lisp/org-gnus.el
@@ -3,6 +3,7 @@
 ;; Copyright (C) 2004, 2005, 2006, 2007, 2008 Free Software Foundation, Inc.
 
 ;; Author: Carsten Dominik <carsten at orgmode dot org>
+;;         Tassilo Horn <tassilo at member dot fsf dot org>
 ;; Keywords: outlines, hypermedia, calendar, wp
 ;; Homepage: http://orgmode.org
 ;; Version: 6.12trans
@@ -37,7 +38,7 @@
 
 ;; Customization variables
 
-(defcustom org-usenet-links-prefer-google nil
+(defcustom org-gnus-prefer-web-links nil
   "Non-nil means, `org-store-link' will create web links to Google groups.
 When nil, Gnus will be used for such links.
 Using a prefix arg to the command \\[org-store-link] (`org-store-link')
@@ -45,6 +46,9 @@ negates this setting for the duration of the command."
   :group 'org-link-store
   :type 'boolean)
 
+(defvaralias 'org-usenet-links-prefer-google 'org-gnus-prefer-web-links
+  "Deprecated name for `org-gnus-prefer-web-links'.")
+
 ;; Declare external functions and variables
 (declare-function gnus-article-show-summary "gnus-art" ())
 (declare-function gnus-summary-last-subject "gnus-sum" ())
@@ -57,50 +61,65 @@ negates this setting for the duration of the command."
 (add-hook 'org-store-link-functions 'org-gnus-store-link)
 
 ;; Implementation
+
+(defun org-gnus-group-link (group)
+  (let ((unprefixed-group (replace-regexp-in-string "^[^:]+:" "" group)))
+    (if (and (string-match "^nntp" group) ;; Only for nntp groups
+            (org-xor current-prefix-arg
+                     org-gnus-prefer-web-links))
+       (concat (if (string-match "gmane" unprefixed-group)
+                   "http://news.gmane.org/";
+                 "http://groups.google.com/group/";)
+               unprefixed-group)
+      (concat "gnus:" group))))
+
+(defun org-gnus-article-link (group newsgroups message-id x-no-archive)
+  (if (and (org-xor current-prefix-arg org-gnus-prefer-web-links)
+          newsgroups     ;; Make web links only for nntp groups
+          (not x-no-archive)) ;; and if X-No-Archive isn't set.
+      (format (if (string-match "gmane\\." newsgroups)
+                 "http://mid.gmane.org/%s";
+               "http://groups.google.com/groups/search?as_umsgid=%s";)
+             (org-fixup-message-id-for-http
+              (replace-regexp-in-string "[<>]" "" message-id)))
+    (org-make-link "gnus:" group "#" message-id)))
+
 (defun org-gnus-store-link ()
   "Store a link to a Gnus folder or message."
   (cond
    ((eq major-mode 'gnus-group-mode)
-    (let ((group (cond ((fboundp 'gnus-group-group-name) ; depending on Gnus
-                       (gnus-group-group-name))         ; version
-                      ((fboundp 'gnus-group-name)
-                       (gnus-group-name))
-                      (t "???")))
-         desc link)
+    (let* ((group (cond ((fboundp 'gnus-group-group-name) ; depending on Gnus
+                        (gnus-group-group-name))         ; version
+                       ((fboundp 'gnus-group-name)
+                        (gnus-group-name))
+                       (t "???")))
+          desc link)
       (unless group (error "Not on a group"))
       (org-store-link-props :type "gnus" :group group)
-      (setq desc (concat
-                 (if (org-xor current-prefix-arg
-                              org-usenet-links-prefer-google)
-                     "http://groups.google.com/groups?group=";
-                   "gnus:")
-                 group)
+      (setq desc (org-gnus-group-link group)
            link (org-make-link desc))
       (org-add-link-props :link link :description desc)
       link))
 
    ((memq major-mode '(gnus-summary-mode gnus-article-mode))
-    (and (eq major-mode 'gnus-article-mode) (gnus-article-show-summary))
+    (and (eq major-mode 'gnus-summary-mode) (gnus-summary-show-article))
     (let* ((group gnus-newsgroup-name)
-          (article (gnus-summary-article-number))
-          (header (gnus-summary-article-header article))
-          (from (mail-header-from header))
-          (message-id (mail-header-id header))
-          (date (mail-header-date header))
-          (extra (mail-header-extra header))
-          (to (cdr (assoc 'To extra)))
+          (header (with-current-buffer gnus-article-buffer
+                    (gnus-summary-toggle-header 1)
+                    (goto-char (point-min))
+                    (mail-header-extract-no-properties)))
+          (from (mail-header 'from header))
+          (message-id (mail-header 'message-id header))
+          (date (mail-header 'date header))
+          (to (mail-header 'to header))
+          (newsgroups (mail-header 'newsgroups header))
+          (x-no-archive (mail-header 'x-no-archive header))
           (subject (gnus-summary-subject-string))
           desc link)
       (org-store-link-props :type "gnus" :from from :subject subject
                            :message-id message-id :group group :to to)
-      (setq desc (org-email-link-description))
-      (if (org-xor current-prefix-arg org-usenet-links-prefer-google)
-         (setq link
-               (format "http://groups.google.com/groups?as_umsgid=%s";
-                       (org-fixup-message-id-for-http message-id)))
-       (setq link (org-make-link "gnus:" group "#"
-                                 (or message-id
-                                     (number-to-string article)))))
+      (setq desc (org-email-link-description)
+           link (org-gnus-article-link group newsgroups message-id 
x-no-archive))
       (org-add-link-props :link link :description desc)
       link))))
 
diff --git a/lisp/org.el b/lisp/org.el
index b660f96..1390fc4 100644
--- a/lisp/org.el
+++ b/lisp/org.el
@@ -6082,7 +6082,7 @@ This link is added to `org-stored-links' and can later be 
inserted
 into an org-buffer with \\[org-insert-link].
 
 For some link types, a prefix arg is interpreted:
-For links to usenet articles, arg negates `org-usenet-links-prefer-google'.
+For links to usenet articles, arg negates `org-gnus-prefer-web-links'.
 For file links, arg negates `org-context-in-file-links'."
   (interactive "P")
   (org-load-modules-maybe)
-- 
1.6.0.4

Bye,
Tassilo
-- 
Some  people check  their  computers for  viruses.  Viruses check  their
computers for Richard Stallman.