;;; ol-gnus.el --- Links to Gnus Groups and Messages -*- lexical-binding: t; -*-
;; Copyright (C) 2004-2020 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: https://orgmode.org
;;
;; This file is part of GNU Emacs.
;;
;; GNU Emacs is free software: you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;; the Free Software Foundation, either version 3 of the License, or
;; (at your option) any later version.
;; GNU Emacs is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
;; GNU General Public License for more details.
;; You should have received a copy of the GNU General Public License
;; along with GNU Emacs. If not, see <https://www.gnu.org/licenses/>.
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;
;;; Commentary:
;; This file implements links to Gnus groups and messages from within Org.
;; Org mode loads this module by default - if this is not what you want,
;; configure the variable `org-modules'.
;;; Code:
(require 'gnus-sum)
(require 'gnus-util)
(require 'nnheader)
(require 'nnselect)
(require 'ol)
;;; Declare external functions and variables
(declare-function gnus-activate-group "gnus-start" (group &optional scan dont-check method dont-sub-check))
(declare-function gnus-find-method-for-group "gnus" (group &optional info))
(declare-function gnus-article-show-summary "gnus-art" ())
(declare-function gnus-group-group-name "gnus-group")
(declare-function gnus-group-jump-to-group "gnus-group" (group &optional prompt))
(declare-function gnus-group-read-group "gnus-group" (&optional all no-article group select-articles))
(declare-function message-fetch-field "message" (header &optional not-all))
(declare-function message-generate-headers "message" (headers))
(declare-function message-narrow-to-headers "message")
(declare-function message-tokenize-header "message" (header &optional separator))
(declare-function message-unquote-tokens "message" (elems))
(declare-function nnvirtual-map-article "nnvirtual" (article))
(defvar gnus-newsgroup-name)
(defvar gnus-summary-buffer)
(defvar gnus-other-frame-object)
;;; Customization variables
(defcustom org-gnus-prefer-web-links nil
"If non-nil, `org-store-link' creates web links to Google groups or Gmane.
\\<org-mode-map>When nil, Gnus will be used for such links.
Using a prefix argument to the command `\\[org-store-link]' (`org-store-link')
negates this setting for the duration of the command."
:group 'org-link-store
:type 'boolean)
(defcustom org-gnus-no-server nil
"Should Gnus be started using `gnus-no-server'?"
:group 'org-gnus
:version "24.4"
:package-version '(Org . "8.0")
:type 'boolean)
;;; Install the link type
(org-link-set-parameters "gnus"
:follow #'org-gnus-open
:store #'org-gnus-store-link)
;;; Implementation
(defun org-gnus-group-link (group)
"Create a link to the Gnus group GROUP.
If GROUP is a newsgroup and `org-gnus-prefer-web-links' is
non-nil, create a link to groups.google.com or gmane.org.
Otherwise create a link to the group inside Gnus.
If `org-store-link' was called with a prefix arg the meaning of
`org-gnus-prefer-web-links' is reversed."
(let ((unprefixed-group (replace-regexp-in-string "^[^:]+:" "" group)))
(if (and (string-prefix-p "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)
"Create a link to a Gnus article.
The article is specified by its MESSAGE-ID. Additional
parameters are the Gnus GROUP, the NEWSGROUPS the article was
posted to and the X-NO-ARCHIVE header value of that article.
If GROUP is a newsgroup and `org-gnus-prefer-web-links' is
non-nil, create a link to groups.google.com or gmane.org.
Otherwise create a link to the article inside Gnus.
If `org-store-link' was called with a prefix arg the meaning of
`org-gnus-prefer-web-links' is reversed."
(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-p "gmane\\." newsgroups)
"http://mid.gmane.org/%s"
"http://groups.google.com/groups/search?as_umsgid=%s")
(url-encode-url message-id))
(concat "gnus:" group "#" message-id)))
(defun org-gnus-store-link ()
"Store a link to a Gnus folder or message."
(pcase major-mode
(`gnus-group-mode
(let ((group (gnus-group-group-name)))
(when group
(org-link-store-props :type "gnus" :group group)
(let ((description (org-gnus-group-link group)))
(org-link-add-props :link description :description description)
description))))
((or `gnus-summary-mode `gnus-article-mode)
(let* ((group
(pcase (gnus-find-method-for-group gnus-newsgroup-name)
(`(nnvirtual . ,_)
(save-excursion
(car (nnvirtual-map-article (gnus-summary-article-number)))))
(`(nnselect . ,_)
(save-excursion
(nnselect-article-group (gnus-summary-article-number))))
(_ gnus-newsgroup-name)))
(header (if (eq major-mode 'gnus-article-mode)
;; When in an article, first move to summary
;; buffer, with point on the summary of the
;; current article before extracting headers.
(save-window-excursion
(save-excursion
(gnus-article-show-summary)
(gnus-summary-article-header)))
(gnus-summary-article-header)))
(from (mail-header-from header))
(message-id (org-unbracket-string "<" ">" (mail-header-id header)))
(date (org-trim (mail-header-date header)))
;; Remove text properties of subject string to avoid Emacs
;; bug #3506.
(subject (org-no-properties
(copy-sequence (mail-header-subject header))))
(to (cdr (assq 'To (mail-header-extra header))))
newsgroups x-no-archive)
;; Fetching an article is an expensive operation; newsgroup and
;; x-no-archive are only needed for web links.
(when (org-xor current-prefix-arg org-gnus-prefer-web-links)
;; Make sure the original article buffer is up-to-date.
(save-window-excursion (gnus-summary-select-article))
(setq to (or to (gnus-fetch-original-field "To")))
(setq newsgroups (gnus-fetch-original-field "Newsgroups"))
(setq x-no-archive (gnus-fetch-original-field "x-no-archive")))
(org-link-store-props :type "gnus" :from from :date date :subject subject
:message-id message-id :group group :to to)
(let ((link (org-gnus-article-link
group newsgroups message-id x-no-archive))
(description (org-link-email-description)))
(org-link-add-props :link link :description description)
link)))
(`message-mode
(setq org-store-link-plist nil) ;reset
(save-excursion
(save-restriction
(message-narrow-to-headers)
(unless (message-fetch-field "Message-ID")
(message-generate-headers '(Message-ID)))
(goto-char (point-min))
(re-search-forward "^Message-ID:" nil t)
(put-text-property (line-beginning-position) (line-end-position)
'message-deletable nil)
(let ((gcc (org-last (message-unquote-tokens
(message-tokenize-header
(mail-fetch-field "gcc" nil t) " ,"))))
(id (org-unbracket-string "<" ">"
(mail-fetch-field "Message-ID")))
(to (mail-fetch-field "To"))
(from (mail-fetch-field "From"))
(subject (mail-fetch-field "Subject"))
newsgroup xarchive) ;those are always nil for gcc
(unless gcc (error "Can not create link: No Gcc header found"))
(org-link-store-props :type "gnus" :from from :subject subject
:message-id id :group gcc :to to)
(let ((link (org-gnus-article-link gcc newsgroup id xarchive))
(description (org-link-email-description)))
(org-link-add-props :link link :description description)
link)))))))
(defun org-gnus-open-nntp (path)
"Follow the nntp: link specified by PATH."
(let* ((spec (split-string path "/"))
(server (split-string (nth 2 spec) "@"))
(group (nth 3 spec))
(article (nth 4 spec)))
(org-gnus-follow-link
(format "nntp+%s:%s" (or (cdr server) (car server)) group)
article)))
(defun org-gnus-open (path)
"Follow the Gnus message or folder link specified by PATH."
(unless (string-match "\\`\\([^#]+\\)\\(#\\(.*\\)\\)?" path)
(error "Error in Gnus link %S" path))
(let ((group (match-string-no-properties 1 path))
(article (match-string-no-properties 3 path)))
(org-gnus-follow-link group article)))
(defun org-gnus-follow-link (&optional group article)
"Follow a Gnus link to GROUP and ARTICLE."
(require 'gnus)
(funcall (cdr (assq 'gnus org-link-frame-setup)))
(when gnus-other-frame-object (select-frame gnus-other-frame-object))
(let ((group (org-no-properties group))
(article (org-no-properties article)))
(cond
((and group article)
(gnus-activate-group group)
(condition-case nil
(let ((msg "Couldn't follow Gnus link. Summary couldn't be opened."))
(pcase (gnus-find-method-for-group group)
(`(nndoc . ,_)
(if (gnus-group-read-group t nil group)
(gnus-summary-goto-article article nil t)
(message msg)))
(_
(let ((articles 1)
group-opened)
(while (and (not group-opened)
;; Stop on integer overflows. Note: We
;; can drop this once we require at least
;; Emacs 27, which supports bignums.
(> articles 0))
(setq group-opened (gnus-group-read-group articles t group))
(setq articles (if (< articles 16)
(1+ articles)
(* articles 2))))
(if group-opened
(gnus-summary-goto-article article nil t)
(message msg))))))
(quit
(message "Couldn't follow Gnus link. The linked group is empty."))))
(group (gnus-group-jump-to-group group)))))
(defun org-gnus-no-new-news ()
"Like `\\[gnus]' but doesn't check for new news."
(cond ((gnus-alive-p) nil)
(org-gnus-no-server (gnus-no-server))
(t (gnus))))
(provide 'ol-gnus)
;;; ol-gnus.el ends here