gnus: RSS
6.5.3 RSS
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Some web sites have an RDF Site Summary (RSS). RSS is a format for
summarizing headlines from news related sites (such as BBC or CNN). But
basically anything list-like can be presented as an RSS feed: weblogs,
changelogs or recent changes to a wiki (e.g.,
<http://cliki.net/site/recent-changes>).
RSS has a quite regular and nice interface, and it’s possible to get
the information Gnus needs to keep groups updated.
Note: you had better use Emacs which supports the ‘utf-8’ coding
system because RSS uses UTF-8 for encoding non-ASCII text by default.
It is also used by default for non-ASCII group names.
Use ‘G R’ from the group buffer to subscribe to a feed—you will be
prompted for the location, the title and the description of the feed.
The title, which allows any characters, will be used for the group name
and the name of the group data file. The description can be omitted.
An easy way to get started with ‘nnrss’ is to say something like the
following in the group buffer: ‘B nnrss RET RET y’, then subscribe to
groups.
The ‘nnrss’ back end saves the group data file in ‘nnrss-directory’
(see below) for each ‘nnrss’ group. File names containing non-ASCII
characters will be encoded by the coding system specified with the
‘nnmail-pathname-coding-system’ variable or other. Also Non-ASCII
Group Names, for more information.
The ‘nnrss’ back end generates ‘multipart/alternative’ MIME articles
in which each contains a ‘text/plain’ part and a ‘text/html’ part.
You can also use the following commands to import and export your
subscriptions from a file in OPML format (Outline Processor Markup
Language).
-- Function: nnrss-opml-import file
Prompt for an OPML file, and subscribe to each feed in the file.
-- Function: nnrss-opml-export
Write your current RSS subscriptions to a buffer in OPML format.
The following ‘nnrss’ variables can be altered:
‘nnrss-directory’
The directory where ‘nnrss’ stores its files. The default is
‘~/News/rss/’.
‘nnrss-file-coding-system’
The coding system used when reading and writing the ‘nnrss’ groups
data files. The default is the value of
‘mm-universal-coding-system’ (which defaults to ‘emacs-mule’ in
Emacs or ‘escape-quoted’ in XEmacs).
‘nnrss-ignore-article-fields’
Some feeds update constantly article fields during their
publications, e.g., to indicate the number of comments. However,
if there is a difference between the local article and the distant
one, the latter is considered to be new. To avoid this and discard
some fields, set this variable to the list of fields to be ignored.
The default is ‘'(slash:comments)’.
‘nnrss-use-local’
If you set ‘nnrss-use-local’ to ‘t’, ‘nnrss’ will read the feeds
from local files in ‘nnrss-directory’. You can use the command
‘nnrss-generate-download-script’ to generate a download script
using ‘wget’.
The following code may be helpful, if you want to show the
description in the summary buffer.
(add-to-list 'nnmail-extra-headers nnrss-description-field)
(setq gnus-summary-line-format "%U%R%z%I%(%[%4L: %-15,15f%]%) %s%uX\n")
(defun gnus-user-format-function-X (header)
(let ((descr
(assq nnrss-description-field (mail-header-extra header))))
(if descr (concat "\n\t" (cdr descr)) "")))
The following code may be useful to open an nnrss url directly from
the summary buffer.
(require 'browse-url)
(defun browse-nnrss-url (arg)
(interactive "p")
(let ((url (assq nnrss-url-field
(mail-header-extra
(gnus-data-header
(assq (gnus-summary-article-number)
gnus-newsgroup-data))))))
(if url
(progn
(browse-url (cdr url))
(gnus-summary-mark-as-read-forward 1))
(gnus-summary-scroll-up arg))))
(with-eval-after-load "gnus"
(define-key gnus-summary-mode-map
(kbd "<RET>") 'browse-nnrss-url))
(add-to-list 'nnmail-extra-headers nnrss-url-field)
Even if you have added ‘text/html’ to the
‘mm-discouraged-alternatives’ variable (Display Customization
(emacs-mime)Display Customization.) since you don’t want to see HTML
parts, it might be more useful especially in ‘nnrss’ groups to display
‘text/html’ parts. Here’s an example of setting
Parameters::) in order to display ‘text/html’ parts only in ‘nnrss’
groups:
;; Set the default value of ‘mm-discouraged-alternatives’.
(with-eval-after-load "gnus-sum"
(add-to-list
'gnus-newsgroup-variables
'(mm-discouraged-alternatives
. '("text/html" "image/.*"))))
;; Display ‘text/html’ parts in ‘nnrss’ groups.
(add-to-list
'gnus-parameters
'("\\`nnrss:" (mm-discouraged-alternatives nil)))