atom.el – An elisp library for creating Atom feeds

The my-atom-feed object in the example above is really only an XML tree as defined by the xml.el package. This means you can manipulate it, as long as you are careful when manipulating the XML structure. For instance, if you want to add somebody as a contributor to an entry, and also add an lang attribute, you could say the following:

(let ((entry (atom-add-html-entry my-atom-feed
                                  "Witty title"
                                  "http://example.org/witty"
                                  "<p>This is <i>clever</i>, isn't it?")))
  (atom-modify-entry entry 'contributor
                     (atom-massage-author '("John Clever" "jc@example.net")))
  (let* ((content (assoc 'content entry))
         (attrs (xml-node-attributes entry)))
    (setcar (cdr entry) (cons '(lang . "en") attrs))))

As of now, the library doesn't check whether there are two entries with the same id value (which is illegal), or with the same updated value (which reportedly confuse some readers).

The encoding of the resulting feed is hard-coded to UTF-8.

Use atom-to-rss-print and atom-to-rss-write-file.

Producing RSS from Atom feeds is not optimal. In particular :

• the updated and the pubDate in the two standards don't seem to have the same semantics (last meaningfull change VS publication of the entry) ;
• the description of the channel is mandatory in RSS. The value for this element is taken from the subtitle element of an Atom feed, which is optional, so this library may produce non conforming RSS feeds.

According to the w3c, relative links in an Atom feed can confuse feed readers. As a result, this library's default behaviour is to translate all addresses in the href attribute of a elements and src of img to absolute links. This can be disabled by setting NOCONVERT to t when calling atom-add-xhtml-entry.

In the pre element, whitespace is significant. However, xml-parse-region then xml-print will add spaces and identation. This is not something that can be fixed from atom.

If you already have ypur XHTML content in Lisp format (as opposed to simply a long string), you can pass it directly, as in:

(atom-add-xhtml-entry
  my-atom-feed
  "An XHTML example"
  "http://example.org/emacs-haiku"
  '((h1 nil "Emacs Haiku")
    (p nil "The friends chat gaily," (br)
       "I stand up to join their talk." (br)
       "My save-excursion." (br))
    (p ((class . "author-name")) nil "Oliver Scholz")))

This will save a call to xml-parse-region.