;; (atom-print-as-rss my-atom-feed))
;; Full documentation is available at <http://tar-jx.bz/code/atom.html>.
-;; See
+;; See atom-tests.el for usage examples.
;;; Code:
- :subtitle is a subtitle for the feed; it can be a bit longer than
TITLE, maybe a paragraph long.
-- :self is the canonical URL to this feed.
+- :self is the canonical URL to this feed. If missing, the resulting
+ feed is non-conforming.
- :id is a unique identifier for this feed. If not given, it
defaults to :self.
- :author is the author of the feed. See `atom-massage-author' for
-the possible ways to specify it. In particular, `nil' uses
-`user-full-name' and `user-mail-address'.
+the possible ways to specify it. In particular, nil uses
+variable `user-full-name' and `user-mail-address'.
- :updated is the date the feed was last updated. If not given,
`(current-time)' is used."
(nconc entry (list elem))))
(defun atom-add-entry (atom title link content &optional props)
- "Add an entry to the atom flux ATOM. Return the newly added
-entry.
+ "Add an entry to the atom flux ATOM.
+
+Return the newly adde dentry.
TITLE is a short, text-only, human readable string.
CONTENT is the content of the entry; use `atom-add-html-entry'
or `atom-add-xhtml-entry' when CONTENT is not text-only.
-If SUMMARY is not given, the entry will not contain any summary.
+PROPS is an optional plist with the following properties:
+
+- :summary, if is not given, the entry will not contain any summary.
+
+- :updated defaults to `(current-time)'.
-UPDATED defaults to `(current-time)' if omitted, which is
-probably not a very good default.
+- :published, if given, is the earliest availability of the
+ entry. It is optional, and shouldn't change even if the entry
+ content (etc.) updated after the initial publication.
-ID defaults to LINK, which is not optimal; see `atom-generate-id'
-for a way to create good identifiers. For a given entry, it must
-not change between successive generations of the atom feed, even
-when the content of the entry changes."
+- :id is a unique ID for the entry; defaulting to LINK. RFC4287
+ has specific requirements about valid IRI that may be used,
+ which this library does not try to enforce."
(let ((entry (list (list 'title nil title))))
(atom-modify-entry entry 'link (list (list (cons 'href link))))
(atom-modify-entry entry 'id (or (plist-get props :id) link))
(atom-modify-entry entry 'updated (atom-format-time (plist-get props :updated)))
+ (if (plist-member props :published)
+ (atom-modify-entry entry 'published (atom-format-time (plist-get props :published))))
(if (plist-member props :summary)
(atom-modify-entry entry 'summary (plist-get props :summary)))
(atom-modify-entry entry 'content content)
`atom-add-entry' for details.")
(defun atom-add-html-entry (atom title link content &optional props)
- "Add an entry to ATOM, with some HTML content. CONTENT should
-be a string enconding a valid HTML fragment. See `atom-add-entry'
-for additional details."
+ "Add an entry to ATOM, with some HTML content.
+
+TITLE, LINK, PROPS as in `atom-add-entry'. CONTENT should be a string
+enconding a valid HTML fragment. See `atom-add-entry' for
+additional details."
(if (plist-member props :summary)
(plist-put props :summary (atom-massage-html (plist-get props :summary))))
(atom-add-entry atom title link (atom-massage-html content) props))
(defun atom-add-xhtml-entry (atom title link content &optional props)
- "Add an entry to ATOM, with some XHTML content. CONTENT may be
-given either as a string, or as an XML tree, of a valid XHTML
-fragment. See `atom-add-entry' for additional details."
+ "Add an entry to ATOM, with some XHTML content.
+
+TITLE, LINK, PROPS as in `atom-add-entry'. CONTENT may be given
+either as a string, or as an XML tree, of a valid XHTML fragment.
+See `atom-add-entry' for additional details."
(if (plist-member props :summary)
(plist-put props :summary (atom-massage-xhtml (plist-get props :summary))))
(atom-add-entry atom title link (atom-massage-xhtml content) props))
+(defvar atom-xml-declaration "<?xml version=\"1.0\" encoding=\"utf-8\"?>\n")
+
(defun atom-print (atom)
"Print the Atom feed ATOM in the current buffer."
(insert atom-xml-declaration)
\f
(defun atom-to-rss (atom &optional rss-self)
- "Translate an Atom feed into an RSS one, returning the translation.
+ "Translate Atom feed ATOM into an RSS one, returning the translation.
+
+If RSS-SELF is given, it is used as self link of the RSS feed.
Some information may be lost or approximated."
(let ((rss (list (assoc 'title atom))))
(reverse rss)))
(defun atom-to-rss-item (entry)
- "Translates an Atom entry into an RSS item."
+ "Translates the Atom entry ENTRY into an RSS item."
(let ((item (list (assoc 'title entry))))
(atom-to-rss-translator
(xml-node-children entry) item
(setcdr (cdr link) (cons link-addr nil)))))
(defun atom-print-as-rss (atom &optional rss-self)
+ "Convert Atom feed ATOM to RSS in the current buffer.
+
+If RSS-SELF is given, it is used as self link of the RSS feed."
(let ((rss (atom-to-rss atom rss-self)))
(insert atom-xml-declaration)
;; xmlns:atom included in order to allow the atom:link rel=self element
(insert "</rss>")))
(defun atom-to-rss-time (time)
- "Translates a string from the format used by Atom into the
-format used by RSS."
+ "Translate TIME from the format used by Atom into the format used by RSS.
+
+TIME is a string."
(let ((system-time-locale "C"))
(format-time-string "%a, %d %b %Y %T %z" (atom-parse-time time))))
(atom-to-rss-time (car (xml-node-children pubDate))))))
(defun atom-to-rss-write-file (atom filename &optional rss-self)
- "Saves ATOM as a RSS feed into FILENAME."
+ "Save ATOM as a RSS feed into FILENAME.
+
+If RSS-SELF is given, it is used as self link of the RSS feed."
(with-temp-buffer
(atom-print-as-rss atom rss-self)
(write-file filename)))
(defvar atom-xhtml-namespace "http://www.w3.org/1999/xhtml")
-(defvar atom-xml-declaration "<?xml version=\"1.0\" encoding=\"utf-8\"?>\n")
-
(defun atom-format-time (&optional time)
- "Format a time according to RFC3339."
+ "Format time value TIME according to RFC3339."
;; The time zone must be specified in numeric form, but with a colon between
;; the hour and minute parts.
(replace-regexp-in-string
(format-time-string atom-time-format-string time)))
(defun atom-parse-time (&optional time)
- "Parse a time as specified in RFC3339 into Emacs's native format."
- ;; Same remark as in `atom-format-time'
+ "Parse string TIME as specified in RFC3339 into Emacs's native format."
+ ;; Same remark as in `atom-format-time': RFC3339 wants a colon between hour
+ ;; and minute parts of the timezome, so remove it before `date-to-time'.
(date-to-time (replace-regexp-in-string ":\\(..\\)$" "\\1" time)))
(defun atom-massage-html (content)
- "Massage CONTENT so it can be used as an HTML fragment in an
-Atom feed. CONTENT must be a string."
+ "Massage CONTENT so it can be used as an HTML fragment in an Atom feed.
+
+CONTENT must be a string."
(list '((type . "html")) content))
(defun atom-string-to-xml (string)
(car (xml-parse-region (point-min) (point-max))))))
(defun atom-massage-xhtml (content)
- "Massage CONTENT so it can be used as an XHTML fragment in an
-Atom feed."
+ "Massage CONTENT so it can be used as an XHTML fragment in an Atom feed."
(list '((type . "xhtml"))
(or (and (stringp content)
(atom-string-to-xml content))
(defun atom-massage-author (author)
"Return an XML node representing the author. AUTHOR can be:
-- nil, in which case `user-full-name' and `user-mail-address' are
- used;
+- nil, in which case variables `user-full-name' and `user-mail-address'
+ are used;
- a single string, the full name of the author; no email address
will be included;
- a list with two elements, the full name and the email address
;;; Functions that should probably not be there
(defun url-canonalize (address base)
- "Make ADRESS an absolute URL, taking it in the BASE context."
+ "Make ADDRESS an absolute URL, taking it in the BASE context."
;; I feel such a function should exist in `url-parse'. Did I miss it?
(let ((url-base (url-generic-parse-url base))
(url-address (url-generic-parse-url address)))
(xml-print (xml-node-children node))
(buffer-string)))
-(defun xml-node-create (name attrlist childlist)
- "Create a new XML node."
- (list name attrlist . childlist))
-
(provide 'atom)
;;; atom.el ends here