-;;; atom.el --- Create an Atom feed
+;;; atom.el --- Create an Atom feed -*- lexical-binding: t -*-
;; Copyright (C) 2011 Frédéric Perrin
;;
;; (atom-print my-atom-feed)
;; ;; If you prefer RSS feeds:
-;; (atom-to-rss-print my-atom-feed))
+;; (atom-print-as-rss my-atom-feed))
;; Full documentation is available at <http://tar-jx.bz/code/atom.html>.
+;; See
;;; Code:
(require 'xml)
(require 'url-parse)
-(require 'cl) ; for setf in url-canonalize
-(defun atom-create (title link &optional subtitle self id author updated)
+(defun atom-create (title link &optional props)
"Create a new atom structure.
TITLE is the title for the feed, a short, text-only, human
LINK is the URL of a page responible for the content of this
feed.
-SUBTITLE is a subtitle for the feed; it can be a bit longer than
-TITLE, maybe a paragraph long.
+PROPS is an optional plist with the following properties:
-SELF is the canonical URL to this feed.
+- :subtitle is a subtitle for the feed; it can be a bit longer than
+ TITLE, maybe a paragraph long.
-ID is a unique identifier for this feed. If not given, it
-defaults to SELF.
+- :self is the canonical URL to this feed.
-AUTHOR is the author of the feed. See `atom-massage-author' for
+- :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'.
-UPDATED is the date the feed was last updated. If not given,
+- :updated is the date the feed was last updated. If not given,
`(current-time)' is used."
(let ((atom-feed (list (list 'title nil title))))
(atom-modify-entry atom-feed 'link `(((href . ,link))))
- (atom-modify-entry atom-feed 'author (atom-massage-author author))
- (if subtitle (atom-modify-entry atom-feed 'subtitle subtitle))
- (if self (atom-modify-entry atom-feed 'link
- `(((href . ,self) (rel . "self")
- (type . "application/atom+xml")))))
- (atom-modify-entry atom-feed 'updated (atom-format-time updated))
- (atom-modify-entry atom-feed 'id (or id self link))
+ (atom-modify-entry atom-feed 'author (atom-massage-author (plist-get props :author)))
+ (if (plist-member props :subtitle)
+ (atom-modify-entry atom-feed 'subtitle (plist-get props :subtitle)))
+ (if (plist-member props :self)
+ (atom-modify-entry atom-feed 'link
+ `(((href . ,(plist-get props :self)) (rel . "self")
+ (type . "application/atom+xml")))))
+ (atom-modify-entry atom-feed 'updated (atom-format-time (plist-get props :updated)))
+ (atom-modify-entry atom-feed 'id (or (plist-get props :id) (plist-get props :self) link))
atom-feed))
(defun atom-push-entry (atom entry)
(cons name val))))
(nconc entry (list elem))))
-(defun atom-add-entry (atom title link content
- &optional updated id summary)
+(defun atom-add-entry (atom title link content &optional props)
"Add an entry to the atom flux ATOM. Return the newly added
entry.
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 ."
+when the content of the entry changes."
(let ((entry (list (list 'title nil title))))
(atom-modify-entry entry 'link (list (list (cons 'href link))))
- (atom-modify-entry entry 'id (or id link))
- (atom-modify-entry entry 'updated (atom-format-time updated))
- (if summary (atom-modify-entry entry 'summary summary))
+ (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 :summary)
+ (atom-modify-entry entry 'summary (plist-get props :summary)))
(atom-modify-entry entry 'content content)
(atom-push-entry atom entry)
entry))
"Add an entry to ATOM, with a textual content. See
`atom-add-entry' for details.")
-(defun atom-add-html-entry (atom title link content
- &optional updated id summary)
+(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."
- (atom-add-entry atom
- title link (atom-massage-html content)
- updated id (and summary (atom-massage-html summary))))
+ (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 updated id summary noconvert)
+(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.
-
-If CONVERT, translate all links in CONTENT so that they are no
-longer relative to LINK."
- (let ((xhtml-content (atom-massage-xhtml content)))
- (unless noconvert
- (atom-xhtml-convert-links (cadr xhtml-content) link))
- (atom-add-entry atom
- title link xhtml-content
- updated id (and summary (atom-massage-xhtml summary)))))
+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))
(defun atom-print (atom)
"Print the Atom feed ATOM in the current buffer."
- (insert "<?xml version=\"1.0\" encoding=\"utf-8\"?>\n")
+ (insert atom-xml-declaration)
(insert "<feed xmlns=\"http://www.w3.org/2005/Atom\">\n")
(xml-print atom)
(insert "\n</feed>"))
"Writes the feed ATOM to FILENAME."
(with-temp-buffer
(atom-print atom)
- (write-region (point-min) (point-max) filename)))
+ (write-file filename)))
\f
(defun atom-to-rss (atom)
(defun atom-print-as-rss (atom)
(let ((rss (atom-to-rss atom)))
- (insert "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n")
+ (insert atom-xml-declaration)
(insert "<rss version=\"2.0\">\n")
(insert " <channel>\n")
(xml-print rss " ")
(defun atom-to-rss-time (time)
"Translates a string from the format used by Atom into the
format used by RSS."
- ;; Same remark as in `atom-format-time'
(let ((system-time-locale "C"))
(format-time-string "%a, %d %b %Y %T %z" (atom-parse-time time))))
"Saves ATOM as a RSS feed into FILENAME."
(with-temp-buffer
(atom-print-as-rss atom)
- (write-region nil nil filename)))
+ (write-file filename)))
\f
(defvar atom-time-format-string "%Y-%m-%dT%T%z"
"The format for string representation of dates.")
+(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."
;; The time zone must be specified in numeric form, but with a colon between
(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'
(date-to-time (replace-regexp-in-string ":\\(..\\)$" "\\1" time)))
(defun atom-massage-html (content)
(defun atom-string-to-xml (string)
"Convert STRING into a Lisp structure as used by `xml.el'."
- (with-temp-buffer
- (insert "<div xmlns=\"http://www.w3.org/1999/xhtml\">")
- (insert string)
- (insert "</div>")
- (xml-parse-region (point-min) (point-max))))
+ (require 'xml-xhtml-entities)
+ (let ((xml-entity-alist xml-xhtml-entities)
+ (xml-validating-parser t))
+ (with-temp-buffer
+ (insert "<div xmlns=\"" atom-xhtml-namespace "\">")
+ (insert string)
+ (insert "</div>")
+ ;; `xml-parse-region' returns a list of elements, even though it
+ ;; requires an only root node. We are only interested in the first
+ ;; one, the DIV we just inserted.
+ (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."
- `(((type . "xhtml"))
- ,@(or (and (stringp content)
- (atom-string-to-xml content))
- content)))
+ (list '((type . "xhtml"))
+ (or (and (stringp content)
+ (atom-string-to-xml content))
+ `(div ((xmlns . ,atom-xhtml-namespace)) ,@content))))
(defun atom-massage-author (author)
"Return an XML node representing the author. AUTHOR can be:
(defun atom-generate-id (link creation-date)
"Generate a string suitable for use as an atom:id element. This
implements Mark Pilgrom's tag: URI method, using the
-CREATION-DATE of the entry, and the domain part of LINK."
+CREATION-DATE of the entry, and the domain part of LINK.
+
+See <https://www.xml.com/pub/a/2004/08/18/pilgrim.html>."
(format "tag:%s,%s:/%s"
(url-host (url-generic-parse-url link))
(format-time-string "%Y-%m-%d" creation-date)
(url-recreate-url url-base))))
(defun xml-node-as-text (node)
- "Return a string representing NODEn, an XML structure."
+ "Return a string representing NODE, an XML structure."
(with-temp-buffer
(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
projects / atom.git / blobdiff