X-Git-Url: http://gitweb.fperrin.net/?p=atom.el.git;a=blobdiff_plain;f=atom.el;h=d19bb3c82edc1e5cc06b0b957fff662f54ca42fd;hp=ce01f85a09e4c18b16c267392ee03fdc64051166;hb=4da2ee38a39546325169b6e1ec259b26e2cdf205;hpb=36d9eaeb906863b92a3756eb6483f7cd05767e04

diff --git a/atom.el b/atom.el
index ce01f85..d19bb3c 100644
--- a/atom.el
+++ b/atom.el
@@ -27,8 +27,7 @@
 ;; permanent link and the content of the entry. Text-only, HTML and
 ;; XHTML entries are supported.
 
-;; A feed is really a Lisp structure as used by the `xml.el' package,
-;; without the parent `feed' element.
+;; It is possible to produce both Atom and RSS feeds.
 
 ;; A typical usage would look like this:
 
@@ -40,31 +39,23 @@
 ;;    "http://example.org/hello"
 ;;    "Hello the world!")
 ;;
-;;   ; A text-only entry, with all the optional pieces of data
-;;   (atom-add-text-entry
-;;    my-atom-feed
-;;    "Bonjour"
-;;    "http://example.org/bonjour"
-;;    "Bonjour à tout le monde !"
-;;    ;; optional: the last modification time
-;;    (date-to-time "2011-01-30 23:40:12")
-;;    ;; optional: an identifier for this entry; a common way to generate it is
-;;    ;; to use the domain name and the creation date of the entry.
-;;    (atom-generate-id "http://example.org"
-;; 		     (date-to-time "2011-01-30 10:01:05"))
-;;    ;; optional: a summary for this entry
-;;    "Bonjour, monde.")
-;;
 ;;   (atom-add-xhtml-entry
 ;;    my-atom-feed
 ;;    "An XHTML example"
 ;;    "http://example.org/html-example"
 ;;    "<p>One can also use <acronym>XHTML</acronym> in the entries.</p>")
-;;   (atom-print my-atom-feed))
+;;
+;;   (atom-print my-atom-feed)
+;;   ;; If you prefer RSS feeds:
+;;   (atom-to-rss-print my-atom-feed))
+
+;; Full documentation is available at <http://tar-jx.bz/code/atom.html>.
 
 ;;; Code:
 
 (require 'xml)
+(require 'url-parse)
+(require 'cl) ; for setf in url-canonalize
 
 (defun atom-create (title link &optional subtitle self id author updated)
   "Create a new atom structure.
@@ -84,7 +75,8 @@ 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.
+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,
 `(current-time)' is used."
@@ -155,17 +147,23 @@ for additional details."
    updated id (and summary (atom-massage-html summary))))
 
 (defun atom-add-xhtml-entry (atom title link content
-				  &optional updated id summary)
+				  &optional updated id summary noconvert)
   "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."
-  (atom-add-entry atom
-   title link (atom-massage-xhtml content)
-   updated id (and summary (atom-massage-xhtml summary))))
+fragment. See `atom-add-entry' for additional details.
+
+If NOCONVERT is nil, 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)))))
 
 (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>"))
@@ -205,7 +203,7 @@ Some information may be lost or approximated."
 	  (setcar (cdr guid) (list (cons 'isPermaLink "false"))))
       (if (and descr
 	       (equal (xml-get-attribute descr 'type) "xhtml"))
-	  (setcar (cddr descr) (xml-node-text descr))))
+	  (setcar (cddr descr) (xml-node-as-text descr))))
     `(item nil ,@item)))
 
 (defun atom-to-rss-translator (source target translations)
@@ -216,22 +214,16 @@ Some information may be lost or approximated."
       (when data
 	(atom-modify-entry target to data)))))
 
-(defun xml-node-text (node)
-  (with-temp-buffer
-    (xml-print (xml-node-children node))
-    (buffer-string)))
-
 (defun atom-to-rss-modify-link (entry)
   (let* ((link (assoc 'link entry))
 	 (link-addr (xml-get-attribute-or-nil link 'href)))
-    (message "%S" link)
     (when link
       (setcar (cdr link) nil)
       (setcdr (cdr link) (cons link-addr nil)))))
 
 (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 "    ")
@@ -241,7 +233,6 @@ Some information may be lost or approximated."
 (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))))
 
@@ -261,6 +252,10 @@ format used by RSS."
 (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
@@ -271,6 +266,7 @@ format used by RSS."
 
 (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)
@@ -281,24 +277,28 @@ Atom feed. CONTENT must be a string."
 (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 "<div xmlns=\"" atom-xhtml-namespace "\">")
     (insert string)
     (insert "</div>")
-    (xml-parse-region (point-min) (point-max))))
+    ;; `xml-parse-region' doesn't require that the XML parsed be enclosed in a
+    ;; root node, and accordingly, returns a list of elements. 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:
 - nil, in which case `user-full-name' and `user-mail-address' are
   used;
-- a single string, the full name of the author;
+- 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
   of the author;
 - something else, assumed to be a complete `atomPersonConstruct'."
@@ -310,7 +310,14 @@ Atom feed."
 				    (email nil ,(cadr author))))
 	   (t `(author nil ,author)))))
 
-(require 'url-parse)
+(defun atom-xhtml-convert-links (node base)
+  "Make all links in NODE (a fragment of an XHTML document)
+absolute, in the context of BASE, an URL."
+  (dolist (attr-name (list 'href 'src))
+    (let ((attr (assoc attr-name (xml-node-attributes node))))
+      (when attr (setcdr attr (url-canonalize (cdr attr) base)))))
+  (dolist (child (xml-node-children node))
+    (when (listp child) (atom-xhtml-convert-links child base))))
 
 (defun atom-generate-id (link creation-date)
   "Generate a string suitable for use as an atom:id element. This
@@ -321,5 +328,30 @@ CREATION-DATE of the entry, and the domain part of LINK."
 	    (format-time-string "%Y-%m-%d" creation-date)
 	    (format-time-string "%Y%m%d%H%M%S" creation-date)))
 
+
+;;; Functions that should probably not be there
+
+(defun url-canonalize (address base)
+  "Make ADRESS 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)))
+    (if (url-host url-address)
+	address
+      (setf (url-filename url-base)
+	    (expand-file-name address
+			      (file-name-directory (url-filename url-base))))
+      (url-recreate-url url-base))))
+
+(defun xml-node-as-text (node)
+  "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