Possibly correct first implementation of automatic RSS feed generation

feed.xml

@@ -0,0 +1 @@
+<rss version="2.0"><channel><title>RSS Test</title><link>http://example.com</link><description>An example blog for testing RSS capability of md4tj.</description><language>en-US</language><pubDate>Tue, 10 Jun 2003 04:00:00 GMT</pubDate><managingEditor>editor@example.com</managingEditor><webMaster>webmaster@example.com</webMaster><docs>https://www.rssboard.org/rss-specification</docs><generator>md4tj-rss.el</generator><lastBuildDate>Mon, 10 Jul 2023 08:50:16 GMT</lastBuildDate></channel><item><title>Blog Post 2</title><author>j4nk</author><link>https://example.com/blog/blogpost2.html</link><guid>https://example.com/blog/blogpost2.html</guid><pubDate>Thu, 02 Mar 2023 19:44:50 EST</pubDate></item><item><title>Blog Post 1</title><author>j4nk</author><link>https://example.com/blog/blogpost1.html</link><guid>https://example.com/blog/blogpost1.html</guid><pubDate>Thu, 02 Mar 2023 19:44:14 EST</pubDate></item></rss>

md4tj.el

@@ -94,8 +94,8 @@
 		  "`\\(.*\\)`"
 		  "<code>\\1</code>" line)))))))))
 				  
-(defun md4tj-convert-line-to-html (line state inbuf)
-  "Process LINE with STATE and return html, INBUF provided."
+(defun md4tj-convert-line-to-html (line state inbuf outfile)
+  "Process LINE with STATE and return html, INBUF provided with OUTFILE."
   (let ((cleanline (md4tj-util-clean-multiline line)))
 	;; If this is a signal to include another file
 	(cond ((string-match "^@@INCLUDE" line) (md4tj-parse-to-string (nth 1 (split-string line))))
@@ -106,6 +106,7 @@
 		  ((string-match "^@@DIV" line) (md4tj-begin-tag "div" (list (list "class" (nth 1 (split-string line))))))
 		  ((string-match "^@@ENDDIV" line) (md4tj-end-tag "div"))
 		  ((string-match "^@@BLOGINSERT" line) (with-current-buffer inbuf (md4tj-blog-html)))
+		  ((string-match "^@@RSSINSERT" line) (md4tj-rss-link-string (md4tj-rss-file-from-outfile outfile)))
 		  ((and (string-match "^$$.*$$" line) (eq (nth 1 state) 'normal)) ;; LaTeX formula
 		   (shell-command (concat "./pnglatex"
 								  " -d 300"
@@ -234,6 +235,8 @@
 	(set-buffer inbuf)
 	(insert-file-contents mdfile)
 	(goto-char (point-min))
+	;; If we need RSS, go ahead and output the XML file here
+	(if (md4tj-rss-needs-rss) (md4tj-rss-to-file mdfile (md4tj-rss-file-from-outfile outfile)))
 	(set-buffer outbuf)
 	(insert (md4tj-begin))
 	(insert (with-current-buffer inbuf (md4tj-head)))
@@ -242,7 +245,7 @@
 	  (setq line (with-current-buffer inbuf (md4tj-util-getline)))
 	  (setq fullstate (md4tj-next-state line (nth 1 fullstate)))
 	  ;; Insert next line(s) into output file
-	  (let ((linehtml (md4tj-convert-line-to-html line fullstate inbuf)))
+	  (let ((linehtml (md4tj-convert-line-to-html line fullstate inbuf outfile)))
 	  (insert (concat linehtml (if (string-empty-p linehtml) "" "\n"))))
 	  ;; Advance input file by a line
 	  (with-current-buffer inbuf (forward-line)))
@@ -264,7 +267,7 @@
 	  (while (< (point) (point-max))
 		(setq line (md4tj-util-getline))
 		(setq fullstate (md4tj-next-state line (nth 1 fullstate)))
-		(setq acc (concat acc (md4tj-convert-line-to-html line fullstate nil) "\n"))
+		(setq acc (concat acc (md4tj-convert-line-to-html line fullstate nil nil) "\n"))
 		(forward-line))
 	  acc)))
 
@@ -369,9 +372,9 @@
 	(goto-char (point-min))
 	(if (search-forward-regexp "^@@RSSENABLE" nil t) t nil)))
 
-(defun md4tj-rss-begin-tag (tag &optional attrs)
-  "Return the RSS text for TAG with ATTRS."
-  (concat "<" tag (mapconcat (lambda (attr) (concat " " (nth 0 attr) "=" "\"" (nth 1 attr) "\"")) attrs "") ">"))
+(defun md4tj-rss-begin-tag (tag &optional attrs self-close)
+  "Return the RSS text for TAG with ATTRS, SELF-CLOSE if necessary."
+  (concat "<" tag (mapconcat (lambda (attr) (concat " " (nth 0 attr) "=" "\"" (nth 1 attr) "\"")) attrs "") (if self-close "/" "") ">"))
 
 (defun md4tj-rss-end-tag (tag)
   "Return the RSS text for ending TAG."
@@ -394,23 +397,67 @@
   "Generate RSS syntax for RSS channel statement tokenized to TOKS."
   (concat (md4tj-rss-begin-tag (car toks)) (mapconcat #'identity (cdr toks) " ") (md4tj-rss-end-tag (car toks))))
 
-(defun md4tj-rss-channel ()
-  "Return the RSS text for channel in current buffer."
+(defun md4tj-rss-channel (rsslink)
+  "Return the RSS text for channel in current buffer with RSSLINK."
   (concat (md4tj-rss-begin-tag "channel")
+		  ;;(md4tj-rss-begin-tag "atom:link" (list (list "href" rsslink) (list "rel" "self") (list "type" "application/rss+xml")) t)
 		  (mapconcat #'md4tj-rss-channel-statement-toks-to-rss (md4tj-rss-get-channel-statements) "")
 		  (md4tj-rss-begin-tag "docs") "https://www.rssboard.org/rss-specification" (md4tj-rss-end-tag "docs")
 		  (md4tj-rss-begin-tag "generator") "md4tj-rss.el" (md4tj-rss-end-tag "generator")
 		  (md4tj-rss-begin-tag "lastBuildDate") (format-time-string "%a, %d %b %Y %H:%M:%S GMT") (md4tj-rss-end-tag "lastBuildDate")
 		  (md4tj-rss-end-tag "channel")))
 
-(defun md4tj-rss ()
-  "Return the RSS text for the current buffer."
+;; Elt is triple of
+;; Title
+;; Time
+;; Link
+(defun md4tj-rss-item (elt)
+  "Return RSS for ELT."
+  (concat (md4tj-rss-begin-tag "item")
+		  (md4tj-rss-begin-tag "title") (nth 0 elt) (md4tj-rss-end-tag "title")
+		  ;; NOTE: change "j4nk" to author name
+		  (md4tj-rss-begin-tag "author") "j4nk" (md4tj-rss-end-tag "author")
+		  (md4tj-rss-begin-tag "link") (nth 2 elt) (md4tj-rss-end-tag "link")
+		  (md4tj-rss-begin-tag "guid") (nth 2 elt) (md4tj-rss-end-tag "guid")
+		  (md4tj-rss-begin-tag "pubDate") (format-time-string "%a, %d %b %Y %H:%M:%S %Z" (string-to-number (nth 1 elt))) (md4tj-rss-end-tag "pubDate")
+		  (md4tj-rss-end-tag "item")))
+
+(defun md4tj-rss-items ()
+  "Return all RSS for all elements."
+  (mapconcat 'md4tj-rss-item (md4tj-blog-all-blogs-list) ""))
+
+  
+
+(defun md4tj-rss (rsslink)
+  "Return the RSS text for the current buffer at RSSLINK."
   (save-excursion
 	(when (md4tj-rss-needs-rss)
 	  (concat
 	   (md4tj-rss-begin)
-	   (md4tj-rss-channel)
+	   (md4tj-rss-channel rsslink)
+	   (md4tj-rss-items)
 	   (md4tj-rss-end-tag "rss")))))
+
+(defun md4tj-rss-to-file (infile outfile)
+  "Write INFILE as RSS to OUTFILE."
+  (with-temp-buffer
+	(insert-file-contents infile)
+	(let ((outbuf (generate-new-buffer " outbuf" t))
+		  (rss-str (md4tj-rss (concat (md4tj-blog-base-url) "/feed.xml"))))
+	  (set-buffer outbuf)
+	  (insert rss-str)
+	  (write-region nil nil outfile nil))))
+
+(defun md4tj-rss-link-string (rsslink)
+  "Return the html of RSS link to RSSLINK as string."
+  (concat (md4tj-begin-tag "div" (list (list "id" "rssicon"))) (md4tj-begin-tag "a" (list (list "href" rsslink))) (md4tj-begin-tag "img" (list (list "src" "rss.png") (list "alt" "RSS icon") (list "style" "width:20px;height:20px;"))) (md4tj-end-tag "img") (md4tj-end-tag "a") (md4tj-end-tag "div")))
+
+(defun md4tj-rss-file-from-outfile (outfile)
+  "Return the filename that the RSS XML should be output to given OUTFILE."
+  (concat (file-name-directory outfile) "/feed.xml"))
+	  
+	  
+
 ;; End md4tj rss stuff
 
 (provide 'md4tj)

test_blog.html

@@ -4,6 +4,7 @@
 
 
 
+
 <title>Test blog</title>
 
 
@@ -18,11 +19,8 @@
 
 </head>
 <body>
-<br>
-
 <h1>Blogs</h1>
-
-<br>
+<a href=".//feed.xml"><img src="rss.png" alt="RSS icon" style="width:20px;height:20px;"></img></a>
 <div class=blogpost>
 <a href="https://example.com/blog/blogpost2.html"><h4>Blog Post 2</h4></a>
 <h5>2023 March 02 19:44</h5>

test_blog.md4tj

@@ -9,9 +9,8 @@
 @@RSSCHANNELmanagingEditor editor@example.com
 @@RSSCHANNELwebMaster webmaster@example.com
 @@TITLE Test blog
-
 # Blogs
-
+@@RSSINSERT
 @@BLOGBASEURL		 https://example.com/blog/
 @@BLOGBASEDIR		./blog/
 @@BLOGINSERT

test_file.html

@@ -75,7 +75,7 @@ int main() {
 
 <p>This is a div that has monospace text.</p>
 </div>
-<p id="lastupdated">Last updated: Sun Jul  9 19:26:42 2023</p>
+<p id="lastupdated">Last updated: Mon Jul 10 08:35:47 2023</p>
 
 <br>