Work in progress rewrite to support RSS.

I got this from
https://writepermission.com/org-blogging-rss-feed.html
and
https://gitlab.com/to1ne/blog/-/blob/master/elisp/publish.el

The RSS in rss.xml is not generated correctly. For example it has

<title>file:/var/www/htdocs/sha256.net/fun-with-org-mode-agenda-views.org</title>

The way the site is published is interesting though.

publish.el

@@ -13,6 +13,7 @@
 
 (unless (package-installed-p 'use-package)
   (package-install 'use-package))
+
 (require 'use-package)
 (setq use-package-always-ensure t)
 
@@ -28,21 +29,68 @@
   :pin org)
 
 (use-package htmlize)
+(use-package ox-rss)
 
 (require 'ox-publish)
 (require 'ox-html)
-(require 'htmlize)
+
+(defvar fo-base-directory "/var/www/htdocs/sha256.net/"
+  "Where the org files live.")
+
+(defvar fo-url "https://openbsd-build.home.narrans.de/sha256.net/"
+  "URL where the site will be published.")
+
+(defvar fo-title "sha256.net - Florian Obser"
+  "Title of the site.")
+
 
 (setq org-html-doctype "html5")
 (setq org-html-htmlize-output-type 'css)
 (setq org-export-time-stamp-file nil)
 (setq org-html-validation-link nil)
 (setq org-html-head-include-default-style nil)
-(setq org-publish-project-alist
+
-      '(("tlakh"
+(defun fo/format-rss-feed-entry (entry style project)
-	 :base-directory "/var/www/sha256.net/"
+  "Format ENTRY for the RSS feed.
-	 :publishing-function org-html-publish-to-html
+ENTRY is a file name.  STYLE is either 'list' or 'tree'.
-	 :publishing-directory "/var/www/sha256.net/"
+PROJECT is the current project."
+  (cond ((not (directory-name-p entry))
+         (let* ((file (org-publish--expand-file-name entry project))
+                (title (org-publish-find-title entry project))
+                (date (format-time-string "%Y-%m-%d" (org-publish-find-date entry project)))
+                (link (concat (file-name-sans-extension entry) ".html")))
+           (with-temp-buffer
+             (insert (format "* [[file:%s][%s]]\n" file title))
+             (org-set-property "RSS_PERMALINK" link)
+             (org-set-property "PUBDATE" date)
+             (insert-file-contents file)
+             (buffer-string))))
+        ((eq style 'tree)
+         ;; Return only last subdir.
+         (file-name-nondirectory (directory-file-name entry)))
+        (t entry)))
+
+(defun fo/format-rss-feed (title list)
+  "Generate RSS feed, as a string.
+TITLE is the title of the RSS feed.  LIST is an internal
+representation for the files to include, as returned by
+`org-list-to-lisp'.  PROJECT is the current project."
+  (concat "#+TITLE: " title "\n\n"
+          (org-list-to-subtree list 1 '(:icount "" :istart ""))))
+
+(defun fo/org-rss-publish-to-rss (plist filename pub-dir)
+  "Publish RSS with PLIST, only when FILENAME is 'rss.org'.
+PUB-DIR is when the output will be placed."
+  (if (equal "rss.org" (file-name-nondirectory filename))
+      (org-rss-publish-to-rss plist filename pub-dir)))
+
+(defvar fo--publish-project-alist
+  (list
+   (list "sha256.net"
+	 :base-directory fo-base-directory
+	 :publishing-function 'org-html-publish-to-html
+	 :publishing-directory fo-base-directory
+	 :exclude (regexp-opt '("rss.org"))
 	 :section-numbers nil
 	 :with-author nil
 	 :with-email nil
@@ -57,6 +105,49 @@ Copyright © 2014 - 2023 Florian Obser. All rights reserved.
 	 :html-head-include-default-style: nil
 	 :html-head "<link rel=\"stylesheet\" href=\"simple.min.css\" type=\"text/css\"/>
 <link rel=\"stylesheet\" href=\"htmlize.min.css\" type=\"text/css\"/>
-<link rel=\"stylesheet\" href=\"custom.css\" type=\"text/css\"/>")))
+<link rel=\"stylesheet\" href=\"custom.css\" type=\"text/css\"/>")
+   (list "sha256.net-rss"
+         :base-directory fo-base-directory
+	 :publishing-directory fo-base-directory
+         :base-extension "org"
+         :recursive nil
+         :exclude (regexp-opt '("rss.org" "index.org" "404.org" "50x.org"))
+         :publishing-function 'fo/org-rss-publish-to-rss
+         :rss-extension "xml"
+         :html-link-home fo-url
+         :html-link-use-abs-url t
+         :html-link-org-files-as-html t
+         :auto-sitemap t
+         :sitemap-filename "rss.org"
+         :sitemap-title fo-title
+         :sitemap-style 'list
+         :sitemap-sort-files 'anti-chronologically
+         :sitemap-function 'fo/format-rss-feed
+         :sitemap-format-entry 'fo/format-rss-feed-entry
+         :author "Florian Obser"
+         :email "")
+   (list "site"
+	 :components '("sha256.net"))))
 
-(org-publish "tlakh")
+(defun fo-publish-all ()
+  "Publish the blog to HTML."
+  (interactive)
+  (let ((org-publish-project-alist       fo--publish-project-alist)
+        (org-publish-timestamp-directory "./.timestamps/")
+        (org-export-with-section-numbers nil)
+        (org-export-with-smart-quotes    t)
+        (org-export-with-toc             nil)
+        (org-export-with-sub-superscripts '{})
+        (org-html-divs '((preamble  "header" "top")
+                         (content   "main"   "content")
+                         (postamble "footer" "postamble")))
+        (org-html-container-element         "section")
+        (org-html-metadata-timestamp-format "%Y-%m-%d")
+        (org-html-checkbox-type             'html)
+        (org-html-html5-fancy               t)
+        (org-html-validation-link           nil)
+        (org-html-doctype                   "html5")
+        (org-html-htmlize-output-type       'css))
+    (org-publish-all)))
+
+(fo-publish-all)