Add RSS support.

TODO

@@ -13,8 +13,7 @@ Plugins? Injection support for HEAD and BODY. What about predicate-based injecti
 How is it served? Hunchentoot, Lighttpd, S3, whomever!
 
 TODO:
-; blockers to use this for redlinernotes: rss/atom feed, markdown support
-; after that, focus on injections for code highlighting and latex
+; after that, focus on markdown support, injections for code highlighting and latex
 
 ; doc themes and plugins
 ; fix plugins: s3

coleslaw.asd

@@ -5,7 +5,7 @@
   :license "BSD"
   :author "Brit Butler <redline6561@gmail.com>"
   :pathname "src/"
-  :depends-on (:closure-template :iolib.os :alexandria :cl-fad)
+  :depends-on (:closure-template :iolib.os :alexandria :cl-fad :local-time)
   :serial t
   :components ((:file "packages")
                (:file "config")
@@ -13,6 +13,7 @@
                (:file "themes")
                (:file "plugins")
                (:file "coleslaw")
+               (:file "feeds")
                (:file "posts")
                (:file "indices"))
   :in-order-to ((test-op (load-op coleslaw-tests)))

src/coleslaw.lisp

@@ -59,7 +59,8 @@ on files that match the given extension."
           (when (probe-file dir)
             (run-program "cp" `("-R" ,(namestring dir) ".")))))
       (render-posts)
-      (render-indices))
+      (render-indices)
+      (render-feed))
     (deploy staging)
     (setf (last-published) (last-commit))))
 

src/feeds.lisp

@@ -0,0 +1,37 @@
+(in-package :coleslaw)
+
+(defun date-to-timestamp (date)
+  "Convert a post DATE to a local-time timestamp."
+  (destructuring-bind (date time) (cl-ppcre:split " " date)
+    (apply 'local-time:encode-timestamp 0
+           (mapcar #'parse-integer
+                   (append (reverse (cl-ppcre:split ":" time))
+                           (reverse (cl-ppcre:split "-" date)))))))
+
+(defun make-pubdate (&optional date)
+  "Make a RFC1123 pubdate representing the current time or DATE, when supplied."
+  (let ((timestamp (if date
+                       (date-to-timestamp date)
+                       (local-time:now))))
+    (local-time:format-rfc1123-timestring nil timestamp)))
+
+(defun xml-escape (string)
+  "Escape the given string for XML."
+  (format nil "<![CDATA[ ~A ]]>" string))
+
+(defun render-feed ()
+  "Render and write the RSS feed for the site."
+  (let* ((posts (subseq (by-date (hash-table-values *posts*)) 0 10))
+         (content (loop for post in posts
+                     collect (list :title (post-title post)
+                                   :url (post-url post)
+                                   :date (make-pubdate (post-date post))
+                                   :tags (mapcar #'xml-escape (post-tags post))
+                                   :content (xml-escape (post-content post))))))
+    (render-page "rss.xml"
+                 (funcall (theme-fn "RSS")
+                          :pubdate (make-pubdate)
+                          :title (title *config*)
+                          :siteroot (domain *config*)
+                          :author (author *config*)
+                          :posts content))))

themes/hyde/rss.tmpl

@@ -0,0 +1,29 @@
+{namespace coleslaw.theme.hyde}
+
+{template rss}
+<?xml version="1.0"?>{\n}
+<rss version="2.0" xmlns:atom="http://www.w3.org/2005/Atom">
+  <channel>
+    <title>{$title}</title>
+    <link>{$siteroot}</link>
+    <atom:link href="{$siteroot}/rss.xml" rel="self" type="application/rss+xml" />
+    <description>{$title}</description>
+    <language>en-us</language>
+    <pubDate>{$pubdate}</pubDate>
+
+    {foreach $post in $posts}
+    <item>
+      <title>{$post.title}</title>
+      <link>{$siteroot}/{$post.url}</link>
+      <pubDate>{$post.date}</pubDate>
+      <author>{$author}</author>
+      {foreach $tag in $tags}
+        <category>{$tag |noAutoescape}</category>
+      {/foreach}
+      <guid isPermaLink="true">{$siteroot}/{$post.url}</guid>
+      <content:encoded>{$post.content |noAutoescape}</content:encoded>
+    </item>
+    {% endfor %}
+
+  </channel>
+</rss>