First attempt at creating per-category Atom feeds.

.themes/classic/source/_includes/custom/category_feed.xml

@@ -0,0 +1,27 @@
+---
+layout: nil
+---
+<?xml version="1.0" encoding="utf-8"?>
+<feed xmlns="http://www.w3.org/2005/Atom">
+
+  <title><![CDATA[{{ page.title }} | {{ site.title }}]]></title>
+  <link href="{{ site.url }}/{{ page.feed_url }}" rel="self"/>
+  <link href="{{ site.url }}/"/>
+  <updated>{{ site.time | date_to_xmlschema }}</updated>
+  <id>{{ site.url }}/</id>
+  <author>
+    <name><![CDATA[{{ site.author | strip_html }}]]></name>
+    {% if site.email %}<email><![CDATA[{{ site.email }}]]></email>{% endif %}
+  </author>
+  <generator uri="http://octopress.org/">Octopress</generator>
+
+  {% for post in site.categories[page.category] limit: 5 %}
+  <entry>
+    <title type="html"><![CDATA[{{ post.title | cdata_escape }}]]></title>
+    <link href="{{ site.url }}{{ post.url }}"/>
+    <updated>{{ post.date | date_to_xmlschema }}</updated>
+    <id>{{ site.url }}{{ post.id }}</id>
+    <content type="html"><![CDATA[{{ post.content | expand_urls: site.url | markdownify | cdata_escape }}]]></content>
+  </entry>
+  {% endfor %}
+</feed>

plugins/category_generator.rb

@@ -48,6 +48,35 @@ def initialize(site, base, category_dir, category)
 
   end
 
+  # The CategoryFeed class creates an Atom feed for the specified category.
+  class CategoryFeed < Page
+
+    # Initializes a new CategoryFeed.
+    #
+    #  +base+         is the String path to the <source>.
+    #  +category_dir+ is the String path between <source> and the category folder.
+    #  +category+     is the category currently being processed.
+    def initialize(site, base, category_dir, category)
+      @site = site
+      @base = base
+      @dir  = category_dir
+      @name = 'atom.xml'
+      self.process(@name)
+      # Read the YAML data from the layout page.
+      self.read_yaml(File.join(base, '_includes/custom'), 'category_feed.xml')
+      self.data['category']    = category
+      # Set the title for this page.
+      title_prefix             = site.config['category_title_prefix'] || 'Category: '
+      self.data['title']       = "#{title_prefix}#{category}"
+      # Set the meta-description for this page.
+      meta_description_prefix  = site.config['category_meta_description_prefix'] || 'Category: '
+      self.data['description'] = "#{meta_description_prefix}#{category}"
+
+      # Set the correct feed URL.
+      self.data['feed_url'] = "#{category_dir}/#{name}"
+    end
+
+  end
 
   # The Site class is a built-in Jekyll class with access to global site config information.
   class Site
@@ -63,6 +92,13 @@ def write_category_index(category_dir, category)
       index.write(self.dest)
       # Record the fact that this page has been added, otherwise Site::cleanup will remove it.
       self.pages << index
+
+      # Create an Atom-feed for each index.
+      feed = CategoryFeed.new(self, self.source, category_dir, category)
+      feed.render(self.layouts, site_payload)
+      feed.write(self.dest)
+      # Record the fact that this page has been added, otherwise Site::cleanup will remove it.
+      self.pages << feed
     end
 
     # Loops through the list of category pages and processes each one.