Adds CDATA sections to atom.xml, fixes imathis#198

.themes/classic/source/atom.xml

@@ -4,26 +4,24 @@ layout: nil
 <?xml version="1.0" encoding="utf-8"?>
 <feed xmlns="http://www.w3.org/2005/Atom">
 
-  <title>{{ site.title | xml_escape }}</title>
+  <title><![CDATA[{{ site.title }}]]></title>
   <link href="{{ site.url }}/atom.xml" rel="self"/>
   <link href="{{ site.url }}/"/>
   <updated>{{ site.time | date_to_xmlschema }}</updated>
   <id>{{ site.url }}/</id>
   <author>
-    <name>{{ site.author | xml_escape }}</name>
-    {% if site.email %}
-      <email>{{ site.email | xml_escape }}</email>
-    {% endif %}
+    <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.posts limit: 20 %}
   <entry>
-    <title>{{ post.title | xml_escape }}</title>
+    <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">{{ post.content | expand_urls: site.url | xml_escape }}</content>
+    <content type="html"><![CDATA[{{ post.content | expand_urls: site.url | cdata_escape }}]]></content>
   </entry>
   {% endfor %}
 </feed>

plugins/octopress_filters.rb

@@ -63,6 +63,11 @@ def raw_content(input)
     return (content.nil?) ? input : content
   end
 
+  # Escapes CDATA sections in post content
+  def cdata_escape(input)
+    input.gsub(/<!\[CDATA\[/, '&lt;![CDATA[').gsub(/\]\]>/, ']]&gt;')
+  end
+
   # Replaces relative urls with full urls
   def expand_urls(input, url='')
     url ||= '/'