/forum_topics.atom: add atom feed for forum topics.

app/views/forum_topics/index.atom.builder

@@ -0,0 +1,16 @@
+atom_feed do |feed|
+  feed.title("Forum Topics")
+  feed.updated(@forum_topics.first.try(:updated_at))
+
+  @forum_topics.each do |topic|
+    feed.entry(topic, published: topic.created_at, updated: topic.updated_at) do |entry|
+      entry.title("[#{topic.category_name}] #{topic.title}")
+      entry.content(format_text(topic.original_post.body), type: "html")
+
+      entry.author do |author|
+        author.name(topic.creator.name)
+        author.uri(user_url(topic.creator_id))
+      end
+    end
+  end
+end

app/views/forum_topics/index.html.erb

@@ -22,3 +22,5 @@
 <% content_for(:page_title) do %>
   Forum - <%= Danbooru.config.app_name %>
 <% end %>
+
+<% content_for(:html_header, auto_discovery_link_tag(:atom, forum_topics_url(:atom), title: "Forum Topics")) %>

app/views/forum_topics/show.atom.builder

@@ -0,0 +1,16 @@
+atom_feed do |feed|
+  feed.title(@forum_topic.title)
+  feed.updated(@forum_topic.try(:updated_at))
+
+  @forum_posts.each do |post|
+    feed.entry(post, published: post.created_at, updated: post.updated_at) do |entry|
+      entry.title("@#{post.creator.name}: #{strip_dtext(post.body).truncate(50, separator: /[[:space:]]/)}")
+      entry.content(format_text(post.body), type: "html")
+
+      entry.author do |author|
+        author.name(post.creator.name)
+        author.uri(user_url(post.creator))
+      end
+    end
+  end
+end

app/views/forum_topics/show.html.erb

@@ -57,3 +57,5 @@
     });
   </script>
 <% end %>
+
+<% content_for(:html_header, auto_discovery_link_tag(:atom, forum_topics_url(@forum_topic, :atom), title: @forum_topic.title)) %>

app/views/static/site_map.html.erb

@@ -79,6 +79,7 @@
         <li><h1>Forum</h1></li>
         <li><%= link_to("Help", wiki_pages_path(:title => "help:forum")) %></li>
         <li><%= link_to("Listing", forum_topics_path) %></li>
+        <li><%= link_to("RSS", forum_topics_path(:atom)) %></li>
       </ul>
       <ul>
         <li><h1>Wiki</h1></li>