fixes #1829

app/controllers/posts_controller.rb

@@ -9,12 +9,17 @@ class PostsController < ApplicationController
   rescue_from ActiveRecord::RecordNotFound, :with => :rescue_exception
 
   def index
-    @post_set = PostSets::Post.new(tag_query, params[:page], params[:limit] || CurrentUser.user.per_page, params[:raw])
-    @posts = @post_set.posts
-    respond_with(@posts) do |format|
-      format.atom
-      format.xml do
-        render :xml => @posts.to_xml(:root => "posts")
+    if params[:md5].present?
+      @post = Post.find_by_md5(params[:md5])
+      redirect_to post_path(@post)
+    else
+      @post_set = PostSets::Post.new(tag_query, params[:page], params[:limit] || CurrentUser.user.per_page, params[:raw])
+      @posts = @post_set.posts
+      respond_with(@posts) do |format|
+        format.atom
+        format.xml do
+          render :xml => @posts.to_xml(:root => "posts")
+        end
       end
     end
   end