FEATURE: Embeddable Discourse comments, now with simple-rss instead of feedzirra

Gemfile

@@ -206,6 +206,10 @@ gem 'unicorn', require: false
 gem 'puma', require: false
 gem 'rbtrace', require: false
 
+# required for feed importing and embedding
+gem 'ruby-readability', require: false
+gem 'simple-rss', require: false
+
 # perftools only works on 1.9 atm
 group :profile do
   # travis refuses to install this, instead of fuffing, just avoid it for now

Gemfile_rails4.lock

@@ -117,6 +117,7 @@ GEM
     fspath (2.0.5)
     given_core (3.1.1)
       sorcerer (>= 0.3.7)
+    guess_html_encoding (0.0.9)
     handlebars-source (1.1.2)
     hashie (2.0.5)
     highline (1.6.20)
@@ -309,6 +310,9 @@ GEM
       rspec-mocks (~> 2.14.0)
     ruby-hmac (0.4.0)
     ruby-openid (2.3.0)
+    ruby-readability (0.5.7)
+      guess_html_encoding (>= 0.0.4)
+      nokogiri (>= 1.4.2)
     sanitize (2.0.6)
       nokogiri (>= 1.4.4)
     sass (3.2.12)
@@ -337,6 +341,7 @@ GEM
       celluloid (>= 0.14.1)
       ice_cube (~> 0.11.0)
       sidekiq (~> 2.15.0)
+    simple-rss (1.3.1)
     simplecov (0.7.1)
       multi_json (~> 1.0)
       simplecov-html (~> 0.7.1)
@@ -466,6 +471,7 @@ DEPENDENCIES
   rinku
   rspec-given
   rspec-rails
+  ruby-readability
   sanitize
   sass
   sass-rails
@@ -474,6 +480,7 @@ DEPENDENCIES
   sidekiq (= 2.15.1)
   sidekiq-failures
   sidetiq (>= 0.3.6)
+  simple-rss
   simplecov
   sinatra
   slim

app/assets/javascripts/embed.js

@@ -0,0 +1,27 @@
+/* global discourseUrl */
+/* global discourseEmbedUrl */
+(function() {
+
+  var comments = document.getElementById('discourse-comments'),
+      iframe = document.createElement('iframe');
+  iframe.src = discourseUrl + "embed/best?embed_url=" + encodeURIComponent(discourseEmbedUrl);
+  iframe.id = 'discourse-embed-frame';
+  iframe.width = "100%";
+  iframe.frameBorder = "0";
+  iframe.scrolling = "no";
+  comments.appendChild(iframe);
+
+
+  function postMessageReceived(e) {
+    if (!e) { return; }
+    if (discourseUrl.indexOf(e.origin) === -1) { return; }
+
+    if (e.data) {
+      if (e.data.type === 'discourse-resize' && e.data.height) {
+        iframe.height = e.data.height + "px";
+      }
+    }
+  }
+  window.addEventListener('message', postMessageReceived, false);
+
+})();

app/assets/stylesheets/embed.css.scss

@@ -0,0 +1,69 @@
+//= require ./vendor/normalize
+//= require ./common/foundation/base
+
+article.post {
+  border-bottom: 1px solid #ddd;
+
+  .post-date {
+    float: right;
+    color: #aaa;
+    font-size: 12px;
+    margin: 4px 4px 0 0;
+  }
+
+  .author {
+    padding: 20px 0;
+    width: 92px;
+    float: left;
+
+    text-align: center;
+
+    h3 {
+      text-align: center;
+      color: #4a6b82;
+      font-size: 13px;
+      margin: 0;
+    }
+  }
+
+  .cooked {
+    padding: 20px 0;
+    margin-left: 92px;
+
+    p {
+      margin: 0 0 1em 0;
+    }
+  }
+}
+
+header {
+  padding: 10px 10px 20px 10px;
+
+  font-size: 18px;
+
+  border-bottom: 1px solid #ddd;
+}
+
+footer {
+  font-size: 18px;
+
+  .logo {
+    margin-right: 10px;
+    margin-top: 10px;
+  }
+
+  a[href].button {
+    margin: 10px 0 0 10px;
+  }
+}
+
+.logo {
+  float: right;
+  max-height: 30px;
+}
+
+a[href].button {
+  background-color: #eee;
+  padding: 5px;
+  display: inline-block;
+}

app/controllers/embed_controller.rb

@@ -0,0 +1,34 @@
+class EmbedController < ApplicationController
+  skip_before_filter :check_xhr
+  skip_before_filter :preload_json
+  before_filter :ensure_embeddable
+
+  layout 'embed'
+
+  def best
+    embed_url = params.require(:embed_url)
+    topic_id = TopicEmbed.topic_id_for_embed(embed_url)
+
+    if topic_id
+      @topic_view = TopicView.new(topic_id, current_user, {best: 5})
+    else
+      Jobs.enqueue(:retrieve_topic, user_id: current_user.try(:id), embed_url: embed_url)
+      render 'loading'
+    end
+
+    discourse_expires_in 1.minute
+  end
+
+  private
+
+    def ensure_embeddable
+      raise Discourse::InvalidAccess.new('embeddable host not set') if SiteSetting.embeddable_host.blank?
+      raise Discourse::InvalidAccess.new('invalid referer host') if URI(request.referer || '').host != SiteSetting.embeddable_host
+
+      response.headers['X-Frame-Options'] = "ALLOWALL"
+    rescue URI::InvalidURIError
+      raise Discourse::InvalidAccess.new('invalid referer host')
+    end
+
+
+end

app/jobs/regular/retrieve_topic.rb

@@ -0,0 +1,24 @@
+require_dependency 'email/sender'
+require_dependency 'topic_retriever'
+
+module Jobs
+
+  # Asynchronously retrieve a topic from an embedded site
+  class RetrieveTopic < Jobs::Base
+
+    def execute(args)
+      raise Discourse::InvalidParameters.new(:embed_url) unless args[:embed_url].present?
+
+      user = nil
+      if args[:user_id]
+        user = User.where(id: args[:user_id]).first
+      end
+
+      TopicRetriever.new(args[:embed_url], no_throttle: user.try(:staff?)).retrieve
+    end
+
+  end
+
+end
+
+

app/jobs/scheduled/poll_feed.rb

@@ -0,0 +1,41 @@
+#
+# Creates and Updates Topics based on an RSS or ATOM feed.
+#
+require 'digest/sha1'
+require_dependency 'post_creator'
+require_dependency 'post_revisor'
+require 'open-uri'
+
+module Jobs
+  class PollFeed < Jobs::Scheduled
+    recurrence { hourly }
+    sidekiq_options retry: false
+
+    def execute(args)
+      poll_feed if SiteSetting.feed_polling_enabled? &&
+                   SiteSetting.feed_polling_url.present? &&
+                   SiteSetting.embed_by_username.present?
+    end
+
+    def feed_key
+      @feed_key ||= "feed-modified:#{Digest::SHA1.hexdigest(SiteSetting.feed_polling_url)}"
+    end
+
+    def poll_feed
+      user = User.where(username_lower: SiteSetting.embed_by_username.downcase).first
+      return if user.blank?
+
+      require 'simple-rss'
+      rss = SimpleRSS.parse open(SiteSetting.feed_polling_url)
+
+      rss.items.each do |i|
+        url = i.link
+        url = i.id if url.blank? || url !~ /^https?\:\/\//
+
+        content = CGI.unescapeHTML(i.content.scrub)
+        TopicEmbed.import(user, url, i.title, content)
+      end
+    end
+
+  end
+end

app/models/post.rb

@@ -60,6 +60,10 @@ class Post < ActiveRecord::Base
     @types ||= Enum.new(:regular, :moderator_action)
   end
 
+  def self.cook_methods
+    @cook_methods ||= Enum.new(:regular, :raw_html)
+  end
+
   def self.find_by_detail(key, value)
     includes(:post_details).where(post_details: { key: key, value: value }).first
   end
@@ -124,6 +128,11 @@ class Post < ActiveRecord::Base
   end
 
   def cook(*args)
+    # For some posts, for example those imported via RSS, we support raw HTML. In that
+    # case we can skip the rendering pipeline.
+    return raw if cook_method == Post.cook_methods[:raw_html]
+
+    # Default is to cook posts
     Plugin::Filter.apply(:after_post_cook, self, post_analyzer.cook(*args))
   end
 

app/models/topic_embed.rb

@@ -0,0 +1,82 @@
+require_dependency 'nokogiri'
+
+class TopicEmbed < ActiveRecord::Base
+  belongs_to :topic
+  belongs_to :post
+  validates_presence_of :embed_url
+  validates_presence_of :content_sha1
+
+  # Import an article from a source (RSS/Atom/Other)
+  def self.import(user, url, title, contents)
+    return unless url =~ /^https?\:\/\//
+
+    contents << "\n<hr>\n<small>#{I18n.t('embed.imported_from', link: "<a href='#{url}'>#{url}</a>")}</small>\n"
+
+    embed = TopicEmbed.where(embed_url: url).first
+    content_sha1 = Digest::SHA1.hexdigest(contents)
+    post = nil
+
+    # If there is no embed, create a topic, post and the embed.
+    if embed.blank?
+      Topic.transaction do
+        creator = PostCreator.new(user, title: title, raw: absolutize_urls(url, contents), skip_validations: true, cook_method: Post.cook_methods[:raw_html])
+        post = creator.create
+        if post.present?
+          TopicEmbed.create!(topic_id: post.topic_id,
+                             embed_url: url,
+                             content_sha1: content_sha1,
+                             post_id: post.id)
+        end
+      end
+    else
+      post = embed.post
+      # Update the topic if it changed
+      if content_sha1 != embed.content_sha1
+        revisor = PostRevisor.new(post)
+        revisor.revise!(user, absolutize_urls(url, contents), skip_validations: true, bypass_rate_limiter: true)
+        embed.update_column(:content_sha1, content_sha1)
+      end
+    end
+
+    post
+  end
+
+  def self.import_remote(user, url, opts=nil)
+    require 'ruby-readability'
+
+    opts = opts || {}
+    doc = Readability::Document.new(open(url).read,
+                                        tags: %w[div p code pre h1 h2 h3 b em i strong a img],
+                                        attributes: %w[href src])
+
+    TopicEmbed.import(user, url, opts[:title] || doc.title, doc.content)
+  end
+
+  # Convert any relative URLs to absolute. RSS is annoying for this.
+  def self.absolutize_urls(url, contents)
+    uri = URI(url)
+    prefix = "#{uri.scheme}://#{uri.host}"
+    prefix << ":#{uri.port}" if uri.port != 80 && uri.port != 443
+
+    fragment = Nokogiri::HTML.fragment(contents)
+    fragment.css('a').each do |a|
+      href = a['href']
+      if href.present? && href.start_with?('/')
+        a['href'] = "#{prefix}/#{href.sub(/^\/+/, '')}"
+      end
+    end
+    fragment.css('img').each do |a|
+      src = a['src']
+      if src.present? && src.start_with?('/')
+        a['src'] = "#{prefix}/#{src.sub(/^\/+/, '')}"
+      end
+    end
+
+    fragment.to_html
+  end
+
+  def self.topic_id_for_embed(embed_url)
+    TopicEmbed.where(embed_url: embed_url).pluck(:topic_id).first
+  end
+
+end

app/views/embed/best.html.erb

@@ -0,0 +1,30 @@
+<header>
+  <%- if @topic_view.posts.present? %>
+    <%= link_to(I18n.t('embed.title'), @topic_view.topic.url, class: 'button', target: '_blank') %>
+  <%- else %>
+    <%= link_to(I18n.t('embed.start_discussion'), @topic_view.topic.url, class: 'button', target: '_blank') %>
+  <%- end if %>
+
+  <%= link_to(image_tag(SiteSetting.logo_url, class: 'logo'), Discourse.base_url) %>
+</header>
+
+<%- if @topic_view.posts.present? %>
+  <%- @topic_view.posts.each do |post| %>
+    <article class='post'>
+      <%= link_to post.created_at.strftime("%e %b %Y"), post.url, class: 'post-date', target: "_blank" %>
+      <div class='author'>
+        <img src='<%= post.user.small_avatar_url %>'>
+        <h3><%= post.user.username %></h3>
+      </div>
+      <div class='cooked'><%= raw post.cooked %></div>
+      <div style='clear: both'></div>
+    </article>
+  <%- end %>
+
+  <footer>
+    <%= link_to(I18n.t('embed.continue'), @topic_view.topic.url, class: 'button', target: '_blank') %>
+    <%= link_to(image_tag(SiteSetting.logo_url, class: 'logo'), Discourse.base_url) %>
+  </footer>
+
+<% end %>
+

app/views/embed/loading.html.erb

@@ -0,0 +1,12 @@
+<header>
+  <%= t 'embed.loading' %>
+  <%= link_to(image_tag(SiteSetting.logo_url, class: 'logo'), Discourse.base_url) %>
+</header>
+
+<script>
+  (function() {
+    setTimeout(function() {
+      document.location.reload();
+    }, 30000);
+  })();
+</script>

app/views/layouts/embed.html.erb

@@ -0,0 +1,20 @@
+<!DOCTYPE html>
+<html>
+  <head>
+    <%= stylesheet_link_tag 'embed' %>
+
+    <script>
+      (function() {
+        window.onload = function() {
+          if (parent) {
+            // Send a post message with our loaded height
+            parent.postMessage({type: 'discourse-resize', height: document['body'].offsetHeight}, '<%= request.referer %>');
+          }
+        }
+      })();
+    </script>
+  </head>
+  <body>
+    <%= yield %>
+  </body>
+</html>

config/locales/client.en.yml

@@ -1474,6 +1474,7 @@ en:
           spam: 'Spam'
           rate_limits: 'Rate Limits'
           developer: 'Developer'
+          embedding: "Embedding"
           uncategorized: 'Uncategorized'
 
     lightbox:

config/locales/server.en.yml

@@ -29,6 +29,14 @@ en:
 
   too_many_replies: "Sorry you can't reply any more times in that topic."
 
+  embed:
+    title: "Discussion Highlights"
+    start_discussion: "Begin the Discussion"
+    continue: "Continue the Discussion"
+    loading: "Loading Discussion..."
+    permalink: "Permalink"
+    imported_from: "Imported from: %{link}"
+
   too_many_mentions:
     zero: "Sorry, you can't mention other users."
     one: "Sorry, you can only mention one other user in a post."
@@ -757,6 +765,11 @@ en:
     short_progress_text_threshold: "After the number of posts in a topic goes above this number, the progress bar will only show the current post number. If you change the progress bar's width, you may need to change this value."
     default_code_lang: "Default programming language syntax highlighting applied to GitHub code blocks (lang-auto, ruby, python etc.)"
 
+    embeddable_host: "Host that can embed the comments from this Discourse forum"
+    feed_polling_enabled: "Whether to import a RSS/ATOM feed as posts"
+    feed_polling_url: "URL of RSS/ATOM feed to import"
+    embed_by_username: "Discourse username of the user who creates the topics"
+
   notification_types:
     mentioned: "%{display_username} mentioned you in %{link}"
     liked: "%{display_username} liked your post in %{link}"

config/routes.rb

@@ -242,6 +242,8 @@ Discourse::Application.routes.draw do
   get "topics/private-messages-sent/:username" => "list#private_messages_sent", as: "topics_private_messages_sent", constraints: {username: USERNAME_ROUTE_FORMAT}
   get "topics/private-messages-unread/:username" => "list#private_messages_unread", as: "topics_private_messages_unread", constraints: {username: USERNAME_ROUTE_FORMAT}
 
+  get 'embed/best' => 'embed#best'
+
   # Topic routes
   get "t/:slug/:topic_id/wordpress" => "topics#wordpress", constraints: {topic_id: /\d+/}
   get "t/:slug/:topic_id/moderator-liked" => "topics#moderator_liked", constraints: {topic_id: /\d+/}

config/site_settings.yml

@@ -350,6 +350,12 @@ developer:
       test: false
       default: true
 
+embedding:
+  embeddable_host: ''
+  feed_polling_enabled: false
+  feed_polling_url: ''
+  embed_by_username: ''
+
 uncategorized:
   tos_url:
     client: true

db/migrate/20131217174004_create_topic_embeds.rb

@@ -0,0 +1,13 @@
+class CreateTopicEmbeds < ActiveRecord::Migration
+  def change
+    create_table :topic_embeds, force: true do |t|
+      t.integer :topic_id, null: false
+      t.integer :post_id, null: false
+      t.string :embed_url, null: false
+      t.string :content_sha1, null: false, limit: 40
+      t.timestamps
+    end
+
+    add_index :topic_embeds, :embed_url, unique: true
+  end
+end

db/migrate/20131219203905_add_cook_method_to_posts.rb

@@ -0,0 +1,5 @@
+class AddCookMethodToPosts < ActiveRecord::Migration
+  def change
+    add_column :posts, :cook_method, :integer, default: 1, null: false
+  end
+end

db/migrate/20131223171005_create_top_topics.rb

@@ -1,6 +1,6 @@
 class CreateTopTopics < ActiveRecord::Migration
   def change
-    create_table :top_topics do |t|
+    create_table :top_topics, force: true do |t|
       t.belongs_to :topic
 
       TopTopic.periods.each do |period|

lib/post_creator.rb

@@ -213,6 +213,7 @@ class PostCreator
       post.send("#{a}=", @opts[a]) if @opts[a].present?
     end
 
+    post.cook_method = @opts[:cook_method] if @opts[:cook_method].present?
     post.extract_quoted_post_numbers
     post.created_at = Time.zone.parse(@opts[:created_at].to_s) if @opts[:created_at].present?
     @post = post

lib/post_revisor.rb

@@ -11,7 +11,6 @@ class PostRevisor
   def revise!(user, new_raw, opts = {})
     @user, @new_raw, @opts = user, new_raw, opts
     return false if not should_revise?
-
     @post.acting_user = @user
     revise_post
     update_category_description
@@ -83,7 +82,8 @@ class PostRevisor
     end
 
     @post.extract_quoted_post_numbers
-    @post.save
+    @post.save(validate: !@opts[:skip_validations])
+
     @post.save_reply_relationships
   end
 

lib/tasks/disqus.thor

@@ -114,7 +114,6 @@ class Disqus < Thor
   method_option :dry_run, required: false, desc: "Just output what will be imported rather than doing it"
   method_option :post_as, aliases: '-p', required: true, desc: "The Discourse username to post as"
   method_option :strip, aliases: '-s', required: false, desc: "Text to strip from titles"
-  method_option :category, aliases: '-c', desc: "The category to post in"
 
   def import
     require './config/environment'
@@ -141,18 +140,12 @@ class Disqus < Thor
 
     SiteSetting.email_domains_blacklist = ""
 
-    category_id = nil
-    if options[:category]
-      category_id = Category.where(name: options[:category]).first.try(:id)
-    end
-
     parser.threads.each do |id, t|
       puts "Creating #{t[:title]}... (#{t[:posts].size} posts)"
 
       if options[:dry_run].blank?
-        creator = PostCreator.new(user, title: t[:title], raw: "\[[Permalink](#{t[:link]})\]", created_at: Date.parse(t[:created_at]), category: category_id)
-        post = creator.create
 
+        post = TopicEmbed.import_remote(user, t[:link], title: t[:title])
         if post.present?
           t[:posts].each do |p|
             post_user = user

lib/topic_retriever.rb

@@ -0,0 +1,55 @@
+class TopicRetriever
+
+  def initialize(embed_url, opts=nil)
+    @embed_url = embed_url
+    @opts = opts || {}
+  end
+
+  def retrieve
+    perform_retrieve unless (invalid_host? || retrieved_recently?)
+  end
+
+  private
+
+    def invalid_host?
+      SiteSetting.embeddable_host != URI(@embed_url).host
+    rescue URI::InvalidURIError
+      # An invalid URI is an invalid host
+      true
+    end
+
+    def retrieved_recently?
+      # We can disable the throttle for some users, such as staff
+      return false if @opts[:no_throttle]
+
+      # Throttle other users to once every 60 seconds
+      retrieved_key = "retrieved:#{@embed_url}"
+      if $redis.setnx(retrieved_key, "1")
+        $redis.expire(retrieved_key, 60)
+        return false
+      end
+
+      true
+    end
+
+    def perform_retrieve
+      # It's possible another process or job found the embed already. So if that happened bail out.
+      return if TopicEmbed.where(embed_url: @embed_url).exists?
+
+      # First check RSS if that is enabled
+      if SiteSetting.feed_polling_enabled?
+        Jobs::PollFeed.new.execute({})
+        return if TopicEmbed.where(embed_url: @embed_url).exists?
+      end
+
+      fetch_http
+    end
+
+    def fetch_http
+      user = User.where(username_lower: SiteSetting.embed_by_username.downcase).first
+      return if user.blank?
+
+      TopicEmbed.import_remote(user, @embed_url)
+    end
+
+end

spec/components/topic_retriever_spec.rb

@@ -0,0 +1,46 @@
+require 'spec_helper'
+require_dependency 'topic_retriever'
+
+describe TopicRetriever do
+
+  let(:embed_url) { "http://eviltrout.com/2013/02/10/why-discourse-uses-emberjs.html" }
+  let(:topic_retriever) { TopicRetriever.new(embed_url) }
+
+  it "does not call perform_retrieve when embeddable_host is not set" do
+    SiteSetting.expects(:embeddable_host).returns(nil)
+    topic_retriever.expects(:perform_retrieve).never
+    topic_retriever.retrieve
+  end
+
+  it "does not call perform_retrieve when embeddable_host is different than the host of the URL" do
+    SiteSetting.expects(:embeddable_host).returns("eviltuna.com")
+    topic_retriever.expects(:perform_retrieve).never
+    topic_retriever.retrieve
+  end
+
+  it "does not call perform_retrieve when the embed url is not a url" do
+    r = TopicRetriever.new("not a url")
+    r.expects(:perform_retrieve).never
+    r.retrieve
+  end
+
+  context "with a valid host" do
+    before do
+      SiteSetting.expects(:embeddable_host).returns("eviltrout.com")
+    end
+
+    it "calls perform_retrieve if it hasn't been retrieved recently" do
+      topic_retriever.expects(:perform_retrieve).once
+      topic_retriever.expects(:retrieved_recently?).returns(false)
+      topic_retriever.retrieve
+    end
+
+    it "doesn't call perform_retrieve if it's been retrieved recently" do
+      topic_retriever.expects(:perform_retrieve).never
+      topic_retriever.expects(:retrieved_recently?).returns(true)
+      topic_retriever.retrieve
+    end
+
+  end
+
+end

spec/controllers/embed_controller_spec.rb

@@ -0,0 +1,58 @@
+require 'spec_helper'
+
+describe EmbedController do
+
+  let(:host) { "eviltrout.com" }
+  let(:embed_url) { "http://eviltrout.com/2013/02/10/why-discourse-uses-emberjs.html" }
+
+  it "is 404 without an embed_url" do
+    get :best
+    response.should_not be_success
+  end
+
+  it "raises an error with a missing host" do
+    SiteSetting.stubs(:embeddable_host).returns(nil)
+    get :best, embed_url: embed_url
+    response.should_not be_success
+  end
+
+  context "with a host" do
+    before do
+      SiteSetting.stubs(:embeddable_host).returns(host)
+    end
+
+    it "raises an error with no referer" do
+      get :best, embed_url: embed_url
+      response.should_not be_success
+    end
+
+    context "success" do
+
+      before do
+        controller.request.stubs(:referer).returns(embed_url)
+      end
+
+      after do
+        response.should be_success
+        response.headers['X-Frame-Options'].should == "ALLOWALL"
+      end
+
+      it "tells the topic retriever to work when no previous embed is found" do
+        TopicEmbed.expects(:topic_id_for_embed).returns(nil)
+        retriever = mock
+        TopicRetriever.expects(:new).returns(retriever)
+        retriever.expects(:retrieve)
+        get :best, embed_url: embed_url
+      end
+
+      it "creates a topic view when a topic_id is found" do
+        TopicEmbed.expects(:topic_id_for_embed).returns(123)
+        TopicView.expects(:new).with(123, nil, {best: 5})
+        get :best, embed_url: embed_url
+      end
+    end
+
+  end
+
+
+end

spec/jobs/poll_feed_spec.rb

@@ -0,0 +1,40 @@
+require 'spec_helper'
+require_dependency 'jobs/regular/process_post'
+
+describe Jobs::PollFeed do
+
+  let(:poller) { Jobs::PollFeed.new }
+
+  context "execute" do
+    let(:url) { "http://eviltrout.com" }
+    let(:embed_by_username) { "eviltrout" }
+
+    it "requires feed_polling_enabled?" do
+      SiteSetting.stubs(:feed_polling_enabled?).returns(false)
+      poller.expects(:poll_feed).never
+      poller.execute({})
+    end
+
+    it "requires feed_polling_url" do
+      SiteSetting.stubs(:feed_polling_url).returns(nil)
+      poller.expects(:poll_feed).never
+      poller.execute({})
+    end
+
+    it "requires embed_by_username" do
+      SiteSetting.stubs(:embed_by_username).returns(nil)
+      poller.expects(:poll_feed).never
+      poller.execute({})
+    end
+
+
+    it "delegates to poll_feed" do
+      SiteSetting.stubs(:feed_polling_enabled?).returns(true)
+      SiteSetting.stubs(:feed_polling_url).returns(url)
+      SiteSetting.stubs(:embed_by_username).returns(embed_by_username)
+      poller.expects(:poll_feed).once
+      poller.execute({})
+    end
+  end
+
+end

spec/models/topic_embed_spec.rb

@@ -0,0 +1,48 @@
+require 'spec_helper'
+
+describe TopicEmbed do
+
+  it { should belong_to :topic }
+  it { should belong_to :post }
+  it { should validate_presence_of :embed_url }
+  it { should validate_presence_of :content_sha1 }
+
+
+  context '.import' do
+
+    let(:user) { Fabricate(:user) }
+    let(:title) { "How to turn a fish from good to evil in 30 seconds" }
+    let(:url) { 'http://eviltrout.com/123' }
+    let(:contents) { "hello world new post <a href='/hello'>hello</a> <img src='/images/wat.jpg'>" }
+
+    it "returns nil when the URL is malformed" do
+      TopicEmbed.import(user, "invalid url", title, contents).should be_nil
+      TopicEmbed.count.should == 0
+    end
+
+    context 'creation of a post' do
+      let!(:post) { TopicEmbed.import(user, url, title, contents) }
+
+      it "works as expected with a new URL" do
+        post.should be_present
+
+        # It uses raw_html rendering
+        post.cook_method.should == Post.cook_methods[:raw_html]
+        post.cooked.should == post.raw
+
+        # It converts relative URLs to absolute
+        post.cooked.start_with?("hello world new post <a href=\"http://eviltrout.com/hello\">hello</a> <img src=\"http://eviltrout.com/images/wat.jpg\">").should be_true
+
+        TopicEmbed.where(topic_id: post.topic_id).should be_present
+      end
+
+      it "Supports updating the post" do
+        post = TopicEmbed.import(user, url, title, "muhahaha new contents!")
+        post.cooked.should =~ /new contents/
+      end
+
+    end
+
+  end
+
+end