Initial release of Discourse

app/models/topic_link.rb

@@ -0,0 +1,112 @@
+require 'uri'
+require_dependency 'slug'
+
+class TopicLink < ActiveRecord::Base
+  
+  belongs_to :topic
+  belongs_to :user
+  belongs_to :post
+  belongs_to :link_topic, class_name: 'Topic'
+
+  validates_presence_of :url
+
+  validates_length_of :url, maximum: 500
+
+  validates_uniqueness_of :url, scope: [:topic_id, :post_id]
+
+  has_many :topic_link_clicks
+
+  validate :link_to_self
+
+  # Make sure a topic can't link to itself
+  def link_to_self
+    errors.add(:base, "can't link to the same topic") if (topic_id == link_topic_id)
+  end
+
+  # Extract any urls in body
+  def self.extract_from(post)
+    return unless post.present?
+    
+    TopicLink.transaction do
+
+      added_urls = []
+      reflected_urls = []
+
+      PrettyText
+        .extract_links(post.cooked)
+        .map{|u| [u, URI.parse(u)] rescue nil}
+        .reject{|u,p| p.nil?}
+        .uniq{|u,p| u}
+        .each do |url, parsed|    
+        begin
+
+          internal = false
+          topic_id = nil
+          post_number = nil
+          if parsed.host == Discourse.current_hostname || !parsed.host
+            internal = true
+            
+            route = Rails.application.routes.recognize_path(parsed.path)
+            topic_id = route[:topic_id]
+            post_number = route[:post_number] || 1
+          end
+
+          # Skip linking to ourselves
+          next if topic_id == post.topic_id
+
+          added_urls << url
+          TopicLink.create(post_id: post.id, 
+                                 user_id: post.user_id, 
+                                 topic_id: post.topic_id,
+                                 url: url,
+                                 domain: parsed.host || Discourse.current_hostname,
+                                 internal: internal,
+                                 link_topic_id: topic_id)
+
+          # Create the reflection if we can
+          if topic_id.present?
+            topic = Topic.where(id: topic_id).first
+
+            if topic && post.topic.archetype != 'private_message' && topic.archetype != 'private_message'
+
+              prefix = Discourse.base_url
+
+              reflected_post = nil
+              if post_number.present?
+                reflected_post = Post.where(topic_id: topic_id, post_number: post_number.to_i).first
+              end
+
+              reflected_url = "#{prefix}#{post.topic.relative_url(post.post_number)}"
+
+              reflected_urls << reflected_url
+              TopicLink.create(user_id: post.user_id,
+                                     topic_id: topic_id,
+                                     post_id: reflected_post.try(:id),
+                                     url: reflected_url,
+                                     domain: Discourse.current_hostname,
+                                     reflection: true,
+                                     internal: true,
+                                     link_topic_id: post.topic_id,
+                                     link_post_id: post.id)
+            end
+          end
+
+        rescue URI::InvalidURIError
+          # if the URI is invalid, don't store it.
+        rescue ActionController::RoutingError
+          # If we can't find the route, no big deal  
+        end
+      end  
+
+      # Remove links that aren't there anymore
+      if added_urls.present?
+        TopicLink.delete_all ["(url not in (:urls)) AND (post_id = :post_id)", urls: added_urls, post_id: post.id]
+        TopicLink.delete_all ["(url not in (:urls)) AND (link_post_id = :post_id)", urls: reflected_urls, post_id: post.id]
+      else
+        TopicLink.delete_all ["post_id = :post_id OR link_post_id = :post_id", post_id: post.id]
+      end
+
+    end
+  end
+
+end