move IncomingLink callbacks into their own methods

app/models/incoming_link.rb

@@ -3,33 +3,36 @@ class IncomingLink < ActiveRecord::Base
 
   validates :domain, length: { in: 1..100 }
   validates :referer, length: { in: 3..1000 }
-  validates_presence_of :url
+  validates :url, presence: true
 
-  # Extract the domain
-  before_validation do
-    # Referer (remote URL)
+  before_validation :extract_domain
+  before_validation :extract_topic_and_post
+  after_create :update_link_counts
+
+  # Internal: Extract the domain from link.
+  def extract_domain
     if referer.present?
-      parsed = URI.parse(referer)
-      self.domain = parsed.host
+      self.domain = URI.parse(referer).host
     end
+  end
 
-    # Our URL
+  # Internal: If link is internal and points to topic/post, extract their IDs.
+  def extract_topic_and_post
     if url.present?
-
       parsed = URI.parse(url)
 
       begin
         params = Rails.application.routes.recognize_path(parsed.path)
-        self.topic_id = params[:topic_id] if params[:topic_id].present?
-        self.post_number = params[:post_number] if params[:post_number].present?
+        self.topic_id = params[:topic_id]
+        self.post_number = params[:post_number]
       rescue ActionController::RoutingError
         # If we can't route to the url, that's OK. Don't save those two fields.
       end
     end
   end
 
-  # Update appropriate incoming link counts
-  after_create do
+  # Internal: Update appropriate link counts.
+  def update_link_counts
     if topic_id.present?
       exec_sql("UPDATE topics
                 SET incoming_link_count = incoming_link_count + 1