use observers

app.rb

@@ -22,6 +22,10 @@ Mongoid.logger.level = Logger::INFO
 
 Dir[File.dirname(__FILE__) + '/lib/**/*.rb'].each {|file| require file}
 Dir[File.dirname(__FILE__) + '/models/*.rb'].each {|file| require file}
+Dir[File.dirname(__FILE__) + '/models/observers/*.rb'].each {|file| require file}
+
+Mongoid.observers = PostReplyObserver, PostTopicObserver, AtUserObserver
+Mongoid.instantiate_observers
 
 api_prefix = CommentService::API_PREFIX
 
@@ -227,7 +231,6 @@ end
 
 put "#{api_prefix}/users/:user_id" do |user_id|
   user.update_attributes(params.slice(*%w[username email]))
-  user.save
   if user.errors.any?
     error 400, user.errors.full_messages.to_json
   else

models/comment.rb

@@ -12,6 +12,7 @@ class Comment < Content
   field :course_id, type: String
   field :endorsed, type: Boolean, default: false
   field :anonymous, type: Boolean, default: false
+  field :at_position_list, type: Array, default: []
 
   belongs_to :author, class_name: "User", index: true
   belongs_to :comment_thread, index: true
@@ -26,7 +27,6 @@ class Comment < Content
   counter_cache :comment_thread
 
   before_destroy :delete_descendants # TODO async
-  after_create :generate_notifications
   
   def self.hash_tree(nodes)
     nodes.map{|node, sub_nodes| node.to_hash.merge("children" => hash_tree(sub_nodes).compact)}
@@ -53,30 +53,4 @@ class Comment < Content
     end
   end
 
-private
-  def generate_notifications
-    if comment_thread.subscribers or (author.followers if not anonymous)
-      notification = Notification.new(
-        notification_type: "post_reply",
-        info: {
-          thread_id: comment_thread.id,
-          thread_title: comment_thread.title,
-          comment_id: id,
-          commentable_id: comment_thread.commentable_id,
-        },
-      )
-      notification.actor = author if not anonymous
-      notification.target = self
-      receivers = comment_thread.subscribers
-      if not anonymous
-        receivers = (receivers + author.followers).uniq_by(&:id)
-      end
-      receivers.delete(author)
-      notification.receivers << receivers
-      notification.save!
-    end
-  end
-
-  handle_asynchronously :generate_notifications
-
 end

models/comment_thread.rb

@@ -13,6 +13,7 @@ class CommentThread < Content
   field :course_id, type: String
   field :commentable_id, type: String
   field :anonymous, type: Boolean, default: false
+  field :at_position_list, type: Array, default: []
 
   include Sunspot::Mongoid
   searchable do
@@ -47,8 +48,6 @@ class CommentThread < Content
   validate :tag_names_valid
   validate :tag_names_unique
 
-  after_create :generate_notifications
-
   def self.new_dumb_thread(options={})
     c = self.new
     c.title = options[:title] || "title"
@@ -106,28 +105,6 @@ class CommentThread < Content
   end
 
 private
-  def generate_notifications
-    if subscribers or (author.followers if not anonymous)
-      notification = Notification.new(
-        notification_type: "post_topic",
-        info: {
-          commentable_id: commentable_id,
-          #commentable_type: commentable.commentable_type,
-          thread_id: id,
-          thread_title: title,
-        },
-      )
-      notification.actor = author if not anonymous
-      notification.target = self
-      receivers = commentable.subscribers
-      if not anonymous
-        receivers = (receivers + author.followers).uniq_by(&:id)
-      end
-      receivers.delete(author)
-      notification.receivers << receivers
-      notification.save!
-    end
-  end
 
   RE_HEADCHAR = /[a-z0-9]/
   RE_ENDONLYCHAR = /\+/
@@ -149,6 +126,4 @@ private
       errors.add :tags, "must be unique"
     end
   end
-
-  handle_asynchronously :generate_notifications
 end

models/content.rb

 class Content
   include Mongoid::Document
-  
-  AT_NOTIFICATION_REGEX = /(?<=^|\s)(@[A-Za-z0-9_]+)(?!\w)/
-  
-
-private
-  def self.get_marked_text(text)
-    counter = -1
-    text.gsub AT_NOTIFICATION_REGEX do
-      counter += 1
-      "#{$1}_#{counter}"
-    end
-  end
-
-  def self.get_at_position_list(text)
-    list = []
-    text.gsub AT_NOTIFICATION_REGEX do
-      parts = $1.rpartition('_')
-      username = parts.first[1..-1]
-      user = User.where(username: username).first
-      if user
-        list << [parts.last.to_i, parts.first[1..-1], user.id]
-      end
-    end
-    list
-  end
-
-  def self.get_valid_at_position_list(text)
-    html = Nokogiri::HTML(RDiscount.new(self.get_marked_text(text)).to_html)
-    html.xpath('//code').each do |c|
-      c.children = ''
-    end
-    self.get_at_position_list html.to_s
-  end
-
-
 end

models/observers/at_user_observer.rb

+require 'set'
+
+class AtUserObserver < Mongoid::Observer
+  observe :comment, :comment_thread
+
+  def after_create(content)
+    self.class.delay.process_at_notifications(content)
+  end
+
+  def self.process_at_notifications(content)
+    text = content.body
+
+    content_type = content.respond_to?(:title) ? :thread : :comment
+    text = content.title + "\n\n" + text if content_type == :thread
+
+    at_positions = self.get_valid_at_position_list text 
+    prev_at_positions = content.at_position_list
+
+    content.update_attributes!(at_position_list: at_positions)
+
+    prev_user_ids = prev_at_positions.map { |x| x[:user_id] }.to_set
+    current_user_ids = at_positions.map { |x| x[:user_id] }.to_set
+
+    new_user_ids = current_user_ids - prev_user_ids
+
+    unless new_user_ids.empty?
+      notification = Notification.new(
+        notification_type: "at_user",
+        info: {
+          content_id: content.id,
+          content_type: content_type,
+          thread_title: content_type == :thread ? content.title : content.comment_thread.title,
+        }
+      )
+      notification.actor = content.author if not content.anonymous
+      notification.target = content
+      receivers = new_user_ids.map { |id| User.find(id) }
+      receivers.delete(content.author)
+      notification.receiverss << receivers
+      notification.save!
+    end
+  end
+
+private
+
+  AT_NOTIFICATION_REGEX = /(?<=^|\s)(@[A-Za-z0-9_]+)(?!\w)/
+
+  def self.get_marked_text(text)
+    counter = -1
+    text.gsub AT_NOTIFICATION_REGEX do
+      counter += 1
+      "#{$1}_#{counter}"
+    end
+  end
+
+  def self.get_at_position_list(text)
+    list = []
+    text.gsub AT_NOTIFICATION_REGEX do
+      parts = $1.rpartition('_')
+      username = parts.first[1..-1]
+      user = User.where(username: username).first
+      if user
+        list << { position: parts.last.to_i, username: parts.first[1..-1], user_id: user.id }#parts.last.to_i, parts.first[1..-1], user.id]
+      end
+    end
+    list
+  end
+
+  def self.get_valid_at_position_list(text)
+    html = Nokogiri::HTML(RDiscount.new(self.get_marked_text(text)).to_html)
+    html.xpath('//code').each do |c|
+      c.children = ''
+    end
+    self.get_at_position_list html.to_s
+  end
+end

models/observers/post_reply_observer.rb

+class PostReplyObserver < Mongoid::Observer
+  observe :comment
+
+  def after_create(comment)
+    self.class.delay.generate_notifications(comment)
+  end
+    
+  def self.generate_notifications(comment)
+    if comment.comment_thread.subscribers or (comment.author.followers if not comment.anonymous)
+      notification = Notification.new(
+        notification_type: "post_reply",
+        info: {
+          thread_id: comment.comment_thread.id,
+          thread_title: comment.comment_thread.title,
+          comment_id: comment.id,
+          commentable_id: comment.comment_thread.commentable_id,
+        },
+      )
+      notification.actor = comment.author if not comment.anonymous
+      notification.target = comment
+      receivers = comment.comment_thread.subscribers
+      if not comment.anonymous
+        receivers = (receivers + comment.author.followers).uniq_by(&:id)
+      end
+      receivers.delete(comment.author)
+      notification.receivers << receivers
+      notification.save!
+    end
+  end
+end

models/observers/post_topic_observer.rb

+class PostTopicObserver < Mongoid::Observer
+  observe :comment_thread
+
+  def after_create(comment_thread)
+    self.class.delay.generate_notifications(comment_thread)
+  end
+  
+  def self.generate_notifications(comment_thread)
+    if comment_thread.commentable.subscribers or (author.followers if not anonymous)
+      notification = Notification.new(
+        notification_type: "post_topic",
+        info: {
+          commentable_id: comment_thread.commentable_id,
+          #commentable_type: commentable.commentable_type,
+          thread_id: comment_thread.id,
+          thread_title: comment_thread.title,
+        },
+      )
+      notification.actor = comment_thread.author if not comment_thread.anonymous
+      notification.target = comment_thread
+      receivers = comment_thread.commentable.subscribers
+      if not comment_thread.anonymous
+        receivers = (receivers + comment_thread.author.followers).uniq_by(&:id)
+      end
+      receivers.delete(comment_thread.author)
+      notification.receivers << receivers
+      notification.save!
+    end
+  end
+end

spec/models/content_spec.rb

@@ -39,8 +39,8 @@ what is the 'at' symbol doing there? @dementrock
   describe "#get_valid_at_position_list(text)" do
     it "returns the list of positions for the valid @ notifications, filtering out the ones in code blocks" do
       list = Content.get_valid_at_position_list(@text)
-      list.should include [0, "tom", "1"]
-      list.should include [1, "pi314", "2"]
+      list.should include({ position: 0, username: "tom", user_id: "1" })
+      list.should include({ position: 1, username: "pi314", user_id: "2" })
       list.length.should == 2
     end
   end