get rid of the commentable collection in the database

app.rb

@@ -19,19 +19,17 @@ Mongoid.logger.level = Logger::INFO
 
 Dir[File.dirname(__FILE__) + '/models/*.rb'].each {|file| require file}
 
-delete '/api/v1/:commentable_type/:commentable_id/threads' do |commentable_type, commentable_id|
-  commentable = Commentable.find_or_initialize_by(commentable_type: commentable_type, commentable_id: commentable_id)
-  commentable.destroy
-  commentable.to_hash.to_json
+delete '/api/v1/:commentable_id/threads' do |commentable_id|
+  Commentable.find(commentable_id).comment_threads.destroy_all
+  {}.to_json
 end
 
-get '/api/v1/:commentable_type/:commentable_id/threads' do |commentable_type, commentable_id|
-  commentable = Commentable.find_or_create_by(commentable_type: commentable_type, commentable_id: commentable_id)
-  commentable.comment_threads.map{|t| t.to_hash(recursive: params["recursive"])}.to_json
+get '/api/v1/:commentable_id/threads' do |commentable_id|
+  Commentable.find(commentable_id).comment_threads.map{|t| t.to_hash(recursive: params["recursive"])}.to_json
 end
 
-post '/api/v1/:commentable_type/:commentable_id/threads' do |commentable_type, commentable_id|
-  commentable = Commentable.find_or_create_by(commentable_type: commentable_type, commentable_id: commentable_id)
+post '/api/v1/:commentable_id/threads' do |commentable_id|
+  commentable = Commentable.find(commentable_id)#_or_create_by(commentable_type: commentable_type, commentable_id: commentable_id)
   thread = commentable.comment_threads.new(params.slice(*%w[title body course_id]))
   thread.author = User.find_or_create_by(external_id: params["user_id"]) if params["user_id"]
   thread.save!
@@ -120,8 +118,8 @@ post '/api/v1/users/:user_id/subscriptions' do |user_id|
       User.find_or_create_by(external_id: params["source_id"])
     when "thread"
       CommentThread.find(params["source_id"])
-    else
-      Commentable.find_or_create_by(commentable_type: params["source_type"], commentable_id: params["source_id"])
+    when "other"
+      Commentable.find(params["source_id"])#find_or_create_by(commentable_type: params["source_type"], commentable_id: params["source_id"])
   end
   user.subscribe(source).to_hash.to_json
 end
@@ -134,7 +132,7 @@ delete '/api/v1/users/:user_id/subscriptions' do |user_id|
     when "thread"
       CommentThread.find(params["source_id"])
     else
-      Commentable.find_or_create_by(commentable_type: params["source_type"], commentable_id: params["source_id"])
+      Commentable.find(params["source_id"])#find_or_create_by(commentable_type: params["source_type"], commentable_id: params["source_id"])
   end
   user.unsubscribe(source).to_hash.to_json
 end

models/comment_thread.rb

@@ -9,13 +9,12 @@ class CommentThread < Content
   field :title, type: String
   field :body, type: String
   field :course_id, type: String, index: true
+  field :commentable_id, type: String, index: true
 
   belongs_to :author, class_name: "User", inverse_of: :comment_threads, index: true, autosave: true
-  belongs_to :commentable, index: true, autosave: true
   has_many :comments, dependent: :destroy, autosave: true# Use destroy to envoke callback on the top-level comments TODO async
-  has_many :subscriptions, as: :source
 
-  attr_accessible :title, :body, :course_id
+  attr_accessible :title, :body, :course_id, :commentable_id
 
   validates_presence_of :title
   validates_presence_of :body
@@ -24,6 +23,14 @@ class CommentThread < Content
 
   after_create :handle_after_create
 
+  def commentable
+    Commentable.find(commentable_id)
+  end
+
+  def subscriptions
+    Subscription.where(source_id: id.to_s, source_type: self.class.to_s)
+  end
+
   def subscribers
     subscriptions.map(&:subscriber)
   end
@@ -44,8 +51,8 @@ private
       notification = Notification.new(
         notification_type: "post_topic",
         info: {
-          commentable_id: commentable.commentable_id,
-          commentable_type: commentable.commentable_type,
+          commentable_id: commentable_id,
+          #commentable_type: commentable.commentable_type,
           thread_id: id,
           thread_title: title,
         },

models/commentable.rb

 class Commentable
-  include Mongoid::Document
 
-  field :commentable_type, type: String
-  field :commentable_id, type: String
+  attr_accessor :id
+  alias_attribute :_id, :id
+  
+  class << self; alias_method :find, :new; end
 
-  has_many :comment_threads, dependent: :destroy
-  has_many :subscriptions, as: :source
-
-  attr_accessible :commentable_type, :commentable_id
+  def initialize(id)
+    self.id = id
+  end
 
-  validates_presence_of :commentable_type
-  validates_presence_of :commentable_id
-  validates_uniqueness_of :commentable_id, scope: :commentable_type
+  def comment_threads
+    CommentThread.where(commentable_id: id)
+  end
 
-  index [[:commentable_type, Mongo::ASCENDING], [:commentable_id, Mongo::ASCENDING]]
+  def subscriptions
+    Subscription.where(source_id: id.to_s, source_type: self.class.to_s)
+  end
 
   def subscribers
     subscriptions.map(&:subscriber)
   end
 
-  def to_hash(params={})
-    as_document.slice(*%w[_id commentable_type commentable_id])
-  end
-
 end

models/subscription.rb

@@ -2,8 +2,9 @@ class Subscription
   include Mongoid::Document
   include Mongoid::Timestamps
   
-  belongs_to :subscriber, class_name: "User", autosave: true, index: true
-  belongs_to :source, polymorphic: true, autosave: true, index: true
+  field :subscriber_id, type: String
+  field :source_id, type: String
+  field :source_type, type: String
   
   index [[:subscriber_id, Mongo::ASCENDING], [:source_id, Mongo::ASCENDING], [:source_type, Mongo::ASCENDING]]
 
@@ -11,4 +12,12 @@ class Subscription
     as_document
   end
 
+  def subscriber
+    User.find(subscriber_id)
+  end
+
+  def source
+    source_type.constantize.find(source_id)
+  end
+
 end

models/user.rb

@@ -7,13 +7,19 @@ class User
   has_many :comments
   has_many :comment_threads, inverse_of: :author
   has_many :activities, class_name: "Notification", inverse_of: :actor
-  has_many :subscriptions_as_source, class_name: "Subscription", as: :source
-  has_many :subscriptions_as_subscriber, class_name: "Subscription", inverse_of: :subscriber
   has_and_belongs_to_many :notifications, inverse_of: :receivers
 
   validates_presence_of :external_id
   validates_uniqueness_of :external_id
 
+  def subscriptions_as_source
+    Subscription.where(source_id: id.to_s, source_type: self.class.to_s)
+  end
+
+  def subscriptions_as_subscriber
+    Subscription.where(subscriber_id: id.to_s)
+  end
+
   def to_hash(params={})
     as_document.slice(*%w[_id external_id])
   end

spec/app_spec.rb

@@ -11,17 +11,15 @@ end
 def init_without_subscriptions
   Comment.delete_all
   CommentThread.delete_all
-  Commentable.delete_all
   User.delete_all
   Notification.delete_all
   Subscription.delete_all
   
-  commentable = Commentable.new(commentable_type: "questions", commentable_id: "1")
-  commentable.save!
+  commentable = Commentable.new("question_1")
 
   user = User.create!(external_id: "1")
 
-  thread = commentable.comment_threads.new(title: "I can't solve this problem", body: "can anyone help me?", course_id: "1")
+  thread = CommentThread.new(title: "I can't solve this problem", body: "can anyone help me?", course_id: "1", commentable_id: commentable.id)
   thread.author = user
   thread.save!
 
@@ -42,7 +40,7 @@ def init_without_subscriptions
   comment1.author = user
   comment1.save!
 
-  thread = commentable.comment_threads.new(title: "This problem is wrong", body: "it is unsolvable", course_id: "2")
+  thread = CommentThread.new(title: "This problem is wrong", body: "it is unsolvable", course_id: "2", commentable_id: commentable.id)
   thread.author = user
   thread.save!
 
@@ -76,7 +74,6 @@ end
 def init_with_subscriptions
   Comment.delete_all
   CommentThread.delete_all
-  Commentable.delete_all
   User.delete_all
   Notification.delete_all
   Subscription.delete_all
@@ -86,14 +83,11 @@ def init_with_subscriptions
 
   user2.subscribe(user1)
 
-  commentable = Commentable.new(commentable_type: "questions", commentable_id: "1")
+  commentable = Commentable.new("question_1")
   user1.subscribe(commentable)
   user2.subscribe(commentable)
-  commentable.save!
 
-  commentable = commentable.reload 
-
-  thread = commentable.comment_threads.new(title: "I can't solve this problem", body: "can anyone help me?", course_id: "1")
+  thread = CommentThread.new(title: "I can't solve this problem", body: "can anyone help me?", course_id: "1", commentable_id: commentable.id)
   thread.author = user1
   user2.subscribe(thread)
   thread.save!
@@ -110,7 +104,7 @@ def init_with_subscriptions
   comment2.author = user2
   comment2.save!
 
-  thread = commentable.comment_threads.new(title: "This problem is wrong", body: "it is unsolvable", course_id: "2")
+  thread = CommentThread.new(title: "This problem is wrong", body: "it is unsolvable", course_id: "2", commentable_id: commentable.id)
   thread.author = user2
   thread.save!
 end
@@ -118,16 +112,16 @@ end
 describe "app" do
   describe "commentables" do
     before(:each) { init_without_subscriptions }
-    describe "DELETE /api/v1/:commentable_type/:commentable_id/threads" do
-      it "delete the commentable object and all of its associated comment threads and comments" do
-        delete '/api/v1/questions/1/threads'
+    describe "DELETE /api/v1/:commentable_id/threads" do
+      it "delete all associated threads and comments of a commentable" do
+        delete '/api/v1/question_1/threads'
         last_response.should be_ok
-        Commentable.count.should == 0
+        Commentable.find("question_1").comment_threads.count.should == 0
       end
     end
-    describe "GET /api/v1/:commentable_type/:commentable_id/threads" do
+    describe "GET /api/v1/:commentable_id/threads" do
       it "get all comment threads associated with a commentable object" do
-        get "/api/v1/questions/1/threads"
+        get "/api/v1/question_1/threads"
         last_response.should be_ok
         threads = Yajl::Parser.parse last_response.body
         threads.length.should == 2
@@ -135,7 +129,7 @@ describe "app" do
         threads.index{|c| c["body"] == "it is unsolvable"}.should_not be_nil
       end
       it "get all comment threads and comments associated with a commentable object" do
-        get "/api/v1/questions/1/threads", recursive: true
+        get "/api/v1/question_1/threads", recursive: true
         last_response.should be_ok
         threads = Yajl::Parser.parse last_response.body
         threads.length.should == 2
@@ -154,9 +148,9 @@ describe "app" do
         not_for_me["children"].first["body"].should == "not for me neither!"
       end
     end
-    describe "POST /api/v1/:commentable_type/:commentable_id/threads" do
+    describe "POST /api/v1/:commentable_id/threads" do
       it "create a new comment thread for the commentable object" do
-        post '/api/v1/questions/1/threads', title: "Interesting question", body: "cool", course_id: "1", user_id: "1"
+        post '/api/v1/question_1/threads', title: "Interesting question", body: "cool", course_id: "1", user_id: "1"
         last_response.should be_ok
         CommentThread.count.should == 3
         CommentThread.where(title: "Interesting question").first.should_not be_nil
@@ -380,17 +374,17 @@ describe "app" do
       end
       it "subscribe a commentable" do
         user3 = User.find_or_create_by(external_id: "3")
-        post "/api/v1/users/#{user3.external_id}/subscriptions", source_type: "questions", source_id: "1"
+        post "/api/v1/users/#{user3.external_id}/subscriptions", source_type: "other", source_id: "question_1"
         last_response.should be_ok
-        Commentable.first.subscribers.length.should == 3
-        Commentable.first.subscribers.should include user3
+        Commentable.find("question_1").subscribers.length.should == 3
+        Commentable.find("question_1").subscribers.should include user3
       end
       it "unsubscribe a commentable" do
         user2 = User.find_or_create_by(external_id: "2")
-        delete "/api/v1/users/#{user2.external_id}/subscriptions", source_type: "questions", source_id: "1"
+        delete "/api/v1/users/#{user2.external_id}/subscriptions", source_type: "other", source_id: "question_1"
         last_response.should be_ok
-        Commentable.first.subscribers.length.should == 1
-        Commentable.first.subscribers.should_not include user2
+        Commentable.find("question_1").subscribers.length.should == 1
+        Commentable.find("question_1").subscribers.should_not include user2
       end
       it "subscribe a comment thread" do
         user1 = User.find_or_create_by(external_id: "1")