more idiomatic models for diary entry subscriptions

app/controllers/diary_entry_controller.rb

@@ -26,7 +26,7 @@ class DiaryEntryController < ApplicationController
         end
 
         # Subscribe user to diary comments
-        @diary_entry.subscribers << @user
+        @diary_entry.subscriptions.create(user: @user)
 
         redirect_to :controller => "diary_entry", :action => "list", :display_name => @user.display_name
       else
@@ -70,7 +70,7 @@ class DiaryEntryController < ApplicationController
       end
 
       # Add the commenter to the subscribers if necessary
-      @entry.subscribers << @user unless @entry.subscribers.exists?(@user.id)
+      @entry.subscriptions.create(user: @user) unless @entry.subscribers.exists?(@user)
 
       redirect_to :controller => "diary_entry", :action => "view", :display_name => @entry.user.display_name, :id => @entry.id
     else
@@ -83,9 +83,7 @@ class DiaryEntryController < ApplicationController
   def subscribe
     diary_entry = DiaryEntry.find(params[:id])
 
-    if ! diary_entry.subscribers.exists?(@user.id)
+    diary_entry.subscriptions.create(user: @user) unless diary_entry.subscribers.exists?(@user)
-      diary_entry.subscribers << @user
-    end
 
     redirect_to :controller => "diary_entry", :action => "view", :display_name => diary_entry.user.display_name, :id => diary_entry.id
   rescue ActiveRecord::RecordNotFound
@@ -95,9 +93,7 @@ class DiaryEntryController < ApplicationController
   def unsubscribe
     diary_entry = DiaryEntry.find(params[:id])
 
-    if diary_entry.subscribers.exists?(@user.id)
+    diary_entry.subscriptions.where(user: @user).delete_all if diary_entry.subscribers.exists?(@user)
-      diary_entry.subscribers.delete(@user)
-    end
 
     redirect_to :controller => "diary_entry", :action => "view", :display_name => diary_entry.user.display_name, :id => diary_entry.id
   rescue ActiveRecord::RecordNotFound

app/models/diary_entry.rb

@@ -4,7 +4,8 @@ class DiaryEntry < ActiveRecord::Base
 
   has_many :comments, -> { order(:id).preload(:user) }, :class_name => "DiaryComment"
   has_many :visible_comments, -> { joins(:user).where(:visible => true, :users => { :status => %w(active confirmed) }).order(:id) }, :class_name => "DiaryComment"
-  has_and_belongs_to_many :subscribers, :class_name => "User", :join_table => "diary_entries_subscribers", :association_foreign_key => "subscriber_id"
+  has_many :subscriptions, :class_name => 'DiaryEntrySubscription'
+  has_many :subscribers, :through => :subscriptions, :source => :user
 
   scope :visible, -> { where(:visible => true) }
 

app/models/diary_entry_subscription.rb

@@ -0,0 +1,4 @@
+class DiaryEntrySubscription < ActiveRecord::Base
+  belongs_to :user
+  belongs_to :diary_entry
+end

app/models/user.rb

@@ -4,7 +4,8 @@ class User < ActiveRecord::Base
   has_many :traces, -> { where(:visible => true) }
   has_many :diary_entries, -> { order(:created_at => :desc) }
   has_many :diary_comments, -> { order(:created_at => :desc) }
-  has_and_belongs_to_many :diary_entries_subscriptions, :class_name => "DiaryEntry", :join_table => "diary_entries_subscribers", :foreign_key => "subscriber_id"
+  has_many :diary_entry_subscriptions, :class_name => 'DiaryEntrySubscription'
+  has_many :diary_subscriptions, :through => :diary_entry_subscriptions, :source => :diary_entry
   has_many :messages, -> { where(:to_user_visible => true).order(:sent_on => :desc).preload(:sender, :recipient) }, :foreign_key => :to_user_id
   has_many :new_messages, -> { where(:to_user_visible => true, :message_read => false).order(:sent_on => :desc) }, :class_name => "Message", :foreign_key => :to_user_id
   has_many :sent_messages, -> { where(:from_user_visible => true).order(:sent_on => :desc).preload(:sender, :recipient) }, :class_name => "Message", :foreign_key => :from_user_id

app/views/diary_entry/_diary_entry.html.erb

@@ -34,6 +34,5 @@
     <%= if_administrator(:li) do %>
       <%= link_to t('diary_entry.diary_entry.hide_link'), hide_diary_entry_path(:display_name => diary_entry.user.display_name, :id => diary_entry.id), :method => :post, :data => { :confirm => t('diary_entry.diary_entry.confirm') } %>
     <% end %>
-
   </ul>
 </div>

app/views/diary_entry/view.html.erb

@@ -21,7 +21,7 @@
     <%= richtext_area :diary_comment, :body, :cols => 80, :rows => 15 %>
     <%= submit_tag t('diary_entry.view.save_button') %>
   <% end %>
-  <% if @user and @entry.subscribers.exists?(@user.id) %>
+  <% if @user and @entry.subscribers and @entry.subscribers.exists?(@user) %>
     <div style='position:relative; top: -30px; left: 130px'><%= link_to t('javascripts.changesets.show.unsubscribe'), diary_entry_unsubscribe_path(:display_name => @entry.user.display_name, :id => @entry.id), :method => :post, :class => :button %></div>
   <% elsif @user %>
     <div style='position:relative; top: -30px; left: 130px'><%= link_to t('javascripts.changesets.show.subscribe'), diary_entry_subscribe_path(:display_name => @entry.user.display_name, :id => @entry.id), :method => :post, :class => :button %></div>

db/migrate/20161002153425_add_join_table_between_users_and_diary_entries.rb

@@ -1,20 +1,17 @@
 class AddJoinTableBetweenUsersAndDiaryEntries < ActiveRecord::Migration
   def change
-    create_table :diary_entries_subscribers, :id => false do |t|
+    create_table :diary_entry_subscriptions, :id => false do |t|
-      t.column :subscriber_id, :bigint, :null => false
+      t.column :user_id, :bigint, :null => false
       t.column :diary_entry_id, :bigint, :null => false
     end
 
-    add_foreign_key :diary_entries_subscribers, :users, :column => :subscriber_id, :name => "diary_entries_subscribers_subscriber_id_fkey"
+    add_index :diary_entry_subscriptions, [:user_id, :diary_entry_id], :unique => true, :name => "index_diary_subscriptions_on_user_id_and_diary_entry_id"
-    add_foreign_key :diary_entries_subscribers, :diary_entries, :column => :diary_entry_id, :name => "diary_entries_subscribers_changeset_id_fkey"
+    add_index :diary_entry_subscriptions, [:diary_entry_id]
-
-    add_index :diary_entries_subscribers, [:subscriber_id, :diary_entry_id], :unique => true, :name => "index_diary_subscribers_on_subscriber_id_and_diary_id"
-    add_index :diary_entries_subscribers, [:diary_entry_id]
   end
 
   def up
     DiaryEntry.find_each do |diary_entry|
-      diary_entry.subscribers << diary_entry.user unless diary_entry.subscribers.exists?(diary_entry.user.id)
+      diary_entry.subscriptions.create(user: diary_entry.user) unless diary_entry.subscribers.exists?(@user)
     end
   end