move item cache sweeping and flex syncing to background tasks

Gemfile.lock

@@ -37,7 +37,7 @@ GIT
 
 GIT
   remote: git://github.com/matchu/flex.git
-  revision: d62f508f795ecdbb383f406865daa72368b43ba5
+  revision: 6d7e3fd6e2845ae978545be67b912323888d1ebb
   specs:
     flex (0.4.1)
       multi_json (~> 1.3.4)
@@ -186,7 +186,7 @@ GEM
     patron (0.4.18)
     polyglot (0.3.3)
     progressbar (0.11.0)
-    prompter (0.1.5)
+    prompter (0.1.6)
       dye (>= 0.1.1)
       yard (>= 0.6.3)
     rack (1.4.5)
@@ -292,7 +292,7 @@ GEM
       activesupport (>= 2.3.4)
       chronic (~> 0.6.3)
     will_paginate (3.0.4)
-    yard (0.8.5.2)
+    yard (0.8.7.3)
 
 PLATFORMS
   ruby

app/models/item.rb

@@ -41,7 +41,8 @@ class Item < ActiveRecord::Base
 
   scope :with_closet_hangers, joins(:closet_hangers)
   
-  flex.sync self
+  # Syncing is now handled in background tasks, created in the ItemObserver.
+  flex.sync self, callbacks: []
   
   def flex_source
     indexed_attributes = {

app/models/item/create_task.rb

@@ -0,0 +1,21 @@
+class Item
+  class CreateTask
+    extend FragmentExpiration
+
+    TIMEOUT_IN_SECONDS = 10
+
+    @queue = :item_create
+
+    def self.perform(id)
+      Timeout::timeout(TIMEOUT_IN_SECONDS) do
+        Item.find(id).flex.sync
+        expire_newest_items
+      end
+    end
+
+    def self.expire_newest_items
+      expire_fragment_in_all_locales('outfits#new newest_items')
+      expire_fragment_in_all_locales('items#index newest_items')
+    end
+  end
+end

app/models/item/destroy_task.rb

@@ -0,0 +1,17 @@
+class Item
+  class DestroyTask
+    extend FragmentExpiration
+
+    TIMEOUT_IN_SECONDS = 10
+
+    @queue = :item_destroy
+
+    def self.perform(id)
+      Timeout::timeout(TIMEOUT_IN_SECONDS) do
+        Item.find(id).flex.sync
+        # TODO: it's kinda ugly to reach across classes like this
+        CreateTask.expire_newest_items
+      end
+    end
+  end
+end

app/models/item/update_task.rb

@@ -0,0 +1,26 @@
+class Item
+  class UpdateTask
+    extend FragmentExpiration
+
+    TIMEOUT_IN_SECONDS = 10
+
+    @queue = :item_update
+
+    def self.perform(id)
+      Timeout::timeout(TIMEOUT_IN_SECONDS) do
+        item = Item.find(id)
+        expire_cache_for(item)
+        item.flex.sync
+      end
+    end
+    
+    private
+
+    def self.expire_cache_for(item)
+      expire_fragment_in_all_locales("items/#{item.id}#item_link_partial")
+      expire_fragment_in_all_locales("items/#{item.id} header")
+      expire_fragment_in_all_locales("items/#{item.id} info")
+      expire_key_in_all_locales("items/#{item.id}#as_json")
+    end
+  end
+end

app/models/item_observer.rb

@@ -2,31 +2,15 @@ class ItemObserver < ActionController::Caching::Sweeper
   include FragmentExpiration
   
   def after_create(item)
-    Rails.logger.debug "Item #{item.id} was just created"
-    expire_newest_items
+    Resque.enqueue(Item::CreateTask, item.id)
   end
   
   def after_update(item)
-    Rails.logger.debug "Item #{item.id} was just updated"
-    expire_cache_for(item)
+    # CONSIDER: can pass item.changes.keys in to choose which caches to expire
+    Resque.enqueue(Item::UpdateTask, item.id)
   end
 
   def after_destroy(item)
-    Rails.logger.debug "Item #{item.id} was just destroyed"
-    expire_cache_for(item)
-  end
-
-  private
-  
-  def expire_cache_for(item)
-    expire_fragment_in_all_locales("items/#{item.id}#item_link_partial")
-    expire_fragment_in_all_locales("items/#{item.id} header")
-    expire_fragment_in_all_locales("items/#{item.id} info")
-    expire_key_in_all_locales("items/#{item.id}#as_json")
-  end
-  
-  def expire_newest_items
-    expire_fragment_in_all_locales('outfits#new newest_items')
-    expire_fragment_in_all_locales('items#index newest_items')
+    Resque.enqueue(Item::DestroyTask, item.id)
   end
 end