Remove ActiveRecord::Base.find(_all)?_cached

Just use Rails.cache.fetch directly.  This fixes some problems that
find_cached wasn't fully serializing the object.

Also, be sure to change cache keys so that we don't get data back
using the old format.

Change-Id: I8beea2f2ba446a97249a495789b25c3a71de420e
Reviewed-on: https://gerrit.instructure.com/5857
Tested-by: Hudson <hudson@instructure.com>
Reviewed-by: Brian Palmer <brianp@instructure.com>

app/models/account.rb

@@ -311,7 +311,7 @@ class Account < ActiveRecord::Base
   end
   
   def self.account_lookup_cache_key(id)
-    ['_account_lookup', id].cache_key
+    ['_account_lookup2', id].cache_key
   end
   
   def find_user_by_unique_id(unique_id)

app/models/account_notification.rb

@@ -27,7 +27,7 @@ class AccountNotification < ActiveRecord::Base
     closed_ids = (user && user.preferences[:closed_notifications]) || []
     now = Time.now.utc
     # Refreshes every 10 minutes at the longest
-    current = AccountNotification.find_all_cached(['account_notifications', account, (now.to_i / 600).to_s].cache_key) do
+    current = Rails.cache.fetch(['account_notifications2', account].cache_key, :expires_in => 10.minutes) do
       AccountNotification.find(:all, :conditions => ['account_id IN (?,?) AND start_at < ? AND end_at > ?', Account.site_admin.id, account.id, now, now], :order => 'start_at DESC')
     end
     current ||= []

app/models/user.rb

@@ -477,7 +477,7 @@ class User < ActiveRecord::Base
   end
   
   def self.user_lookup_cache_key(id)
-    ['_user_lookup', id].cache_key
+    ['_user_lookup2', id].cache_key
   end
   
   def self.invalidate_cache(id)
@@ -527,7 +527,7 @@ class User < ActiveRecord::Base
   
   def self.cached_name(id)
     key = user_lookup_cache_key(id)
-    user = find_cached(key) do
+    user = Rails.cache.fetch(key) do
       User.find_by_id(id)
     end
     user && user.name

config/initializers/active_record.rb

@@ -57,42 +57,6 @@ class ActiveRecord::Base
     res
   end
   
-  def self.find_cached(key, opts = nil, &block)
-    attrs = Rails.cache.read(key)
-    if !attrs || attrs.empty? || attrs.is_a?(String) || attrs[:assigned_cache_key] != key
-      obj = block.call rescue nil
-      attrs = obj && obj.is_a?(self) ? obj.attributes : nil
-      attrs[:assigned_cache_key] = key if attrs
-      Rails.cache.write(key, attrs, opts) if attrs
-    end
-    return nil if !attrs || attrs.empty?
-    obj = self.new
-    attrs = attrs.dup if attrs.frozen?
-    attrs.delete(:assigned_cache_key)
-    obj.instance_variable_set("@attributes", attrs)
-    obj.instance_variable_set("@new_record", false)
-    obj
-  end
-  
-  def self.find_all_cached(key, opts = nil, &block)
-    attrs_list = Rails.cache.read(key)
-    if !attrs_list || attrs_list.empty? || !attrs_list.is_a?(Array) || attrs_list.any?{|attr| attr[:assigned_cache_key] != key }
-      list = block.call.to_a rescue nil
-      attrs_list = list.map{|obj| obj && obj.is_a?(self) ? obj.attributes : nil }.compact
-      attrs_list.each{|attrs| attrs[:assigned_cache_key] = key }
-      Rails.cache.write(key, attrs_list, opts)
-    end
-    return [] if !attrs_list || attrs_list.empty?
-    attrs_list.map do |attrs|
-      obj = self.new
-      attrs = attrs.dup if attrs.frozen?
-      attrs.delete(:assigned_cache_key)
-      obj.instance_variable_set("@attributes", attrs)
-      obj.instance_variable_set("@new_record", false)
-      obj
-    end
-  end
-  
   def asset_string
     @asset_string ||= "#{self.class.base_ar_class.name.underscore}_#{id.to_s}"
   end