aboutsummaryrefslogblamecommitdiffstats
path: root/activerecord/lib/active_record/query_cache.rb
blob: dcb2bd3d848d68e058db50fc285c7a7b4e54dd72 (plain) (tree)
1
2
3
4
5
6
7
8
9
                   
                               


                                                                               
                                                     
                       
                                        
                                  

               
           
         

                                                                                
                                                     
                          
                                        
                                     

               





                       
       
 
                 

                                                    
                                                      
                                    
 

                                                       
                                                            
         
 
              
                         







                                                            
                                                     
                                                                       
       
 
     
   
module ActiveRecord
  # = Active Record Query Cache
  class QueryCache
    module ClassMethods
      # Enable the query cache within the block if Active Record is configured.
      # If it's not, it will execute the given block.
      def cache(&block)
        if ActiveRecord::Base.connected?
          connection.cache(&block)
        else
          yield
        end
      end

      # Disable the query cache within the block if Active Record is configured.
      # If it's not, it will execute the given block.
      def uncached(&block)
        if ActiveRecord::Base.connected?
          connection.uncached(&block)
        else
          yield
        end
      end
    end

    def initialize(app)
      @app = app
    end

    def call(env)
      connection    = ActiveRecord::Base.connection
      enabled       = connection.query_cache_enabled
      connection_id = ActiveRecord::Base.connection_id
      connection.enable_query_cache!

      response = @app.call(env)
      response[2] = Rack::BodyProxy.new(response[2]) do
        restore_query_cache_settings(connection_id, enabled)
      end

      response
    rescue Exception => e
      restore_query_cache_settings(connection_id, enabled)
      raise e
    end

    private

    def restore_query_cache_settings(connection_id, enabled)
      ActiveRecord::Base.connection_id = connection_id
      ActiveRecord::Base.connection.clear_query_cache
      ActiveRecord::Base.connection.disable_query_cache! unless enabled
    end

  end
end