action_cache.rb in merb-0.4.0

- old
+ new
@@ -1,56 +1,92 @@
 module Merb
   module Caching
-  
+    
+    
+    # Action caching provides the ability to cache the output of individual actions.  This output will be stored using fragment caching 
+    # (Merb::Caching::Fragment).  The output is stored based on a multipart key, which is comprised of the following pieces, in this order:
+    # * controller
+    # * action
+    # * parameters  (represented as a list of parameter name/value pairs, sorted by name)
+    # 
+    #
+    # === Examples
+    #
+    #  class UserController < Merb::Controller 
+    #    cache_action(:show, :index) 
+    # 
+    #    def show 
+    #       ... do some work to show a user ... 
+    #    end  
+    #    
+    #    def index
+    #       ... get the list of users ...
+    #    end
+    #  end 
+    #
+    # In this case, we would expect show to take an :id parameter, and index to take no parameters, so the fragment stored for this action 
+    # will be represented thus:
+    #   get :show, :id => 25    => [:user_controller, :show, :id, 25]
+    #   get :index => [:user_controller, :index]
+    # 
+    # Action caches are expired based on the action alone (TODO: We need to modify expire action to allow expiration for specific parameter values).
+    #   expire_action(:show)  => This will expire all cached show actions (i.e. All users, in this case)    
+     
     module Actions 
   
       def self.included(base) # :nodoc: 
-        base.class_eval {
-          def caching_enabled?
-            @_caching_enabled ||= ::Merb::Server.cache_templates
-          end
-        }
+
         base.extend(ClassMethods)
       end
   
       module ClassMethods
   
-        # Cache the given actions.
-        
+        # Cache the specific actions.  If those actions take parameters, then those parameters will be considered part of the key.
+        # 
         def cache_action(*actions)
-          return unless caching_enabled?
           before :_get_action_fragment, :only => actions        
           after :_store_action_fragment, :only => actions
         end
         
       end
-  
-      private 
-  
+
+      
+      # Expire all cached content for the specific action, or array of actions.  
+      def expire_action(*actions)
+        return unless _caching_enabled?        
+        for action in [actions].flatten
+          ::Merb::Caching::Fragment.expire_fragment(params_key(:action => action))
+        end
+      end
+
+      
+      private
+
+      def _caching_enabled?
+        ::Merb::Server.config[:cache_templates]
+      end
+
       def _get_action_fragment
-        fragment_name = "#{params[:action]}#{@request.query_string}"
-        if fragment = ::Merb::Caching::Fragment.get(fragment_name)
+        return unless _caching_enabled?        
+        if fragment = ::Merb::Caching::Fragment.get(params_key)
           throw :halt, fragment
         end
       end
-  
-      def _store_action_fragment
-        fragment_name = "#{params[:action]}#{@request.query_string}"
-        ::Merb::Caching::Fragment.put(fragment_name, @body)
+      
+      def _store_action_fragment        
+        return unless _caching_enabled?
+        ::Merb::Caching::Fragment.put(params_key, body)
       end
-  
-      def caching_enabled?
-        @_caching_enabled ||= ::Merb::Server.cache_templates
-      end
       
-      def expire_action(*actions)
-        return unless caching_enabled?
-        for action in [actions].flatten
-          expire_fragment(action)
-        end
+      
+      def params_key(overrides = {})
+        key = []
+        additional_parameters = params.clone.merge(overrides)
+        key << additional_parameters.delete(:controller).to_s.snake_case        
+        key << additional_parameters.delete(:action).to_s.snake_case        
+        key << additional_parameters.keys.sort{|a,b| a.to_s <=> b.to_s}.collect{|k| [k.to_s, additional_parameters[k].to_s]}.flatten
+        key.flatten
       end
   
     end
-  
   end
-  
 end  
\ No newline at end of file