Merge pull request #165 from kickstarter/fix-dalli-dependency

Refactor StoreProxy to avoid autoloading MemCacheStore

CHANGELOG.md

@@ -2,6 +2,9 @@
 
 ## master (unreleased)
 
+  - Fix an error affecting apps using Redis::Store saying that dalli was a
+    required dependency. Learn about ActiveSupport autoloading. (#165)
+
 ## v4.4.0 - 10 Feb 2016
 
   - New: support for MemCacheStore (#153). Thanks @elhu.

lib/rack/attack/store_proxy.rb

@@ -3,26 +3,30 @@ class Attack
     module StoreProxy
       PROXIES = [DalliProxy, MemCacheProxy, RedisStoreProxy]
 
+      ACTIVE_SUPPORT_WRAPPER_CLASSES = Set.new(['ActiveSupport::Cache::MemCacheStore', 'ActiveSupport::Cache::RedisStore']).freeze
+      ACTIVE_SUPPORT_CLIENTS = Set.new(['Redis::Store', 'Dalli::Client', 'MemCache']).freeze
+
       def self.build(store)
-        # RedisStore#increment needs different behavior, so detect that
-        # (method has an arity of 2; must call #expire separately
-        if (defined?(::ActiveSupport::Cache::RedisStore) && store.is_a?(::ActiveSupport::Cache::RedisStore)) ||
-          (defined?(::ActiveSupport::Cache::MemCacheStore) && store.is_a?(::ActiveSupport::Cache::MemCacheStore))
+        client = unwrap_active_support_stores(store)
+        klass = PROXIES.find { |proxy| proxy.handle?(client) }
+        klass ? klass.new(client) : client
+      end
+
 
-          # ActiveSupport::Cache::RedisStore doesn't expose any way to set an expiry,
-          # so use the raw Redis::Store instead.
-          # We also want to use the underlying Dalli client instead of ::ActiveSupport::Cache::MemCacheStore,
-          # and the MemCache client if using Rails 3.x
-          client = store.instance_variable_get(:@data)
-          if (defined?(::Redis::Store) && client.is_a?(Redis::Store)) ||
-            (defined?(Dalli::Client) && client.is_a?(Dalli::Client)) || (defined?(MemCache) && client.is_a?(MemCache))
-            store = store.instance_variable_get(:@data)
-          end
+      private
+      def self.unwrap_active_support_stores(store)
+        # ActiveSupport::Cache::RedisStore doesn't expose any way to set an expiry,
+        # so use the raw Redis::Store instead.
+        # We also want to use the underlying Dalli client instead of ::ActiveSupport::Cache::MemCacheStore,
+        # and the MemCache client if using Rails 3.x
+
+        client = store.instance_variable_get(:@data)
+        if ACTIVE_SUPPORT_WRAPPER_CLASSES.include?(store.class.to_s) && ACTIVE_SUPPORT_CLIENTS.include?(client.class.to_s)
+          client
+        else
+          store
         end
-        klass = PROXIES.find { |proxy| proxy.handle?(store) }
-        klass ? klass.new(store) : store
       end
-
     end
   end
 end

lib/rack/attack/version.rb

@@ -1,5 +1,5 @@
 module Rack
   class Attack
-    VERSION = '4.4.0'
+    VERSION = '4.4.1'
   end
 end