Add per-controller middleware

actionpack/lib/action_controller/metal.rb

@@ -88,6 +88,16 @@ module ActionController
       end
     end
 
+    extlib_inheritable_accessor(:middleware_stack) { ActionDispatch::MiddlewareStack.new }
+
+    def self.use(*args)
+      middleware_stack.use(*args)
+    end
+
+    def self.middleware
+      middleware_stack
+    end
+
     # Return a rack endpoint for the given action. Memoize the endpoint, so
     # multiple calls into MyController.action will return the same object
     # for the same action.
@@ -99,7 +109,10 @@ module ActionController
     # Proc:: A rack application
     def self.action(name)
       @actions ||= {}
-      @actions[name.to_s] ||= ActionEndpoint.new(self, name)
+      @actions[name.to_s] ||= begin
+        endpoint = ActionEndpoint.new(self, name)
+        middleware_stack.build(endpoint)
+      end
     end
   end
 end

actionpack/test/new_base/middleware_test.rb

@@ -0,0 +1,77 @@
+require File.join(File.expand_path(File.dirname(__FILE__)), "test_helper")
+
+module MiddlewareTest
+  class MyMiddleware
+    def initialize(app)
+      @app = app
+    end
+
+    def call(env)
+      result = @app.call(env)
+      result[1]["Middleware-Test"] = "Success"
+      result[1]["Middleware-Order"] = "First"
+      result
+    end
+  end
+
+  class ExclaimerMiddleware
+    def initialize(app)
+      @app = app
+    end
+
+    def call(env)
+      result = @app.call(env)
+      result[1]["Middleware-Order"] << "!"
+      result
+    end
+  end
+
+  class MyController < ActionController::Metal
+    use MyMiddleware
+
+    middleware.insert_before MyMiddleware, ExclaimerMiddleware
+
+    def index
+      self.response_body = "Hello World"
+    end
+  end
+
+  class InheritedController < MyController
+  end
+
+  module MiddlewareTests
+    extend ActiveSupport::Testing::Declarative
+
+    test "middleware that is 'use'd is called as part of the Rack application" do
+      result = @app.call(env_for("/"))
+      assert_equal "Hello World", result[2]
+      assert_equal "Success", result[1]["Middleware-Test"]
+    end
+
+    test "the middleware stack is exposed as 'middleware' in the controller" do
+      result = @app.call(env_for("/"))
+      assert_equal "First!", result[1]["Middleware-Order"]
+    end
+  end
+
+  class TestMiddleware < ActiveSupport::TestCase
+    include MiddlewareTests
+
+    def setup
+      @app = MyController.action(:index)
+    end
+
+    def env_for(url)
+      Rack::MockRequest.env_for(url)
+    end
+  end
+
+  class TestInheritedMiddleware < TestMiddleware
+    def setup
+      @app = InheritedController.action(:index)
+    end
+
+    test "middleware inherits" do
+    end
+  end
+end