Backport of: added block arguments to ActionController::Metal#use

Commit: f0dbcc7a692bc375e3e52a9661af4037392ee52f
Useful for cases such as warden, where a block configuration is taken.

    class SomeController < ApplicationController
      use RailsWarden::Manager do |manager|
        manager.default_strategies :facebook_oauth
        manager.failure_app = SomeController.action(:authorize)
      end
    end

actionpack/lib/action_controller/metal.rb

@@ -12,7 +12,7 @@ module ActionController
   #
   class MiddlewareStack < ActionDispatch::MiddlewareStack #:nodoc:
     class Middleware < ActionDispatch::MiddlewareStack::Middleware #:nodoc:
-      def initialize(klass, *args)
+      def initialize(klass, *args, &block)
         options = args.extract_options!
         @only   = Array(options.delete(:only)).map(&:to_s)
         @except = Array(options.delete(:except)).map(&:to_s)
@@ -147,8 +147,8 @@ def self.inherited(base)
       super
     end
 
-    def self.use(*args)
-      middleware_stack.use(*args)
+    def self.use(*args, &block)
+      middleware_stack.use(*args, &block)
     end
 
     def self.middleware

actionpack/test/controller/new_base/middleware_test.rb

@@ -25,8 +25,25 @@ def call(env)
       result
     end
   end
+
+  class BlockMiddleware
+    attr_accessor :configurable_message
+    def initialize(app, &block)
+      @app = app
+      yield(self) if block_given?
+    end
+
+    def call(env)
+      result = @app.call(env)
+      result[1]["Configurable-Message"] = configurable_message
+      result
+    end
+  end
 
   class MyController < ActionController::Metal
+    use BlockMiddleware do |config|
+      config.configurable_message = "Configured by block."
+    end
     use MyMiddleware
     middleware.insert_before MyMiddleware, ExclaimerMiddleware
 
@@ -67,6 +84,11 @@ def setup
       assert_equal "First!", result[1]["Middleware-Order"]
     end
 
+    test "middleware stack accepts block arguments" do
+      result = @app.call(env_for("/"))
+      assert_equal "Configured by block.", result[1]["Configurable-Message"]
+    end
+
     test "middleware stack accepts only and except as options" do
       result = ActionsController.action(:show).call(env_for("/"))
       assert_equal "First!", result[1]["Middleware-Order"]

actionpack/test/dispatch/middleware_stack_test.rb

@@ -4,6 +4,12 @@ class MiddlewareStackTest < ActiveSupport::TestCase
   class FooMiddleware; end
   class BarMiddleware; end
   class BazMiddleware; end
+  class BlockMiddleware
+    attr_reader :block
+    def initialize(&block)
+      @block = block
+    end
+  end
 
   def setup
     @stack = ActionDispatch::MiddlewareStack.new
@@ -39,7 +45,16 @@ def setup
     assert_equal BazMiddleware, @stack.last.klass
     assert_equal([true, {:foo => "bar"}], @stack.last.args)
   end
-
+
+  test "use should push middleware class with block arguments onto the stack" do
+    proc = Proc.new {}
+    assert_difference "@stack.size" do
+      @stack.use(BlockMiddleware, &proc)
+    end
+    assert_equal BlockMiddleware, @stack.last.klass
+    assert_equal proc, @stack.last.block
+  end
+
   test "insert inserts middleware at the integer index" do
     @stack.insert(1, BazMiddleware)
     assert_equal BazMiddleware, @stack[1].klass