Extract ActionController rescue templates into Rescue and ShowExcepti…

…ons middleware.

This commit breaks all exception catching plugins like ExceptionNotifier. These plugins should be rewritten as middleware instead overriding Controller#rescue_action_in_public.

actionpack/lib/action_controller.rb

@@ -60,7 +60,7 @@ def self.load_all!
   autoload :Redirector, 'action_controller/base/redirect'
   autoload :Renderer, 'action_controller/base/render'
   autoload :RequestForgeryProtection, 'action_controller/base/request_forgery_protection'
-  autoload :Rescue, 'action_controller/dispatch/rescue'
+  autoload :Rescue, 'action_controller/base/rescue'
   autoload :Resources, 'action_controller/routing/resources'
   autoload :Responder, 'action_controller/base/responder'
   autoload :Routing, 'action_controller/routing'

actionpack/lib/action_controller/base/base.rb

@@ -30,10 +30,6 @@ def initialize(*allowed_methods)
     def allowed_methods_header
       allowed_methods.map { |method_symbol| method_symbol.to_s.upcase } * ', '
     end
-
-    def handle_response!(response)
-      response.headers['Allow'] ||= allowed_methods_header
-    end
   end
 
   class NotImplemented < MethodNotAllowed #:nodoc:
@@ -510,9 +506,8 @@ def exempt_from_layout(*types)
 
     public
       def call(env)
-        # HACK: For global rescue to have access to the original request and response
-        request = env["action_dispatch.rescue.request"] ||= ActionDispatch::Request.new(env)
-        response = env["action_dispatch.rescue.response"] ||= ActionDispatch::Response.new
+        request = ActionDispatch::Request.new(env)
+        response = ActionDispatch::Response.new
         process(request, response).to_a
       end
 

actionpack/lib/action_controller/base/rescue.rb

@@ -0,0 +1,50 @@
+module ActionController #:nodoc:
+  # Actions that fail to perform as expected throw exceptions. These
+  # exceptions can either be rescued for the public view (with a nice
+  # user-friendly explanation) or for the developers view (with tons of
+  # debugging information). The developers view is already implemented by
+  # the Action Controller, but the public view should be tailored to your
+  # specific application.
+  #
+  # The default behavior for public exceptions is to render a static html
+  # file with the name of the error code thrown.  If no such file exists, an
+  # empty response is sent with the correct status code.
+  #
+  # You can override what constitutes a local request by overriding the
+  # <tt>local_request?</tt> method in your own controller. Custom rescue
+  # behavior is achieved by overriding the <tt>rescue_action_in_public</tt>
+  # and <tt>rescue_action_locally</tt> methods.
+  module Rescue
+    def self.included(base) #:nodoc:
+      base.send :include, ActiveSupport::Rescuable
+      base.extend(ClassMethods)
+
+      base.class_eval do
+        alias_method_chain :perform_action, :rescue
+      end
+    end
+
+    module ClassMethods
+      def rescue_action(env)
+        exception = env.delete('action_dispatch.rescue.exception')
+        request   = ActionDispatch::Request.new(env)
+        response  = ActionDispatch::Response.new
+        new.process(request, response, :rescue_action, exception).to_a
+      end
+    end
+
+    protected
+      # Exception handler called when the performance of an action raises
+      # an exception.
+      def rescue_action(exception)
+        rescue_with_handler(exception) || raise(exception)
+      end
+
+    private
+      def perform_action_with_rescue
+        perform_action_without_rescue
+      rescue Exception => exception
+        rescue_action(exception)
+      end
+  end
+end

actionpack/lib/action_controller/dispatch/dispatcher.rb

@@ -75,18 +75,10 @@ def call(env)
     end
 
     def _call(env)
-      begin
-        run_callbacks :before_dispatch
-        Routing::Routes.call(env)
-      rescue Exception => exception
-        if controller ||= (::ApplicationController rescue Base)
-          controller.call_with_exception(env, exception)
-        else
-          raise exception
-        end
-      ensure
-        run_callbacks :after_dispatch, :enumerator => :reverse_each
-      end
+      run_callbacks :before_dispatch
+      Routing::Routes.call(env)
+    ensure
+      run_callbacks :after_dispatch, :enumerator => :reverse_each
     end
 
     def flush_logger

actionpack/lib/action_controller/dispatch/middlewares.rb

@@ -3,6 +3,11 @@
 }
 
 use "ActionDispatch::Failsafe"
+use "ActionDispatch::ShowExceptions", lambda { ActionController::Base.consider_all_requests_local }
+use "ActionDispatch::Rescue", lambda {
+  controller = (::ApplicationController rescue ActionController::Base)
+  controller.method(:rescue_action)
+}
 
 use lambda { ActionController::Base.session_store },
     lambda { ActionController::Base.session_options }

actionpack/lib/action_dispatch.rb

@@ -48,6 +48,8 @@ module ActionDispatch
   autoload :Failsafe, 'action_dispatch/middleware/failsafe'
   autoload :ParamsParser, 'action_dispatch/middleware/params_parser'
   autoload :Reloader, 'action_dispatch/middleware/reloader'
+  autoload :Rescue, 'action_dispatch/middleware/rescue'
+  autoload :ShowExceptions, 'action_dispatch/middleware/show_exceptions'
   autoload :MiddlewareStack, 'action_dispatch/middleware/stack'
 
   autoload :Assertions, 'action_dispatch/testing/assertions'

actionpack/lib/action_dispatch/middleware/rescue.rb

@@ -0,0 +1,14 @@
+module ActionDispatch
+  class Rescue
+    def initialize(app, rescuer)
+      @app, @rescuer = app, rescuer
+    end
+
+    def call(env)
+      @app.call(env)
+    rescue Exception => exception
+      env['action_dispatch.rescue.exception'] = exception
+      @rescuer.call(env)
+    end
+  end
+end