provide a request and response to all controllers

Controllers should always have a request and response when responding.
Since we make this The Rule(tm), then controllers don't need to be
somewhere in limbo between "asking a response object for a rack
response" or "I, myself contain a rack response".  This duality leads to
conditionals spread through the codebase that we can delete:

  * https://github.com/rails/rails/blob/85a78d9358aa728298cd020cdc842b55c16f9549/actionpack/lib/action_controller/metal.rb#L221-L223

3 files changed, 29 insertions, 30 deletions

diff --git a/actionpack/lib/action_controller/metal.rb b/actionpack/lib/action_controller/metal.rb
index 54980aa453..129e0bbd3c 100644
--- a/actionpack/lib/action_controller/metal.rb
+++ b/actionpack/lib/action_controller/metal.rb
@@ -132,6 +132,12 @@ module ActionController
       @controller_name ||= name.demodulize.sub(/Controller$/, '').underscore
     end
 
+    def self.make_response!(request)
+      ActionDispatch::Response.new.tap do |res|
+        res.request = request
+      end
+    end
+
     # Delegates to the class' <tt>controller_name</tt>
     def controller_name
       self.class.controller_name
@@ -143,11 +149,10 @@ module ActionController
     # and response object available. You might wish to control the
     # environment and response manually for performance reasons.
 
-    attr_internal :headers, :response, :request
-    delegate :session, :to => "@_request"
+    attr_internal :response, :request
+    delegate :session, :headers, :to => "@_request"
 
     def initialize
-      @_headers = {"Content-Type" => "text/html"}
       @_status = 200
       @_request = nil
       @_response = nil
@@ -168,7 +173,7 @@ module ActionController
     # in Renderer and Redirector.
 
     def content_type=(type)
-      headers["Content-Type"] = type.to_s
+      response.content_type = type
     end
 
     def content_type
@@ -199,6 +204,7 @@ module ActionController
 
     def response_body=(body)
       body = [body] unless body.nil? || body.respond_to?(:each)
+      response.body = body
       super
     end
 
@@ -207,12 +213,17 @@ module ActionController
       response_body || (response && response.committed?)
     end
 
-    def dispatch(name, request) #:nodoc:
+    def dispatch(name, request, response) #:nodoc:
       set_request!(request)
+      set_response!(response)
       process(name)
       to_a
     end
 
+    def set_response!(response) # :nodoc:
+      @_response = response
+    end
+
     def set_request!(request) #:nodoc:
       @_request = request
       @_request.controller_instance = self
@@ -253,20 +264,26 @@ module ActionController
     def self.action(name)
       if middleware_stack.any?
         middleware_stack.build(name) do |env|
-          new.dispatch(name, ActionDispatch::Request.new(env))
+          req = ActionDispatch::Request.new(env)
+          res = make_response! req
+          new.dispatch(name, req, res)
         end
       else
-        lambda { |env| new.dispatch(name, ActionDispatch::Request.new(env)) }
+        lambda { |env|
+          req = ActionDispatch::Request.new(env)
+          res = make_response! req
+          new.dispatch(name, req, res)
+        }
       end
     end
 
     # Direct dispatch to the controller.  Instantiates the controller, then
     # executes the action named +name+.
-    def self.dispatch(name, req)
+    def self.dispatch(name, req, res)
       if middleware_stack.any?
-        middleware_stack.build(name) { |env| new.dispatch(name, req) }.call req.env
+        middleware_stack.build(name) { |env| new.dispatch(name, req, res) }.call req.env
       else
-        new.dispatch(name, req)
+        new.dispatch(name, req, res)
       end
     end
   end
diff --git a/actionpack/lib/action_controller/metal/head.rb b/actionpack/lib/action_controller/metal/head.rb
index 056962b38c..7dbd5ef328 100644
--- a/actionpack/lib/action_controller/metal/head.rb
+++ b/actionpack/lib/action_controller/metal/head.rb
@@ -36,6 +36,8 @@ module ActionController
         headers[key.to_s.dasherize.split('-').each { |v| v[0] = v[0].chr.upcase }.join('-')] = value.to_s
       end
 
+      response.status = Rack::Utils.status_code(status)
+
       self.status = status
       self.location = url_for(location) if location
 
@@ -44,9 +46,6 @@ module ActionController
       if include_content?(self.response_code)
         self.content_type = content_type || (Mime[formats.first] if formats)
         self.response.charset = false if self.response
-      else
-        headers.delete('Content-Type')
-        headers.delete('Content-Length')
       end
 
       true
diff --git a/actionpack/lib/action_controller/metal/rack_delegation.rb b/actionpack/lib/action_controller/metal/rack_delegation.rb
index eb8bca1d92..5ba9a47d63 100644
--- a/actionpack/lib/action_controller/metal/rack_delegation.rb
+++ b/actionpack/lib/action_controller/metal/rack_delegation.rb
@@ -12,17 +12,6 @@ module ActionController
       def build_with_env(env = {}) #:nodoc:
         new.tap { |c| c.set_request! ActionDispatch::Request.new(env) }
       end
-
-      def make_response!(request)
-        ActionDispatch::Response.new.tap do |res|
-          res.request = request
-        end
-      end
-    end
-
-    def set_request!(request) #:nodoc:
-      super
-      set_response!(request)
     end
 
     def response_body=(body)
@@ -33,11 +22,5 @@ module ActionController
     def reset_session
       @_request.reset_session
     end
-
-    private
-
-    def set_response!(request)
-      @_response = self.class.make_response! request
-    end
   end
 end