Add config.default_method_for_update to support PATCH

PATCH is the correct HTML verb to map to the #update action. The
semantics for PATCH allows for partial updates, whereas PUT requires a
complete replacement.

Changes:
* adds config.default_method_for_update you can set to :patch
* optionally use PATCH instead of PUT in resource routes and forms
* adds the #patch verb to routes to detect PATCH requests
* adds #patch? to Request
* changes documentation and comments to indicate support for PATCH

This change maintains complete backwards compatibility by keeping :put
as the default for config.default_method_for_update.

2 files changed, 50 insertions, 2 deletions

diff --git a/railties/test/application/configuration_test.rb b/railties/test/application/configuration_test.rb
index 3dffd1c74c..bf44a8b10b 100644
--- a/railties/test/application/configuration_test.rb
+++ b/railties/test/application/configuration_test.rb
@@ -146,7 +146,7 @@ module ApplicationTests
     test "frameworks are not preloaded by default" do
       require "#{app_path}/config/environment"
 
-      assert ActionController.autoload?(:RecordIdentifier)
+      assert ActionController.autoload?(:Caching)
     end
 
     test "frameworks are preloaded with config.preload_frameworks is set" do
@@ -156,7 +156,7 @@ module ApplicationTests
 
       require "#{app_path}/config/environment"
 
-      assert !ActionController.autoload?(:RecordIdentifier)
+      assert !ActionController.autoload?(:Caching)
     end
 
     test "filter_parameters should be able to set via config.filter_parameters" do
@@ -246,6 +246,49 @@ module ApplicationTests
       assert last_response.body =~ /csrf\-param/
     end
 
+    test "default method for update can be changed" do
+      app_file 'app/models/post.rb', <<-RUBY
+      class Post
+        extend ActiveModel::Naming
+        def to_key; [1]; end
+        def persisted?; true; end
+      end
+      RUBY
+
+      app_file 'app/controllers/posts_controller.rb', <<-RUBY
+      class PostsController < ApplicationController
+        def show
+          render :inline => "<%= begin; form_for(Post.new) {}; rescue => e; e.to_s; end %>"
+        end
+
+        def update
+          render :text => "update"
+        end
+      end
+      RUBY
+
+      add_to_config <<-RUBY
+        config.default_method_for_update = :patch
+        routes.prepend do
+          resources :posts
+        end
+      RUBY
+
+      require "#{app_path}/config/environment"
+
+      assert_equal ActionView::Base.default_method_for_update, :patch
+      assert_equal ActionDispatch::Routing::Mapper.default_method_for_update, :patch
+
+      get "/posts/1"
+      assert_match /patch/, last_response.body
+
+      patch "/posts/1"
+      assert_match /update/, last_response.body
+
+      put "/posts/1"
+      assert_equal 404, last_response.status
+    end
+
     test "request forgery token param can be changed" do
       make_basic_app do
         app.config.action_controller.request_forgery_protection_token = '_xsrf_token_here'
diff --git a/railties/test/generators/app_generator_test.rb b/railties/test/generators/app_generator_test.rb
index a3c24c392b..55c7ce1047 100644
--- a/railties/test/generators/app_generator_test.rb
+++ b/railties/test/generators/app_generator_test.rb
@@ -325,6 +325,11 @@ class AppGeneratorTest < Rails::Generators::TestCase
     assert_file "config/application.rb", /#\s+require\s+["']active_record\/railtie["']/
   end
 
+  def test_default_method_for_update_is_not_patch
+    run_generator [destination_root, "--skip-test-unit", "--skip-active-record"]
+    assert_file "config/application.rb", /#\s+config\.default_method_for_update\s+=\s+:patch/
+  end
+
   def test_new_hash_style
     run_generator [destination_root]
     assert_file "config/initializers/session_store.rb" do |file|