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.

1 files changed, 9 insertions, 6 deletions

diff --git a/actionpack/lib/action_dispatch/routing.rb b/actionpack/lib/action_dispatch/routing.rb
index 107fe80d1f..38a0270151 100644
--- a/actionpack/lib/action_dispatch/routing.rb
+++ b/actionpack/lib/action_dispatch/routing.rb
@@ -182,10 +182,13 @@ module ActionDispatch
   #
   # == HTTP Methods
   #
-  # Using the <tt>:via</tt> option when specifying a route allows you to restrict it to a specific HTTP method.
-  # Possible values are <tt>:post</tt>, <tt>:get</tt>, <tt>:put</tt>, <tt>:delete</tt> and <tt>:any</tt>.
-  # If your route needs to respond to more than one method you can use an array, e.g. <tt>[ :get, :post ]</tt>.
-  # The default value is <tt>:any</tt> which means that the route will respond to any of the HTTP methods.
+  # Using the <tt>:via</tt> option when specifying a route allows you to
+  # restrict it to a specific HTTP method.  Possible values are <tt>:post</tt>,
+  # <tt>:get</tt>, <tt>:patch</tt>, <tt>:put</tt>, <tt>:delete</tt> and
+  # <tt>:any</tt>.  If your route needs to respond to more than one method you
+  # can use an array, e.g. <tt>[ :get, :post ]</tt>.  The default value is
+  # <tt>:any</tt> which means that the route will respond to any of the HTTP
+  # methods.
   #
   # Examples:
   #
@@ -198,7 +201,7 @@ module ActionDispatch
   # === HTTP helper methods
   #
   # An alternative method of specifying which HTTP method a route should respond to is to use the helper
-  # methods <tt>get</tt>, <tt>post</tt>, <tt>put</tt> and <tt>delete</tt>.
+  # methods <tt>get</tt>, <tt>post</tt>, <tt>patch</tt>, <tt>put</tt> and <tt>delete</tt>.
   #
   # Examples:
   #
@@ -283,6 +286,6 @@ module ActionDispatch
     autoload :PolymorphicRoutes, 'action_dispatch/routing/polymorphic_routes'
 
     SEPARATORS = %w( / . ? ) #:nodoc:
-    HTTP_METHODS = [:get, :head, :post, :put, :delete, :options] #:nodoc:
+    HTTP_METHODS = [:get, :head, :post, :patch, :put, :delete, :options] #:nodoc:
   end
 end