Extended url_for to handle specifying which router should be used.

A few examples:
url_for Blog::Engine, :posts_path
url_for Blog::Engine, @post
url_for Blog::Engine, :action => "main", :controller => "index"

actionpack/lib/action_dispatch/routing/polymorphic_routes.rb

@@ -111,7 +111,7 @@ def polymorphic_url(record_or_hash_or_array, options = {})
           args.last.kind_of?(Hash) ? args.last.merge!(url_options) : args << url_options
         end
 
-        send(named_route, *args)
+        url_for _routes.url_helpers.__send__("hash_for_#{named_route}", *args)
       end
 
       # Returns the path component of a URL for the given record. It uses

actionpack/lib/action_dispatch/routing/route_set.rb

@@ -158,10 +158,17 @@ def define_hash_access(route, name, kind, options)
 
             # We use module_eval to avoid leaks
             @module.module_eval <<-END_EVAL, __FILE__, __LINE__ + 1
-              def #{selector}(options = nil)                                      # def hash_for_users_url(options = nil)
+              def #{selector}(*args)
-                options ? #{options.inspect}.merge(options) : #{options.inspect}  #   options ? {:only_path=>false}.merge(options) : {:only_path=>false}
+                options = args.extract_options!
-              end                                                                 # end
+
-              protected :#{selector}                                              # protected :hash_for_users_url
+                if args.any?
+                  options[:_positional_args] = args
+                  options[:_positional_keys] = #{route.segment_keys.inspect}
+                end
+
+                options ? #{options.inspect}.merge(options) : #{options.inspect}
+              end
+              protected :#{selector}
             END_EVAL
             helpers << selector
           end
@@ -185,14 +192,7 @@ def define_url_helper(route, name, kind, options)
 
             @module.module_eval <<-END_EVAL, __FILE__, __LINE__ + 1
               def #{selector}(*args)
-                options =  #{hash_access_method}(args.extract_options!)
+                url_for(#{hash_access_method}(*args))
-
-                if args.any?
-                  options[:_positional_args] = args
-                  options[:_positional_keys] = #{route.segment_keys.inspect}
-                end
-
-                url_for(options)
               end
             END_EVAL
             helpers << selector

actionpack/lib/action_dispatch/routing/url_for.rb

@@ -123,13 +123,24 @@ def url_options
       #    url_for :controller => 'tasks', :action => 'testing', :host=>'somehost.org', :anchor => 'ok', :only_path => true    # => '/tasks/testing#ok'
       #    url_for :controller => 'tasks', :action => 'testing', :trailing_slash=>true  # => 'http://somehost.org/tasks/testing/'
       #    url_for :controller => 'tasks', :action => 'testing', :host=>'somehost.org', :number => '33'  # => 'http://somehost.org/tasks/testing?number=33'
-      def url_for(options = nil)
+      def url_for(*args)
+        if args.first.respond_to?(:routes)
+          app = args.shift
+          _with_routes(app.routes) do
+            if args.first.is_a? Symbol
+              named_route = args.shift
+              url_for _routes.url_helpers.__send__("hash_for_#{named_route}", *args)
+            else
+              url_for(*args)
+            end
+          end
+        else
+          options = args.first
           case options
           when String
             options
           when nil, Hash
             routes = (options ? options.delete(:routes) : nil) || _routes
-
             _with_routes(routes) do
               routes.url_for((options || {}).reverse_merge!(url_options).symbolize_keys)
             end
@@ -137,7 +148,9 @@ def url_for(options = nil)
             polymorphic_url(options)
           end
         end
+      end
 
+      protected
         def _with_routes(routes)
           old_routes, @_routes = @_routes, routes
           yield

actionpack/test/dispatch/url_for_test.rb

@@ -0,0 +1,52 @@
+require 'abstract_unit'
+
+module UrlForGeneration
+  class UrlForTest < ActionDispatch::IntegrationTest
+
+    Routes = ActionDispatch::Routing::RouteSet.new
+    Routes.draw { match "/foo", :to => "my_route_generating#index", :as => :foo }
+
+    class BlogEngine
+      def self.routes
+        @routes ||= begin
+          routes = ActionDispatch::Routing::RouteSet.new
+          routes.draw do
+            resources :posts
+          end
+          routes
+        end
+      end
+    end
+
+    class Post
+      extend ActiveModel::Naming
+
+      def to_param
+        "1"
+      end
+
+      def self.model_name
+        klass = "Post"
+        def klass.name; self end
+
+        ActiveModel::Name.new(klass)
+      end
+    end
+
+    include Routes.url_helpers
+
+    test "url_for with named url helpers" do
+      assert_equal "/posts", url_for(BlogEngine, :posts_path)
+    end
+
+    test "url_for with polymorphic routes" do
+      assert_equal "http://www.example.com/posts/1", url_for(BlogEngine, Post.new)
+    end
+
+    test "url_for with named url helper with arguments" do
+      assert_equal "/posts/1", url_for(BlogEngine, :post_path, 1)
+      assert_equal "/posts/1", url_for(BlogEngine, :post_path, :id => 1)
+      assert_equal "/posts/1.json", url_for(BlogEngine, :post_path, :id => 1, :format => :json)
+    end
+  end
+end

actionpack/test/dispatch/url_generation_test.rb

@@ -41,3 +41,4 @@ def app
     end
   end
 end
+

actionpack/test/template/form_helper_test.rb

@@ -77,13 +77,35 @@ def @post.to_param; '123'; end
     @post.written_on  = Date.new(2004, 6, 15)
   end
 
+  Routes = ActionDispatch::Routing::RouteSet.new
+  Routes.draw do
+    resources :posts do
+      resources :comments
+    end
+
+    namespace :admin do
+      resources :posts do
+        resources :comments
+      end
+    end
+
+    match "/foo", :to => "controller#action"
+    root :to => "main#index"
+  end
+
+  def _routes
+    Routes
+  end
+
+  include Routes.url_helpers
+
   def url_for(object)
     @url_for_options = object
-    if object.is_a?(Hash)
+    if object.is_a?(Hash) && object[:use_route].blank? && object[:controller].blank?
-      "http://www.example.com"
+      object.merge!(:controller => "main", :action => "index")
-    else
-      super
     end
+    object
+    super
   end
 
   def test_label
@@ -628,7 +650,7 @@ def test_form_for
     end
 
     expected =
-      "<form accept-charset='UTF-8' action='http://www.example.com' id='create-post' method='post'>" +
+      "<form accept-charset='UTF-8' action='/' id='create-post' method='post'>" +
       snowman +
       "<label for='post_title'>The Title</label>" +
       "<input name='post[title]' size='30' type='text' id='post_title' value='Hello World' />" +
@@ -683,7 +705,7 @@ def test_form_for_with_method
       end
     end
 
-    expected =  whole_form("http://www.example.com", "create-post", nil, "put") do
+    expected =  whole_form("/", "create-post", nil, "put") do
       "<input name='post[title]' size='30' type='text' id='post_title' value='Hello World' />" +
       "<textarea name='post[body]' id='post_body' rows='20' cols='40'>Back to the hill and over it again!</textarea>" +
       "<input name='post[secret]' type='hidden' value='0' />" +
@@ -702,7 +724,7 @@ def test_form_for_with_remote
       end
     end
 
-    expected =  whole_form("http://www.example.com", "create-post", nil, :method => "put", :remote => true) do
+    expected =  whole_form("/", "create-post", nil, :method => "put", :remote => true) do
       "<input name='post[title]' size='30' type='text' id='post_title' value='Hello World' />" +
       "<textarea name='post[body]' id='post_body' rows='20' cols='40'>Back to the hill and over it again!</textarea>" +
       "<input name='post[secret]' type='hidden' value='0' />" +
@@ -721,7 +743,7 @@ def test_form_for_with_remote_without_html
       end
     end
 
-    expected =  whole_form("http://www.example.com", nil, nil, :remote => true) do
+    expected =  whole_form("/", nil, nil, :remote => true) do
       "<input name='post[title]' size='30' type='text' id='post_title' value='Hello World' />" +
       "<textarea name='post[body]' id='post_body' rows='20' cols='40'>Back to the hill and over it again!</textarea>" +
       "<input name='post[secret]' type='hidden' value='0' />" +
@@ -738,7 +760,7 @@ def test_form_for_without_object
       concat f.check_box(:secret)
     end
 
-    expected =  whole_form("http://www.example.com", "create-post") do
+    expected =  whole_form("/", "create-post") do
       "<input name='post[title]' size='30' type='text' id='post_title' value='Hello World' />" +
       "<textarea name='post[body]' id='post_body' rows='20' cols='40'>Back to the hill and over it again!</textarea>" +
       "<input name='post[secret]' type='hidden' value='0' />" +
@@ -1478,7 +1500,7 @@ def test_form_for_and_fields_for
     end
 
     expected =
-      "<form accept-charset='UTF-8' action='http://www.example.com' id='create-post' method='post'>" +
+      "<form accept-charset='UTF-8' action='/' id='create-post' method='post'>" +
       snowman +
       "<input name='post[title]' size='30' type='text' id='post_title' value='Hello World' />" +
       "<textarea name='post[body]' id='post_body' rows='20' cols='40'>Back to the hill and over it again!</textarea>" +
@@ -1502,7 +1524,7 @@ def test_form_for_and_fields_for_with_object
     end
 
     expected =
-      whole_form("http://www.example.com", "create-post") do
+      whole_form("/", "create-post") do
         "<input name='post[title]' size='30' type='text' id='post_title' value='Hello World' />" +
         "<textarea name='post[body]' id='post_body' rows='20' cols='40'>Back to the hill and over it again!</textarea>" +
         "<input name='post[comment][name]' type='text' id='post_comment_name' value='new comment' size='30' />"
@@ -1546,7 +1568,7 @@ def snowman(method = nil)
     txt << %{</div>}
   end
 
-  def form_text(action = "http://www.example.com", id = nil, html_class = nil, remote = nil)
+  def form_text(action = "/", id = nil, html_class = nil, remote = nil)
     txt =  %{<form accept-charset="UTF-8" action="#{action}"}
     txt << %{ data-remote="true"} if remote
     txt << %{ class="#{html_class}"} if html_class
@@ -1554,7 +1576,7 @@ def form_text(action = "http://www.example.com", id = nil, html_class = nil, rem
     txt << %{ method="post">}
   end
 
-  def whole_form(action = "http://www.example.com", id = nil, html_class = nil, options = nil)
+  def whole_form(action = "/", id = nil, html_class = nil, options = nil)
     contents = block_given? ? yield : ""
 
     if options.is_a?(Hash)
@@ -1655,7 +1677,7 @@ def test_form_for_with_html_options_adds_options_to_form_tag
     assert_deprecated do
       form_for(:post, @post, :html => {:id => 'some_form', :class => 'some_class'}) do |f| end
     end
-    expected = whole_form("http://www.example.com", "some_form", "some_class")
+    expected = whole_form("/", "some_form", "some_class")
 
     assert_dom_equal expected, output_buffer
   end
@@ -1710,14 +1732,14 @@ def test_form_for_with_existing_object_in_list
     @comment.save
     form_for([@post, @comment]) {}
 
-    expected = whole_form(comment_path(@post, @comment), "edit_comment_1", "edit_comment", "put")
+    expected = whole_form(post_comment_path(@post, @comment), "edit_comment_1", "edit_comment", "put")
     assert_dom_equal expected, output_buffer
   end
 
   def test_form_for_with_new_object_in_list
     form_for([@post, @comment]) {}
 
-    expected = whole_form(comments_path(@post), "new_comment", "new_comment")
+    expected = whole_form(post_comments_path(@post), "new_comment", "new_comment")
     assert_dom_equal expected, output_buffer
   end
 
@@ -1725,14 +1747,14 @@ def test_form_for_with_existing_object_and_namespace_in_list
     @comment.save
     form_for([:admin, @post, @comment]) {}
 
-    expected = whole_form(admin_comment_path(@post, @comment), "edit_comment_1", "edit_comment", "put")
+    expected = whole_form(admin_post_comment_path(@post, @comment), "edit_comment_1", "edit_comment", "put")
     assert_dom_equal expected, output_buffer
   end
 
   def test_form_for_with_new_object_and_namespace_in_list
     form_for([:admin, @post, @comment]) {}
 
-    expected = whole_form(admin_comments_path(@post), "new_comment", "new_comment")
+    expected = whole_form(admin_post_comments_path(@post), "new_comment", "new_comment")
     assert_dom_equal expected, output_buffer
   end
 
@@ -1749,38 +1771,6 @@ def test_fields_for_returns_block_result
   end
 
   protected
-    def comments_path(post)
-      "/posts/#{post.id}/comments"
-    end
-    alias_method :post_comments_path, :comments_path
-
-    def comment_path(post, comment)
-      "/posts/#{post.id}/comments/#{comment.id}"
-    end
-    alias_method :post_comment_path, :comment_path
-
-    def admin_comments_path(post)
-      "/admin/posts/#{post.id}/comments"
-    end
-    alias_method :admin_post_comments_path, :admin_comments_path
-
-    def admin_comment_path(post, comment)
-      "/admin/posts/#{post.id}/comments/#{comment.id}"
-    end
-    alias_method :admin_post_comment_path, :admin_comment_path
-
-    def posts_path
-      "/posts"
-    end
-
-    def post_path(post, options = {})
-      if options[:format]
-        "/posts/#{post.id}.#{options[:format]}"
-      else
-        "/posts/#{post.id}"
-      end
-    end
-
     def protect_against_forgery?
       false
     end

actionpack/test/template/test_test.rb

@@ -39,7 +39,7 @@ def test_link_to_person
     with_test_route_set do
       person = mock(:name => "David")
       person.class.extend ActiveModel::Naming
-      expects(:mocha_mock_path).with(person).returns("/people/1")
+      _routes.url_helpers.expects(:hash_for_mocha_mock_path).with(person).returns("/people/1")
       assert_equal '<a href="/people/1">David</a>', link_to_person(person)
     end
   end