Added ability to set asset_path for engines

actionpack/lib/action_dispatch/testing/test_request.rb

@@ -10,7 +10,7 @@ module ActionDispatch
     end
 
     def initialize(env = {})
-      env = Rails.application.env_defaults.merge(env) if defined?(Rails.application)
+      env = Rails.application.env_config.merge(env) if defined?(Rails.application)
       super(DEFAULT_ENV.merge(env))
 
       self.host        = 'test.host'

actionpack/lib/action_view/helpers/asset_tag_helper.rb

@@ -727,6 +727,9 @@ module ActionView
 
           source += ".#{ext}" if rewrite_extension?(source, dir, ext)
           source  = "/#{dir}/#{source}" unless source[0] == ?/
+          if controller.respond_to?(:env) && controller.env["action_dispatch.asset_path"]
+            source = rewrite_asset_path(source, controller.env["action_dispatch.asset_path"])
+          end
           source = rewrite_asset_path(source, config.asset_path)
 
           has_request = controller.respond_to?(:request)

actionpack/test/template/asset_tag_helper_test.rb

@@ -387,6 +387,15 @@ class AssetTagHelperTest < ActionView::TestCase
     assert_equal %(<img alt="Rails" src="#{expected_path}" />), image_tag("rails.png")
   end
 
+  def test_env_asset_path
+    @controller.config.asset_path = "/assets%s"
+    def @controller.env; @_env ||= {} end
+    @controller.env["action_dispatch.asset_path"] = "/omg%s"
+
+    expected_path = "/assets/omg/images/rails.png"
+    assert_equal %(<img alt="Rails" src="#{expected_path}" />), image_tag("rails.png")
+  end
+
   def test_proc_asset_id
     @controller.config.asset_path = Proc.new do |asset_path|
       "/assets.v12345#{asset_path}"
@@ -396,6 +405,20 @@ class AssetTagHelperTest < ActionView::TestCase
     assert_equal %(<img alt="Rails" src="#{expected_path}" />), image_tag("rails.png")
   end
 
+  def test_env_proc_asset_path
+    @controller.config.asset_path = Proc.new do |asset_path|
+      "/assets.v12345#{asset_path}"
+    end
+
+    def @controller.env; @_env ||= {} end
+    @controller.env["action_dispatch.asset_path"] = Proc.new do |asset_path|
+      "/omg#{asset_path}"
+    end
+
+    expected_path = "/assets.v12345/omg/images/rails.png"
+    assert_equal %(<img alt="Rails" src="#{expected_path}" />), image_tag("rails.png")
+  end
+
   def test_image_tag_interpreting_email_cid_correctly
     # An inline image has no need for an alt tag to be automatically generated from the cid:
     assert_equal '<img src="cid:thi%25%25sis@acontentid" />', image_tag("cid:thi%25%25sis@acontentid")

railties/lib/rails/application.rb

@@ -124,16 +124,12 @@ module Rails
 
     alias :build_middleware_stack :app
 
-    def call(env)
-      env["action_dispatch.routes"] = routes
-      app.call(env.reverse_merge!(env_defaults))
-    end
-
-    def env_defaults
-      @env_defaults ||= {
+    def env_config
+      @env_config ||= super.merge({
         "action_dispatch.parameter_filter" => config.filter_parameters,
-        "action_dispatch.secret_token" => config.secret_token
-      }
+        "action_dispatch.secret_token" => config.secret_token,
+        "action_dispatch.asset_path" => nil
+      })
     end
 
     def initializers

railties/lib/rails/application/configuration.rb

@@ -25,6 +25,18 @@ module Rails
         @middleware = app_middleware
       end
 
+      def asset_path=(value)
+        action_mailer.asset_path = value if respond_to?(:action_mailer) && action_mailer
+        action_controller.asset_path = value if respond_to?(:action_controller) && action_controller
+        super(value)
+      end
+
+      def asset_host=(value)
+        action_mailer.asset_host = value if action_mailer
+        action_controller.asset_host = value if action_controller
+        super(value)
+      end
+
       def encoding=(value)
         @encoding = value
         if "ruby".encoding_aware?

railties/lib/rails/engine.rb

@@ -147,6 +147,19 @@ module Rails
   #
   # Now, Engine will get only requests that were not handled by application.
   #
+  # == Asset path
+  #
+  # When you use engine with its own public directory, you will probably want to copy or symlink it
+  # to application's public directory. To simplify generating paths for assets, you can set asset_path
+  # for an Engine:
+  #
+  # class MyEngine::Engine < Rails::Engine
+  #   config.asset_path = "/my_engine/%s"
+  # end
+  #
+  # With such config, asset paths will be automatically modified inside Engine:
+  # image_path("foo.jpg") #=> "/my_engine/images/foo.jpg"
+  #
   class Engine < Railtie
     autoload :Configurable,  "rails/engine/configurable"
     autoload :Configuration, "rails/engine/configuration"
@@ -219,8 +232,14 @@ module Rails
     end
 
     def call(env)
-      env["action_dispatch.routes"] = routes
-      app.call(env)
+      app.call(env.merge!(env_config))
+    end
+
+    def env_config
+      @env_config ||= {
+        'action_dispatch.routes' => routes,
+        'action_dispatch.asset_path' => config.asset_path
+      }
     end
 
     def routes

railties/lib/rails/engine/configuration.rb

@@ -5,7 +5,7 @@ module Rails
     class Configuration < ::Rails::Railtie::Configuration
       attr_reader :root
       attr_writer :eager_load_paths, :autoload_once_paths, :autoload_paths
-      attr_accessor :middleware, :plugins
+      attr_accessor :middleware, :plugins, :asset_path
 
       def initialize(root=nil)
         super()

railties/test/application/configuration_test.rb

@@ -260,5 +260,20 @@ module ApplicationTests
       get "/"
       assert_not_equal res, last_response.body
     end
+
+    test "config.asset_path is not passed through env" do
+      make_basic_app do |app|
+        app.config.asset_path = "/omg%s"
+      end
+
+      class ::OmgController < ActionController::Base
+        def index
+          render :inline => "<%= image_path('foo.jpg') %>"
+        end
+      end
+
+      get "/"
+      assert_equal "/omg/images/foo.jpg", last_response.body
+    end
   end
 end

railties/test/railties/engine_test.rb

@@ -199,5 +199,65 @@ module RailtiesTest
 
       assert_equal Rails.application.routes, env['action_dispatch.routes']
     end
+
+    test "it allows to set asset_path" do
+      @plugin.write "lib/bukkits.rb", <<-RUBY
+        class Bukkits
+          class Engine < ::Rails::Engine
+            config.asset_path = "/bukkits%s"
+          end
+        end
+      RUBY
+
+
+      @plugin.write "config/routes.rb", <<-RUBY
+        Bukkits::Engine.routes.draw do
+          match "/foo" => "foo#index"
+        end
+      RUBY
+
+      @plugin.write "app/controllers/foo_controller.rb", <<-RUBY
+        class FooController < ActionController::Base
+          def index
+            render :index
+          end
+        end
+      RUBY
+
+      @plugin.write "app/views/foo/index.html.erb", <<-RUBY
+        <%= compute_public_path("/foo", "") %>
+        <%= image_path("foo.png") %>
+        <%= javascript_include_tag("foo") %>
+        <%= stylesheet_link_tag("foo") %>
+      RUBY
+
+
+      app_file "app/controllers/bar_controller.rb", <<-RUBY
+        class BarController < ActionController::Base
+          def index
+            render :index
+          end
+        end
+      RUBY
+
+      app_file "app/views/bar/index.html.erb", <<-RUBY
+        <%= compute_public_path("/foo", "") %>
+      RUBY
+
+      add_to_config 'config.asset_path = "/omg%s"'
+
+      boot_rails
+
+      env = Rack::MockRequest.env_for("/foo")
+      response = Bukkits::Engine.call(env)
+      stripped_body = response[2].body.split("\n").map(&:strip).join("\n")
+
+      expected =  "/omg/bukkits/foo\n" +
+                  "/omg/bukkits/images/foo.png\n" +
+                  "<script src=\"/omg/bukkits/javascripts/foo.js\" type=\"text/javascript\"></script>\n" +
+                  "<link href=\"/omg/bukkits/stylesheets/foo.css\" media=\"screen\" rel=\"stylesheet\" type=\"text/css\" />"
+      assert_equal expected, stripped_body
+
+    end
   end
 end