2 files changed, 63 insertions, 24 deletions

diff --git a/actionpack/lib/action_dispatch/routing/inspector.rb b/actionpack/lib/action_dispatch/routing/inspector.rb
index 73b2b4ac1d..7ae1d2a0ee 100644
--- a/actionpack/lib/action_dispatch/routing/inspector.rb
+++ b/actionpack/lib/action_dispatch/routing/inspector.rb
@@ -61,21 +61,33 @@ module ActionDispatch
 
     ##
     # This class is just used for displaying route information when someone
-    # executes `rake routes`.  People should not use this class.
+    # executes `rake routes` or looks at the RoutingError page.
+    # People should not use this class.
     class RoutesInspector # :nodoc:
-      def initialize
-        @engines = Hash.new
+      def initialize(routes)
+        @engines = {}
+        @routes = routes
       end
 
-      def format(all_routes, filter = nil)
-        if filter
-          all_routes = all_routes.select{ |route| route.defaults[:controller] == filter }
+      def format(formatter, filter = nil)
+        routes_to_display = filter_routes(filter)
+
+        routes = collect_routes(routes_to_display)
+        formatter.section :application, 'Application routes', routes
+
+        @engines.each do |name, routes|
+          formatter.section :engine, "Routes for #{name}", routes
         end
 
-        routes = collect_routes(all_routes)
+        formatter.result
+      end
 
-        formatted_routes(routes) +
-          formatted_routes_for_engines
+      def filter_routes(filter)
+        if filter
+          @routes.select { |route| route.defaults[:controller] == filter }
+        else
+          @routes
+        end
       end
 
       def collect_routes(routes)
@@ -100,22 +112,32 @@ module ActionDispatch
           @engines[name] = collect_routes(routes.routes)
         end
       end
+    end
 
-      def formatted_routes_for_engines
-        @engines.map do |name, routes|
-          ["\nRoutes for #{name}:"] + formatted_routes(routes)
-        end.flatten
+    class ConsoleFormatter
+      def initialize
+        @buffer = []
       end
 
-      def formatted_routes(routes)
-        name_width = routes.map{ |r| r[:name].length }.max
-        verb_width = routes.map{ |r| r[:verb].length }.max
-        path_width = routes.map{ |r| r[:path].length }.max
+      def result
+        @buffer.join("\n")
+      end
 
-        routes.map do |r|
-          "#{r[:name].rjust(name_width)} #{r[:verb].ljust(verb_width)} #{r[:path].ljust(path_width)} #{r[:reqs]}"
-        end
+      def section(type, title, routes)
+        @buffer << "\n#{title}:" unless type == :application
+        @buffer << draw_section(routes)
       end
+
+      private
+        def draw_section(routes)
+          name_width = routes.map { |r| r[:name].length }.max
+          verb_width = routes.map { |r| r[:verb].length }.max
+          path_width = routes.map { |r| r[:path].length }.max
+
+          routes.map do |r|
+            "#{r[:name].rjust(name_width)} #{r[:verb].ljust(verb_width)} #{r[:path].ljust(path_width)} #{r[:reqs]}"
+          end
+        end
     end
   end
 end
diff --git a/actionpack/test/dispatch/routing/inspector_test.rb b/actionpack/test/dispatch/routing/inspector_test.rb
index c058bd4909..46e1cab30b 100644
--- a/actionpack/test/dispatch/routing/inspector_test.rb
+++ b/actionpack/test/dispatch/routing/inspector_test.rb
@@ -8,7 +8,6 @@ module ActionDispatch
     class RoutesInspectorTest < ActiveSupport::TestCase
       def setup
         @set = ActionDispatch::Routing::RouteSet.new
-        @inspector = ActionDispatch::Routing::RoutesInspector.new
         app = ActiveSupport::OrderedOptions.new
         app.config = ActiveSupport::OrderedOptions.new
         app.config.assets = ActiveSupport::OrderedOptions.new
@@ -17,9 +16,10 @@ module ActionDispatch
         Rails.stubs(:env).returns("development")
       end
 
-      def draw(&block)
+      def draw(options = {}, &block)
         @set.draw(&block)
-        @inspector.format(@set.routes)
+        inspector = ActionDispatch::Routing::RoutesInspector.new(@set.routes)
+        inspector.format(ActionDispatch::Routing::ConsoleFormatter.new, options[:filter]).split("\n")
       end
 
       def test_displaying_routes_for_engines
@@ -40,7 +40,8 @@ module ActionDispatch
         expected = [
           "custom_assets GET /custom/assets(.:format) custom_assets#show",
           "         blog     /blog                    Blog::Engine",
-          "\nRoutes for Blog::Engine:",
+          "",
+          "Routes for Blog::Engine:",
           "cart GET /cart(.:format) cart#show"
         ]
         assert_equal expected, output
@@ -165,6 +166,22 @@ module ActionDispatch
         assert_equal "   bar GET /bar(.:format)    redirect(307, path: /foo/bar)", output[1]
         assert_equal "foobar GET /foobar(.:format) redirect(301)", output[2]
       end
+
+      def test_routes_can_be_filtered
+        output = draw(filter: 'posts') do
+          resources :articles
+          resources :posts
+        end
+
+        assert_equal ["    posts GET    /posts(.:format)          posts#index",
+                      "          POST   /posts(.:format)          posts#create",
+                      " new_post GET    /posts/new(.:format)      posts#new",
+                      "edit_post GET    /posts/:id/edit(.:format) posts#edit",
+                      "     post GET    /posts/:id(.:format)      posts#show",
+                      "          PATCH  /posts/:id(.:format)      posts#update",
+                      "          PUT    /posts/:id(.:format)      posts#update",
+                      "          DELETE /posts/:id(.:format)      posts#destroy"], output
+      end
     end
   end
 end