This commit merges most of the work done by Piotr Sarnacki in his Ruby Summer of Code project.

His work brings several capabilities from app to engines, as routes, middleware stack, asset handling and much more. Please check Rails::Engine documentation for more refenrences.

Merge remote branch 'drogus/engines'

9 files changed, 214 insertions, 43 deletions

diff --git a/actionpack/lib/action_dispatch/middleware/stack.rb b/actionpack/lib/action_dispatch/middleware/stack.rb
index 5a029a60d1..6f243574e4 100644
--- a/actionpack/lib/action_dispatch/middleware/stack.rb
+++ b/actionpack/lib/action_dispatch/middleware/stack.rb
@@ -1,4 +1,5 @@
 require "active_support/inflector/methods"
+require "active_support/dependencies"
 
 module ActionDispatch
   class MiddlewareStack < Array
diff --git a/actionpack/lib/action_dispatch/middleware/static.rb b/actionpack/lib/action_dispatch/middleware/static.rb
index d7e88a54e4..581cadbeb4 100644
--- a/actionpack/lib/action_dispatch/middleware/static.rb
+++ b/actionpack/lib/action_dispatch/middleware/static.rb
@@ -1,12 +1,47 @@
 require 'rack/utils'
 
 module ActionDispatch
+  class FileHandler
+    def initialize(at, root)
+      @at, @root = at.chomp('/'), root.chomp('/')
+      @compiled_at = Regexp.compile(/^#{Regexp.escape(at)}/) unless @at.blank?
+      @compiled_root = Regexp.compile(/^#{Regexp.escape(root)}/)
+      @file_server = ::Rack::File.new(root)
+    end
+
+    def match?(path)
+      path = path.dup
+      if @compiled_at.blank? || path.sub!(@compiled_at, '')
+        full_path = File.join(@root, ::Rack::Utils.unescape(path))
+        paths = "#{full_path}#{ext}"
+
+        matches = Dir[paths]
+        match = matches.detect { |m| File.file?(m) }
+        if match
+          match.sub!(@compiled_root, '')
+          match
+        end
+      end
+    end
+
+    def call(env)
+      @file_server.call(env)
+    end
+
+    def ext
+      @ext ||= begin
+        ext = ::ActionController::Base.page_cache_extension
+        "{,#{ext},/index#{ext}}"
+      end
+    end
+  end
+
   class Static
     FILE_METHODS = %w(GET HEAD).freeze
 
-    def initialize(app, root)
+    def initialize(app, roots)
       @app = app
-      @file_server = ::Rack::File.new(root)
+      @file_handlers = create_file_handlers(roots)
     end
 
     def call(env)
@@ -14,15 +49,10 @@ module ActionDispatch
       method = env['REQUEST_METHOD']
 
       if FILE_METHODS.include?(method)
-        if file_exist?(path)
-          return @file_server.call(env)
-        else
-          cached_path = directory_exist?(path) ? "#{path}/index" : path
-          cached_path += ::ActionController::Base.page_cache_extension
-
-          if file_exist?(cached_path)
-            env['PATH_INFO'] = cached_path
-            return @file_server.call(env)
+        @file_handlers.each do |file_handler|
+          if match = file_handler.match?(path)
+            env["PATH_INFO"] = match
+            return file_handler.call(env)
           end
         end
       end
@@ -31,14 +61,12 @@ module ActionDispatch
     end
 
     private
-      def file_exist?(path)
-        full_path = File.join(@file_server.root, ::Rack::Utils.unescape(path))
-        File.file?(full_path) && File.readable?(full_path)
-      end
+      def create_file_handlers(roots)
+        roots = { '' => roots } unless roots.is_a?(Hash)
 
-      def directory_exist?(path)
-        full_path = File.join(@file_server.root, ::Rack::Utils.unescape(path))
-        File.directory?(full_path) && File.readable?(full_path)
+        roots.map do |at, root|
+          FileHandler.new(at, root) if File.exist?(root)
+        end.compact
       end
   end
 end
diff --git a/actionpack/lib/action_dispatch/routing.rb b/actionpack/lib/action_dispatch/routing.rb
index 0b9689dc88..b2b0f4c08e 100644
--- a/actionpack/lib/action_dispatch/routing.rb
+++ b/actionpack/lib/action_dispatch/routing.rb
@@ -268,6 +268,7 @@ module ActionDispatch
     autoload :Mapper, 'action_dispatch/routing/mapper'
     autoload :Route, 'action_dispatch/routing/route'
     autoload :RouteSet, 'action_dispatch/routing/route_set'
+    autoload :RoutesProxy, 'action_dispatch/routing/routes_proxy'
     autoload :UrlFor, 'action_dispatch/routing/url_for'
     autoload :PolymorphicRoutes, 'action_dispatch/routing/polymorphic_routes'
 
diff --git a/actionpack/lib/action_dispatch/routing/mapper.rb b/actionpack/lib/action_dispatch/routing/mapper.rb
index a2570cb877..900900ee24 100644
--- a/actionpack/lib/action_dispatch/routing/mapper.rb
+++ b/actionpack/lib/action_dispatch/routing/mapper.rb
@@ -261,7 +261,11 @@ module ActionDispatch
 
           raise "A rack application must be specified" unless path
 
+          options[:as] ||= app_name(app)
+
           match(path, options.merge(:to => app, :anchor => false, :format => false))
+
+          define_generate_prefix(app, options[:as])
           self
         end
 
@@ -269,6 +273,40 @@ module ActionDispatch
           @set.default_url_options = options
         end
         alias_method :default_url_options, :default_url_options=
+
+        def with_default_scope(scope, &block)
+          scope(scope) do
+            instance_exec(&block)
+          end
+        end
+
+        private
+          def app_name(app)
+            return unless app.respond_to?(:routes)
+
+            if app.respond_to?(:railtie_name)
+              app.railtie_name
+            else
+              class_name = app.class.is_a?(Class) ? app.name : app.class.name
+              ActiveSupport::Inflector.underscore(class_name).gsub("/", "_")
+            end
+          end
+
+          def define_generate_prefix(app, name)
+            return unless app.respond_to?(:routes)
+
+            _route = @set.named_routes.routes[name.to_sym]
+            _routes = @set
+            app.routes.define_mounted_helper(name)
+            app.routes.class_eval do
+              define_method :_generate_prefix do |options|
+                prefix_options = options.slice(*_route.segment_keys)
+                # we must actually delete prefix segment keys to avoid passing them to next url_for
+                _route.segment_keys.each { |k| options.delete(k) }
+                _routes.url_helpers.send("#{name}_path", prefix_options)
+              end
+            end
+          end
       end
 
       module HttpHelpers
diff --git a/actionpack/lib/action_dispatch/routing/polymorphic_routes.rb b/actionpack/lib/action_dispatch/routing/polymorphic_routes.rb
index fb2118a8d7..02ba5236ee 100644
--- a/actionpack/lib/action_dispatch/routing/polymorphic_routes.rb
+++ b/actionpack/lib/action_dispatch/routing/polymorphic_routes.rb
@@ -42,6 +42,18 @@ module ActionDispatch
     #
     #   edit_polymorphic_path(@post)              # => "/posts/1/edit"
     #   polymorphic_path(@post, :format => :pdf)  # => "/posts/1.pdf"
+    #
+    # == Using with mounted engines
+    #
+    # If you use mounted engine, there is a possibility that you will need to use
+    # polymorphic_url pointing at engine's routes. To do that, just pass proxy used
+    # to reach engine's routes as a first argument:
+    #
+    # For example:
+    #
+    # polymorphic_url([blog, @post])  # it will call blog.post_path(@post)
+    # form_for([blog, @post])         # => "/blog/posts/1
+    #
     module PolymorphicRoutes
       # Constructs a call to a named RESTful route for the given record and returns the
       # resulting URL string. For example:
@@ -78,6 +90,9 @@ module ActionDispatch
       def polymorphic_url(record_or_hash_or_array, options = {})
         if record_or_hash_or_array.kind_of?(Array)
           record_or_hash_or_array = record_or_hash_or_array.compact
+          if record_or_hash_or_array.first.is_a?(ActionDispatch::Routing::RoutesProxy)
+            proxy = record_or_hash_or_array.shift
+          end
           record_or_hash_or_array = record_or_hash_or_array[0] if record_or_hash_or_array.size == 1
         end
 
@@ -111,7 +126,14 @@ module ActionDispatch
           args.last.kind_of?(Hash) ? args.last.merge!(url_options) : args << url_options
         end
 
-        send(named_route, *args)
+        if proxy
+          proxy.send(named_route, *args)
+        else
+          # we need to use url_for, because polymorphic_url can be used in context of other than
+          # current routes (e.g. engine's routes). As named routes from engine are not included
+          # calling engine's named route directly would fail.
+          url_for _routes.url_helpers.__send__("hash_for_#{named_route}", *args)
+        end
       end
 
       # Returns the path component of a URL for the given record. It uses
@@ -155,7 +177,7 @@ module ActionDispatch
               if parent.is_a?(Symbol) || parent.is_a?(String)
                 parent
               else
-                ActiveModel::Naming.plural(parent).singularize
+                ActiveModel::Naming.route_key(parent).singularize
               end
             end
           end
@@ -163,7 +185,7 @@ module ActionDispatch
           if record.is_a?(Symbol) || record.is_a?(String)
             route << record
           else
-            route << ActiveModel::Naming.plural(record)
+            route << ActiveModel::Naming.route_key(record)
             route = [route.join("_").singularize] if inflection == :singular
             route << "index" if ActiveModel::Naming.uncountable?(record) && inflection == :plural
           end
diff --git a/actionpack/lib/action_dispatch/routing/route_set.rb b/actionpack/lib/action_dispatch/routing/route_set.rb
index b531cc1a8e..107e44287d 100644
--- a/actionpack/lib/action_dispatch/routing/route_set.rb
+++ b/actionpack/lib/action_dispatch/routing/route_set.rb
@@ -158,10 +158,17 @@ module ActionDispatch
 
             # 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)
-                options ? #{options.inspect}.merge(options) : #{options.inspect}  #   options ? {:only_path=>false}.merge(options) : {:only_path=>false}
-              end                                                                 # end
-              protected :#{selector}                                              # protected :hash_for_users_url
+              def #{selector}(*args)
+                options = args.extract_options!
+
+                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
@@ -185,21 +192,14 @@ module ActionDispatch
 
             @module.module_eval <<-END_EVAL, __FILE__, __LINE__ + 1
               def #{selector}(*args)
-                options =  #{hash_access_method}(args.extract_options!)
-
-                if args.any?
-                  options[:_positional_args] = args
-                  options[:_positional_keys] = #{route.segment_keys.inspect}
-                end
-
-                url_for(options)
+                url_for(#{hash_access_method}(*args))
               end
             END_EVAL
             helpers << selector
           end
       end
 
-      attr_accessor :set, :routes, :named_routes
+      attr_accessor :set, :routes, :named_routes, :default_scope
       attr_accessor :disable_clear_and_finalize, :resources_path_names
       attr_accessor :default_url_options, :request_class, :valid_conditions
 
@@ -230,7 +230,11 @@ module ActionDispatch
         if block.arity == 1
           mapper.instance_exec(DeprecatedMapper.new(self), &block)
         else
-          mapper.instance_exec(&block)
+          if default_scope
+            mapper.with_default_scope(default_scope, &block)
+          else
+            mapper.instance_exec(&block)
+          end
         end
 
         finalize! unless @disable_clear_and_finalize
@@ -261,6 +265,31 @@ module ActionDispatch
         named_routes.install(destinations, regenerate_code)
       end
 
+      module MountedHelpers
+      end
+
+      def mounted_helpers(name = nil)
+        define_mounted_helper(name) if name
+        MountedHelpers
+      end
+
+      def define_mounted_helper(name)
+        return if MountedHelpers.method_defined?(name)
+
+        routes = self
+        MountedHelpers.class_eval do
+          define_method "_#{name}" do
+            RoutesProxy.new(routes, self._routes_context)
+          end
+        end
+
+        MountedHelpers.class_eval <<-RUBY
+          def #{name}
+            @#{name} ||= _#{name}
+          end
+        RUBY
+      end
+
       def url_helpers
         @url_helpers ||= begin
           routes = self
@@ -283,7 +312,7 @@ module ActionDispatch
               singleton_class.send(:define_method, :_routes) { routes }
             end
 
-            define_method(:_routes) { routes }
+            define_method(:_routes) { @_routes || routes }
           end
 
           helpers
@@ -303,10 +332,9 @@ module ActionDispatch
       end
 
       class Generator #:nodoc:
-        attr_reader :options, :recall, :set, :script_name, :named_route
+        attr_reader :options, :recall, :set, :named_route
 
         def initialize(options, recall, set, extras = false)
-          @script_name = options.delete(:script_name)
           @named_route = options.delete(:use_route)
           @options     = options.dup
           @recall      = recall.dup
@@ -401,7 +429,7 @@ module ActionDispatch
           return [path, params.keys] if @extras
 
           path << "?#{params.to_query}" if params.any?
-          "#{script_name}#{path}"
+          path
         rescue Rack::Mount::RoutingError
           raise_routing_error
         end
@@ -453,7 +481,11 @@ module ActionDispatch
         Generator.new(options, recall, self, extras).generate
       end
 
-      RESERVED_OPTIONS = [:anchor, :params, :only_path, :host, :protocol, :port, :trailing_slash]
+      RESERVED_OPTIONS = [:anchor, :params, :only_path, :host, :protocol, :port, :trailing_slash, :script_name]
+
+      def _generate_prefix(options = {})
+        nil
+      end
 
       def url_for(options)
         finalize!
@@ -464,7 +496,6 @@ module ActionDispatch
         rewritten_url = ""
 
         path_segments = options.delete(:_path_segments)
-
         unless options[:only_path]
           rewritten_url << (options[:protocol] || "http")
           rewritten_url << "://" unless rewritten_url.match("://")
@@ -476,9 +507,12 @@ module ActionDispatch
           rewritten_url << ":#{options.delete(:port)}" if options.key?(:port)
         end
 
+        script_name = options.delete(:script_name)
+        path = (script_name.blank? ? _generate_prefix(options) : script_name).to_s
+
         path_options = options.except(*RESERVED_OPTIONS)
         path_options = yield(path_options) if block_given?
-        path = generate(path_options, path_segments || {})
+        path << generate(path_options, path_segments || {})
 
         # ROUTES TODO: This can be called directly, so script_name should probably be set in the routes
         rewritten_url << (options[:trailing_slash] ? path.sub(/\?|\z/) { "/" + $& } : path)
diff --git a/actionpack/lib/action_dispatch/routing/routes_proxy.rb b/actionpack/lib/action_dispatch/routing/routes_proxy.rb
new file mode 100644
index 0000000000..f7d5f6397d
--- /dev/null
+++ b/actionpack/lib/action_dispatch/routing/routes_proxy.rb
@@ -0,0 +1,35 @@
+module ActionDispatch
+  module Routing
+    class RoutesProxy #:nodoc:
+      include ActionDispatch::Routing::UrlFor
+
+      attr_accessor :scope, :routes
+      alias :_routes :routes
+
+      def initialize(routes, scope)
+        @routes, @scope = routes, scope
+      end
+
+      def url_options
+        scope.send(:_with_routes, routes) do
+          scope.url_options
+        end
+      end
+
+      def method_missing(method, *args)
+        if routes.url_helpers.respond_to?(method)
+          self.class.class_eval <<-RUBY, __FILE__, __LINE__ + 1
+            def #{method}(*args)
+              options = args.extract_options!
+              args << url_options.merge((options || {}).symbolize_keys)
+              routes.url_helpers.#{method}(*args)
+            end
+          RUBY
+          send(method, *args)
+        else
+          super
+        end
+      end
+    end
+  end
+end
diff --git a/actionpack/lib/action_dispatch/routing/url_for.rb b/actionpack/lib/action_dispatch/routing/url_for.rb
index 28ec830fe8..e836cf7c8e 100644
--- a/actionpack/lib/action_dispatch/routing/url_for.rb
+++ b/actionpack/lib/action_dispatch/routing/url_for.rb
@@ -133,6 +133,18 @@ module ActionDispatch
           polymorphic_url(options)
         end
       end
+
+      protected
+        def _with_routes(routes)
+          old_routes, @_routes = @_routes, routes
+          yield
+        ensure
+          @_routes = old_routes
+        end
+
+        def _routes_context
+          self
+        end
     end
   end
 end
diff --git a/actionpack/lib/action_dispatch/testing/test_request.rb b/actionpack/lib/action_dispatch/testing/test_request.rb
index b3e67f6e36..c587a36930 100644
--- a/actionpack/lib/action_dispatch/testing/test_request.rb
+++ b/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'