add RackMapped adapter that correctly handles routing when hosted from a rack mapped URI

`Webmachine::Adapters::RackMapped` is implemented as a subclass of
`Webmachine::Adapters::Rack`, and simply overrides the way the
`Webmachine::Request` is built to explicitly set the `routing_tokens`
from the rack request `PATH_INFO` string - rather than from the full
uri path string as the base rack adapter does.

Rack provides the path that the app should use in the `PATH_INFO` env
var. This is the correct value to use for routing etc to work with
mapped apps.

Note, this was done as a separate class as suggested by @bethesque to
preserve backward compatibility. If any webmachine apps are running as
mapped rack apps already, they may have gotten around not being able to
host the app on a mapped path by specifying the full URI path in the
routing config - which would no longer work if this change was made on
the base rack adapter.

Author: madlep

lib/webmachine/adapters/rack.rb

@@ -59,10 +59,7 @@ def call(env)
         headers = Webmachine::Headers.from_cgi(env)
 
         rack_req = ::Rack::Request.new env
-        request = Webmachine::Request.new(rack_req.request_method,
-                                          rack_req.url,
-                                          headers,
-                                          RequestBody.new(rack_req))
+        request = build_webmachine_request(rack_req, headers)
 
         response = Webmachine::Response.new
         application.dispatcher.dispatch(request, response)
@@ -95,6 +92,14 @@ def call(env)
         rack_res.finish
       end
 
+      private
+      def build_webmachine_request(rack_req, headers)
+        Webmachine::Request.new(rack_req.request_method,
+                                rack_req.url,
+                                headers,
+                                RequestBody.new(rack_req))
+      end
+
       class RackResponse
         ONE_FIVE = '1.5'.freeze
 
@@ -167,5 +172,16 @@ def each
       end # class RequestBody
     end # class Rack
 
+    class RackMapped < Rack
+      def build_webmachine_request(rack_req, headers)
+        request = super
+        routing_match = rack_req.path_info.match(Webmachine::Request::ROUTING_PATH_MATCH)
+        routing_path = routing_match ? routing_match[1] : ""
+        routing_tokens = routing_path.split(SLASH)
+        request.routing_tokens = routing_tokens
+        request
+      end
+    end
+
   end # module Adapters
 end # module Webmachine

spec/webmachine/adapters/rack_spec.rb

@@ -14,6 +14,16 @@
   end
 end
 
+describe Webmachine::Adapters::RackMapped do
+  it_should_behave_like :adapter_lint do
+    it "should set Server header" do
+      response = client.request(Net::HTTP::Get.new("/test"))
+      expect(response["Server"]).to match(/Webmachine/)
+      expect(response["Server"]).to match(/Rack/)
+    end
+  end
+end
+
 describe Webmachine::Adapters::Rack::RackResponse do
   context "on Rack < 1.5 release" do
     before { allow(Rack).to receive_messages(:release => "1.4") }
@@ -55,3 +65,27 @@
     end
   end
 end
+
+describe Webmachine::Adapters::RackMapped do
+  let(:app) do
+    Rack::Builder.new do
+      map '/some/route' do
+        run(Webmachine::Application.new do |app|
+          app.add_route(["test"], Test::Resource)
+          app.configure do | config |
+            config.adapter = :RackMapped
+          end
+        end.adapter)
+      end
+    end
+  end
+
+  context "using Rack::Test" do
+    include Rack::Test::Methods
+
+    it "provides the full request URI" do
+      rack_response = get "some/route/test", nil, {"HTTP_ACCEPT" => "test/response.request_uri"}
+      expect(rack_response.body).to eq "http://example.org/some/route/test"
+    end
+  end
+end