fix replace_response_host to not add a 443 port for https requests

When proxying an https request, rack reverse proxy would always add a :443
port to the raplaced host, even though that's the default port for https
requests. This fixes the behaviour by not adding any port when the port is
default for the protocol.

Author: pigoz

lib/rack_reverse_proxy/middleware.rb

@@ -115,8 +115,11 @@ def proxy(env, source_request, rule)
       # Replace the location header with the proxy domain
       if response_headers["Location"] && options[:replace_response_host]
         response_location = URI(response_headers["location"])
-        response_location.host = source_request.host
-        response_location.port = source_request.port
+        response_location.scheme = source_request.scheme
+        response_location.host   = source_request.host
+        unless default_port_for_scheme?(source_request.scheme, source_request.port)
+          response_location.port = source_request.port
+        end
         response_headers["Location"] = response_location.to_s
       end
 
@@ -155,5 +158,9 @@ def format_headers(headers)
         acc
       end
     end
+
+    def default_port_for_scheme?(scheme, port)
+      scheme == 'http' && port == 80 || scheme == 'https' && port == 443
+    end
   end
 end

spec/rack/reverse_proxy_spec.rb

@@ -255,6 +255,16 @@ def app
         get "http://example.com:3000/test/stuff"
         expect(last_response.headers["location"]).to eq("http://example.com:3000/bar")
       end
+
+      it "doesn't keep the port when it's default for the protocol" do
+        # webmock doesn't allow to stub an https URI, but this is enough to
+        # reply to the https code path
+        stub_request(:get, "http://example.com/test/stuff").to_return(
+          :headers => { "location" => "http://test.com/bar" }
+        )
+        get "https://example.com/test/stuff"
+        expect(last_response.headers["location"]).to eq("https://example.com/bar")
+      end
     end
 
     describe "with ambiguous routes and all matching" do