From b8922604a64d070a68ee68445b139744522a2602 Mon Sep 17 00:00:00 2001
From: rustyx <me@rustyx.org>
Date: Fri, 8 Feb 2019 22:35:55 +0100
Subject: [PATCH] handler can receive response as argument without request
 being another argument.

PR #312 ukseong
---
 include/crow/http_response.h |  6 ++++++
 include/crow/routing.h       | 27 ++++++++++++++++++++++++++-
 2 files changed, 32 insertions(+), 1 deletion(-)

diff --git a/include/crow/http_response.h b/include/crow/http_response.h
index 794017479..2e738a8a3 100644
--- a/include/crow/http_response.h
+++ b/include/crow/http_response.h
@@ -110,6 +110,12 @@ namespace crow
             }
         }
 
+        void end(const int &_code)
+        {
+            code = _code;
+            end();
+        }
+
         void end(const std::string& body_part)
         {
             body += body_part;
diff --git a/include/crow/routing.h b/include/crow/routing.h
index 83c43e820..edbb1b2ca 100644
--- a/include/crow/routing.h
+++ b/include/crow/routing.h
@@ -516,7 +516,32 @@ namespace crow
         template <typename Func>
         typename std::enable_if<
             !black_magic::CallHelper<Func, black_magic::S<Args...>>::value &&
-            !black_magic::CallHelper<Func, black_magic::S<crow::request, Args...>>::value, 
+            !black_magic::CallHelper<Func, black_magic::S<crow::request, Args...>>::value &&
+            black_magic::CallHelper<Func, black_magic::S<crow::response&, Args...>>::value,
+            void>::type
+            operator()(Func&& f) {
+            static_assert(black_magic::CallHelper<Func, black_magic::S<Args...>>::value ||
+                          black_magic::CallHelper<Func, black_magic::S<crow::response&, Args...>>::value
+                          ,
+                          "Handler type is mismatched with URL parameters");
+            static_assert(std::is_same<void, decltype(f(std::declval<crow::response&>(), std::declval<Args>()...))>::value,
+                          "Handler function with response argument should have void return type");
+            handler_ = (
+#ifdef CROW_CAN_USE_CPP14
+                [f = std::move(f)]
+#else
+                [f]
+#endif
+            (const crow::request& req, crow::response& res, Args ... args){
+                f(res, args...);
+            });
+        }
+
+        template <typename Func>
+        typename std::enable_if<
+            !black_magic::CallHelper<Func, black_magic::S<Args...>>::value &&
+            !black_magic::CallHelper<Func, black_magic::S<crow::request, Args...>>::value &&
+            !black_magic::CallHelper<Func, black_magic::S<crow::response&, Args...>>::value,
             void>::type
         operator()(Func&& f)
         {