diff --git a/examples/client/main.cpp b/examples/client/main.cpp
index fe43de1..6e5abaa 100644
--- a/examples/client/main.cpp
+++ b/examples/client/main.cpp
@@ -338,16 +338,14 @@ void test_callback() {
 				return;
 			}
 
-			req_result result(data);
-			auto str = result.as<std::string>();
+			auto str = as<std::string>(data);
 			std::cout << "echo " << str << '\n';
 		}, test);
 
 		std::string test1 = "test" + std::to_string(i + 2);
 		//zero means no timeout check, no param means using default timeout(5s)
 		client.async_call<0>("echo", [](const boost::system::error_code & ec, string_view data) {
-			req_result result(data);
-			auto str = result.as<std::string>();
+			auto str = as<std::string>(data);
 			std::cout << "echo " << str << '\n';
 		}, test1);
 	}
diff --git a/include/client_util.hpp b/include/client_util.hpp
index 1df0a4a..5afc72d 100644
--- a/include/client_util.hpp
+++ b/include/client_util.hpp
@@ -30,7 +30,16 @@ namespace rest_rpc {
 	template<typename T>
 	inline T get_result(string_view result) {
 		rpc_service::msgpack_codec codec;
-		auto err_tp = codec.unpack<std::tuple<int, T>>(result.data(), result.size());
-		return std::get<1>(err_tp);
+		auto tp = codec.unpack<std::tuple<int, T>>(result.data(), result.size());
+		return std::get<1>(tp);
+	}
+
+	template<typename T>
+	inline T as(string_view result) {
+		if (has_error(result)) {
+			throw std::logic_error("rpc error");
+		}
+
+		return get_result<T>(result);
 	}
 }
\ No newline at end of file