Add ping handler (#503)

Fix #506

CMakeLists.txt

@@ -112,7 +112,8 @@ if(BUILD_TESTS)
     unittests/rpc/ErrorTests.cpp
     unittests/rpc/BaseTests.cpp
     unittests/rpc/handlers/TestHandlerTests.cpp
-    unittests/rpc/handlers/DefaultProcessorTests.cpp)
+    unittests/rpc/handlers/DefaultProcessorTests.cpp
+    unittests/rpc/handlers/PingTest.cpp)
   include(CMake/deps/gtest.cmake)
 
   # if CODE_COVERAGE enable, add clio_test-ccov

src/rpc/common/Concepts.h

@@ -49,12 +49,21 @@ concept Requirement = requires(T a) {
  */
 // clang-format off
 template <typename T>
-concept Handler = requires(T a, typename T::Input in, typename T::Output out) {
+concept HandlerWithInput = requires(T a, typename T::Input in, typename T::Output out) {
     { a.spec() } -> std::same_as<RpcSpecConstRef>;
-    { a.process(in) } -> std::same_as<HandlerReturnType<decltype(out)>>;
+    { a.process(in) } -> std::same_as<HandlerReturnType<decltype(out)>>;}
-} 
+    && boost::json::has_value_to<typename T::Input>::value;
-&& boost::json::has_value_from<typename T::Output>::value
+
-&& boost::json::has_value_to<typename T::Input>::value;
+template <typename T>
+concept HandlerWithoutInput = requires(T a, typename T::Output out) {
+    { a.process() } -> std::same_as<HandlerReturnType<decltype(out)>>;};
+
+template <typename T>
+concept Handler = 
+(HandlerWithInput<T>
+||
+HandlerWithoutInput<T>)
+&& boost::json::has_value_from<typename T::Output>::value;
 // clang-format on
 
 }  // namespace RPCng

src/rpc/common/Types.h

@@ -53,4 +53,14 @@ struct FieldSpec;
 
 using RpcSpecConstRef = RpcSpec const&;
 
+struct VoidOutput
+{
+};
+
+inline void
+tag_invoke(boost::json::value_from_tag, boost::json::value& jv, VoidOutput)
+{
+    jv = boost::json::object{};
+}
+
 }  // namespace RPCng

src/rpc/common/impl/Processors.h

@@ -24,6 +24,9 @@
 
 namespace RPCng::detail {
 
+template <typename>
+static constexpr bool unsupported_handler_v = false;
+
 template <Handler HandlerType>
 struct DefaultProcessor final
 {
@@ -33,19 +36,35 @@ struct DefaultProcessor final
     {
         using boost::json::value_from;
         using boost::json::value_to;
+        if constexpr (HandlerWithInput<HandlerType>)
+        {
+            // first we run validation
+            auto const spec = handler.spec();
+            if (auto const ret = spec.validate(value); not ret)
+                return Error{ret.error()};  // forward Status
 
-        // first we run validation
+            auto const inData = value_to<typename HandlerType::Input>(value);
-        auto const spec = handler.spec();
-        if (auto const ret = spec.validate(value); not ret)
-            return Error{ret.error()};  // forward Status
 
-        auto const inData = value_to<typename HandlerType::Input>(value);
+            // real handler is given expected Input, not json
-
+            if (auto const ret = handler.process(inData); not ret)
-        // real handler is given expected Input, not json
+                return Error{ret.error()};  // forward Status
-        if (auto const ret = handler.process(inData); not ret)
+            else
-            return Error{ret.error()};  // forward Status
+                return value_from(ret.value());
+        }
+        else if constexpr (HandlerWithoutInput<HandlerType>)
+        {
+            // no input to pass, ignore the value
+            if (auto const ret = handler.process(); not ret)
+                return Error{ret.error()};  // forward Status
+            else
+                return value_from(ret.value());
+        }
         else
-            return value_from(ret.value());
+        {
+            // when concept HandlerWithInput and HandlerWithoutInput not cover
+            // all Handler case
+            static_assert(unsupported_handler_v<HandlerType>);
+        }
     }
 };
 

src/rpc/ngHandlers/Ping.h

@@ -0,0 +1,38 @@
+//------------------------------------------------------------------------------
+/*
+    This file is part of clio: https://github.com/XRPLF/clio
+    Copyright (c) 2023, the clio developers.
+
+    Permission to use, copy, modify, and distribute this software for any
+    purpose with or without fee is hereby granted, provided that the above
+    copyright notice and this permission notice appear in all copies.
+
+    THE  SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+    WITH  REGARD  TO  THIS  SOFTWARE  INCLUDING  ALL  IMPLIED  WARRANTIES  OF
+    MERCHANTABILITY  AND  FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+    ANY  SPECIAL,  DIRECT,  INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+    WHATSOEVER  RESULTING  FROM  LOSS  OF USE, DATA OR PROFITS, WHETHER IN AN
+    ACTION  OF  CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+    OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+*/
+//==============================================================================
+
+#pragma once
+
+#include <rpc/common/Types.h>
+
+namespace RPCng {
+
+class PingHandler
+{
+public:
+    using Output = VoidOutput;
+    using Result = HandlerReturnType<Output>;
+
+    Result
+    process() const
+    {
+        return Output{};
+    }
+};
+}  // namespace RPCng

unittests/rpc/handlers/DefaultProcessorTests.cpp

@@ -52,6 +52,19 @@ TEST_F(RPCDefaultProcessorTest, ValidInput)
     ASSERT_TRUE(ret);  // no error
 }
 
+TEST_F(RPCDefaultProcessorTest, NoInputVaildCall)
+{
+    HandlerWithoutInputMock handler;
+    RPCng::detail::DefaultProcessor<HandlerWithoutInputMock> processor;
+
+    auto const data = InOutFake{"works"};
+    auto const input = json::parse(R"({})");
+    EXPECT_CALL(handler, process()).WillOnce(Return(data));
+
+    auto const ret = processor(handler, input);
+    ASSERT_TRUE(ret);  // no error
+}
+
 TEST_F(RPCDefaultProcessorTest, InvalidInput)
 {
     HandlerMock handler;

unittests/rpc/handlers/PingTest.cpp

@@ -0,0 +1,37 @@
+//------------------------------------------------------------------------------
+/*
+    This file is part of clio: https://github.com/XRPLF/clio
+    Copyright (c) 2023, the clio developers.
+
+    Permission to use, copy, modify, and distribute this software for any
+    purpose with or without fee is hereby granted, provided that the above
+    copyright notice and this permission notice appear in all copies.
+
+    THE  SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+    WITH  REGARD  TO  THIS  SOFTWARE  INCLUDING  ALL  IMPLIED  WARRANTIES  OF
+    MERCHANTABILITY  AND  FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+    ANY  SPECIAL,  DIRECT,  INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+    WHATSOEVER  RESULTING  FROM  LOSS  OF USE, DATA OR PROFITS, WHETHER IN AN
+    ACTION  OF  CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+    OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+*/
+//==============================================================================
+
+#include <rpc/common/AnyHandler.h>
+#include <rpc/ngHandlers/Ping.h>
+#include <util/Fixtures.h>
+
+using namespace RPCng;
+
+class RPCHandlerTest : public NoLoggerFixture
+{
+};
+
+// example handler tests
+TEST_F(RPCHandlerTest, Ping)
+{
+    auto const handler = AnyHandler{PingHandler{}};
+    auto const output = handler.process(boost::json::parse(R"({})"));
+    ASSERT_TRUE(output);
+    EXPECT_EQ(output.value(), boost::json::parse(R"({})"));
+}

unittests/rpc/handlers/TestHandlerTests.cpp

@@ -50,6 +50,16 @@ TEST_F(RPCTestHandlerTest, HandlerSuccess)
     EXPECT_EQ(val.as_object().at("computed").as_string(), "world_10");
 }
 
+TEST_F(RPCTestHandlerTest, NoInputHandlerSuccess)
+{
+    auto const handler = AnyHandler{NoInputHandlerFake{}};
+    auto const output = handler.process(json::parse(R"({})"));
+    ASSERT_TRUE(output);
+
+    auto const val = output.value();
+    EXPECT_EQ(val.as_object().at("computed").as_string(), "test");
+}
+
 TEST_F(RPCTestHandlerTest, HandlerErrorHandling)
 {
     auto const handler = AnyHandler{HandlerFake{}};

unittests/rpc/handlers/impl/FakesAndMocks.h

@@ -98,6 +98,19 @@ public:
     }
 };
 
+class NoInputHandlerFake
+{
+public:
+    using Output = TestOutput;
+    using Result = RPCng::HandlerReturnType<Output>;
+
+    Result
+    process() const
+    {
+        return Output{"test"};
+    }
+};
+
 // example handler that returns custom error
 class FailingHandlerFake
 {
@@ -165,4 +178,12 @@ struct HandlerMock
     MOCK_METHOD(Result, process, (Input), (const));
 };
 
+struct HandlerWithoutInputMock
+{
+    using Output = InOutFake;
+    using Result = RPCng::HandlerReturnType<Output>;
+
+    MOCK_METHOD(Result, process, (), (const));
+};
+
 }  // namespace unittests::detail