Extensive rewrite of basyx::vab

This commit
 - Significantly improves and simplifies frame handling
 - Introduces proper exception handling in vab return frames
 - Adjusts VAB behaviour to reflect changes made in the Java SDK
 - Fixes bugs in server code
 - Fixes bugs in model provider code

Change-Id: Iada7096102c3dc6d42a4832ab488d0b4799dd15c
Signed-off-by: Thomas Psota <thomas.psota@iese.fraunhofer.de>
diff --git a/sdks/c++/basys.sdk.cc/src/vab/vab/backend/connector/native/BaSyxConnector.cpp b/sdks/c++/basys.sdk.cc/src/vab/vab/backend/connector/native/BaSyxConnector.cpp
index c5fdd01..8924014 100644
--- a/sdks/c++/basys.sdk.cc/src/vab/vab/backend/connector/native/BaSyxConnector.cpp
+++ b/sdks/c++/basys.sdk.cc/src/vab/vab/backend/connector/native/BaSyxConnector.cpp
@@ -6,7 +6,8 @@
 */
 
 #include <BaSyx/vab/backend/connector/native/BaSyxConnector.h>
-#include <BaSyx/vab/backend/connector/native/frame/BaSyxNativeFrameBuilder.h>
+#include <BaSyx/vab/backend/connector/native/frame/Frame.h>
+#include <BaSyx/vab/backend/connector/native/frame/EntityWrapper.h>
 #include <BaSyx/vab/provider/native/frame/BaSyxNativeFrameHelper.h>
 
 #include <BaSyx/shared/serialization/json.h>
@@ -22,8 +23,7 @@
 namespace native {
 
 NativeConnector::NativeConnector(std::string const& address, int port)
-	: builder{}
-	, socket{ basyx::net::tcp::Socket::Connect(address, port) }
+	: socket{ basyx::net::tcp::Socket::Connect(address, port) }
 	, log{ "NativeConnector" }
 {
 	log.trace("Connected to {}:{}", address, port);
@@ -32,7 +32,6 @@
 
 
 NativeConnector::~NativeConnector() {
-	this->socket.Close();
 }
 
 
@@ -42,65 +41,69 @@
 	log.trace("basysGet() called:");
 	log.trace("    path: {}", path);
 
-	auto entityWrapper = basysGetRaw(path);
-	auto value = basyx::serialization::json::deserialize(entityWrapper["entity"]);
+	auto value = basysProcess(Frame::Builder::Get(path));
 	return value;
 }
 
-nlohmann::json NativeConnector::basysGetRaw(std::string const& path) {
-	size_t size = builder.buildGetFrame(path, buffer.data() + BASYX_FRAMESIZE_SIZE);
-	sendData(buffer.data(), size);
-	size = receiveData(buffer.data());
-	if (buffer[4] != 0) { // Error happened
-		return ""_json; // TODO: Error handling
-	}
-	std::string data = StringTools::fromArray(buffer.data() + BASYX_FRAMESIZE_SIZE + 1);
-	return nlohmann::json::parse(data);
-}
+basyx::object NativeConnector::basysProcess(const Frame & frame)
+{
+	this->sendFrame(frame);
 
-void NativeConnector::basysSet(std::string const& path, const basyx::object & newValue)
+	auto response_frame = this->recvFrame();
+	if (response_frame.getFlag() != 0x00) {
+		return basyx::object::make_error(basyx::object::error::MalformedRequest, "invalid frame received");
+	};
+
+	auto entityWrapper = nlohmann::json::parse(response_frame.getFirstValue());
+
+	auto value = basyx::vab::EntityWrapper::from_json(entityWrapper);
+	return value;
+};
+
+basyx::object NativeConnector::basysSet(std::string const& path, const basyx::object & newValue)
 {
 	log.trace("basysSet() called:");
 	log.trace("    path: {}", path);
 
-	size_t size = builder.buildSetFrame(path, newValue, buffer.data() + BASYX_FRAMESIZE_SIZE);
-	sendData(buffer.data(), size);
-	size = receiveData(buffer.data());
+	auto return_code = basysProcess(Frame::Builder::Set(path, newValue));
+	return return_code;
 }
 
-void NativeConnector::basysCreate(std::string const& path, const basyx::object & val)
+basyx::object NativeConnector::basysCreate(std::string const& path, const basyx::object & val)
 {
-	size_t size = builder.buildCreateFrame(path, val, buffer.data() + BASYX_FRAMESIZE_SIZE);
-	sendData(buffer.data(), size);
-	size = receiveData(buffer.data());
+	log.trace("basysCreate() called:");
+	log.trace("    path: {}", path);
+
+	auto return_code = basysProcess(Frame::Builder::Create(path, val));
+	return return_code;
 }
 
 basyx::object NativeConnector::basysInvoke(std::string const& path, const basyx::object & param)
 {
-	size_t size = builder.buildInvokeFrame(path, param, buffer.data() + BASYX_FRAMESIZE_SIZE);
-	sendData(buffer.data(), size);
-	size = receiveData(buffer.data());
-	return decode(buffer.data() + 5);
+	log.trace("basysInvoke() called:");
+	log.trace("    path: {}", path);
+
+	auto return_code = basysProcess(Frame::Builder::Invoke(path, param));
+	return return_code;
 }
 
-void NativeConnector::basysDelete(std::string const& path)
+basyx::object NativeConnector::basysDelete(std::string const& path)
 {
-	size_t size = builder.buildDeleteFrame(path, buffer.data() + BASYX_FRAMESIZE_SIZE);
-	sendData(buffer.data(), size);
-	size = receiveData(buffer.data());
+	log.trace("basysDelete() called:");
+	log.trace("    path: {}", path);
+
+	auto return_code = basysProcess(Frame::Builder::Delete(path));
+	return return_code;
 }
 
-void NativeConnector::basysDelete(std::string const& path, const basyx::object & obj) {
-	size_t size = builder.buildDeleteFrame(path, obj, buffer.data() + BASYX_FRAMESIZE_SIZE);
-	sendData(buffer.data(), size);
-	size = receiveData(buffer.data());
-}
+basyx::object NativeConnector::basysDelete(std::string const& path, const basyx::object & obj) 
+{
+	log.trace("basysDelete() called:");
+	log.trace("    path: {}", path);
 
-// TODO: Error handling
-/**
-	* Builds a send frame and sends it to server
-	* @param msg a frame constructed with the BaSyxNativeFrameBuilder
-	*/
+	auto return_code = basysProcess(Frame::Builder::Delete(path, obj));
+	return return_code;
+}
 
 void NativeConnector::sendData(char* msg, size_t size) 
 {
@@ -110,10 +113,6 @@
 
 	CoderTools::setInt32(msg, 0, size);
 	size += BASYX_FRAMESIZE_SIZE;
-#ifdef PRINT_FRAME
-	log.debug("Sending:");
-	vab::provider::native::frame::BaSyxNativeFrameHelper::printFrame(msg, size);
-#endif
 
 	log.debug("Sending {} bytes.", size);
 	int sent_bytes = this->socket.Send(basyx::net::make_buffer(msg, size));
@@ -125,7 +124,8 @@
 }
 
 // TODO: Error handling
-size_t NativeConnector::receiveData(char* data) {
+size_t NativeConnector::receiveData(char* data) 
+{
 	log.trace("receiveData() called");
 	log.trace("    data: 0x{0:x}", (std::size_t)data);
 
@@ -135,10 +135,6 @@
 	log.debug("Received {} bytes.", recv_bytes);
 
 	if (recv_bytes > 0) {
-#ifdef PRINT_FRAME
-		log.debug("Received:");
-		vab::provider::native::frame::BaSyxNativeFrameHelper::printFrame(data, recv_bytes);
-#endif
 		return recv_bytes;
 	}
 	else {
@@ -147,10 +143,23 @@
 	}
 }
 
-basyx::object NativeConnector::decode(char* buffer)
+void NativeConnector::sendFrame(const Frame & frame)
 {
-	std::string data = StringTools::fromArray(buffer);
-	return basyx::serialization::json::deserialize(data).Get<basyx::object::object_map_t&>()["entity"];
+	Frame::write_to_buffer(
+		basyx::net::make_buffer(
+			buffer.data() + BASYX_FRAMESIZE_SIZE, default_buffer_length - BASYX_FRAMESIZE_SIZE), 
+		frame);
+
+	sendData(buffer.data(), frame.size());
+};
+
+Frame NativeConnector::recvFrame()
+{
+	this->receiveData(buffer.data());
+	auto size = *reinterpret_cast<uint32_t*>(buffer.data());
+	auto frame = Frame::read_from_buffer(basyx::net::make_buffer(this->buffer.data() + BASYX_FRAMESIZE_SIZE, size));
+
+	return frame;
 };
 
 }
diff --git a/sdks/c++/basys.sdk.cc/src/vab/vab/backend/connector/native/frame/BaSyxNativeFrameBuilder.cpp b/sdks/c++/basys.sdk.cc/src/vab/vab/backend/connector/native/frame/BaSyxNativeFrameBuilder.cpp
deleted file mode 100644
index 34987eb..0000000
--- a/sdks/c++/basys.sdk.cc/src/vab/vab/backend/connector/native/frame/BaSyxNativeFrameBuilder.cpp
+++ /dev/null
@@ -1,91 +0,0 @@
-/*
- * BaSyxNativeFrameBuilder.cpp
- *
- *  Created on: 14.08.2018
- *      Author: schnicke
- */
-
-#include <BaSyx/vab/backend/connector/native/frame/BaSyxNativeFrameBuilder.h>
-
-#include <BaSyx/shared/serialization/json.h>
-
-#include <BaSyx/util/tools/StringTools.h>
-
-namespace basyx {
-namespace vab {
-namespace connector {
-namespace native {
-namespace frame {
-
-	
-BaSyxNativeFrameBuilder::BaSyxNativeFrameBuilder() { };
-
-size_t BaSyxNativeFrameBuilder::buildGetFrame(std::string const& path, char * buffer)
-{
-	return encodeCommandAndPath(BaSyxCommand::Get, path, buffer);
-}
-
-size_t BaSyxNativeFrameBuilder::buildSetFrame(std::string const& path, const basyx::object & newVal, char * buffer)
-{
-	size_t size = encodeCommandAndPath(BaSyxCommand::Set, path, buffer);
-	size += encodeValue(newVal, buffer + size);
-	return size;
-}
-
-size_t BaSyxNativeFrameBuilder::buildCreateFrame(std::string const& path, const basyx::object & newVal, char * buffer)
-{
-	size_t size = encodeCommandAndPath(BaSyxCommand::Create, path, buffer);
-	size += encodeValue(newVal, buffer + size);
-	return size;
-}
-
-size_t BaSyxNativeFrameBuilder::buildDeleteFrame(std::string const& path, char * buffer)
-{
-	return encodeCommandAndPath(BaSyxCommand::Delete, path, buffer);
-}
-
-size_t BaSyxNativeFrameBuilder::buildDeleteFrame(std::string const& path, const basyx::object & deleteVal, char * buffer)
-{
-	size_t size = encodeCommandAndPath(BaSyxCommand::Delete, path, buffer);
-	size += encodeValue(deleteVal, buffer + size);
-	return size;
-}
-
-size_t BaSyxNativeFrameBuilder::buildInvokeFrame(std::string const& path, const basyx::object & param, char * buffer)
-{
-	size_t size = encodeCommandAndPath(BaSyxCommand::Invoke, path, buffer);
-	size += encodeValue(param, buffer + size);
-	return size;
-}
-
-size_t BaSyxNativeFrameBuilder::buildInvokeFrame(std::string const& path, const basyx::object::object_list_t & params, char * buffer)
-{
-	size_t size = encodeCommandAndPath(BaSyxCommand::Invoke, path, buffer);
-	size += encodeValue(params, buffer + size);
-	return size;
-}
-
-size_t BaSyxNativeFrameBuilder::encodeCommand(BaSyxCommand command, char* buffer)
-{
-	buffer[0] = static_cast<uint8_t>(command);
-	return 1;
-}
-
-std::size_t BaSyxNativeFrameBuilder::encodeValue(const basyx::object & value, char * buffer)
-{
-	std::string dumped = basyx::serialization::json::serialize(value).dump(4);
-	return StringTools::toArray(dumped, buffer);
-}
-
-size_t BaSyxNativeFrameBuilder::encodeCommandAndPath(BaSyxCommand command, std::string const& path, char* buffer)
-{
-	size_t size = encodeCommand(command, buffer);
-	size += StringTools::toArray(path, buffer + size);
-	return size;
-}
-
-}
-}
-}
-}
-}
diff --git a/sdks/c++/basys.sdk.cc/src/vab/vab/backend/connector/native/frame/EntityWrapper.cpp b/sdks/c++/basys.sdk.cc/src/vab/vab/backend/connector/native/frame/EntityWrapper.cpp
new file mode 100644
index 0000000..37c2989
--- /dev/null
+++ b/sdks/c++/basys.sdk.cc/src/vab/vab/backend/connector/native/frame/EntityWrapper.cpp
@@ -0,0 +1,112 @@
+#include <BaSyx/vab/backend/connector/native/frame/EntityWrapper.h>
+
+using basyx::vab::EntityWrapper;
+
+
+namespace {
+	std::string prepareErrorCode(basyx::object::error errorCode)
+	{
+		std::string error;
+		switch (errorCode)
+		{
+		case basyx::object::error::PropertyNotFound:
+			error = "ResourceNotFoundException";
+			break;
+		case basyx::object::error::ObjectAlreadyExists:
+			error = "ResourceAlreadyExistsException";
+			break;
+		case basyx::object::error::MalformedRequest:
+			error = "MalformedRequestException";
+			break;
+		default:
+			error = "ProviderException";
+			break;
+		};
+		return error;
+	};
+
+	std::string prepareErrorMessage(basyx::object::error errorCode, const std::string & message)
+	{
+		return prepareErrorCode(errorCode) + ": " + message;
+	};
+}
+
+basyx::object build_exception(const std::string & type, const std::string & message)
+{
+	basyx::object::error error = basyx::object::error::ProviderException;
+
+	if (type == "ResourceNotFoundException")
+	{
+		error = basyx::object::error::PropertyNotFound;
+	}
+	else if (type == "ResourceAlreadyExistsException")
+	{
+		error = basyx::object::error::ObjectAlreadyExists;
+	}
+	else if (type == "MalformedRequestException")
+	{
+		error = basyx::object::error::MalformedRequest;
+	}
+	else if (type == "ProviderException")
+	{
+		error = basyx::object::error::ProviderException;
+	};
+
+	return basyx::object::make_error(error, message);
+};
+
+basyx::json_t EntityWrapper::build_from_error(basyx::object::error error, const std::string & message)
+{
+	json_t msg;
+	msg["messageType"] = 6;
+	msg["text"] = prepareErrorMessage(error, message);
+	msg["code"] = nullptr;
+
+	basyx::json_t j_obj;
+	j_obj["success"] = false;
+	j_obj["isException"] = true;
+	j_obj["messages"] = json_t::array({ msg });
+	j_obj["entityType"] = prepareErrorCode(error);
+	return j_obj;
+};
+
+basyx::json_t EntityWrapper::build_from_object(const basyx::object & object)
+{
+	basyx::json_t j_obj;
+	if (object.IsError())
+	{
+		return build_from_error(object.getError(), object.getErrorMessage());
+	}
+	else
+	{
+		j_obj["success"] = true;
+//		j_obj["isException"] = false;
+		j_obj["entityType"] = "entity";
+		j_obj["entity"] = basyx::serialization::json::serialize(object);
+	}
+	return j_obj;
+};
+
+
+basyx::object EntityWrapper::from_json(const basyx::json_t & json)
+{
+	bool success = json["success"];
+	// everyhing okay, deserialize entity
+	if (success)
+	{
+		if (json.contains("entity"))
+			return basyx::serialization::json::deserialize(json["entity"]);
+		else
+			return basyx::object::make_null();
+	}
+	// something went wrong, check for exception
+	else if (json.contains("isException") && json.contains("messages"))
+	{
+		return build_exception(json["entityType"], json["messages"][0]["text"]);
+	}
+	// error and no exception; create one
+	else
+	{
+		return basyx::object::make_error(basyx::object::error::MalformedRequest);
+	};
+};
\ No newline at end of file
diff --git a/sdks/c++/basys.sdk.cc/src/vab/vab/backend/connector/native/frame/Frame.cpp b/sdks/c++/basys.sdk.cc/src/vab/vab/backend/connector/native/frame/Frame.cpp
new file mode 100644
index 0000000..9d7a649
--- /dev/null
+++ b/sdks/c++/basys.sdk.cc/src/vab/vab/backend/connector/native/frame/Frame.cpp
@@ -0,0 +1,166 @@
+#include <BaSyx/vab/backend/connector/native/frame/Frame.h>
+
+#include <BaSyx/util/tools/StringTools.h>
+
+using namespace basyx::vab::connector::native;
+
+Frame::Frame()
+	: flag(0xFF)
+	, value_1()
+	, value_2()
+{
+};
+
+Frame::Frame(uint8_t flag, const std::string & value_1) 
+	: flag(flag)
+	, value_1(value_1)
+	, value_2()
+{
+};
+
+Frame::Frame(uint8_t flag, const std::string & value_1, const std::string & value_2)
+	: flag(flag)
+	, value_1(value_1)
+	, value_2(value_2)
+{
+};
+
+uint8_t Frame::getFlag() const
+{
+	return this->flag;
+};
+
+void Frame::setFlag(uint8_t flag)
+{
+	this->flag = flag;
+};
+
+void Frame::setFlag(BaSyxCommand flag)
+{
+	this->flag = static_cast<decltype(this->flag)>(flag);
+};
+
+const std::string & Frame::getFirstValue() const
+{
+	return this->value_1;
+};
+
+void Frame::setFirstValue(const std::string & value)
+{
+	this->value_1 = value;
+};
+
+const std::string & Frame::getSecondValue() const
+{
+	return this->value_2;
+};
+
+void Frame::setSecondValue(const std::string & value)
+{
+	this->value_2 = value;
+};
+
+bool Frame::write_to_buffer(const basyx::net::Buffer & buffer, const Frame & frame)
+{
+	// bail out if buffer to small
+	if (frame.size() > buffer.size())
+		return false;
+
+	std::size_t pos = 0;
+	char * data = reinterpret_cast<char*>(buffer.data());
+
+	// write command field
+	data[pos] = static_cast<uint8_t>(frame.getFlag());
+	pos += 1;
+	
+	// write first value field
+	pos += StringTools::toArray(frame.getFirstValue(), &data[pos]);
+
+	// write second value field
+	if (!frame.getSecondValue().empty())
+	{
+		pos += StringTools::toArray(frame.getSecondValue(), &data[pos]);
+	};
+
+	return true;
+};
+
+Frame Frame::read_from_buffer(const basyx::net::Buffer & buffer)
+{
+	Frame frame;
+
+	std::size_t pos = 0;
+	char * data = reinterpret_cast<char*>(buffer.data());
+	
+	uint8_t flag = static_cast<uint8_t>(data[pos]);
+	frame.setFlag(flag);
+	pos += 1;
+
+	frame.setFirstValue(StringTools::fromArray(&data[pos]));
+	pos += frame.getFirstValue().size() + sizeof(uint32_t);
+
+	if (pos < buffer.size())
+	{
+		frame.setSecondValue(StringTools::fromArray(&data[pos]));
+		pos += frame.getSecondValue().size() + sizeof(uint32_t);
+	};
+
+	return frame;
+};
+
+std::size_t Frame::size() const
+{
+	std::size_t size = 1; // size of flag field
+	size += sizeof(uint32_t) + this->getFirstValue().size(); // size of first value + length
+
+	if(!this->getSecondValue().empty())
+		size += sizeof(uint32_t) + this->getSecondValue().size(); // size of second value + length
+
+	return size;
+};
+
+Frame Frame::Builder::Get(const std::string & path)
+{
+	return Frame{ static_cast<uint8_t>(BaSyxCommand::Get), path };
+};
+
+Frame Frame::Builder::Set(const std::string & path, const basyx::object & value)
+{
+	return Frame{
+		static_cast<uint8_t>(BaSyxCommand::Set),
+		path,
+		basyx::serialization::json::serialize(value).dump(4)
+	};
+};
+
+Frame Frame::Builder::Create(const std::string & path, const basyx::object & value)
+{
+	return Frame{
+		static_cast<uint8_t>(BaSyxCommand::Create),
+		path,
+		basyx::serialization::json::serialize(value).dump(4)
+	};
+};
+
+Frame Frame::Builder::Delete(const std::string & path)
+{
+	return Frame{ static_cast<uint8_t>(BaSyxCommand::Delete), path };
+}; 
+
+Frame Frame::Builder::Delete(const std::string & path, const basyx::object & value)
+{
+	return Frame{
+		static_cast<uint8_t>(BaSyxCommand::Delete),
+		path,
+		basyx::serialization::json::serialize(value).dump(4)
+	};
+};
+
+Frame Frame::Builder::Invoke(const std::string & path, const basyx::object & value)
+{
+	return Frame{
+		static_cast<uint8_t>(BaSyxCommand::Invoke),
+		path,
+		basyx::serialization::json::serialize(value).dump(4)
+	};
+};
\ No newline at end of file