RPC流程三 - Client端编写

最新推荐文章于 2023-08-02 16:59:24 发布

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最新推荐文章于 2023-08-02 16:59:24 发布

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文章标签： protobuf c++11 rpc

本文链接：https://blog.youkuaiyun.com/wd3cwg38/article/details/104418123

版权

本文详细介绍了RPC流程中的Client端编写，包括google的实现、三种Coder实现（RpcChannel、RpcChannelImpl、RpcController）以及Client端通信流程。重点讲述了如何使用protobuf和C++11编写EchoRequest，并通过RpcChannel与服务端进行通信。

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流程二：https://blog.youkuaiyun.com/wd3cwg38/article/details/104417616

int main()
{
	echo::EchoRequest   request;
	echo::EchoResponse  response;
	request.set_message("hello tonull, from client");
	
	char* ip          = argv[1];
	char* port        = argv[2];
	std::string addr  = std::string(ip) + ":" + std::string(port);
	RpcChannel    rpc_channel(addr);
	echo::EchoServer_Stub stub(&rpc_channel);
	
	RpcController controller;
	stub.Echo(&controller, &request, &response, nullptr);
	
	if (controller.Failed())
		std::cout << "request failed: %s" << controller.ErrorText().c_str();
	else
		std::cout << "resp: " << response.message() << std::endl;
	
	return 0;
}

- google实现

// google::protobuf::RpcChannel
class RpcChannel {}

// google::protobuf::RpcController
class RpcController {}

- Client端实现

Coder实现一：RpcChannel

class RpcChannel : public google::protobuf::RpcChannel {
public:
 	RpcChannel(std::string& server_addr);
  	virtual ~RpcChannel();
 
  	virtual void CallMethod(
  		const ::google::protobuf::MethodDescriptor* method,
 		::google::protobuf::RpcController* controller,
    	const ::google::protobuf::Message* request,
       	::google::protobuf::Message* response,
       	::google::protobuf::Closure* done
   	);
private:
  	RpcChannelImpl* impl_; // RpcChannel具体实现
};

Coder实现二：RpcChannelImpl

// 主要实现CallMethod()用于调用服务
class RpcChannelImpl : public google::protobuf::RpcChannel {
public:
	RpcChannelImpl(std::string& server_addr) {}
	virtual ~RpcChannelImpl() {}

	virtual void Init(std::string& server_addr);
  	virtual void CallMethod(
  		const ::google::protobuf::MethodDescriptor* method,
 		::google::protobuf::RpcController* controller,
    	const ::google::protobuf::Message* request,
       	::google::protobuf::Message* response,
       	::google::protobuf::Closure* done
   	);
private:
	std::string server_addr_;
	boost::shared_ptr<boost::asio::io_service> io_;
	boost::shared_ptr<boost::asio::ip::tcp::socket> socket_;
};

// client
RpcChannel    rpc_channel(addr);
echo::EchoServer_Stub stub(&rpc_channel);

// client CallMethod
stub.Echo(&controller, &request, &response, nullptr);

Coder实现三：RpcController

// 用于对RPC过程中的信息进行反馈
class RpcController : public google::protobuf::RpcController {
public:
	RpcController() { Reset(); }
	virtual ~RpcController() {}
	
	virtual void Reset() { is_failed_ = false; error_code_ = ""; }
	virtual bool Failed() const { return is_failed_; }
	virtual void SetFailed(const std::string& reason) { is_failed_ = true; error_code_ = reason;}
	virtual std::string ErrorText() const { return error_code_; }
	virtual void StartCancel() { };
	virtual bool IsCanceled() const { return false; };
	virtual void NotifyOnCancel(::google::protobuf::Closure* /* callback */) { };

private:
	 bool is_failed_;
	 std::string error_code_;
};