hel*_*lix 4 c++ boost network-programming
我已经为客户端和服务器编写了一个程序。该程序当前执行以下操作：
我正在异步执行此操作。但是，问题是他们只能发送/接收一条消息。之后，他们就终止了。下面是我的代码：
#include <iostream>
#include <vector>
#include<boost/asio.hpp>
std::vector<char> buff(256);
void SendHandler(boost::system::error_code ex){
std::cout << " do something here" << std::endl;
}
void ReadHandler(boost::system::error_code ex){
std::cout << " print the buffer data..." << std::endl;
std::cout << buff.data() << std::endl;
}
void Server(){
boost::asio::io_service service;
using namespace boost::asio::ip;
tcp::endpoint endpoint(tcp::v4(), 4000);
tcp::acceptor acceptor(service, endpoint);
tcp::socket socket(service);
std::cout << "[Server] Waiting for connection" << std::endl;
acceptor.accept(socket);
std::cout << "[Server] Accepted a connection from client" << std::endl;
std::string msg = "Message from server";
socket.async_send(boost::asio::buffer(msg), SendHandler);
service.run();
}
void Client(){
boost::asio::io_service service;
using namespace boost::asio::ip;
tcp::endpoint endpoint(address::from_string("127.0.0.1"), 4000);
tcp::socket socket(service);
std::cout << "[Client] Connecting to server..." << std::endl;
socket.connect(endpoint);
std::cout << "[Client] Connection successful" << std::endl;
socket.async_read_some(boost::asio::buffer(buff), ReadHandler);
service.run();
}
int main(int argc, char **argv) {
if(argc == 1){
std::cout << "Please specify s for server or c for client" << std::endl;
return -1;
}
if(argv[1][0] == 's'){
Server();
}
else{
Client();
}
return 0;
}
我想扩展这个程序，以便：
将async_send()and置于service.run()无限循环中并没有帮助。它只是在客户端一遍又一遍地打印消息，直到客户端终止。
我什至boost::asio对network programming. 请告诉我应该在代码中修改哪些位置以及哪些内容？
小智 6
异步 TCP 服务器是满足以下条件的分布式应用程序的一部分：
\n典型的异步 TCP 服务器按照以下算法工作：
\n//responsible for handling a single client by reading the request message, processing it, and then sending back the response message.\n//Each instance of the Service class is intended to handle one connected client\n//by reading the request message, processing it, and then sending the response message back.\nclass Service\n{\npublic:\n //The class\'s constructor accepts a shared pointer to an object representing a socket connected to a particular client as an argument\n // and caches this pointer. This socket will be used later to communicate with the client application.\n Service(std::shared_ptr<asio::ip::tcp::socket> sock) : m_sock(sock)\n\n //This method starts handling the client by initiating the asynchronous reading operation\n //to read the request message from the client specifying the onRequestReceived() method as a callback.\n void StartHandling()\n\nprivate:\n void onRequestReceived(const boost::system::error_code &ec,\n std::size_t bytes_transferred)\n\n\n void onResponseSent(const boost::system::error_code &ec,\n std::size_t bytes_transferred)\n\n // Here we perform the cleanup.\n void onFinish()\n {\n delete this;\n }\n\n //To keep things simple, we implement a dummy service which only emulates the execution of certain operations\n //The request processing emulation consists of performing many increment operations to emulate operations\n //that intensively consume CPU and then putting the thread of control to sleep for some time to emulate I/O operations\n std::string ProcessRequest(asio::streambuf &request)\n\nprivate:\n std::shared_ptr<asio::ip::tcp::socket> m_sock;\n std::string m_response;\n asio::streambuf m_request;\n};\n\n//responsible for accepting the connection requests arriving from clients and instantiating the objects of the Service class,\n// which will provide the service to connected clients.\nclass Acceptor\n{\npublic:\n //Its constructor accepts a port number on which it will listen for the incoming connection requests as its input argument. \n Acceptor(asio::io_service &ios, unsigned short port_num) : m_ios(ios),\n //The object of this class contains an instance of the asio::ip::tcp::acceptor class as its member named m_acceptor,\n //which is constructed in the Acceptor class\'s constructor.\n m_acceptor(m_ios,\n asio::ip::tcp::endpoint(\n asio::ip::address_v4::any(),\n port_num)),\n m_isStopped(false)\n\n //The Start() method is intended to instruct an object of the Acceptor class to start listening and accepting incoming connection requests.\n void Start()\n\n // Stop accepting incoming connection requests.\n void Stop()\n\n\nprivate:\n void InitAccept()\n\n void onAccept(const boost::system::error_code &ec,\n std::shared_ptr<asio::ip::tcp::socket> sock)\n\nprivate:\n asio::io_service &m_ios;\n //used to asynchronously accept the incoming connection requests.\n asio::ip::tcp::acceptor m_acceptor;\n std::atomic<bool> m_isStopped;\n};\n\n//represents the server itself\nclass Server\n{\npublic:\n Server()\n\n // Start the server.\n // Accepts a protocol port number on which the server should listen for the incoming connection requests\n // and the number of threads to add to the pool as input arguments and starts the server\n // Nonblocking Method\n void Start(unsigned short port_num,\n unsigned int thread_pool_size)\n\n // Stop the server.\n // Blocks the caller thread until the server is stopped and all the threads running the event loop exit.\n void Stop()\n\nprivate:\n asio::io_service m_ios;\n std::unique_ptr<asio::io_service::work> m_work;\n std::unique_ptr<Acceptor> acc;\n std::vector<std::unique_ptr<std::thread>> m_thread_pool;\n};\n\nint main()\n{\n unsigned short port_num = 3333;\n\n try\n {\n //it instantiates an object of the Server class named srv.\n Server srv;\n\n //before starting the server, the optimal size of the pool is calculated.\n // The general formula often used in parallel applications to find the optimal number of threads is the number of processors the computer has multiplied by 2.\n // We use the std::thread::hardware_concurrency() static method to obtain the number of processors. \n unsigned int thread_pool_size =\n std::thread::hardware_concurrency() * 2;\n\n //because this method may fail to do its job returning 0,\n // we fall back to default value represented by the constant DEFAULT_THREAD_POOL_SIZE, which is equal to 2 in our case.\n if (thread_pool_size == 0)\n thread_pool_size = DEFAULT_THREAD_POOL_SIZE;\n\n srv.Start(port_num, thread_pool_size);\n\n std::this_thread::sleep_for(std::chrono::seconds(60));\n\n srv.Stop();\n }\n catch (system::system_error &e)\n {\n std::cout << "Error occured! Error code = "\n << e.code() << ". Message: "\n << e.what();\n }\n\n return 0;\n}\n支持异步执行请求和请求取消功能的异步 TCP 客户端应用程序：
\n// Function pointer type that points to the callback\n// function which is called when a request is complete.\n// Based on the values of the parameters passed to it, it outputs information about the finished request.\ntypedef void (*Callback)(unsigned int request_id, // unique identifier of the request is assigned to the request when it was initiated.\n const std::string &response, // the response data\n const system::error_code &ec); // error information\n\n// data structure whose purpose is to keep the data related to a particular request while it is being executed\nstruct Session\n{\n Session(asio::io_service &ios,\n const std::string &raw_ip_address,\n unsigned short port_num,\n const std::string &request,\n unsigned int id,\n Callback callback) : m_sock(ios),\n m_ep(asio::ip::address::from_string(raw_ip_address),\n port_num),\n m_request(request),\n m_id(id),\n m_callback(callback),\n m_was_cancelled(false) {}\n\n asio::ip::tcp::socket m_sock; // Socket used for communication\n asio::ip::tcp::endpoint m_ep; // Remote endpoint.\n std::string m_request; // Request string.\n\n // streambuf where the response will be stored.\n asio::streambuf m_response_buf;\n std::string m_response; // Response represented as a string.\n\n // Contains the description of an error if one occurs during\n // the request lifecycle.\n system::error_code m_ec;\n\n unsigned int m_id; // Unique ID assigned to the request.\n\n // Pointer to the function to be called when the request\n // completes.\n Callback m_callback;\n\n bool m_was_cancelled;\n std::mutex m_cancel_guard;\n};\n\n// class that provides the asynchronous communication functionality.\nclass AsyncTCPClient : public boost::noncopyable\n{\npublic:\n AsyncTCPClient(unsigned char num_of_threads)\n\n // initiates a request to the server\n void emulateLongComputationOp(\n unsigned int duration_sec, //represents the request parameter according to the application layer protocol\n const std::string &raw_ip_address, //specify the server to which the request should be sent.\n unsigned short port_num, //specify the server to which the request should be sent.\n Callback callback, //callback function, which will be called when the request is complete.\n unsigned int request_id) // unique identifier of the request\n\n\n // cancels the previously initiated request designated by the request_id argument\n void cancelRequest(unsigned int request_id) //accepts an identifier of the request to be canceled as an argument.\n\n\n // blocks the calling thread until all the currently running requests complete and deinitializes the client.\n void close()\n\n\nprivate:\n // method is called whenever the request completes with any result.\n void onRequestComplete(std::shared_ptr<Session> session)\n\nprivate:\n asio::io_service m_ios;\n std::map<int, std::shared_ptr<Session>> m_active_sessions;\n std::mutex m_active_sessions_guard;\n std::unique_ptr<boost::asio::io_service::work> m_work;\n std::list<std::unique_ptr<std::thread>> m_threads;\n};\n\n// a function that will serve as a callback, which we\'ll pass to the AsyncTCPClient::emulateLongComputationOp() method\n// It outputs the result of the request execution and the response message to the standard output stream if the request is completed successfully\nvoid handler(unsigned int request_id,\n const std::string &response,\n const system::error_code &ec)\n\nint main()\n{\n try\n {\n AsyncTCPClient client(4);\n\n // Here we emulate the user\'s behavior.\n\n // creates an instance of the AsyncTCPClient class and then calls its emulateLongComputationOp() method to initiate three asynchronous requests\n // User initiates a request with id 1.\n client.emulateLongComputationOp(10, "127.0.0.1", 3333, handler, 1);\n\n // Decides to exit the application.\n client.close();\n }\n catch (system::system_error &e)\n {\n std::cout << "Error occured! Error code = " << e.code()\n << ". Message: " << e.what();\n\n return e.code().value();\n }\n\n return 0;\n};\n1.安装CMake
\ncd ~\nwget https://github.com/Kitware/CMake/releases/download/v3.14.5/cmake-3.14.5.tar.gz\ntar xf cmake-3.14.5.tar.gz\ncd cmake-3.14.5\n./bootstrap --parallel=10\nmake -j4\nsudo make -j4 install\n2.安装Boost
\ncd ~\nwget https://boostorg.jfrog.io/artifactory/main/release/1.69.0/source/boost_1_69_0.tar.gz\ntar xf boost_1_69_0.tar.gz\ncd boost_1_69_0\n./bootstrap.sh\n./b2 ... cxxflags="-std=c++0x -stdlib=libc++" linkflags="-stdlib=libc++" ...\nsudo ./b2 toolset=gcc -j4 install\nmkdir build\ncd build\ncmake ..\ncmake --build .\n./bin/server\n\n我们可以检查服务器是否运行
\nnetstat -tulpn | grep LISTEN\n\ntcp 0 0 0.0.0.0:445 0.0.0.0:* LISTEN -\ntcp 0 0 0.0.0.0:3333 0.0.0.0:* LISTEN 6866/./bin/server <===============\ntcp 0 0 0.0.0.0:139 0.0.0.0:* LISTEN -\ntcp 0 0 127.0.0.53:53 0.0.0.0:* LISTEN -\ntcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN -\ntcp 0 0 127.0.0.1:631 0.0.0.0:* LISTEN -\ntcp 0 0 127.0.0.1:5433 0.0.0.0:* LISTEN -\ntcp6 0 0 :::445 :::* LISTEN -\ntcp6 0 0 :::5000 :::* LISTEN -\ntcp6 0 0 :::5001 :::* LISTEN -\ntcp6 0 0 :::139 :::* LISTEN -\ntcp6 0 0 :::22 :::* LISTEN -\ntcp6 0 0 ::1:631 :::* LISTEN -\n./bin/client\n\nRequest #1 has completed. Response: Response from server\n您可以在Boost Asio C++ Network Programming Client Server中找到该项目
\n| 归档时间： |
|
| 查看次数： |
20181 次 |
| 最近记录： |