BOOST::ASIO实现回显服务器

BOOST::ASIO回显服务器

一、需要注意的坑

server端

• std::ostringstream在接收数据前要清空
• boost::asio::streambuf将数据读出后也需要清空-consume()函数

server和client端

• 一个socket数据发送以及接受都结束之后，需要将其关闭sock.close()
• read_until需要配合boost::asio::streambuf使用

二、代码

server端

#include <iostream>
#include <sstream>
#include <functional>
#include <boost/asio.hpp>
#include <boost/bind.hpp>
#include <boost/system/error_code.hpp>

using namespace boost::asio;

void handle_connections()
{
    io_service ios;
    boost::asio::streambuf buff;
    std::ostringstream copy;

    ip::tcp::endpoint ep = ip::tcp::endpoint(ip::tcp::v4(), 9999);
    ip::tcp::acceptor acceptor(ios, ep);
    std::string msg("");

    while (true) {
        ip::tcp::socket sock(ios);
        acceptor.accept(sock);
        size_t bytes = read_until(sock, buff, '\n');
        //利用空字符串清空stream
        copy.str("");
        //给stream赋值
        copy << &buff;
        //清空boost::asio::streambuf
        buff.consume(bytes);

        msg = copy.str();
        std::cout << "server receive message: " << copy.str() << std::unitbuf;
        sock.write_some(buffer(msg));
        //关闭socket
        sock.close();
    }
}

int main(int argc, char* argv[])
{
    handle_connections();
}

client端

#include <iostream>
#include <sstream>
#include <vector>
#include <functional>
#include <boost/asio.hpp>
#include <boost/bind.hpp>
#include <boost/thread.hpp>

using namespace boost::asio;
using namespace boost::system;

void sync_echo(std::string msg)
{
    msg.append("\n");
    io_service io_server;
    ip::tcp::socket sock(io_server);
    ip::tcp::endpoint ep(ip::address_v4::from_string("127.0.0.1"), 9999);
    sock.connect(ep);

    sock.write_some(buffer(msg));
    boost::asio::streambuf buf;
    int bytes = read_until(sock, buf, "\n");
    if(bytes == 0) {
        std::cout << "no message" << std::endl;
        return;
    }

    std::ostringstream copy;
    copy << &buf;
    std::cout << "server echoed our " << msg << ": " << (copy.str() == msg ? "GOOD" : "FAIL") << std::endl;
     //关闭socket
    sock.close();

}

int main(int argc, char* argv[])
{
    std::string messages[4] = {"John says hi", "so does James", "Lucy just got home", "Boost.Asio is Fun!"};
    boost::thread_group threads;

    for (auto & message : messages) {
        threads.create_thread(boost::bind(sync_echo, message));
    }
    threads.join_all();
}