使用Boost asio实现异步的TCP/IP通信

　　可以先了解一下Boost asio基本概念，以下是Boost asio实现的异步TCP/IP通信：

　　服务器：

#include "stdafx.h"
#include <iostream>
#include <boost/shared_ptr.hpp>
#include <boost/asio.hpp>
#include <boost/asio/placeholders.hpp>
#include <boost/system/error_code.hpp>
#include <boost/bind/bind.hpp>

using namespace boost::asio;
using namespace std;

class server
{
    typedef server this_type;
    typedef ip::tcp::acceptor acceptor_type;
    typedef ip::tcp::endpoint endpoint_type;
    typedef ip::tcp::socket socket_type;
    typedef ip::address address_type;
    typedef boost::shared_ptr<socket_type> sock_ptr;

private:
    io_service m_io;
    acceptor_type m_acceptor;

public:
    server() : m_acceptor(m_io, endpoint_type(ip::tcp::v4(), 6688))
    {    accept();    }

    void run(){ m_io.run();}

    void accept()
    {
        sock_ptr sock(new socket_type(m_io));
        m_acceptor.async_accept(*sock, boost::bind(&this_type::accept_handler, this, boost::asio::placeholders::error, sock));
    }

    void accept_handler(const boost::system::error_code& ec, sock_ptr sock)
    {
        if (ec)
        {    return;    }

        cout<<"Client:";
        cout<<sock->remote_endpoint().address()<<endl;
        sock->async_write_some(buffer("hello asio"), boost::bind(&this_type::write_handler, this, boost::asio::placeholders::error));
        // 发送完毕后继续监听，否则io_service将认为没有事件处理而结束运行
        accept();
    }

    void write_handler(const boost::system::error_code&ec)
    {
        cout<<"send msg complete"<<endl;
    }
};

int main()
{
    try
    {
        cout<<"Server start."<<endl;
        server srv;
        srv.run();
    }
    catch (std::exception &e)
    {
        cout<<e.what()<<endl;
    }

    return 0;
}

　　客户端：

#include "stdafx.h"
#include <iostream>
#include <boost/shared_ptr.hpp>
#include <boost/asio.hpp>
#include <boost/asio/placeholders.hpp>
#include <boost/system/error_code.hpp>
#include <boost/bind/bind.hpp>

using namespace boost::asio;
using namespace std;

class client
{
    typedef client this_type;
    typedef ip::tcp::acceptor acceptor_type;
    typedef ip::tcp::endpoint endpoint_type;
    typedef ip::tcp::socket socket_type;
    typedef ip::address address_type;
    typedef boost::shared_ptr<socket_type> sock_ptr;
    typedef vector<char> buffer_type;

private:
    io_service m_io;
    buffer_type m_buf;
    endpoint_type m_ep;
public:
    client(): m_buf(100, 0), m_ep(address_type::from_string("127.0.0.1"), 6688)
    {    start();    }

    void run()
    {    m_io.run();}

    void start()
    {
        sock_ptr sock(new socket_type(m_io));
        sock->async_connect(m_ep, boost::bind(&this_type::conn_handler, this, boost::asio::placeholders::error, sock));
    }

    void conn_handler(const boost::system::error_code&ec, sock_ptr sock)
    {
        if (ec)
        {return;}
        cout<<"Receive from "<<sock->remote_endpoint().address()<<": "<<endl;
        sock->async_read_some(buffer(m_buf), boost::bind(&client::read_handler, this, boost::asio::placeholders::error, sock));
    }

    void read_handler(const boost::system::error_code&ec, sock_ptr sock)
    {
        if (ec)
        {return;}
        sock->async_read_some(buffer(m_buf), boost::bind(&client::read_handler, this, boost::asio::placeholders::error, sock));
        cout<<&m_buf[0]<<endl;
    }
};

int main()
{
    try
    {
        cout<<"Client start."<<endl;
        client cl;
        cl.run();
    }
    catch (std::exception &e)
    {
        cout<<e.what()<<endl;
    }

    return 0;
}