学步园

    
#include <cstdlib>    
#include <iostream>    
#include <boost/bind.hpp>    
#include <boost/asio.hpp>    
using boost::asio::ip::tcp;    
   
class session
 {    
public:    
    session(boost::asio::io_service& io_service) :    
        socket_(io_service) {    
    }    
   
    tcp::socket& socket() {    
        return socket_;    
    }    
   
    void start() {    
        socket_.async_read_some(boost::asio::buffer(data_, max_length),    
                boost::bind(&session::handle_read, this,    
                        boost::asio::placeholders::error,    
                        boost::asio::placeholders::bytes_transferred));    
    }    
   
    void handle_read(const boost::system::error_code& error,    
            size_t bytes_transferred) {    
        if (!error) {    
            boost::asio::async_write(socket_, boost::asio::buffer(data_,    
                    bytes_transferred), boost::bind(&session::handle_write,    
                    this, boost::asio::placeholders::error));    
        } else {    
            delete this;    
        }    
    }    
   
    void handle_write(const boost::system::error_code& error) {    
        if (!error) {    
            socket_.async_read_some(boost::asio::buffer(data_, max_length),    
                    boost::bind(&session::handle_read, this,    
                            boost::asio::placeholders::error,    
                            boost::asio::placeholders::bytes_transferred));    
        } else {    
            delete this;    
        }    
    }    
   
private:    
    tcp::socket socket_;    
    enum {    
        max_length = 1024    
    };    
    char data_[max_length];    
};    
   
class server {    
public:    
    server(boost::asio::io_service& io_service, short port) :    
        io_service_(io_service), acceptor_(io_service, tcp::endpoint(tcp::v4(),    
                port)) {    
        session* new_session = new session(io_service_);    
        acceptor_.async_accept(new_session->socket(), boost::bind(    
                &server::handle_accept, this, new_session,    
                boost::asio::placeholders::error));    
    }    
   
    void handle_accept(session* new_session,    
            const boost::system::error_code& error) {    
        if (!error) {    
            new_session->start();    
            new_session = new session(io_service_);    
            acceptor_.async_accept(new_session->socket(), boost::bind(    
                    &server::handle_accept, this, new_session,    
                    boost::asio::placeholders::error));    
        } else {    
            delete new_session;    
        }    
    }    
   
private:    
    boost::asio::io_service& io_service_;    
    tcp::acceptor acceptor_;    
};    
   
int main(int argc, char* argv[]) {    
    try {    
        if (argc != 2) {    
            std::cerr << "Usage: async_tcp_echo_server <port>\n";    
            return 1;    
        }    
   
        boost::asio::io_service io_service;    
   
        using namespace std;    
        // For atoi.    
        server s(io_service, atoi(argv[1]));    
   
        io_service.run();    
    } catch (std::exception& e) {    
        std::cerr << "Exception: " << e.what() << "\n";    
    }    
   
    return 0;    
}  

二、编译代码

$ g++ －g3 －Wall -o"async_tcp_echo_server" async_tcp_echo_server.cpp -lboost_system

注意：boost.asio库依赖boost_system

三、运行 async_tcp_echo_server

$ ./async_tcp_echo_server 8868   # 8868 是async_tcp_echo_server listen的端口号

四、用 telnet 命令作为客户端测试

新开启一个终端，注意：同样要登录到Linux实验室，执行： telnet localhost 8868

$ telnet localhost 8868

Trying ::1...

Trying 127.0.0.1...

Connected to localhost.

Escape character is '^]'.

the first line    # 这是我们的输入

the first line    # 这是服务器 async_tcp_echo_server 的回应，以下类推

the second line

the second line

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