socks4withasynchronousboost::asio

socks4是一种网络代理协议，它可以使本地计算机向远程服务器发送请求，并通过该服务器进行网络连接。使用boost::asio库可以实现异步socks4代理。具体实现方式如下：

1. 安装boost库和asio库

2. 创建异步socks4类

class Socks4Async{
public:
    Socks4Async(boost::asio::io_service& io_service):resolver_(io_service),socket_(io_service){}
    void connect(std::string host,std::string port){
        endpoint_iterator_ = resolver_.resolve({host,port});
        boost::asio::async_connect(socket_,endpoint_iterator_,boost::bind(&Socks4Async::handle_connect, this, _1));
    }
private:
    void handle_connect(const boost::system::error_code& error){
        if(!error){
            std::cout<<"Connect successfully!"<<std::endl;
        }else{
            std::cout<<"Connect failed!"<<std::endl;
        }
    }
    boost::asio::ip::tcp::resolver resolver_;
    boost::asio::ip::tcp::socket socket_;
    boost::asio::ip::tcp::resolver::iterator endpoint_iterator_;
};

3. 创建socks4代理连接

class Socks4Async{
public:
    Socks4Async(boost::asio::io_service& io_service):resolver_(io_service),socket_(io_service){}
    void connect(std::string host,std::string port){
        endpoint_iterator_ = resolver_.resolve({host,port});
        boost::asio::async_connect(socket_,endpoint_iterator_,boost::bind(&Socks4Async::handle_connect, this, _1));
    }
    void socks4_connect(std::string socks4_host,int socks4_port,std::string remote_host,int remote_port){
        uint8_t request[10] = {4,1,remote_port>>8,remote_port&0xff,remote_host[0],remote_host[1],remote_host[2],remote_host[3],0};
        socket_.async_send(boost::asio::buffer(request),boost::bind(&Socks4Async::handle_send_request,this,socks4_host,socks4_port,_1,_2));
    }
private:
    void handle_connect(const boost::system::error_code& error){
        if(!error){
            std::cout<<"Connect successfully!"<<std::endl;
        }else{
            std::cout<<"Connect failed!"<<std::endl;
        }
    }
    void handle_send_request(std::string socks4_host,int socks4_port,const boost::system::error