c++ - 使用 Boost.Asio 连接到域以托管服务器

Question

如何通过我的服务器连接到我的域，以便我可以“托管”它？

我尝试更改下面的代码片段以将 IP 与我的域名相匹配，但出现异常，提示提供了无效参数，我认为我应该解析域名、获取 IP 并使用 IP我得到了而不是下面代码片段中的那个，但似乎我正在连接到我的外部 IP，这不允许我托管服务器，因为它说机器主动拒绝连接。

这是代码片段:

boost::asio::ip::tcp::acceptor acceptor(service, boost::asio::ip::tcp::endpoint(boost::asio::ip::address::from_string("192.168.1.3"), 8001));

完整代码:

main.cpp

#include "Server.h"

#include <string>
#include <iostream>
#include <boost/bind.hpp>
#include <boost/thread.hpp>
#include <boost/shared_ptr.hpp>
#include <boost/enable_shared_from_this.hpp>
#include <boost/asio.hpp>

int main()
{
    Server server;
    boost::thread([&server] {
        server.handleConnections();
    }).join();

    return 0;
}

Server.h

#ifndef SERVER_H
#define SERVER_H

#include <string>
#include <iostream>
#include <boost/bind.hpp>
#include <boost/thread.hpp>
#include <boost/shared_ptr.hpp>
#include <boost/enable_shared_from_this.hpp>
#include <boost/asio.hpp>

class Server
{
private:
    boost::asio::io_service service;
    boost::asio::ip::tcp::socket sock;
protected:

public:
    Server() : service(), sock(service) {

    }

    ~Server() {

    }

    void handleConnections();
};

#endif

服务器.cpp

#include "Server.h"

void Server::handleConnections() {
    boost::system::error_code err;
    try {
        boost::asio::ip::tcp::acceptor acceptor(service, boost::asio::ip::tcp::endpoint(boost::asio::ip::address::from_string("192.168.1.3"), 8001));
        std::cout << acceptor.local_endpoint(err) << std::endl;
        while (true) {
            sock = boost::asio::ip::tcp::socket(service);
            boost::system::error_code errCode;
            acceptor.accept(this->sock, acceptor.local_endpoint(), errCode);
            boost::asio::write(sock, boost::asio::buffer("Olá"), errCode);
        }
        this->sock.close();
    }
    catch (std::exception & e)
    {
        std::cout << e.what();
    }
}

Answer 1

1. 首先

   acceptor.accept(this->sock, acceptor.local_endpoint(), errCode);
   

   documentation说:

   This function is used to accept a new connection from a peer into the given socket, and additionally provide the endpoint of the remote peer. The function call will block until a new connection has been accepted successfully or an error occurs.

   您...将接受者的本地端点作为端点传递以接收对等端的远程端点(如果编译成功我会感到惊讶)。这没什么意义。我建议您不需要知道远程端点¹:

   acceptor.accept(this->sock, errCode);
   

2. 其次，您已经绑定(bind)到环回适配器:

   boost::asio::ip::tcp::acceptor acceptor(service, boost::asio::ip::tcp::endpoint(boost::asio::ip::address::from_string("192.168.1.3"), 8001));
   

   这直接意味着您无法从网络访问它²。将其更改为与 NIC 无关:

   tcp::acceptor acceptor(service, tcp::endpoint(ip::address(), 8001));
   

---

¹ 您通常可以稍后使用 socket_->remote_endpoint() 从套接字中获取它，除非套接字已变得无效(例如关闭)

² 除非你实现一些时髦的路由/隧道逻辑，这太牵强了

更新

带有错误处理的独立演示:

Live On Coliru

#include <iostream>
#include <boost/asio.hpp>

class Server
{
    boost::asio::io_service service;
public:
    void handleConnections() 
    {
        using namespace boost::asio;

        boost::system::error_code err;

        try {
            ip::tcp::acceptor acceptor(service, ip::tcp::endpoint(ip::address(), 6768));

            std::cout << acceptor.local_endpoint(err) << std::endl;

            while (!err) {
                ip::tcp::socket sock(service);

                if (   !acceptor.accept(sock, err)
                    && !write(sock, buffer("Olá"), err)
                    && !sock.close(err))
                {
                    std::cout << "Error in connection: " << err << " " << err.message() << "\n";
                }
            }
        } catch (std::exception & e) {
            std::cout << e.what();
        }
    }
};

#include <boost/thread.hpp>

int main() {
    Server server;
    boost::thread([&server] { server.handleConnections(); }).join();
}

输出:

$ ./a.out& 
0.0.0.0:6768

$ while sleep 1; do nc 127.0.0.1 6768; done
OláOláOláOláOláOláOláOláOláOláOláOláOláOláOláOláOláOláOláOláOláOláOláOláOláOláOláOláOláOláOláOláOláOláOláOláOláOláOláOláOláOláOláOláOláOláOláOláOláOláOlá