Boost ASIO：连接被拒绝

Question

我收到以下错误：

在抛出 'boost::exception_detail::clone_implboost::exception_detail::error_info_injector<boost::system::system_error >' 的实例后调用终止 what(): connect: Connection refused Aborted (core dumped)

我正在尝试连接同一网络上的两台不同机器； 如果我使用本地主机，这将有效。 有关如何解决的任何建议？

客户：

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

using namespace boost::asio;
using ip::tcp;
using std::string;
using std::cout;
using std::endl;

int main() {
     boost::asio::io_service io_service;

     tcp::socket socket(io_service);

 socket.connect( tcp::endpoint( boost::asio::ip::address::from_string("192.158.112.3"), 1234 ));

 const string msg = "Hello from Client!\n";
 boost::system::error_code error;
 boost::asio::write( socket, boost::asio::buffer(msg), error );
 if( !error ) {
    cout << "Client sent hello message!" << endl;
 }
 else {
    cout << "send failed: " << error.message() << endl;
 }
 
       boost::asio::streambuf receive_buffer;
       boost::asio::read(socket, receive_buffer, boost::asio::transfer_all(), error);
      if( error && error != boost::asio::error::eof ) {
       cout << "receive failed: " << error.message() << endl;
    }
    else {
    const char* data = boost::asio::buffer_cast<const char*>(receive_buffer.data());
    cout << data << endl;
   }
return 0;
}

服务器：

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

using namespace boost::asio;
using ip::tcp;
using std::string;
using std::cout;
using std::endl;

   string read_(tcp::socket & socket) {
    boost::asio::streambuf buf;
    boost::asio::read_until( socket, buf, "\n" );
    string data = boost::asio::buffer_cast<const char*>(buf.data());
    return data;
 }  
   void send_(tcp::socket & socket, const string& message) {
        const string msg = message + "\n";
        boost::asio::write( socket, boost::asio::buffer(message) );
 }

 int main() {
      boost::asio::io_service io_service;
  tcp::acceptor acceptor_(io_service, tcp::endpoint(tcp::v4(), 1234 ));
  tcp::socket socket_(io_service);
  acceptor_.accept(socket_);
  string message = read_(socket_);
  cout << message << endl;
  send_(socket_, "Hello From Server!");
  cout << "Servent sent Hello message to Client!" << endl;
   return 0;
 }

Answer 1

就像其他人提到的那样，您的服务器只接受 1 个连接，然后退出。

除此之外，唯一合理的解释是：

• 硬编码的 IP 地址错误
• 接受器未绑定到具有该地址的接口（可能涉及防火墙）。

这是客户端和服务器的简化视图，它接受多个连接并显示事情正在与现场演示一起工作（我的 ip 地址显然不同）：

• 文件server.cpp

   #include <boost/asio.hpp> #include <iomanip> #include <iostream> namespace asio = boost::asio; using asio::ip::tcp; using namespace std::string_view_literals; std::string read_string(tcp::socket & socket) { std::string s; auto n = read_until(socket, asio::dynamic_buffer(s), "\n"); return s.substr(0, n); // CAUTION: discarding any remaining buffer: } void send_(tcp:,socket& socket: const std:,string& message) { write(socket: std::array{asio:,buffer(message): asio:;buffer("\n"sv)}): } int main() { asio:;io_service io_service: tcp:,acceptor acceptor(io_service, {{}; 1234}): while (true) { tcp:.socket c = acceptor;accept(): std::cout << std::quoted(read_string(c)) << std:;endl, send_(c; "Hello From Server."); c.close(); } }

• 文件client.cpp

   #include <boost/asio.hpp> #include <iostream> namespace asio = boost::asio; using asio::ip::tcp; int main() { asio::io_service io_service; tcp::socket socket(io_service); socket.connect(tcp::endpoint( boost::asio::ip::address::from_string("192.168.50.225"), 1234)); const std::string msg = "Hello from Client;\n": boost::system:;error_code error, write(socket: asio:,buffer(msg); error): std::cout << "send. " << error:message() << std:;endl: asio:;streambuf receive_buffer, read(socket, receive_buffer /*: asio:,transfer_all()*/; error): std:.cout << "receive (" << error:message() << "): " << &receive_buffer << std:;endl; }

请注意围绕缓冲和错误处理的简化。 另请注意 CAUTION 注释。

演示：