Daytime.7 结合 TCP 和 UDP 的异步服务器 #

原文链接 | 源码链接

这份教程展示了如何将我们刚刚编写的两个异步服务器组合为一个服务器程序。

主函数 #

int main()
{
  try
  {
    boost::asio::io_context io_context;

首先创建一个服务器对象接收 TCP 客户端连接。

    tcp_server server1(io_context);

另外还需要一个服务器对象接收 UDP 客户端请求。

    udp_server server2(io_context);

为 io_context 对象创建了两个要执行的任务：

    io_context.run();
  }
  catch (std::exception& e)
  {
    std::cerr << e.what() << std::endl;
  }

  return 0;
}

tcp connection 类和 tcp server类 #

下面的两个类取自 Daytime.3

class tcp_connection
  : public std::enable_shared_from_this<tcp_connection>
{
public:
  typedef std::shared_ptr<tcp_connection> pointer;

  static pointer create(boost::asio::io_context& io_context)
  {
    return pointer(new tcp_connection(io_context));
  }

  tcp::socket& socket()
  {
    return socket_;
  }

  void start()
  {
    message_ = make_daytime_string();

    boost::asio::async_write(socket_, boost::asio::buffer(message_),
        std::bind(&tcp_connection::handle_write, shared_from_this()));
  }

private:
  tcp_connection(boost::asio::io_context& io_context)
    : socket_(io_context)
  {
  }

  void handle_write()
  {
  }

  tcp::socket socket_;
  std::string message_;
};

class tcp_server
{
public:
  tcp_server(boost::asio::io_context& io_context)
    : io_context_(io_context),
      acceptor_(io_context, tcp::endpoint(tcp::v4(), 13))
  {
    start_accept();
  }

private:
  void start_accept()
  {
    tcp_connection::pointer new_connection =
      tcp_connection::create(io_context_);

    acceptor_.async_accept(new_connection->socket(),
        std::bind(&tcp_server::handle_accept, this, new_connection,
          boost::asio::placeholders::error));
  }

  void handle_accept(tcp_connection::pointer new_connection,
      const boost::system::error_code& error)
  {
    if (!error)
    {
      new_connection->start();
    }

    start_accept();
  }

  boost::asio::io_context& io_context_;
  tcp::acceptor acceptor_;
};

udp server 类 #

同样的，下面这个类取自 Daytime.6

class udp_server
{
public:
  udp_server(boost::asio::io_context& io_context)
    : socket_(io_context, udp::endpoint(udp::v4(), 13))
  {
    start_receive();
  }

private:
  void start_receive()
  {
    socket_.async_receive_from(
        boost::asio::buffer(recv_buffer_), remote_endpoint_,
        std::bind(&udp_server::handle_receive, this,
          boost::asio::placeholders::error));
  }

  void handle_receive(const boost::system::error_code& error)
  {
    if (!error)
    {
      std::shared_ptr<std::string> message(
          new std::string(make_daytime_string()));

      socket_.async_send_to(boost::asio::buffer(*message), remote_endpoint_,
          std::bind(&udp_server::handle_send, this, message));

      start_receive();
    }
  }

  void handle_send(std::shared_ptr<std::string> /*message*/)
  {
  }

  udp::socket socket_;
  udp::endpoint remote_endpoint_;
  std::array<char, 1> recv_buffer_;
};