text: #include <websocketpp/config/asio_no_tls.hpp>
  
  #include <websocketpp/server.hpp>
  
  #include <iostream>
  
  typedef websocketpp::server<websocketpp::config::asio> server;
  
  using websocketpp::lib::placeholders::_1;
  using websocketpp::lib::placeholders::_2;
  using websocketpp::lib::bind;
  
  // pull out the type of messages sent by our config
  typedef server::message_ptr message_ptr;
  
  // Define a callback to handle incoming messages
  void on_message(server* s, websocketpp::connection_hdl hdl, message_ptr msg) {
      std::cout << "on_message called with hdl: " << hdl.lock().get()
                << " and message: " << msg->get_payload()
                << std::endl;
  
      // check for a special command to instruct the server to stop listening so
      // it can be cleanly exited.
      if (msg->get_payload() == "stop-listening") {
          s->stop_listening();
          return;
      }
  
      try {
          s->send(hdl, msg->get_payload(), msg->get_opcode());
      } catch (websocketpp::exception const & e) {
          std::cout << "Echo failed because: "
                    << "(" << e.what() << ")" << std::endl;
      }
  }
  
  int main() {
      // Create a server endpoint
      server echo_server;
  
      try {
          // Set logging settings
          echo_server.set_access_channels(websocketpp::log::alevel::all);
          echo_server.clear_access_channels(websocketpp::log::alevel::frame_payload);
  
          // Initialize Asio
          echo_server.init_asio();
  
          // Register our message handler
          echo_server.set_message_handler(bind(&on_message,&echo_server,::_1,::_2));
  
          // Listen on port 9002
          echo_server.listen(9002);
  
          // Start the server accept loop
          echo_server.start_accept();
  
          // Start the ASIO io_service run loop
          echo_server.run();
      } catch (websocketpp::exception const & e) {
          std::cout << e.what() << std::endl;
      } catch (...) {
          std::cout << "other exception" << std::endl;
      }
  }
  