websocket++简单使用及实例分析

所属分类：软件编程 / C 语言阅读数： 77

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前言

html5支持使用websocket协议与服务器保持一个长连接，方便双方互相传输数据，而且服务器也能主动发送信息给客户端，而在这之前使用HTTP是很难做到的。下面介绍使用C++实现的websocket++的简单使用。websocket++更详细介绍点此。

websocket++需要boost的支持，所以工程中需要包含boost的头文件和库。boost在VS中的如何使用参考此文章。

C++代码

#include "stdafx.h"
#include <iostream>

using namespace std;

#include <websocketpp/config/asio_no_tls.hpp>
#include <websocketpp/server.hpp>

typedef websocketpp::server<websocketpp::config::asio> WebsocketServer;
typedef WebsocketServer::message_ptr message_ptr;

using websocketpp::lib::placeholders::_1;
using websocketpp::lib::placeholders::_2;
using websocketpp::lib::bind;

void OnOpen(WebsocketServer *server, websocketpp::connection_hdl hdl)
{
  cout << "have client connected" << endl;
}

void OnClose(WebsocketServer *server, websocketpp::connection_hdl hdl)
{
  cout << "have client disconnected" << endl;
}

void OnMessage(WebsocketServer *server, websocketpp::connection_hdl hdl, message_ptr msg)
{
  string strMsg = msg->get_payload();
  cout << strMsg << endl;

  string strRespon = "receive: ";
  strRespon.append(strMsg);

  server->send(hdl, strRespon, websocketpp::frame::opcode::text);
}

int main()
{
  WebsocketServer          server;

  // Set logging settings
  server.set_access_channels(websocketpp::log::alevel::all);
  server.clear_access_channels(websocketpp::log::alevel::frame_payload);

  // Initialize ASIO
  server.init_asio();

  // Register our open handler
  server.set_open_handler(bind(&OnOpen, &server, ::_1));

  // Register our close handler
  server.set_close_handler(bind(&OnClose, &server, _1));

  // Register our message handler
  server.set_message_handler(bind(&OnMessage, &server, _1, _2));

  //Listen on port 2152
  server.listen(8090);

  //Start the server accept loop
  server.start_accept();

  //Start the ASIO io_service run loop
  server.run();

  return 0;
}

Html代码

<!DOCTYPE html>
<html>
<head>
<title>Testing websockets</title>
</head>
<body>
 <div>
  <input type="submit" value="Start" onclick="start()" />
 </div>
 <div id="messages"></div>
 <script type="text/javascript">
  var webSocket =
   new WebSocket('ws://localhost:8090');
 
  webSocket.onerror = function(event) {
   onError(event)
  };
 
  webSocket.onopen = function(event) {
   onOpen(event)
  };
  
  webSocket.onclose = function(event) {
   onClose(event)
  };
 
  webSocket.onmessage = function(event) {
   onMessage(event)
  };
 
  function onMessage(event) {
   document.getElementById('messages').innerHTML
    += '<br />' + event.data;
  }
 
  function onOpen(event) {
   document.getElementById('messages').innerHTML
    = 'Connection established';
  }
  
  function onClose(event) {
   document.getElementById('messages').innerHTML
    += '<br />disconnection';
  }
  function onError(event) {
   alert(event.data);
  }
 
  function start() {
   webSocket.send('hello');
   return false;
  }
 </script>
</body>
</html>

运行结果