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websocket心跳包实现

发布时间：2018-09-17 03:36:23编辑：slayer.hover阅读（5023）

应用场景：在APP中用户登陆后，需要向服务器端发报告说明当前在线。在有业务发生时，服务器会向所有在线的特定用户推送消息。

APP里打开websocket连接后，在网络异常情况下，可能会异常断开。所以需要用心跳包来保持长时间的连接。




服务器端使用swoole的swoole_websocket_server实现，用户上线后，将其数据存放于redis

class WS_Server
{
    private $serv;
    private static $cache;
    private static $cache_set = [
        'host'=>'127.0.0.1', 
        'port'=>6379, 
        'db'=>5
    ];
    public function __construct() {
        self::$cache = new \Redis();
        self::$cache->connect(self::$cache_set['host'], self::$cache_set['port']);
        self::$cache->select(self::$cache_set['db']);
        $this->serv = new \swoole_websocket_server("0.0.0.0", 9502);
        $this->serv->on('open',[$this,'onOpen']);
        $this->serv->on('message',[$this,'onMessage']);
        $this->serv->on('close',    [$this,'onClose']);
        $this->serv->start();
    }
    
    public function onMessage($serv, $frame){
        if($frame->data=='ping'){
            #处理心跳包
            $serv->push($frame->fd, 'pong'); 
        }else {
            $data = json_decode($frame->data, TRUE);
            if ($data) {
                switch ($data['action']) {
                    #新用户上线,接收open数据包
                    case 'open':
                        $mem = [
                            'id'   => $data['id'],
                            'type' => $data['type'],
                            'name' => $data['name'],
                            'phone'=> $data['phone'],
                        ];
                        self::$cache->hset('members', $frame->fd, json_encode($mem));
                        #清除意外断掉的用户
                        $allmem = self::$cache->hGetAll('members');
                        if (!empty($allmem)) {
                            foreach ($allmem as $k => $v) {
                                $row = json_decode($v, true);
                                if ($k != $frame->fd && $row['id'] == $data['id']) {
                                    self::$cache->hdel('members', $k);
                                }
                            }
                        }
                        break;                        
                    #其它具体业务处理    
                    case 'otherEvent':
                        ...
                        break;
                }
            }
        }
      }
      
      public function onClose($serv, $fd){
        self::$cache->hDel('members', $fd);
      }




websocket客户端实现：

    
    var heartCheck = {
        timeout: 60000, //心跳间隔
        timeoutObj: null,
        serverTimeoutObj: null,
        reset: function(){
            clearTimeout(heartCheck.timeoutObj);
            clearTimeout(heartCheck.serverTimeoutObj);
            return this;
        },
        start: function(){
            heartCheck.timeoutObj && clearTimeout(heartCheck.timeoutObj);
            heartCheck.serverTimeoutObj && clearTimeout(heartCheck.serverTimeoutObj);
            heartCheck.timeoutObj = setTimeout(function(){
                if(vm.socket && vm.socket.readyState===1) {
                    vm.socket.send("ping");
                    heartCheck.serverTimeoutObj = setTimeout(function () {
                        vm.reconnect();
                    }, heartCheck.timeout);
                }
            }, heartCheck.timeout)
        }
    };
    
    var vm = new Vue({
        el: '#app',
        data: {            
            userInfo: null,            
            webSocket_url: 'ws://127.0.0.1:9502',
            socket: null,
            lockReconnect: false, //重连标识
            jump: null, //心跳
        },
        methods: {
            wsconnect: function () {
                try{
                    vm.socket=new WebSocket(vm.webSocket_url);
                }catch(e){
                    console.log('websocket error');
                    return false;
                }
                vm.socket.onmessage= function(msg){
                    if(msg.data!='pong') {
                        //根据msg.data处理具体业务
                        ...
                    }
                    heartCheck.reset().start();
                }
                vm.socket.onclose=function(){
                    vm.reconnect();
                }
                vm.socket.onerror=function(){
                    vm.reconnect();
                }
                vm.socket.onopen=function(){
                    heartCheck.reset().start();
                }
            },
            reconnect:function(){
                    if(vm.lockReconnect) {
                        return false;
                    };
                    vm.lockReconnect = true;
                    vm.jump && clearTimeout(vm.jump);
                    vm.jump = setTimeout(function () {
                        vm.wsconnect();
                        vm.lockReconnect = false;
                    }, 4000);
            },
            wsopen:function(){
                !vm.socket && vm.wsconnect();
                if(vm.socket.readyState===1) {
                    vm.userInfo = localStorage.getItem('userInfo');
                    //推送用户上线消息
                    vm.socket.send(JSON.stringify({
                        action: 'open',
                        id: vm.userInfo.id,
                        type: vm.userInfo.type,                            
                        name: vm.userInfo.name,
                        phone:vm.userInfo.phone,
                    }));
                        
                }else{
                    setTimeout(function(){
                        vm.wsopen();
                    }, 1000);
                }
            }
        }
    });
    
    //此页面最好在整个项目中只会执行一次,并且不会关掉
    window.onLoad= function(){
        //判断用户登陆后，打开websocket连接
        if(localStorage.getItem('userInfo')){
            vm.wsopen();
        }
    }




经测试，只要App进程没被杀死，基本可保持用户长期在线。