微信小程序websocket

微信小程序websocket

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微信小程序带有websocket可以提供使用,但是官方文档写的东西很少,而且小程序后台能力弱这一点也是十分的坑爹,这就导致了socket长连接一切后台就会出现断开的情况,并且难受的是.这个时候你重新调用链接函数也会链接不上,可能直接影响到你的业务逻辑

解决方法就是手动关闭和开启链接,不要让链接在程序切后台的时候被关掉,代码如下↓

• onHide监听程序进入后台的时候,手动关闭链接

  onHide: function() {
    var that = this;
    console.log('程序进入了后台');
    that.closeSocket();
  }

• onShow监听程序进入后台的时候,手动开启链接

 onShow: function() {
    var that = this;
    that.connectSocket();
  }

• connectSocket函数

/**
   * 链接会话，
   * 每间隔一秒链接一次，知道链接成功后停止链接
   */
  connectSocket() {
    var that = this;
    var wss_linker = setInterval(function() {
      if (that.globalData.user) {
        that.globalData.socketTask = wx.connectSocket({
          url: that.globalData.socket_url + that.globalData.user.userId,
          fail: function(res) {
            wx.showModal({
              title: '提示',
              content: 'socket链接异常,请删除程序重试',
            })
          }
        })
        //监听链接开启
        that.globalData.socketTask.onOpen(function(res) {
          that.globalData.isConnect = true;
          var keep_msg = "keep_connect";
          that.globalData.keepConnectInterval = setInterval(function() {
            wx.sendSocketMessage({
              data: keep_msg,
            })
            console.log(keep_msg)
            if (JSON.stringify(that.globalData.newMsg) == "{}") {
              that.globalData.have_new_msg = false;
            }
          }, 1000)

          //获取离线消息
          that.get_old_msg(res => {
            // 获取在线消息
            that.globalData.socketTask.onMessage(function(res) {
              var storage_msg = [];
              var msg_obj = JSON.parse(res.data);
              if (msg_obj.code && msg_obj.code == -1) {
                wx.showModal({
                  title: '发送通知',
                  content: msg_obj.msg,
                })
                // that.globalData.flag=true;
              } else {
                wx.showToast({
                  title: 'You got a msg'
                })
                // 处理时间
                that.format_date(msg_obj.chatTime, res => {
                  msg_obj.chatTime = res
                  var chatRequestUserId = msg_obj.chatRequestUserId + "";
                  // 把获取的消息存入缓存
                  that.set_chat_storage(chatRequestUserId, msg_obj);
                  that.update_unread_msg(chatRequestUserId, msg_obj);
                })
              }
            })
          })
          console.log('webSocket is open');
        })

        that.globalData.socketTask.onClose(function(res){
          that.globalData.isConnect = false;
        })
        clearInterval(wss_linker); //停止计时器
      } else {
        console.log('还没有链接')
      }
    }, 1000)
  }

• closeSocket函数

  /**
   * 关闭socket
   */
  closeSocket(){
    var that=this;
    that.globalData.socketTask.close();
    clearInterval(that.globalData.keepConnectInterval);
  }

在connectSocket函数中,将建立socket链接返回的socketTask储存在全局变量,用以后续的消息监听、消息发送和socket断开。同时,这里用了全局变量,是为了保持链接一直只有一个。减少程序
错误的情况

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ps:这个项目要求在小程序里面做一个聊天的模块=-= 不过也借此熟悉了socket的前后端应用