Question

I'm trying to reconnect a websocket automatically with a function. I want it to keep the same variable name, but i'm having some issues. here is the function I'm using

function reconnect(obj){
    try{
        obj=new WebSocket(obj.url);
        }
     except{
        setTimeout(reconnect,5000,obj);
    }
}

mysocket=new Websocket(myurl);
mysocket.close()
reconnect(mysocket)

After the reconnect function runs successfully but mysocket is still referenced to the old closed Websocket. I'm not sure how to transfer to new Websocket object to the old variable.

Answer 1

You are overriding the variable. There are multiple ways to do it, quickest would be to pass an object.

function reconnect(obj){
    var mySocket = obj.mySocket;
    try {
        obj.mySocket=new WebSocket(mySocket.url);
    }
    except {
        setTimeout(reconnect, 5000, obj);
    }
}

mysocket=new Websocket(myurl);
mysocket.close()
var wrapperObject = {mysocket};
reconnect(wrapperObject);
// At any point of time `wrapperObject.mysocket` will have the latest socket instance

A more cleaner approach would be to define a wrapper class/function which scopes the mySocket variable privately. EX:

function ReconnectSocket (mySocket) {
    this.mySocket = mySocket
}

ReconnectSocket.prototype.reconnect = function () {
    try {
        this.mySocket = new WebSocket(this.mySocket.url);
    }
    except {
        setTimeout(reconnect, 5000);
    }
}

ReconnectSocket.prototype.getSocket = function () {
    return this.mySocket
}

var mysocket=new Websocket(myurl);
mysocket.close()
var reconnectSocket = new ReconnectSocket(mysocket).reconnect()
// `reconnectSocket.getSocket()` will give the latest instance at any point of time

Answer 2

First approach is using global variable

    function reconnect(){
        try{
            mysocket=new WebSocket(mysocket.url);
            }
         except{
            setTimeout(reconnect,5000);
        }
    }

    mysocket=new Websocket(myurl);
    mysocket.close()
    reconnect()

Second approach, I think you should wrap your socket in a object

    function reconnect(obj){
        try{
            obj.mysocket=new WebSocket(obj.mysocket.url);
            }
         except{
            setTimeout(reconnect,5000,obj);
        }
    }

    var socketObject = {};
    socketObject.mysocket=new Websocket(myurl);
    socketObject.mysocket.close()
    reconnect(socketObject)

JavaScript WebSocket replace reference with new socket

2 个答案: