Websocket reconnect after page refresh

Question

I am using websocket in conjuction with an http server for a Node.js SPA. My use of websocket is to read an index file from the server and push it to the client. The websocket is working except when I refresh the page.

Can someone assist me in reconnecting the websocket? I am listening for an onClose event and calling the method that creates the websocket. The error I get once I refresh the page is:

Socket encountered error:  write after end Closing socket

/home/pi/data_collector_access_point/node_modules/ws/lib/websocket.js:829
websocket.readyState = WebSocket.CLOSING;
                       ^

TypeError: Cannot set property 'readyState' of undefined
    at Socket.socketOnClose (/home/pi/data_collector_access_point/node_modules/ws/lib/websocket.js:829:24)
    at emitOne (events.js:121:20)
    at Socket.emit (events.js:211:7)
    at TCP._handle.close [as _onclose] (net.js:567:12)

Server.js

serverWS(address){
        let server = address
        const WebSocket = require('ws');
        let wss = new WebSocket.Server({ server });
        var socketstate = 1;
        wss.on('connection', function connection(ws, req) {

            ws.on('message', function incoming(message) {
            });

            ws.onclose = function(){
                socketstate = 0
                console.log('ws.onclose()')
                setTimeout(function(){
                    console.log('reconnct ', server)
                    let fti_server = new create_server()
                    fti_server.serverWS(server)
                },3000);
            };

             ws.onerror = function(err) {
                console.error('Socket encountered error: ', err.message, 'Closing socket');
                ws.close();
             };

            function sendme(data){
                switch(socketstate){
                    case 0:
                        console.log('sendme() socket state', socketstate)
                        break;
                    case 1:
                        console.log('sendme() socket state', socketstate)
                        if(ws.readyState == 1){
                            updater((data)=>{
                                ws.send(data)   
                            })
                        }
                        break;
                }


            }

            function reOpen(){
                console.log('reopen', wss)
                wss = new WebSocket.Server({ server });
            }

            setInterval(()=>{
                switch(ws.readyState){
                    case 1 :
                        console.log('switch case ws state on')
                            sendme(data)
                        break;
                    case 2 :
                        console.log('ws state 2')
                        break
                    case 3 :
                        console.log('switch case ws state not on')
                        break;

                }
            },1000); 
        })

    }

I am listening to the websocketReadystate to see if the websocket is open, closed, closing etc. Once opened I would continue sending the index data.

I am referencing this reconnection situation .

score 1 · Answer 1 · answered Mar 15 '19 at 15:57

For those interested I got it working by allowing the browser to establish a connection without calling the websocket setup function again. I modified the onclose() and it works!

ws.onclose = function(){
                socketstate = 0
                ws.close()
            };

Websocket reconnect after page refresh

1 Answers1