So I have created a new web application that uses a WebSocket to Node.JS WebSocket server. Now the Node server does everything it needs to and works perfectly. My problem is with the browser implementation.
I have looked at a lot of the libraries other people have been given in the answers, but I want to see if their is a better or cleaner way to do this.
So in my instance, I essentially create an object, which wraps the WebSocket and then uses a setInterval to reconnect, by calling connect(url), which will create another WebSocket instance.
I have been looking at connections and clients, and it seems that if a connection closes, say the server goes down, or something happens, it looks as though sometimes, in a longer period of time, the WebSocket connections are doubling up, so instead of 1 connection per client, it is 2, 3 or 4...?
I have a feeling this is because I am making a new instance of the WebSocket each time?
Code below:
// Main Function
function WSWrapper() {
// Variables
this.socket = null;
this.enabled = false;
this.retry = false;
// Connect
this.connect = function(address) {
// Sets the address
this.address = address;
// Creates the websocket connection
this.socket = new WebSocket(address);
// On message event handler
this.socket.onmessage = function(event) {
// Do stuff here
}
this.socket.onopen = function(event) {
// On connect, disable retry system
window.ta.enabled = true;
window.ta.retry = false;
}
this.socket.onclose = function(event) {
// On close, enable retry system, disable bidding
window.ta.enabled = false;
window.ta.retry = true;
window.ta.bidEnabled = false;
}
this.socket.onerror = function(event) {
// Set variables off
window.ta.enabled = false;
window.ta.bidEnabled = false;
window.ta.retry = true;
}
return true;
}
// Close Socket
this.closeSocket = function() {
// Shutdown websocket
this.socket.close();
return true;
}
// Send Message
this.socketSend = function(content) {
this.socket.send(content);
return true;
}
// Retry System: Attempts to reconnect when a connection is dropped
this.repeat = setInterval(function() {
if (window.ta.enabled == false && window.ta.retry == true) {
window.ta.connect(window.ta.address);
}
}, 2000);
}
window.ta = new WSWrapper();
window.ta.connect('wss://example.com');
I have come up with some thoughts and questions, any answers would be good.
Is there a way to reconnect the same socket? like an .open(url) function that will re-open the connection? I looked in the chrome console, and went through the prototype for the WebSocket, but I see nothing there, so I don't think so but would love to be told otherwise.
Could I fix this by using some functions that take the information, so for example, I create the WebSocket instance and then pass all requests to another function to manage the message information, and then when a connection disconnects, I can somehow delete the old instance and re-create a new one?
Anything would be good, as I am really not sure, it seems that everyone makes a wrapper (like I am doing), but does things differently, so what is the best way or the preferred way, that won't cause multiple instances of the socket to keep running? If there is a problem with my code then please explain!
Thanks
just an update on this, I was able to take the following code: https://github.com/websockets/ws/wiki/Websocket-client-implementation-for-auto-reconnect
And amend it to work for me in the browser. See the below code, remember this is an adaption from the above, so I take no credit in the code.
// Define WSClient instance
window.WSClient = {
// Default reconnect interval
reconnectInterval: 5000,
// Define whether it has ever reconnected
reconnected: false,
// Log messages
debug: false,
// Open the URL
open: function(url) {
// Define that
var that = this;
// Open the URL
this.url = url;
// Create underlying websocket instance
this.instance = new WebSocket(this.url);
// Setup the event handler for onopen
this.instance.onopen = function (ev) {
// If it has ever reconnected lets say that
if (that.reconnected && that.debug) {
console.log('[WS]: Reconnected.');
}
// Run the open function
that.onopen(ev);
}
// Setup the event handler for onmessage
this.instance.onmessage = function(data, flags) {
that.onmessage(data, flags);
}
// Setup the event handler for onclose
this.instance.onclose = function(e) {
switch (e){
// Normal closure
case 1000:
if (that.debug) {
console.log("[WS]: Closed");
}
break;
// Abnormal closure
default:
that.reconnect(e);
break;
}
// Run onclose event
that.onclose(e);
}
// Setup the event handler for onerror
this.instance.onerror = function(e) {
switch (e.code){
// Try and reconnect
case 'ECONNREFUSED':
that.reconnect(e);
break;
// Otherwise run error
default:
that.onerror(e);
break;
}
}
},
// Setup send function
sendRaw: function(data, option) {
try {
this.instance.send(data, option);
} catch (e) {
this.instance.emit('error', e);
}
},
// Send the content
send: function(content) {
this.instance.send(content);
},
// Define the reconnection function
reconnect: function(e) {
// Define that
var that = this;
// Log reconnection
if (that.debug) {
console.log(`[WS]: Reconnecting in ${this.reconnectInterval / 1000} seconds.`);
}
// Set reconnect timeout
setTimeout(function() {
// Log reconnecting
if (that.debug) {
console.log("[WS]: Reconnecting...");
}
// Define has reconnected
that.reconnected = true;
// Try and open the URL
that.open(that.url);
}, this.reconnectInterval);
},
}
So I use this in the Vue.JS framework like so:
<script type="text/javascript">
// Define the websocket
window.vm['socket_example'] = new Vue({
el: '#socket_example',
name: 'SocketExample',
data: {},
methods: {
// On connection open
socket_open: function(event) {
// Send get lots function
this.$socket.send('some_content_here');
},
// On connection close
socket_close: function(event) {
},
// On connection error
socket_error: function(error) {
},
// On connection message
socket_message: function(event) {
},
},
mounted: function() {
// Setup WebSocket connection
this.$socket = WSClient;
this.$socket.debug = true;
this.$socket.open('<?php echo $endpoint; ?>');
// Setup websocket listeners
this.$socket.onopen = this.socket_open;
this.$socket.onclose = this.socket_close;
this.$socket.onerror = this.socket_error;
this.$socket.onmessage = this.socket_message;
},
});
</script>
Anyway I hope this was helpful!