I need to connect to websocket even if the first attemp is not successful. I need some loop.
Now I have:
ws = new WebSocket('ws://domain');
if(!ws) return;
ws.onopen = function() {
ws.send('getpayments '+ response );
}; ...
and I need do this until connect.
Please help me.
Not really a loop but recursive retries:
var retry_connecting = function(domain, clb) {
var ws = new WebSocket(domain);
ws.onerror = function() {
console.log('WS Error! Retrying...');
// let the client breath for 100 millis
setTimeout(function() {
retry_connecting(domain, clb);
}, 100);
};
ws.onopen = function() {
clb(ws);
};
};
and usage
retry_connecting('ws://domain', function(ws) {
console.log('We are connected!');
});
This code will try to connect ad infinitum. I don't recommend that. But I'm sure you'll be able to modify it to run only a finite number of times and then return an error after too many retries.
Related
I have a webserver with websockets set up on an ESP8266. The application runs fine on both client and server sides, sending and receiving data. However, if the server side disconnects (power cycle or upload new code), the client (Chrome) won't reconnect to the websocket. I can reload/refresh the web page, and it claims (according to the console log) to be connecting to the websocket, but it does not. The only solution I have found that works is to close the tab, and then restart a new session.
My code is heavily based on this tutorial from Random Nerd Tutorials
var gateway = `ws://${window.location.hostname}/ws`;
var websocket;
function initWebSocket() {
console.log('Trying to open a WebSocket connection...');
websocket = new WebSocket(gateway);
websocket.onopen = onOpen;
websocket.onclose = onClose;
websocket.onmessage = onMessage; // <-- add this line
}
function onOpen(event) {
console.log('Connection opened');
}
function onClose(event) {
console.log('Connection closed');
setTimeout(initWebSocket, 2000);
}
Is there something that is missing from the code above to make it more reliable?
You probably need to use setInterval. Try this, you may have to tweek it a bit.
var gateway = `ws://${window.location.hostname}/ws`;
var websocket, sockTimer=null;
function initWebSocket() {
console.log('Trying to open a WebSocket connection...');
websocket = new WebSocket(gateway);
websocket.onopen = onOpen;
websocket.onerror = onError; // new
websocket.onclose = onClose;
websocket.onmessage = onMessage; // <-- add this line
}
function onOpen(event) {
clearInterval(sockTimer) // <= better
console.log('Connection opened');
}
function onError() { // <= New
sockTimer = setInterval(init, 1000 * 60);
};
function onClose(event) {
console.log('Connection closed');
//setTimeout(initWebSocket, 2000);
sockTimer = setInterval(initWebSocket, 1000 * 60); // <=new
}
var ws = new WebSocket('ws://localhost:8080');
ws.onopen = function () {
ws.send(JSON.stringify({
.... some message the I must send when I connect ....
}));
};
ws.onmessage = function (e) {
console.log('Got a message')
console.log(e.data);
};
ws.onclose = function(e) {
console.log('socket closed try again');
}
ws.onerror = function(err) {
console.error(err)
};
When I first connect to the socket, I must first send a message to the server to authenticate myself and subscribe to channels.
The problem I have is that sometimes the socket server is unreliable and that triggers the onerror and onclose events of the 'ws' object.
Question: What is a good design pattern that would allow me, whenever the socket closes or encounters an error, wait for 10 seconds and then reconnect to the socket server (and resend the initial message to the server)
Here is what I ended up with. It works for my purposes.
function connect() {
var ws = new WebSocket('ws://localhost:8080');
ws.onopen = function() {
// subscribe to some channels
ws.send(JSON.stringify({
//.... some message the I must send when I connect ....
}));
};
ws.onmessage = function(e) {
console.log('Message:', e.data);
};
ws.onclose = function(e) {
console.log('Socket is closed. Reconnect will be attempted in 1 second.', e.reason);
setTimeout(function() {
connect();
}, 1000);
};
ws.onerror = function(err) {
console.error('Socket encountered error: ', err.message, 'Closing socket');
ws.close();
};
}
connect();
This worked for me with setInterval, because client connection can be lost.
ngOnInit(): void {
if (window.location.protocol.includes('https')) {
this.protocol = 'wss';
}
this.listenChanges();
}
listenChanges(): void {
this.socket = new WebSocket(`${this.protocol}://${window.location.host}/v1.0/your/url`);
this.socket.onmessage = (event): void => {
// your subscription stuff
this.store.dispatch(someAction);
};
this.socket.onerror = (): void => {
this.socket.close();
};
this.socket.onopen = (): void => {
clearInterval(this.timerId);
this.socket.onclose = (): void => {
this.timerId = setInterval(() => {
this.listenChanges();
}, 10000);
};
};
}
Don't forget to call clearInterval when the socket has been opened.
This isn't explicitly a react question but here is a react style answer:
TLDR: You can use setInterval to periodically check the websocket connection status and try to re-connect if the connection is closed. https://developer.mozilla.org/en-US/docs/Web/API/WebSocket/readyState
class TestComponent extends React.Component {
constructor(props) {
super(props);
this.state = {};
this.connect = this.connect.bind(this);
}
componentDidMount() {
this.interval = setInterval(this.connect, 1000);
}
componentWillUnmount() {
if (this.ws) this.ws.close();
if (this.interval) clearInterval(this.interval);
}
connect() {
// https://developer.mozilla.org/en-US/docs/Web/API/WebSocket/readyState
if (this.ws === undefined || (this.ws && this.ws.readyState === 3)) {
this.ws = new WebSocket(`ws://localhost:8080`);
this.ws.onmessage = (e) => {
console.log(JSON.parse(e.data));
};
}
}
render() {
return <div>Hey!</div>;
}
}
I found that this package https://github.com/pladaria/reconnecting-websocket can solve the reconnection issues for Websocket connections. And it has the list of configurable options, one of them is reconnectionDelayGrowFactor which determines how fast the reconnection delay grows.
using async-await if socket closed or any error occurred on the server the client will try to connect automatically every 5 sec forever
have a look to my answer
UPDATED answer:
At last, (if you are not using java) I found you'd better implement your own "ping/pong" strategy. (if you are using java, please take a look at ping/pong "action type", I don't remember very clear... )
client sent "ping" to server every 5 seconds.
server should echo a "pong" to the client once it receive "ping".
client should reconnect server if doesn't receive "pong" in 5 seconds.
Don't rely on any third party libs.
WARNING: DO NOT use these tools: (reason: they are not reliable and not stable and works in a very limited way. )
check if the network is available: https://github.com/hubspot/offline
to re-connect: https://github.com/joewalnes/reconnecting-websocket
You can use a small library if you want - ReconnectingWebSocket
Add reconnecting-websocket.js in your script tag and
It is API compatible, so when you have:
var ws = new WebSocket('ws://....');
you can replace with:
var ws = new ReconnectingWebSocket('ws://....');
Try this:
const observable = Observable.create(
(obs: Observer<MessageEvent>) => {
this.ws.onmessage = obs.next.bind(obs);
this.ws.onerror = obs.error.bind(obs);
// this.ws.onclose = obs.complete.bind(obs);
this.ws.onclose = function () {
window.location.reload()
}
return this.ws.close.bind(this.ws);
});
const observer = {
next: (data: Object) => {
if (this.ws.readyState === WebSocket.OPEN) {
this.ws.send(JSON.stringify(data));
}
}
};
and component
getDatas() {
let url = environment.apiwebsocket
this.webSocketService.connect(url)
.subscribe(evt => {
let jsonObj = JSON.parse(evt.data)
});}
I used to have this somewhere in project:
let rc = new WebSocket(
'ws://'
+ window.location.host
+ `/ws/chat/${window.seen.pk}/`
)
now I switched to:
// ws create the websocket and returns it
function autoReconnect(ws_create){
let ws = ws_create();
function startReconnecting(){
let interval = setInterval(()=>{
console.log('trying')
ws = ws_create();
ws.onopen = () => {
console.log('stop');
ws.onclose = startReconnecting;
clearInterval(interval);
}
}, 3000);
}
ws.onclose = startReconnecting;
}
let rc;
autoReconnect(()=>{
rc = new WebSocket(
'ws://'
+ window.location.host
+ `/ws/chat/${window.seen.pk}/`
)
return rc;
});
test it by running and stop local host, it works fine. (btw I found it weird this question has been posted for a long time, but there is not a short and elegant solution)
the benefit of this method, is that it allows you to pass in an arrow function, so that you can assign variable to any outer scope.
Here's a simple version I use in my projects. It includes an incrementing wait timer for reconnects.
//wsURL - the string URL of the websocket
//waitTimer - the incrementing clock to use if no connection made
//waitSeed - used to reset the waitTimer back to default on a successful connection
//multiplier - how quickly you want the timer to grow on each unsuccessful connection attempt
const openSocket = (wsURL, waitTimer, waitSeed, multiplier) =>{
let ws = new WebSocket(wsURL);
console.log(`trying to connect to: ${ws.url}`);
ws.onopen = () => {
console.log(`connection open to: ${ws.url}`);
waitTimer = waitSeed; //reset the waitTimer if the connection is made
ws.onclose = () => {
console.log(`connection closed to: ${ws.url}`);
openSocket(ws.url, waitTimer, waitSeed, multiplier);
};
ws.onmessage = (message) => {
//do something with messge...
};
};
ws.onerror = () => {
//increaese the wait timer if not connected, but stop at a max of 2n-1 the check time
if(waitTimer < 60000) waitTimer = waitTimer * multiplier;
console.log(`error opening connection ${ws.url}, next attemp in : ${waitTimer/1000} seconds`);
setTimeout(()=>{openSocket(ws.url, waitTimer, waitSeed, multiplier)}, waitTimer);
}
}
openSocket(`ws://localhost:3000`, 1000, 1000, 2)
Alternatively you can explore socket.io. It offers this feature
on the client side you indicate reconnection: true
const io = require("socket.io-client");
const socket = io('ws://'+WS_REMOTE_ADDRESS,{
reconnection: true,
});
I write angularjs app and have some problem. My app use socket connection to get some data every time. For this reason i write factory(code below).
var Service = {};
var ws = new WebSocket("url");
var timer;
Service.onMessage = function(message) { /* some code */};
Service.onClose = function() {
timer = $interval(function () {
ws = new WebSocket("url");
Service.connect();
}, 1000);
};
Service.onOpen = function() {
console.log("open");
if (timer) $interval.cancel(timer);
};
Service.onError = function(error) { /* some code */};
Service.connect = function() {
// (Re)connect
// Reattaching handlers to object
ws.onmessage = Service.onMessage;
ws.onclose = Service.onClose;
ws.onopen = Service.onOpen;
ws.onerror = Service.onError;
}
return Service;
And what problem i have? For simplicity lats imagine that my server is down. And socket connection is down too. After that onclose event will start. But i dont understand how to re-connect with socket. I should check connection every 1 or 5 seconds, for example. In my code if socket closed, i create new socket object and try to connect anew. And what i have? When server is up, i have many-many objects which connect to socket. Please help me. How i can fixed this, for example, to have one object(one current connect)?
But i dont understand how to re-connect with socket. I should check
connection every 1 or 5 seconds
I think this is not a pure angular related question, here a general JavaScript answer (non tested):
function reconnect(url){
ws = new WebSocket(url);
}
ws.onclose = function(){
myTimeout = setTimeout(function(){reconnect('mywsURL')}, 5000);
};
In angular use:
var interval = $interval(your_callback, 5000);
and to cancel the timeout:
$interval.cancel(interval);
I suggest you to read the code of this lib, really interesting.
I searched for a while but couldn't find a working solution for my particular problem.
I have the "default" WebSocket implementation in my JavaScript file. It works but it does not work everytime. Sometimes (can be the first time but could also be the 101st time) the event don't fire. Shouldn't at least the onclose-event fire with wasClean == false?
Maybe someone can help me out with this.
Edit: Forgot something. Only happens if I provide a wrong IP-Adress for:
ws = new WebSocket("ws://" + ip + ":9999/");
So server-side code is not necessary to answer this question.
$(document).ready(function () {
ws = new WebSocket("ws://" + ip + ":9999/");
ws.onopen = function(evt) {
console.log("CONNECTED");
doSend("getInfo");
};
ws.onclose = function(evt) {
if (!evt.wasClean) {
showError();
return;
}
console.log("DISCONNECTED");
};
ws.onmessage = function(evt) {
newIP = evt.data;
};
});
Solved it myself.
Problem was that the no-route-to-host error wasn't firing fast enough if there is no device behind the given IP-Adress. So I implemented a timeout which checks if the readyState of the socket is zero after 100 ms (Application runs in a Local Area Network so the time should be large enough)
function checkServer(ip, port) {
var ws = new WebSocket("ws://" + ip + ":" + port);
setTimeout(function() {
if (ws.readyState == 0) {
showError();
}
else {
ws.close();
ConnectToServer();
}
}, 100);
}
var ws = new WebSocket('ws://localhost:8080');
ws.onopen = function () {
ws.send(JSON.stringify({
.... some message the I must send when I connect ....
}));
};
ws.onmessage = function (e) {
console.log('Got a message')
console.log(e.data);
};
ws.onclose = function(e) {
console.log('socket closed try again');
}
ws.onerror = function(err) {
console.error(err)
};
When I first connect to the socket, I must first send a message to the server to authenticate myself and subscribe to channels.
The problem I have is that sometimes the socket server is unreliable and that triggers the onerror and onclose events of the 'ws' object.
Question: What is a good design pattern that would allow me, whenever the socket closes or encounters an error, wait for 10 seconds and then reconnect to the socket server (and resend the initial message to the server)
Here is what I ended up with. It works for my purposes.
function connect() {
var ws = new WebSocket('ws://localhost:8080');
ws.onopen = function() {
// subscribe to some channels
ws.send(JSON.stringify({
//.... some message the I must send when I connect ....
}));
};
ws.onmessage = function(e) {
console.log('Message:', e.data);
};
ws.onclose = function(e) {
console.log('Socket is closed. Reconnect will be attempted in 1 second.', e.reason);
setTimeout(function() {
connect();
}, 1000);
};
ws.onerror = function(err) {
console.error('Socket encountered error: ', err.message, 'Closing socket');
ws.close();
};
}
connect();
This worked for me with setInterval, because client connection can be lost.
ngOnInit(): void {
if (window.location.protocol.includes('https')) {
this.protocol = 'wss';
}
this.listenChanges();
}
listenChanges(): void {
this.socket = new WebSocket(`${this.protocol}://${window.location.host}/v1.0/your/url`);
this.socket.onmessage = (event): void => {
// your subscription stuff
this.store.dispatch(someAction);
};
this.socket.onerror = (): void => {
this.socket.close();
};
this.socket.onopen = (): void => {
clearInterval(this.timerId);
this.socket.onclose = (): void => {
this.timerId = setInterval(() => {
this.listenChanges();
}, 10000);
};
};
}
Don't forget to call clearInterval when the socket has been opened.
This isn't explicitly a react question but here is a react style answer:
TLDR: You can use setInterval to periodically check the websocket connection status and try to re-connect if the connection is closed. https://developer.mozilla.org/en-US/docs/Web/API/WebSocket/readyState
class TestComponent extends React.Component {
constructor(props) {
super(props);
this.state = {};
this.connect = this.connect.bind(this);
}
componentDidMount() {
this.interval = setInterval(this.connect, 1000);
}
componentWillUnmount() {
if (this.ws) this.ws.close();
if (this.interval) clearInterval(this.interval);
}
connect() {
// https://developer.mozilla.org/en-US/docs/Web/API/WebSocket/readyState
if (this.ws === undefined || (this.ws && this.ws.readyState === 3)) {
this.ws = new WebSocket(`ws://localhost:8080`);
this.ws.onmessage = (e) => {
console.log(JSON.parse(e.data));
};
}
}
render() {
return <div>Hey!</div>;
}
}
I found that this package https://github.com/pladaria/reconnecting-websocket can solve the reconnection issues for Websocket connections. And it has the list of configurable options, one of them is reconnectionDelayGrowFactor which determines how fast the reconnection delay grows.
using async-await if socket closed or any error occurred on the server the client will try to connect automatically every 5 sec forever
have a look to my answer
UPDATED answer:
At last, (if you are not using java) I found you'd better implement your own "ping/pong" strategy. (if you are using java, please take a look at ping/pong "action type", I don't remember very clear... )
client sent "ping" to server every 5 seconds.
server should echo a "pong" to the client once it receive "ping".
client should reconnect server if doesn't receive "pong" in 5 seconds.
Don't rely on any third party libs.
WARNING: DO NOT use these tools: (reason: they are not reliable and not stable and works in a very limited way. )
check if the network is available: https://github.com/hubspot/offline
to re-connect: https://github.com/joewalnes/reconnecting-websocket
You can use a small library if you want - ReconnectingWebSocket
Add reconnecting-websocket.js in your script tag and
It is API compatible, so when you have:
var ws = new WebSocket('ws://....');
you can replace with:
var ws = new ReconnectingWebSocket('ws://....');
Try this:
const observable = Observable.create(
(obs: Observer<MessageEvent>) => {
this.ws.onmessage = obs.next.bind(obs);
this.ws.onerror = obs.error.bind(obs);
// this.ws.onclose = obs.complete.bind(obs);
this.ws.onclose = function () {
window.location.reload()
}
return this.ws.close.bind(this.ws);
});
const observer = {
next: (data: Object) => {
if (this.ws.readyState === WebSocket.OPEN) {
this.ws.send(JSON.stringify(data));
}
}
};
and component
getDatas() {
let url = environment.apiwebsocket
this.webSocketService.connect(url)
.subscribe(evt => {
let jsonObj = JSON.parse(evt.data)
});}
I used to have this somewhere in project:
let rc = new WebSocket(
'ws://'
+ window.location.host
+ `/ws/chat/${window.seen.pk}/`
)
now I switched to:
// ws create the websocket and returns it
function autoReconnect(ws_create){
let ws = ws_create();
function startReconnecting(){
let interval = setInterval(()=>{
console.log('trying')
ws = ws_create();
ws.onopen = () => {
console.log('stop');
ws.onclose = startReconnecting;
clearInterval(interval);
}
}, 3000);
}
ws.onclose = startReconnecting;
}
let rc;
autoReconnect(()=>{
rc = new WebSocket(
'ws://'
+ window.location.host
+ `/ws/chat/${window.seen.pk}/`
)
return rc;
});
test it by running and stop local host, it works fine. (btw I found it weird this question has been posted for a long time, but there is not a short and elegant solution)
the benefit of this method, is that it allows you to pass in an arrow function, so that you can assign variable to any outer scope.
Here's a simple version I use in my projects. It includes an incrementing wait timer for reconnects.
//wsURL - the string URL of the websocket
//waitTimer - the incrementing clock to use if no connection made
//waitSeed - used to reset the waitTimer back to default on a successful connection
//multiplier - how quickly you want the timer to grow on each unsuccessful connection attempt
const openSocket = (wsURL, waitTimer, waitSeed, multiplier) =>{
let ws = new WebSocket(wsURL);
console.log(`trying to connect to: ${ws.url}`);
ws.onopen = () => {
console.log(`connection open to: ${ws.url}`);
waitTimer = waitSeed; //reset the waitTimer if the connection is made
ws.onclose = () => {
console.log(`connection closed to: ${ws.url}`);
openSocket(ws.url, waitTimer, waitSeed, multiplier);
};
ws.onmessage = (message) => {
//do something with messge...
};
};
ws.onerror = () => {
//increaese the wait timer if not connected, but stop at a max of 2n-1 the check time
if(waitTimer < 60000) waitTimer = waitTimer * multiplier;
console.log(`error opening connection ${ws.url}, next attemp in : ${waitTimer/1000} seconds`);
setTimeout(()=>{openSocket(ws.url, waitTimer, waitSeed, multiplier)}, waitTimer);
}
}
openSocket(`ws://localhost:3000`, 1000, 1000, 2)
Alternatively you can explore socket.io. It offers this feature
on the client side you indicate reconnection: true
const io = require("socket.io-client");
const socket = io('ws://'+WS_REMOTE_ADDRESS,{
reconnection: true,
});