How to catch ERR_CONNECTION_REFUSED thrown by browser if server goes down?

Question

I think this question is pretty straightforward, but I haven't found an answer yet in the official Socket.io docs.

I have my Socket.io server and client communicating successfully, and when I shut down the server, the client will attempt to reconnect with the server unsuccessfully. This is shown in the Chrome developer's console here:

enter image description here

Is there any way to detect this event in the client-side Javscript and react to it some way? I'm thinking I would display a dialog on the page, such as "Sorry, server is under heavy load", etc.

score 43 · Accepted Answer · answered Jul 14 '14 at 23:53

43

The correct way to handle this, as of Socket 1.x, is to use the Manager object for a given socket. It throws a connect_error event that can be handled as shown:

socket.io.on('connect_error', function(err) {
  // handle server error here
  console.log('Error connecting to server');
});

answered Jul 14 '14 at 23:53

Matt Vukas

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Many thanks, you saved the day, it's not documented well. – moeinghasemi Nov 29 '22 at 12:26

score 4 · Answer 2 · answered Jul 10 '14 at 19:08

4

This should work:

var socket = io('http://localhost');
socket.on('connect_error', function(err) {
  // notify user
});

answered Jul 10 '14 at 19:08

glortho

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2

A small correction: the valid form is `socket.io.on('connect_error', function() {...})` – Oleg Jul 10 '14 at 19:37
For some reason, I couldn't get this to work. I see the errors popping up in the console, but the handler is never called. – Matt Vukas Jul 14 '14 at 23:24
All I'm trying to do is catch the error on the client side, if the server was down, for example. Any ideas? – Matt Vukas Jul 14 '14 at 23:25
@BigMario I'm not able to get it fixed. Can you explain how curious comment helped you ? – Tarun Gupta Jan 13 '15 at 05:41

score 1 · Answer 3 · answered Feb 11 '20 at 12:54

As of now and in the past there is no way to "handle" the red messages. You can't hide them.

Reference: https://stackoverflow.com/a/43056626/5563074

You can't hide them but socket.io does have a way to catch them like presented earlier.

socket.on('connect_error', function(e){
   //Do something
   //console.log(e);
});

Docs: https://socket.io/docs/client-api/#Event-%E2%80%98connect-error%E2%80%99

How to catch ERR_CONNECTION_REFUSED thrown by browser if server goes down?

3 Answers3

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