Suggest possible wrong Socket.IO URL instead of CORS error #1979
Comments
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+1 |
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would be useful |
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@rauchg can you explain a little bit the situation? I'm having this cors trouble and I can't find a solution to it. I'm using express and socket.io, on express side I've cors package which enable cors for all domains, than on socketio i'm using the The express/socket server is on a different subdomain than the client but all normal requests work pretty good but when it comes to socketio it doesn't set the headers.
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Having the same issue, can't find a fix. anyone any idea? |
The close event will now include additional details to help debugging
if anything has gone wrong.
Example when a payload is over the maxHttpBufferSize value in HTTP
long-polling mode:
```js
socket.on("close", (reason, details) => {
console.log(reason); // "transport error"
// in that case, details is an error object
console.log(details.message); "xhr post error"
console.log(details.description); // 413 (the HTTP status of the response)
// details.context refers to the XMLHttpRequest object
console.log(details.context.status); // 413
console.log(details.context.responseText); // ""
});
```
Note: the error object was already included before this commit and is
kept for backward compatibility
Example when a payload is over the maxHttpBufferSize value with
WebSockets:
```js
socket.on("close", (reason, details) => {
console.log(reason); // "transport close"
// in that case, details is a plain object
console.log(details.description); // "websocket connection closed"
// details.context is a CloseEvent object
console.log(details.context.code); // 1009 (which means "Message Too Big")
console.log(details.context.reason); // ""
});
```
Example within a cluster without sticky sessions:
```js
socket.on("close", (reason, details) => {
console.log(details.context.status); // 400
console.log(details.context.responseText); // '{"code":1,"message":"Session ID unknown"}'
});
```
Note: we could also print some warnings in development for the "usual"
errors:
- CORS error
- HTTP 400 with multiple nodes
- HTTP 413 with maxHttpBufferSize
but that would require an additional step when going to production
(i.e. setting NODE_ENV variable to "production"). This is open to
discussion!
Related:
- socketio/socket.io#3946
- socketio/socket.io#1979
- socketio/socket.io-client#1518
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There is still such a problem, and it seems that it has not been solved |
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@sugar258596 the problem is that I don't think we can really tell a CORS issue from a network issue, since the preflight requests are automatically sent by the browser. The XMLHttpRequest object does not give much information:
Open to discuss about this though! |
and others
A lot of people seem to be mistaking the error
No 'Access-Control-Allow-Origin' header is present on the requested resourcefor lack of CORS support in Socket.IO.This seems to be due to usually trying to initialize a socket to the wrong URL. The URL exists and responds, but obviously it doesn't set CORS headers. And even if it did, it wouldn't be where the socket.io server is hosted.
Maybe we could
console.warnin these situations to warn the developer about a potential URL error.The text was updated successfully, but these errors were encountered: