Websocket error on Safari

[gabridego]

I am developing a WebRTC service which uses your library for the signalling phase. Everything works well on Chrome, Firefox and Android, but I am experiencing an error on Safari (macOS Ventura 13.3) and iOS:

[Error] WebSocket connection to 'wss://myapp.com/ws' failed: The operation couldn’t be completed. Socket is not connected

Anyway, it works on Safari when disabling the experimental feature 'NSURLSession WebSocket', which makes me suspect of a possible issue with WebSocket compression. Some related issues:

• iOS 15 WKWebView websocket behaviour
• Safari websocket compression is broken gorilla/websocket#731
• Compressed messages fail in Safari coder/websocket#218

Is there any configuration I can use to make my websocket application work on Safari and iOS as well? Thank you!

[cristaloleg]

Hi, thank you for the detailed issue. I haven't met problems so far, so I cannot share any meaningful configuration.

I will try to debug it but no idea will I find something or not.

[gabridego]

Hi, thank you for your quick reply!
I can reproduce the issue with a very minimal example:

package main

import (
	"net/http"

	"github.com/gobwas/ws"
	"github.com/gobwas/ws/wsutil"
)

func main() {
	http.ListenAndServe(":9090", http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		conn, _, _, _ := ws.UpgradeHTTP(r, w)
		defer conn.Close()

		wsutil.WriteServerText(conn, []byte("ciao"))
	}))
}

On Safari console:

ws = new WebSocket("ws://127.0.0.1:9090")
ws.onmessage = (msg) => console.log(msg.data)

With NSURLSession WebSocket enabled, it prints ciao and then gives the error. With the function disabled, just the message with no error.

Am I doing anything wrong? Thanks!

[sudhakar]

More discussion about this with possible workarounds in uNetworking/uWebSockets#1347. As per the thread only "Safari 15.0-15.3" is affected and looks like 15.4 onwards works fine

Some workarounds discussed there are,

1. Disable compression if useragent is "Safari 15.0-15.3"
2. If compression is needed, have sufficient buffer size, so that message is not fragmented and hence wont trigger this bug in broken safari (Safari (macOS 12, iOS 15) and compression is broken uNetworking/uWebSockets#1347 (comment))

If anybody gets to test any of these workarounds, please report here

[FZambia]

The example shown by @gabridego does not use compression. Also, I tested it on Safari 16.1 - and the error is still there. So I think those are two different Safari problems.