🐛 Bug Report — WebSocket API client connection throws internal error #5452
Description
Description
When using WebSocket API in the Workers handler to initiate a connection as client, it throws an internal error, disrupting the Upgrade connection. The remote server itself is reachable and can accept the connection successfully in other runtimes (like Bun and Node.js) and tools like Postman.
The method in the WebSocket API documentation also does not work in this case.
Error Detail
✘ [ERROR] WebSocket error: ErrorEvent {
filename: '',
message: 'Uncaught Error: internal error; reference = lu5vo78l8a10giumjpb6k6j6',
lineno: 0,
colno: 0,
error: [Error: internal error; reference = lu5vo78l8a10giumjpb6k6j6] {
[stack]: [Getter/Setter],
[message]: 'internal error; reference = lu5vo78l8a10giumjpb6k6j6',
remote: true
},
type: 'error',
eventPhase: 2,
composed: false,
bubbles: false,
cancelable: false,
defaultPrevented: false,
returnValue: true,
currentTarget: WebSocket {
readyState: 3,
url: 'wss://openmd.shinnytech.com/t/md/front/mobile',
protocol: '',
extensions: ''
},
target: WebSocket {
readyState: 3,
url: 'wss://openmd.shinnytech.com/t/md/front/mobile',
protocol: '',
extensions: ''
},
srcElement: WebSocket {
readyState: 3,
url: 'wss://openmd.shinnytech.com/t/md/front/mobile',
protocol: '',
extensions: ''
},
timeStamp: 0,
isTrusted: true,
cancelBubble: false,
NONE: 0,
CAPTURING_PHASE: 1,
AT_TARGET: 2,
BUBBLING_PHASE: 3
}
WebSocket connection closed
Sample Code
This will output WebSocket connection opened in Bun but will throw the above error in Workers runtime.
export default {
async fetch(request): Promise<Response> {
const ws = new WebSocket('wss://openmd.shinnytech.com/t/md/front/mobile');
ws.addEventListener('open', () => {
console.log('WebSocket connection opened');
});
ws.addEventListener('close', () => {
console.log('WebSocket connection closed');
});
ws.addEventListener('error', (event) => {
console.error('WebSocket error:', event);
});
ws.addEventListener('message', (event) => {
console.log('Received message:', event.data);
});
await new Promise((resolve) => setTimeout(resolve, 5000));
return new Response('Something', {
headers: {
'content-type': 'text/html;charset=UTF-8',
},
});
},
};