Websocket Shutdown Codes

Here are codes that you can see in onclose event handler:

var ws = new WebSocket(..)
os.onclose = function(ev) {
     console.log(ev.code, ev.reason)
}

Note

Chromium doesn’t report custom shutdown codes to Javascript. So we also duplicate same erorr using Fatal Errors (fatal_error).

Our custom codes (and reasons):

• 4001, session_pool_stopped – session pool is closed, basically this means that this specific application is not supported by this server any more. This message may be received at any time.
• 4400, backend_error – no websockets allowed at this route
• 4401, backend_error – unauthorized (i.e. no cookie or other authentication data)
• 4403, backend_error – forbidden (i.e. authorized but not allowed
• 4404, backend_error – route not found (http status: Not Found)
• 4410, backend_error – route not found (http status: Gone)
• 4500, backend_error – internal server error when authorizing
• 4503, backend_error – temporary error, unable to authorize

Bacically we have reserved these status codes to correspond to HTTP error codes returned from backend. But we only guarantee to propagate codes described above, because other ones may impose security vulnerability.

• 4400-4499, backend_error – for HTTP codes 400-499
• 4500-4599, backend_error – for HTTP codes 500-599

These errors only propagate on connection authorization. When single request fails we respond with ["error"...] as websocket message.