Throwing from onConnect - what's the proper pattern?

[theogravity]

If I throw from the onConnect handler, i'll get a message like this:

Internal error occurred during message handling. Please check your implementation

I get the sense that I shouldn't be throwing an error, but instead closing the socket with some kind of message. What's a good example of that?

Does this also apply to the other event listeners as well?

[theogravity]

The docs does say that I should be able to throw from it, and the socket will close appropriately, but should I be getting that specific error on the server-side? I'm throwing an ApolloError type, but I can throw a normal Error if required.

https://github.com/enisdenjo/graphql-ws/blob/master/docs/interfaces/server.ServerOptions.md#onconnect

[enisdenjo]

Throwing from any of the server hooks close the WebSocket connection with a: 4500: Internal server error. The close reason indicates that the server occurred an unexpected error, is terminal by nature and should not happen. Important thing to note is that the client will report the 4500 close code immediately and not retry.

graphql-ws doesn't have opinions on how closing connections on errors should look like, so it just offers a basic solution in case of thrown errors in unexpected places. There are numerous close codes you can use on a WebSocket, they're all in your hands.

With this liberty, you can catch an error in a hook, close with whatever code is agreed with a client for that specific error, have the client do something fancy; or just ignore the error all-together and proceed with execution, it's up to you. Note that graphql-ws handles cleanup when closing sockets abruptly, both on the server and client. Whenever you choose to ctx.extra.socket.close(4321, 'My error') in any of the hooks, the library will take care of ending active subscriptions and will perform proper disposal.

[theogravity]

Thank you!