How to return an error from an extension?

[otryshko]

How do I bubble an exception out from extension? If I just raise one, request fails with a 500; I'd prefer the exception to be present in the errors node of the standard graphql response payload.

[rafalp]

Can you share what is your usecase? Generally you shouldn't use extension system for any heavy logic that may be raising exceptions.

[otryshko]

@rafalp Authentication is the simplest case - if the request auth header is invalid, send back corresponding error.

[rafalp]

You are not supposed to use extension system for authentication. I've explained this more here.

[otryshko]

@rafalp I assume you suggest pushing auth to the hosting runtime/middleware? Then we'll have to replicate graphql data formatter there (that data.errors json blob). It would be nice to be able to reuse an existing exception -> json code path

[rafalp]

data.errors is not created by error formatter, only result.errors which is level above.

Replicating formatter here should be as simple as returning JSON response with {"data": None, "errors": [format_error(any_error)]}, but relying on result.errors is popularly considered less productive approach than using custom error messaging in schema.