Add option to set a status code for server error / runtime error on a case by case basis

[lovetodream]

Motivation

Currently, every ServerError throws a 500 status code (at least when using hummingbird-transport).
This might be very subjective, but a response with a 500 status code indicates a problem on the server which requires immediate attention and ultimately a fix. The name indicates that some internals failed, which often isn't the case with ServerErrors.

E.g. decoding or invalid content type errors should rather be handled as bad requests, as the responsibility to provide a valid request lays on the client side, this is nothing the server can fix.

Proposed solution

Consider adding a status code property to ServerError (maybe an Optional desiredStatusCode). This can be used by server runtime authors/users to provide better status codes to their consumers and improve error monitoring.

Alternatives considered

Adding a middleware to set the status code based on ServerError.underlyingError. This works for many cases, but doesn't work for RuntimeError, as it is internal, and cannot be bundled in one status code.

let statusCode: HTTPResponse.Status = switch self.underlyingError {
    case is DecodingError:
        .badRequest
    ...
    default:
        .internalServerError
    }

Additional information

I am just starting to use OpenAPI, maybe I'm missing something here :)

[czechboy0]

Hi @lovetodream, thanks for the feature request - yes we're having some discussions about improving this use case. Let us post here when we have more to share.