Uncaught Exceptions from within `ModelViewSet` are returned as HTML

[thatmattlove]

NetBox version

v3.0.0

Python version

3.8

Steps to Reproduce

This can be tricky - something needs to done to trigger an uncaught exception from within ModelViewSet. I suppose you could add this...

raise Exception('test')

...here, and then make an API request.

Expected Behavior

At a minimum, I think we should append useful information to the error. Ideally, however, no HTML would be returned to an API client.

Observed Behavior

The returned value is something along the lines of:

{
  "error": "<giant unreadable HTML string>"
}

[jeremystretch]

Any exceptions raised by an API view should get caught and handled by ExceptionHandlingMiddleware (unless debugging is enabled). I can confirm that this works as expected when intentionally raising an exception in ModelViewSet.dispatch().

Can we just extend the middleware to evaluate the request type and act accordingly? I.e. invoke rest_api_server_error() only if it's an API request and JSON content was requested?

[thatmattlove]

Cool, looks good! I didn't delve deep enough to see the exception middleware, so your solution makes more sense. It like the content-type is now evaluated before the debug setting as well, so this should disappear from development environments as well (I suspect that's the reason I noticed this).