Debugging errors in the backend

Hello, firstly I want to say thank you because I find this project very useful! I was finding it difficult to debug some errors in a project that I’m working on, so I subclassed the middleware to return errors to the frontend like this:

import traceback

from django.conf import settings
from django.http import HttpResponse


from django_htmx.middleware import HtmxMiddleware


class HtmxDebugMiddleware(HtmxMiddleware):
    def process_exception(self, request, exception):
        if request.htmx and settings.DEBUG:
            content = (
                "<h1>Django HTMX Error</h1><b>%s</b>"
                "<h3>Traceback</h3><textarea rows=10>%s</textarea>"
            ) % (
                exception,
                traceback.format_exc(),
            )

            return HttpResponse(content, status=200)

        return None

Here is an example of what the solution above produces when raise RuntimeError("Something bad happened on the backend!") is encountered:

Would it be desirable to include something similar in this project?

[adamchainz]

Just released in version 1.2.0 - check it out!

[adamchainz]

Yes, my concern was for the case when debug is not enabled and the script replaces the page with non-debug server error response. The templatetag approach should resolve this by only running this behaviour when debug is enabled.

Ah good, my misunderstanding… I’ve just seen too many people running debug mode in prod 😅

The potential confusion I was alluding to was that in the process of debugging some cases (e.g multiple load triggers) it might seem like the first error was resolved by some change after reloading the page and a different error just happens to return before the previous error is encountered again.

Yes this is true. I’m not sure there’s much we can do about that. Thankfully most pages should be fairly deterministic in the order that errors occur.