How to check HTTP status code in Apache configuration

Question

Is it possible to check Http status code in Apache configuration as %{REQUEST_STATUS} for instance?

Answer 1

There is no such thing as a "request status", and no way for a server to interact with a browser in the middle of serving an error message.

HTTP is not an interactive protocol; the browser sends a request, the server sends a response, and that's it. So if the browser sends a request, and the application crashes, the server can send a response with 500 and the error details, or a response with 401 requesting the user to log in. Either way, that's the end of the conversation.

When it receives a 401 response, the browser can't say "here's the login details, carry on with the current request", it has to make a new request. It can make an identical request, which might reproduce the error message; but the original error message is gone.

If the requirement is to show a different amount of detail to different users, you need some notion of optional authentication, so that the server can decide immediately whether to include the error details or not, without an extra round-trip to the browser. I would suggest either:

• Have a list of IP addresses which the application can check against; if the IP address of the request is in the list, include the error details.
• Have a custom login system where you can authenticate and set a "session cookie" in the browser. If the user has an active session cookie, include the error details.