Mention that simple local webservers often don't handle 404s by default

[jdillard]

I don't know if it is worth mentioning in the docs somewhere, but http.server (and other simple webservers I'm sure) don't have a default handler for 404 codes, so people might run into issues when attempting to test out the extension locally.

I also don't know if the docs would need to go this far, but here is an example of adding a custom request handler for 404 codes: https://stackoverflow.com/questions/22467908/python-simplehttpserver-404-page

[humitos]

Hi! Thanks for sharing this. It's interesting that you can add the handler to make it work locally without too much code.

I don't think the documentation needs to go too deep on this, but maybe worth to mention it in the FAQ. We do have a warning note saying that 404.html won't work properly locally: https://sphinx-notfound-page.readthedocs.io/en/latest/installation.html

Maybe we can link to a FAQ from that note, explain a little more there and link to the Stack Overflow solution?

[jdillard]

Doh, I did a bad job of putting on my "new user" hat and somehow clicked on every page but installation. If I had to guess, it was because the installation is pretty much documented in the README as well, so I decided to skip that page thinking I had already read that content. (For backstory, I happened to see someone else using the extension get confused by the lack of a 404, so I was attempting to be helpful.)

Adding it to the FAQ sounds like a good idea. I don't mind making a PR if you want. Maybe:

Why is my local webserver not showing a 404.html?
-------------------------------------------------

Simple webservers, such as ``http.server``, don't have a default handler for 404 codes, so it doesn't know to point to the generated ``404.html``.

To see an example of adding a custom request handler for 404 codes, see: https://stackoverflow.com/questions/22467908/python-simplehttpserver-404-page

And append to the installation warning:

If you can't see the 404.html file using a local simple webserver, it is most likely because they often don't support requests for 404 codes. Refer to the :doc:`faq` for more information.