Good practices regarding MIME type

[Solène Rapenne]

Hi,

I wrote a gemini server in C and I currently use an hardcoded list of 
file extensions <-> MIME type assocation.
This isn't great because it relies on file extension which can be wrong, 
but a file without extension would
use a default.

I chose to set a default text/gemini in case the extension is unknown or 
if the file has no extension.

What are the good practices to determine a file MIME type?

regards
Solène