Modern Python Standard Library Cookbook

How it works...

The mimetypes module keeps a list of MIME types associated to each file extension. 

When a filename is provided, only the extension is analyzed.

If the extension is in a list of known MIME types, the associated type is returned. Otherwise None is returned.

Calling mimetypes.init() also loads any MIME type registered in your system configuration, usually from /etc/mime.types on Linux systems and from the registry on Windows systems.

This allows us to cover far more extensions that might not be known by Python itself and to also easily support custom extensions if your system is configured to support them.