Only accept a certain file type in FileField, server-side

Question

How can I restrict FileField to only accept a certain type of file (video, audio, pdf, etc.) in an elegant way, server-side?

Answer 1

I think you would be best suited using the ExtFileField that Dominic Rodger specified in his answer and python-magic that Daniel Quinn mentioned is the best way to go. If someone is smart enough to change the extension at least you will catch them with the headers.