Question

I want to avoid .. for image files. In my validations, the regex reads:

%r{\.(gif|png|jpg)$}i 

for image URLs. The problem is that fred..png will also pass instead of recognising the double ..

Thanks for helping.

Answer 1

To prevent the case you described, which would only be for a double dot right before the extension:

%r{[^.]\.(gif|png|jpg)$}i 

Edit: If you want to have it such that .. is nowhere in the string, it would be easiest to do that in code (pseudo: if regex.matches(filename) and '..' not in filename).