Is it safe to validate a URL with a regexp?
- by Vilx-
In my web app I've got a form field where the user can enter an URL. I'm already doing some preliminary client-side validation and I was wondering if I could use a regexp to validate if the entered string is a valid URL. So, two questions:
Is it safe to do this with a regexp? A URL is a complex beast, and just like you shouldn't use a regexp for parsing HTML, I'm worried that it might be unsuitable for a URL as well.
If it can be done, what would be a good regexp for the task? (I know that Google turns up countless regexps, but I'm worried about their quality).
My goal is to prevent a situation where the URL appears in the web page and is unusable by the browser.