Daring Fireball: An Improved Liberal, Accurate Regex Pattern for Matching URLs
An Improved Liberal, Accurate Regex Pattern for Matching URLs
(?xi) \b ( # Capture 1: entire matched URL (?: [a-z][\w-]+: # URL protocol and colon (?: /{1,3} # 1-3 slashes | # or [a-z0-9%] # Single letter or digit or '%' # (Trying not to match e.g. "URI::Escape") ) | # or www\d{0,3}[.] # "www.", "www1.", "www2." … "www999." | # or [a-z0-9.\-]+[.][a-z]{2,4}/ # looks like domain name followed by a slash ) (?: # One or more: [^\s()<>]+ # Run of non-space, non-()<> | # or \(([^\s()<>]+|(\([^\s()<>]+\)))*\) # balanced parens, up to 2 levels )+ (?: # End with: \(([^\s()<>]+|(\([^\s()<>]+\)))*\) # balanced parens, up to 2 levels | # or [^\s`!()\[\]{};:'".,<>?«»“”‘’] # not a space or one of these punct chars ) )
