Validate URL query string with regex

Question

I\'m trying to validate a query string with regex. Note that I\'m not trying to match out the values, but validate its syntax. I\'m doing this to practice regex, so I\'d app

Answer 1

This seems to be what you want:

^\?([\w-]+(=[\w-]*)?(&[\w-]+(=[\w-]*)?)*)?$

See live demo

This considers each "pair" as a key followed by an optional value (which maybe blank), and has a first pair, followed by an optional & then another pair,and the whole expression (except for the leading?) is optional. Doing it this way prevents matching ?&abc=def

Also note that hyphen doesn't need escaping when last in the character class, allowing a slight simplification.

You seem to want to allow hyphens anywhere in keys or values. If keys need to be hyphen free:

^\?(\w+(=[\w-]*)?(&\w+(=[\w-]*)?)*)?$