preg for validating URL

Answer 1

What is wrong with web site like RegExLib.com ("url" section) ?

You should find what you need and test it for yourself there.

Anyway, this regex validate what you wants and exclude what you do not want.

(?ms)^(https?|ftp|telnet):\/\/((?:(?:(?=[^\r\n]*@)\w|-)+(?:(?::)(?:\w|-)+)?)?)@?((?:(?:(?:\w|-)+)\.)+(?:\w|-)+)(\:\d+)?((?:(?:/(?:\w|-)+(?:\.(?:\w|-)+)?)+)?)((?:\?(?:(?:\w|-)+\=(?:\w|[\.\-\*\:\+\#])*\&?)+)*)$

with:

• group 1: protocol
• group 2: username[:password]
• group 3: domain (www.xxx)
• group 4: empty
• group 5: address (XX/yyy/zzzz)
• group 6: parameters (?key1a=value1a&key2a=value2a?key1b=value1b&key2b=value2b...)

Answer 2

Here you go:

\^(https?|ftp|telnet):\/\/((?:[a-z0-9@:.-]|%[0-9A-F]{2}){3,})(?::(\d+))?((?:\/(?:[a-z0-9-._~!$&'()*+,;=:@]|%[0-9A-F]{2})*)*)(?:\?((?:[a-z0-9-._~!$&'()*+,;=:\/?@]|%[0-9A-F]{2})*))?(?:#((?:[a-z0-9-._~!$&'()*+,;=:\/?@]|%[0-9A-F]{2})*))?$/i

This was based on code found here: http://snipplr.com/view/6889/regular-expressions-for-uri-validationparsing/ with several edits.

You can test it on this page: http://regexpal.com/ (paste the regex as:

^(https?|ftp|telnet):\/\/((?:[a-z0-9@:.-]|%[0-9A-F]{2}){3,})(?::(\d+))?((?:\/(?:[a-z0-9-._~!$&'()*+,;=:@]|%[0-9A-F]{2})*)*)(?:\?((?:[a-z0-9-._~!$&'()*+,;=:\/?@]|%[0-9A-F]{2})*))?(?:#((?:[a-z0-9-._~!$&'()*+,;=:\/?@]|%[0-9A-F]{2})*))?

and select "case insensitive")

Good luck!

Answer 3

This is not really a task for regular expression.

I mean - it's possible to write a regexp based, fully working validator, but it has more or less the same sense as writing regexp to validate an email address.

I don't know what language you're using, but I would guess that in most modern languages there should be library/module to parse and validate urls.