用于验证URL的PHP​​正则表达式

Question

I'm looking for a decent regex to match a URL (a full URL with scheme, domain, path etc.) I would normally use filter_var but I can't in this case as I have to support PHP<5.2!

I've searched the web but can't find anything that I'm confident will be fool-proof, and all I can find on SO is people saying to use filter_var.

Does anybody have a regex that they use for this?

My code (just so you can see what I'm trying to achieve):

function validate_url($url){
    if (function_exists('filter_var')){
        return filter_var($url, FILTER_VALIDATE_URL);
        }
    return preg_match(REGEX_HERE, $url);
    }

Answer 1

You could try this one. I haven't tried it myself but it's surely the biggest regexp I've ever seen, haha.

^(?#Protocol)(?:(?:ht|f)tp(?:s?)\:\/\/|~\/|\/)?(?#Username:Password)(?:\w+:\w+@)?(?#Subdomains)(?:(?:[-\w]+\.)+(?#TopLevel Domains)(?:com|org|net|gov|mil|biz|info|mobi|name|aero|jobs|museum|travel|[a-z]{2}))(?#Port)(?::[\d]{1,5})?(?#Directories)(?:(?:(?:\/(?:[-\w~!$+|.,=]|%[a-f\d]{2})+)+|\/)+|\?|#)?(?#Query)(?:(?:\?(?:[-\w~!$+|.,*:]|%[a-f\d{2}])+=?(?:[-\w~!$+|.,*:=]|%[a-f\d]{2})*)(?:&(?:[-\w~!$+|.,*:]|%[a-f\d{2}])+=?(?:[-\w~!$+|.,*:=]|%[a-f\d]{2})*)*)*(?#Anchor)(?:#(?:[-\w~!$+|.,*:=]|%[a-f\d]{2})*)?$