PHP url validation + detection

Question

So here is what I need to do.

If an user enters this: http://site.com I need to remove http:// so the string will be site.com , if an user enters http://www.site.com I need to remove http://www. or if the user enters www.site.com I need to remove www. or he can also enter site.com it will be good as well.

I have a function here, but doesn't work how I want to, and I suck at regex.

preg_match('|^http(s)?://[a-z0-9-]+(.[a-z0-9-]+)*(:[0-9]+)?(/.*)?$|i', $_POST['link'])

just want to notice, that sometimes "domain.tld" is not the same as "www.domain.tld" — zerkms
– zerkms, Commented Sep 29, 2010 at 23:40

Aillyn · Accepted Answer · 2010-09-29 23:38:57Z

3

Use filter_var() instead.

if (filter_var($_POST['link'], FILTER_VALIDATE_URL)) {
    // valid URL
} else {
   // not valid
}

answered Sep 29, 2010 at 23:38

Aillyn

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Comments

Martin · Accepted Answer · 2010-09-29 23:41:25Z

3

There is also parse_url function.

answered Sep 29, 2010 at 23:41

Martin

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Andrew · Accepted Answer · 2010-09-29 23:43:36Z

2

I don't think I'd use regex for this, since you're only really checking for what is at the beginning of the string. So:

$link = $_POST['link'];
if (stripos($link, 'http://') === 0)
{
    $link = substr($link, 7);
}
elseif (stripos($link, 'https://') === 0)
{
    $link = substr($link, 8);
}
if (stripos($link, 'www.') === 0)
{
    $link = substr($link, 4);
}

should take care of it.

answered Sep 29, 2010 at 23:43

Andrew

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Ascherer · Accepted Answer · 2010-09-29 23:41:37Z

0

i always go with str_replace haha

str_replace('http://','',str_replace('www.','',$url))

answered Sep 29, 2010 at 23:41

Ascherer

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6 Comments

Andrew Over a year ago

If there happens to be another 'www.' in the string except at the beginning, this approach would have a problem.

zerkms Over a year ago

Removing of "www." can be a problem in any case ;-)

Ascherer Over a year ago

alrighty, how bout this str_replace('','',str_replace('http://','',$url))

Andrew Over a year ago

@Ascherer You would never reach the outer str_replace with anything that it would replace if the original $url is valid. You would already have stripped off the http://.

Ascherer Over a year ago

yeah, i did it backwards, im gonna stop commenting on this one cause im getting tired, but u get the picture, just a simple way, that with work, could also be used.

|

Gus · Accepted Answer · 2010-09-29 23:44:59Z

0

I think what you're looking for is a multi-stage preg_replace():

$tmp = strtolower($_POST['link']) ;
$tmp = preg_replace('/^http(s)?/', '', $tmp);
$domain = preg_replace('/^www./', '', $tmp) ;

This simplifies the required regex quite a bit too.

answered Sep 29, 2010 at 23:44

Gus

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