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URL Validation

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Join Date: Sep 2006

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fernandodonster fernandodonster is offline

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URL Validation

Dec 28th, 2006

How do we validate URL either with PHP/javascript? could u help me?for example,
whether input text is in the format http://www.google.com or not?

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Join Date: Aug 2006

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php_daemon php_daemon is offline

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Re: URL Validation

Dec 28th, 2006

 Help with Code Tags 
 php Syntax (Toggle Plain Text) 
if (!preg_match("#^http://www\.[a-z0-9-_.]+\.[a-z]{2,4}$#i",$url)) {
  echo "wrong url";
} else {
  echo "ok";
}
if (!preg_match("#^http://www\.[a-z0-9-_.]+\.[a-z]{2,4}$#i",$url)) {
  echo "wrong url";
} else {
  echo "ok";
}

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Join Date: Oct 2004

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paradox814 paradox814 is offline

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Re: URL Validation

Dec 29th, 2006

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Originally Posted by php_daemon

Help with Code Tags

php Syntax (Toggle Plain Text)
if (!preg_match("#^http://www\.[a-z0-9-_.]+\.[a-z]{2,4}$#i",$url)) {
  echo "wrong url";
} else {
  echo "ok";
}
if (!preg_match("#^http://www\.[a-z0-9-_.]+\.[a-z]{2,4}$#i",$url)) { echo "wrong url"; } else { echo "ok"; }

that looks good, except that only letters, numbers, and hypens are allowed in a domain name (underscores are not allowed), and due to ICANN limitation domain names are limited to 64 characters. This regular expression also limits a lot of cases, for instance none of the following special cases would work...

any website with a subdomain/or lack of one other than www, for instance
http://slashdot.org/ (has no www and no subdomain)
http://en.wikipedia.org/ (has a subdomain en, but no www)

subfolders
http://www.mozilla.com/en-US/firefox/

ip addresses...
http://64.233.167.99/
you will actually get google.com (that is its ip address as of this current moment).

specifying port numbers:
http://glcfapp.umiacs.umd.edu:8080

entering username/passwords directly into the url
http://username: password@example.com

i recommend going here: http://regexlib.com/Search.aspx
and performing a search for category "Uri" and see which regular expression you thing would work best for this example. here is a sample i got from that site, of course this one is not perfect either, but it's another sample.

 Help with Code Tags 
 PHP Syntax (Toggle Plain Text) 
(http|ftp|https):\/\/[\w\-_]+(\.[\w\-_]+)+([\w\-\.,@?^=%&amp;:/~\+#]*[\w\-\@?^=%&amp;/~\+#])?
(http|ftp|https):\/\/[\w\-_]+(\.[\w\-_]+)+([\w\-\.,@?^=%&amp;:/~\+#]*[\w\-\@?^=%&amp;/~\+#])?

just know that it will probably be virtually impossible to find a perfect regex expression to match all possible URL's, one way would be to see if it starts with http:// and if it does, then see if you can make a connection to it with php, if the headers return a status code of 200, then you are good and you know it's a valid url, but that is a lot of work in itself.

Last edited by paradox814; Dec 29th, 2006 at 1:00 am.

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Join Date: Aug 2006

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php_daemon php_daemon is offline

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Re: URL Validation

Dec 29th, 2006

Yes, indeed. Though if the OP needs to check for the urls of specific format only, such as the one provided as an example, a simple regexp would do quite well.

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Join Date: Jun 2009

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ym_chaitu

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21 Days Ago

check this out

 Help with Code Tags 
 PHP Syntax (Toggle Plain Text) 
<?php
$subscr=$_REQUEST['subscr'];
 
//url validation
 
if (preg_match('|^http(s)?://[a-z0-9-]+(.[a-z0-9-]+)*(:[0-9]+)?(/.*)?$|i', $subscr)) 
{
    print "$subscr url OK.";
} else {
    print "$subscr url not valid!";
}
//echo("$subscr");
?>
<?php
$subscr=$_REQUEST['subscr'];

//url validation

if (preg_match('|^http(s)?://[a-z0-9-]+(.[a-z0-9-]+)*(:[0-9]+)?(/.*)?$|i', $subscr)) 
{
    print "$subscr url OK.";
} else {
    print "$subscr url not valid!";
}
//echo("$subscr");
?>