php preg_match validate domain

Question

I want to validate a domain .The expression must only be in the format .

   anywordwithoutspace.any

Here's my code

<?php
function validatereg($str1) {
    //validate domain
    if(preg_match('/^([a-z0-9])*(\.([a-z0-9])([-a-z0-9_-])?([a-z0-9])+)+$/i', $str1) {
        //valid domain
    }
    else {
        //not a valid domain
    }
}
?>

I am not sure if its correct. Also please take note that after the period(which was 'any') can be any letter of maximum 4 letters.

Thanks in advance.

possible duplicate of [Domain name validation with RegEx](http://stackoverflow.com/questions/10306690/domain-name-validation-with-regex) — Rikesh, Mar 20 '14 at 05:29

score 1 · Answer 1 · answered Mar 20 '14 at 08:41

1

You'd better use filter_var with FILTER_VALIDATE_URL:

if (filter_var('http://example.com', FILTER_VALIDATE_URL)) {
    echo "Domain is valid\n";
}

answered Mar 20 '14 at 08:41

Toto

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125

FILTER_VALIDATE_DOMAIN is better – Alexey Khachatryan Mar 24 '20 at 00:37

score -1 · Accepted Answer · answered Mar 20 '14 at 05:30

-1

 if (preg_match("!"#$%&\'()*+,-./@:;<=>[\\]^_`{|}~", $myString)) 
    {
       //valid url
    }

This should do...

answered Mar 20 '14 at 05:30

Amit

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31

nice, i was only looking for a simple domain validator. – CudoX Mar 20 '14 at 05:33
give it few more seconds until im able to do that – CudoX Mar 20 '14 at 05:41

score -2 · Answer 3 · answered Mar 20 '14 at 06:05

-2

<?php
function is_valid_domain_name($domain_name)
{
    return (preg_match("/^([a-z\d](-*[a-z\d])*)(\.([a-z\d](-*[a-z\d])*))*$/i", $domain_name) //valid chars check
            && preg_match("/^.{1,253}$/", $domain_name) //overall length check
            && preg_match("/^[^\.]{1,63}(\.[^\.]{1,63})*$/", $domain_name)   ); //length of each label
}
?>

answered Mar 20 '14 at 06:05

Sandy

23
5

1

this one accepts local domains (like "localhost") It will even accept a phone number "123-332-123" and it will reject but valid UTF 8 domains. Also you "borrowed" it from another answer. – John Nov 17 '18 at 01:54

php preg_match validate domain

3 Answers3