Question

I’ve been using this regex to validate domain names, and it does really well. I need to add a http://www. or https://www.to it. I’m afraid I’ll mess things up. It currently does not use a http://www.

Also, is there any way to bend this so it’ll reject sub-domains?

So in all it’ll be:

http://www.domain.com -> valid
www.domain.com - > Invalid (Should have the http://www. part)
http://sub.domain.com - > Invalid (Subdomain)
http://www.sub.domain.com -> Invlaid (Subdomain)

I tried doing things with the http://www. part, but ended with error. I’m clueless how to do the sub-domain reject part.

   function isurl($this_url)
    {
            if(preg_match("/^([a-z0-9]([-a-z0-9]*[a-z0-9])?\.)+((a[cdefgilmnoqrstuwxz]|aero|arpa)|(b[abdefghijmnorstvwyz]|biz)|(c[acdfghiklmnorsuvxyz]|cat|com|coop)|d[ejkmoz]|(e[ceghrstu]|edu)|f[ijkmor]|(g[abdefghilmnpqrstuwy]|gov)|h[kmnrtu]|(i[delmnoqrst]|info|int)|(j[emop]|jobs)|k[eghimnprwyz]|l[abcikrstuvy]|(m[acdghklmnopqrstuvwxyz]|mil|mobi|museum)|(n[acefgilopruz]|name|net)|(om|org)|(p[aefghklmnrstwy]|pro)|qa|r[eouw]|s[abcdeghijklmnortvyz]|(t[cdfghjklmnoprtvwz]|travel)|u[agkmsyz]|v[aceginu]|w[fs]|y[etu]|z[amw])$/i", $this_url)) 
                {
                return true;
                }

    }

    $this_url = "www.domain.com";

    if (isurl($this_url)) 
    {echo "Success";} 
    else 
    {echo "Fail";}

Answer 1

try this in htaccess

RewriteCond %{HTTP_HOST} !^(www\.)?mysite\.tld$ [NC]
RewriteRule ^ - [F,L]

RewriteCond %{HTTP_HOST} !^www\. [NC]
RewriteRule ^ http://www.%{HTTP_HOST}%{REQUEST_URI} [L,R=301]

or use this regx

/^(http?:\/\/)?([\da-z\.-]+)\.([a-z\.]{2,6})([\/\w \.-]*)*\/?$/

for perticular

   /^http?://([a-z0-9-]+\.)*blah\.com(/.*)?$/