Question

In my signup form, I ask users to enter an email with the same domain name as they enter in the url field above.

Right now, I collect data this way:

URL : http://www.domain.com The domain.com part is what the user enters. The http://www is hard coded.

Email : info@ domain.com The bold part is entered by the user. The @ is hard coded.

The domain.com part in the url and domain.com part in the email should match. Right now, I can match the two fields since they are separate.

But I want to give up the above approach and make the user enter the entire domain name and email. When that’s the case, what would be a good way to check if a user entered an email with the same domain he entered in the url field above.

I’m doing all this using php.

Answer 1

    <?php

    //extract domain from email
    $email_domain_temp = explode("@", $_POST['email']);
    $email_domain = $email_domain_temp[1];

    //extract domain from url
    $url_domain_temp = parse_url($_POST['url']);
    $url_domain = strip_out_subdomain($url_domain_temp['host']);

    //compare
    if ($email_domain == $url_domain){
        //match
    }

    function strip_out_subdomain($domain){
        //do nothing if only 1 dot in $domain
        if (substr_count($domain, ".") == 1){
             return $domain;
        }
        $only_my_domain = preg_replace("/^(.*?)\.(.*)$/","$2",$domain);
        return $only_my_domain;
    }

So what this does is :

First, split the email string in 2 parts in an array. The second part is the domain.

Second, use the php built in function to parse the url, then extract the “host”, while removing the (optionnal) subdomain.

Then compare.