Domain specific email validation - php

Question

I am trying to code a registration form where I am validating the email used to sign up.
In a nutshell, I want to ensure that the email ID used to register, is a company domain, and not something like gmail or yahoo.
I have the following code to check IF an email is a part of the given domain, how can I modify this to check that it ISNT in a given list of domains? (eg : gmail.com, yahoo.com,hotmail.com, etc).
return (bool) preg_match('/^([a-z0-9\+\_\-\.]+)#([a-z0-9\+\_\-\.]{2,})(\.[a-z]{2,4})$/i', $domain);
Im thinking it should be along these lines, but not entirely sure :
function validate($email)
{
$error = 0;
$domains = array('gmail.com','yahoo.com','hotmail.com');
foreach($domains as $key=>$value)
{
if(preg_match('/^([a-z0-9\+\_\-\.]+)#([a-z0-9\+\_\-\.]{2,})(\.[a-z]{2,4})$/i', $value)
{
$error=1;
}
}
if($error==0)
return true;
else
return false;
EDIT : I tried all the answers given here, the form still submits without a problem no matter what domain I use! (Even a non email seems to work!)
This is how I'm calling the function -
if(isset($_POST['clients_register']))
{
//Must contain only letters and numbers
if(!preg_match('/^[a-zA-Z0-9]$/', $_POST['name']))
{
$error[]='The username does not match the requirements';
}
//Password validation: must contain at least 1 letter and number. Allows characters !##$% and be 8-15 characters
if(!preg_match('/^(?=.*\d)(?=.*[A-Za-z])[0-9A-Za-z!##$%]{8,15}$/', $_POST['password']))
{
$error[]='The password does not match the requirements';
}
//Email validation
if (validateEmail($_POST['email'])==false)
{
$error[]='Invalid E-mail';
}
//Output error in array as each line
if ( count($error) > 0)
{
foreach ($error as $output) {
echo "{$output} <br>";
}
} else {
//Syntax for SQL Insert into table and Redirect user to confirmation page
}
}
Problem is, no matter what I do, the user gets redirected to the confirmation page (Even with a name made of numbers and an email like "table".

Answer 1

You should do that in a separate step. First check if the e-mailaddress has a valid syntax. Than extract the domain and see if it's not in your blacklist.
function validate($email)
{
if (!preg_match('/^([a-z0-9\+\_\-\.]+)#([a-z0-9\+\_\-\.]{2,})(\.[a-z]{2,4})$/i', $email)) return false;
$domains = array('gmail.com','yahoo.com','hotmail.com');
list(, $email_domain) = explode('#', $email, 2);
return !in_array($email_domain, $domains);
}

Answer 2

function validateEmail($email)
{
// Etc, just an array of the blacklisted domains
$blacklistDomains = ['gmail.com', 'yahoo.com', 'hotmail.com', 'googlemail.com'];
// Check if the email is valid
if (!filter_var($email, FILTER_VALIDATE_EMAIL)) {
return false;
}
// Split the email after the '#' to get the domain
$emailParts = explode('#', $email);
if (in_array(end($emailParts), $blacklistDomains)) {
return false;
}
return true;
}
You'll need a pretty big list of domains.

Answer 3

PHP
// Suposing that $email is a valid email
function validate($email) {
$invalidDomains = array('gmail.com','yahoo.com','hotmail.com');
$parts = explode('#',$email);
$domain = $parts[1];
if(!in_array($domain,$invalidDomains)) return true;
return false;
}
Let me know if it's useful.