Checks birthday on checkout to confirm member is over 21 years.

pmpro-rh-dob-check.php

function my_pmprorh_init()
{
	//don't break if Register Helper is not loaded
	if(!function_exists( 'pmprorh_add_registration_field' )) {
		return false;
	}
	
	//define the fields
	$fields = array();
	$fields[] = new PMProRH_Field(
		'dob',
		'date',
		array(
			'label'		=> 'Birthday',
			'size'		=> 40,
			'profile'	=> true,
			'required'	=> true,
			'hint'		 => 'You must be over 21 to signup.',

		)
	);

	
	//add the fields into a new checkout_boxes are of the checkout page
	foreach($fields as $field)
		pmprorh_add_registration_field(
			'checkout_boxes',				// location on checkout page
			$field						// PMProRH_Field object
		);function my_pmprorh_init()
{
	//don't break if Register Helper is not loaded
	if(!function_exists( 'pmprorh_add_registration_field' )) {
		return false;
	}
	
	//define the fields
	$fields = array();
	$fields[] = new PMProRH_Field(
		'dob',
		'date',
		array(
			'label'		=> 'Birthday',
			'size'		=> 40,
			'profile'	=> true,
			'required'	=> true,
			'hint'		 => 'You must be over 21 to signup.',

		)
	);

	
	//add the fields into a new checkout_boxes are of the checkout page
	foreach($fields as $field)
		pmprorh_add_registration_field(
			'checkout_boxes',				// location on checkout page
			$field						// PMProRH_Field object
		);
	//that's it. see the PMPro Register Helper readme for more information and examples.
}
add_action( 'init', 'my_pmprorh_init' );

//require the fields
function my_pmpro_registration_checks()
{
	global $pmpro_msg, $pmpro_msgt, $current_user;
	$birthday = $_REQUEST['dob'];
		
	$month =str_pad($birthday['m'], 2, '0', STR_PAD_LEFT);
	$day = str_pad($birthday['d'], 2, '0', STR_PAD_LEFT);
	$year = $birthday['y'];
	
	$age = get_age($year.'-'.$month.'-'.$day);
	
	if(!validateDate($year.'-'.$month.'-'.$day))
	{
		$pmpro_msg = "Please enter a valid birthday";
		$pmpro_msgt = "pmpro_error";
		return false;
	}
	
	if($age > 20 || $current_user->ID)
	{
		//all good
		return true;
	}
	else
	{
		$pmpro_msg = "You must be over 21 years old to signup";
		$pmpro_msgt = "pmpro_error";
		return false;
	}
}
add_filter("pmpro_registration_checks", "my_pmpro_registration_checks");


//Taken from: http://gazelleincorporated.com/how-to-calculate-age-from-date-of-birth-in-php
//$dob = birthdate in the form "YYYY-MM-DD"
//Extract the month, day and year from the $dob
//Compare to current month, day, year to get AGE
function get_age($dob) 
{ 
        $dob=explode("-",$dob); 
        $curMonth = date("m");
        $curDay = date("j");
        $curYear = date("Y");
        $age = $curYear - $dob[0]; 
        if($curMonth<$dob[1] || ($curMonth==$dob[1] && $curDay<$dob[2])) 
                $age--; 
        return $age; 
}


//Taken from: https://stackoverflow.com/questions/19271381/correctly-determine-if-date-string-is-a-valid-date-in-that-format
function validateDate($date, $format = 'Y-m-d')
{
    $d = DateTime::createFromFormat($format, $date);
    return $d && $d->format($format) == $date;
}

	//that's it. see the PMPro Register Helper readme for more information and examples.
}
add_action( 'init', 'my_pmprorh_init' );

//require the fields
function my_pmpro_registration_checks()
{
	global $pmpro_msg, $pmpro_msgt, $current_user;
	$birthday = $_REQUEST['dob'];
	
	$age = get_age($birthday['y'].'-'.$birthday['m'].'-'.$birthday['d']);

	if($age > 20 || $current_user->ID)
	{
		//all good
		return true;
	}
	else
	{
		$pmpro_msg = "You must be over 21 years old to signup";
		$pmpro_msgt = "pmpro_error";
		return false;
	}
}
add_filter("pmpro_registration_checks", "my_pmpro_registration_checks");


//Taken from: http://gazelleincorporated.com/how-to-calculate-age-from-date-of-birth-in-php
//$dob = birthdate in the form "YYYY-MM-DD"
//Extract the month, day and year from the $dob
//Compare to current month, day, year to get AGE
function get_age($dob) 
{ 
        $dob=explode("-",$dob); 
        $curMonth = date("m");
        $curDay = date("j");
        $curYear = date("Y");
        $age = $curYear - $dob[0]; 
        if($curMonth<$dob[1] || ($curMonth==$dob[1] && $curDay<$dob[2])) 
                $age--; 
        return $age; 
}