I’m building a plugin that will hide a specific payment method based on the email address or phone number typed in the checkout form by the customer.

So at first I used this JS code to catch the onChange of those two fields:

$(document).ready(function () {
    if ($('form.woocommerce-checkout').length) {
        $('#billing_phone_field, #billing_email_field').on('change', function () {
            $('body').trigger('update_checkout');
        });
    }
});

Then, I used the hook that’s appropriate for manipulating the payment methods array, that is woocommerce_available_payment_gateways in the following way:

public function update_payment_methods_based_on_user_input( $available_gateways ) {

    if ( is_admin() ) return $available_gateways;
    if ( ! is_checkout() ) return $available_gateways;

    $wp_session = isset( WC()->session ) && WC()->session->has_session() ? WC()->session : null;

    if ( is_a( $wp_session, 'WC_Session_Handler' ) ) {
        $cust_session = $wp_session->get( 'customer' );

        file_put_contents( ABSPATH . '/wp-content/cust_session.txt', print_r( $cust_session, true ) );
    }

    return $available_gateways;

}

What I was hoping with this was to catch the email address and phone number in the cust_session.txt file, to first check that they exist in the session… But they don’t as both email and phone array values are empty.

Am I doing something wrong? How am I supposed to get those two fields if not through the session?