wordpress-notices-with-nonce.php

<?php
/**
 * Proptotype
 */
namespace DoggieRescue\Notices;

class AdminNotice {
	public static function process_messages() {
		$notice = self::get_admin_message();
		if ( ! empty( $notice ) && is_array( $notice ) ) {
			$status  = \array_key_exists( 'status' , $notice) ? $notice['status'] : 'success';
			$message = \array_key_exists('message', $notice) ? $notice['message'] : '';
			$nonce   = \array_key_exists('nonce', $notice) ? $notice['nonce'] : '';
			
			if ( false === \wp_verify_nonce( $nonce, 'message_for__' . \get_current_user_id() ) ) {
				return;
			}
			?>
			<div class="notice notice-<?php echo $status ?> is-dismissible">
				<h3><?php echo \ucfirst( $status); ?></h3>
				<p><?php echo $message ?></p>
			</div>
			<?php
		}
	}

	public static function display_admin_message( $message, $status = 'success' ) {
		$user_id = get_current_user_id();
		set_transient(
			"{$user_id}_message",
			array(
				'message' => $message,
				'status'  => $status,
				'nonce'   => \wp_create_nonce( "message_for_{$user_id}"),
			)
		);
	}

	private static function get_admin_message() {
		$transient = \get_transient( \get_current_user_id() . '_message' );
		if ( $transient ) {
			\delete_transient( \get_current_user_id() . '_message' );
		}
		return $transient;
	}
}