day_13_signup_process.php

<?php

	if (isset($_POST['signup_submit'])) {
		include_once '../includes/dbconnection.php';

		$name = mysqli_real_escape_string($conn, $_POST['name']);
		$email = mysqli_real_escape_string($conn, $_POST['email']);
		$username = mysqli_real_escape_string($conn, $_POST['username']);
		$password = mysqli_real_escape_string($conn, $_POST['password']);

		if(empty($name) || empty($email) || empty($username) || empty($password)) {
			header("Location: signup.php?error=empty_fields");
			exit;
		} else {
			// Check if input characters are valid
			if(!preg_match("/^[a-zA-Z]*$/", $name) || !preg_match("/^[a-zA-Z]*$/", $username)) {
				header("Location: signup.php?error=char_error");
				exit;
			} else {
				if(!filter_var($email, FILTER_VALIDATE_EMAIL)) {
					header("Location: signup.php?error=email_error");
					exit;
				} else {
					header("Location: signup.php?error=success");
					exit;
				}
			}
		}


	} else {
		header('Location: signup.php');
		exit;
	}