How do I handle and display multiple form validation errors? - php

Question

So I have a form and need to validate it. So what I'm doing is
if(empty($name) || empty($username) || empty($email) || empty($password)){
$_SESSION['comp_form'] = "Complete all fields";
header('Location: register.php');
}
if(strlen($password) < 5){
$_SESSION['pass_leng'] = "Choose a longer password";
header('Location: register.php');
}
I'm doing this because I need to display the Session on another page, but only one error gets shown. What I'm trying to do is something like this where all errors are shown at once.
Am I on the right track? Or is there another way to go about this. Because I can only display one message at a time using
$_SESSION['comp_form'] = "Complete all fields";
header('Location: register.php');
exit()

Answer 1

You can build up an array of errors during your validation, then check to see if there are errors in the array and redirect if there is. You could also use array keys to identify which field to show each error on.
Here's an example:
$errors = array();
if(empty($name) || empty($username) || empty($email) || empty($password)){
$errors['comp_form'] = "Complete all fields";
}
if(strlen($password) < 5){
$errors['pass_leng'] = "Choose a longer password";
}
// more validation here if you wish
if(count($errors) > 0) {
$_SESSION['errors'] = $errors;
header("Location: register.php");
exit;
} else {
// clean up previous validation errors, everything's fine
unset($_SESSION['errors']);
}
Then on your form you can check for errors:
<!-- add hasError class to input when validation failed to allow you to style it -->
<input type="password" name="password" class="<?php if(isset($_SESSION['errors']['pass_leng'])) echo 'hasError'; ?>">
<!-- if there's an error, output it on a generic error message element -->
<?php if(isset($_SESSION['errors']['pass_leng'])) echo '<p class="formError">' . $_SESSION['errors']['pass_leng'] . '</p>'; ?>

Answer 2

You could try something like this:
$_SESSION['error'] = 0;
if(empty($name) || empty($username) || empty($email) || empty($password)){
$_SESSION['comp_form'] = "Complete all fields";
$_SESSION['error'] = 1;
}
if(strlen($password) < 5){
$_SESSION['pass_leng'] = "Choose a longer password";
$_SESSION['error'] = 1;
}
if($_SESSION['error'] == 1){
header('Location: register.php');
}
Just unless you want to use AJAX which will improve the smoothness of your Site at the cost of using JavaScript.

Answer 3

Create an array of fields you require to be validated (which match up with their $_POST names):
$fields = array(
'name' => 'Name',
'username' => 'Username',
'email' => 'E-Mail',
'password' => 'Password'
);
Then loop over them, if they aren't valid, add them to your $_SESSION['errors'] array:
$_SESSION['errors'] = array();
foreach ($fields as $field => $niceName) {
if (empty($_POST[$field])) {
$_SESSION['errors'][$field] = $niceName . ' cannot be empty';
} elseif ($field == 'password' && strlen($_POST[$field]) < 5) {
$_SESSION['errors'][$field] = 'Choose a longer password';
}
}
Then, if $_SESSION['errors'] isn't empty, you can redirect:
if (!empty($_SESSION['errors'])) {
header('Location: register.php');
exit();
}