Question

Basically I wish to write my registration page in such a way that errors (such as invalid username, short password, too long username, invalid email, etc.) are returned (at the same time) when user is redirected back to the same page.

I have often seen a lot of websites that have this:

There are X errors in the data you submitted:

1. Username is too short
2. Password is too short
3. Etc. etc.

And these errors are returned when the user submits the form and is redirected back.

I thought of returning the errors via numbers in $_GET however I’d like to avoid this. And I also would like to avoid using JS/AJAX and $_SESSION.

Answer 1

With a library:

if ($_POST)
{
    $form_helper = new FormHelper();

    $form_helper->validate($_POST["username"], "username");
    $form_helper->validate($_POST["password"], "password");

    if (! $form_helper->notifications())
    {
        // Process form.
    }
}

// Show errors if necessary when rendering the form.

Without a library:

$errors = array();

if ($_POST)
{
    // Validate username by hand (let's pretend it passes).
    // Validate password by hand (let's pretend it fails).

    array_push($errors, "The username or password is incorrect.");

    if (! $errors)
    {
        // Process form.
    }
}

// Show errors if necessary when rendering the form.