How to Implement 'Remember Me' Functionality in a PHP Login System for Enhanced User Experience?-PHP Tutorial-php.cn

How to Implement 'Remember Me' Functionality in a PHP Login System for Enhanced User Experience?

Barbara Streisand

Release： 2024-11-10 00:06:02

Original

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How to Implement

PHP Login System with "Remember Me" Functionality [Duplicate]

To enhance the user experience, you can implement a "remember me" feature in your PHP login system, allowing users to stay logged in across multiple sessions.

Secure Cookie Storage

The best practice for storing a persistent cookie is to use a separate table in the database called auth_tokens:

CREATE TABLE `auth_tokens` (
    `id` integer(11) not null UNSIGNED AUTO_INCREMENT,
    `selector` char(12),
    `token` char(64),
    `userid` integer(11) not null UNSIGNED,
    `expires` datetime,
    PRIMARY KEY (`id`)
);

Copy after login

After Login

Upon login, generate unique random values for selector and token:

if ($login->success && $login->rememberMe) {
    $selector = base64_encode(random_bytes(9));
    $authenticator = random_bytes(33);

    setcookie(
        'remember',
        $selector . ':' . base64_encode($authenticator),
        time() + 864000, // 10 days
        '/',
        'yourdomain.com',
        true, // TLS-only
        true  // http-only
    );

    // Insert data into the database
    $database->exec(
        "INSERT INTO auth_tokens (selector, token, userid, expires) VALUES (?, ?, ?, ?)",
        [
            $selector,
            hash('sha256', $authenticator),
            $login->userId,
            date('Y-m-d\TH:i:s', time() + 864000)
        ]
    );
}

Copy after login

Re-Authentication

if (empty($_SESSION['userid']) && !empty($_COOKIE['remember'])) {
    list($selector, $authenticator) = explode(':', $_COOKIE['remember']);

    // Retrieve row from the database
    $row = $database->selectRow(
        "SELECT * FROM auth_tokens WHERE selector = ?",
        [
            $selector
        ]
    );

    // Verify hash and set session
    if (hash_equals($row['token'], hash('sha256', base64_decode($authenticator)))) {
        $_SESSION['userid'] = $row['userid'];
        // Regenerate a login token as per previous example
    }
}

Copy after login

Details

The selector provides 36 bits of collision resistance, preventing brute force attacks.
The authenticator provides ample unpredictability with 264 bits of randomness.
The hash mitigates impersonation risks after potential information leaks.
Hashing with hash_equals() prevents timing attacks.
Separating selector and authenticator optimizes database lookups.

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