LoginLink.md

One Time Login Links

Send your user(s) an email with a login link. Usually thats your login action with ?token={token} appended.

You can generate one using:

$tokensTable = $this->fetchTable('Tools.Tokens');
$token = $tokensTable->newKey('login_link', null, $user->id);

If you want a custom token to be used:

$token = $tokensTable->newKey('login_link', '123', $user->id);

Then, implement your authenticator on the other side in your Application.php:

$service->loadIdentifier('Tools.LoginLink', [
    'resolver' => [
        'className' => 'Authentication.Orm',
    ],
]);

// Session, Form, Cookie first
$service->loadAuthenticator('Tools.LoginLink', [
    'loginUrl' => [
        'prefix' => false,
        'plugin' => false,
        'controller' => 'Account',
        'action' => 'login',
    ],
    'urlChecker' => 'Authentication.CakeRouter',
]);

Now you should be able to log your users in on top of classic form login.

Note: It is advised to set a url here, and to the login url. This way it will not collide with other pages and possible token query strings.

Email confirmation

When you not just send login link emails to already verified users, but if you replace the registration login process with such quick-logins, you will need to use a callback to set the email active when the authenticator gets called. This way your custom finder (e.g. 'active') will actually find the user then.

$service->loadIdentifier('Tools.LoginLink', [
    'resolver' => [
        'className' => 'Authentication.Orm',
        'finder' => 'active',
    ],
    'preCallback' => function (int $id) {
        TableRegistry::getTableLocator()->get('Users')->confirmEmail($id);
    },
]);

Here you want to additionally confirm that the email matches. So make sure to add that to the Token content:

$token = TableRegistry::getTableLocator()->get('Tools.Tokens')
    ->newKey('login_link', null, $user->id, $user->email);

Sending mails via queue

It is highly advised to do any (email) sending here via queue. Just add the $token into it and you are good to go:

$queuedJobsTable = TableRegistry::getTableLocator()->get('Queue.QueuedJobs');
$token = ...;
$email = $user->email;
$data = [
    'to' => $user->email,
    'toName' => $user->full_name,
    'subject' => __('Login link'),
    'template' => 'login_link',
    'vars' => compact('email', 'token'),
];
$queuedJobsTable->createJob('Email', $data); // Your Email queue task

Put this in the email template (linking to your login action):

<?= $this->Url->build(['controller' => 'Account', 'action' => 'login', '?' => ['token' => $token]], ['fullBase' => true]) ?>