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Access Token Authenticator

The Access Token authenticator supports the use of revoke-able API tokens without using OAuth. These are commonly used to provide third-party developers access to your API. These tokens typically have a very long expiration time, often years.

These are also suitable for use with mobile applications. In this case, the user would register/sign-in with their email/password. The application would create a new access token for them, with a recognizable name, like John's iPhone 12, and return it to the mobile application, where it is stored and used in all future requests.

Access Token/API Authentication

Using access tokens requires that you either use/extend CodeIgniter\Shield\Models\UserModel or use the CodeIgniter\Shield\Authentication\Traits\HasAccessTokens on your own user model. This trait provides all of the custom methods needed to implement access tokens in your application. The necessary database table, auth_identities, is created in Shield's only migration class, which must be run before first using any of the features of Shield.

Generating Access Tokens

Access tokens are created through the generateAccessToken() method on the user. This takes a name to give to the token as the first argument. The name is used to display it to the user so they can differentiate between multiple tokens.

$token = $user->generateAccessToken('Work Laptop');

This creates the token using a cryptographically secure random string. The token is hashed (sha256) before saving it to the database. The method returns an instance of CodeIgniters\Shield\Authentication\Entities\AccessToken. The only time a plain text version of the token is available is in the AccessToken returned immediately after creation.

The plain text version should be displayed to the user immediately so they can copy it for their use. If a user loses it, they cannot see the raw version anymore, but they can generate a new token to use.

$token = $user->generateAccessToken('Work Laptop');

// Only available immediately after creation.
echo $token->raw_token;

Revoking Access Tokens

Access tokens can be revoked through the revokeAccessToken() method. This takes the plain-text access token as the only argument. Revoking simply deletes the record from the database.

$user->revokeAccessToken($token);

Typically, the plain text token is retrieved from the request's headers as part of the authentication process. If you need to revoke the token for another user as an admin, and don't have access to the token, you would need to get the user's access tokens and delete them manually.

If you don't have the raw token usable to remove the token there is the possibility to remove it using the tokens secret thats stored in the database. It's possible to get a list of all tokens with there secret using the accessTokens() function.

$user->revokeAccessTokenBySecret($secret);

You can revoke all access tokens with the revokeAllAccessTokens() method.

$user->revokeAllAccessTokens();

Retrieving Access Tokens

The following methods are available to help you retrieve a user's access tokens:

// Retrieve a single token by plain text token
$token = $user->getAccessToken($rawToken);

// Retrieve a single token by it's database ID
$token = $user->getAccessTokenById($id);

// Retrieve all access tokens as an array of AccessToken instances.
$tokens = $user->accessTokens();

Access Token Scopes

Each token can be given one or more scopes they can be used within. These can be thought of as permissions the token grants to the user. Scopes are provided when the token is generated and cannot be modified afterword.

$token = $user->generateAccessToken('Work Laptop', ['posts.manage', 'forums.manage']);

By default a user is granted a wildcard scope which provides access to all scopes. This is the same as:

$token = $user->generateAccessToken('Work Laptop', ['*']);

During authentication, the token the user used is stored on the user. Once authenticated, you can use the tokenCan() and tokenCant() methods on the user to determine if they have access to the specified scope.

if ($user->tokenCan('posts.manage')) {
    // do something....
}

if ($user->tokenCant('forums.manage')) {
    // do something....
}

Configuration

Configure app/Config/AuthToken.php for your needs.

Note

Shield does not expect you use the Access Token Authenticator and HMAC Authenticator at the same time. Therefore, some Config items are common.

Access Token Lifetime

Tokens will expire after a specified amount of time has passed since they have been used.

By default, this is set to 1 year. You can change this value by setting the $unusedTokenLifetime value. This is in seconds so that you can use the time constants that CodeIgniter provides.

public $unusedTokenLifetime = YEAR;

Login Attempt Logging

By default, only failed login attempts are recorded in the auth_token_logins table.

This can be modified by changing the $recordLoginAttempt value.

public int $recordLoginAttempt = Auth::RECORD_LOGIN_ATTEMPT_FAILURE;

If you don't want any logs, set it to Auth::RECORD_LOGIN_ATTEMPT_NONE.

If you want to log all login attempts, set it to Auth::RECORD_LOGIN_ATTEMPT_ALL. It means you log all requests.

Logging

Login attempts are recorded in the auth_token_logins table, according to the configuration above.

When a failed login attempt is logged, the raw token value sent is saved in the identifier column.

When a successful login attempt is logged, the token name is saved in the identifier column.