|
|
|
Authentication
|
|
|
|
==============
|
|
|
|
|
|
|
|
Unlike Web applications, RESTful APIs are usually stateless, which means sessions or cookies should not
|
|
|
|
be used. Therefore, each request should come with some sort of authentication credentials because
|
|
|
|
the user authentication status may not be maintained by sessions or cookies. A common practice is
|
|
|
|
to send a secret access token with each request to authenticate the user. Since an access token
|
|
|
|
can be used to uniquely identify and authenticate a user, **API requests should always be sent
|
|
|
|
via HTTPS to prevent man-in-the-middle (MitM) attacks**.
|
|
|
|
|
|
|
|
There are different ways to send an access token:
|
|
|
|
|
|
|
|
* [HTTP Basic Auth](http://en.wikipedia.org/wiki/Basic_access_authentication): the access token
|
|
|
|
is sent as the username. This should only be used when an access token can be safely stored
|
|
|
|
on the API consumer side. For example, the API consumer is a program running on a server.
|
|
|
|
* Query parameter: the access token is sent as a query parameter in the API URL, e.g.,
|
|
|
|
`https://example.com/users?access-token=xxxxxxxx`. Because most Web servers will keep query
|
|
|
|
parameters in server logs, this approach should be mainly used to serve `JSONP` requests which
|
|
|
|
cannot use HTTP headers to send access tokens.
|
|
|
|
* [OAuth 2](http://oauth.net/2/): the access token is obtained by the consumer from an authorization
|
|
|
|
server and sent to the API server via [HTTP Bearer Tokens](http://tools.ietf.org/html/rfc6750),
|
|
|
|
according to the OAuth2 protocol.
|
|
|
|
|
|
|
|
Yii supports all of the above authentication methods. You can also easily create new authentication methods.
|
|
|
|
|
|
|
|
To enable authentication for your APIs, do the following steps:
|
|
|
|
|
|
|
|
1. Configure the `user` application component:
|
|
|
|
- Set the [[yii\web\User::enableSession|enableSession]] property to be `false`.
|
|
|
|
- Set the [[yii\web\User::loginUrl|loginUrl]] property to be `null` to show a HTTP 403 error instead of redirecting to the login page.
|
|
|
|
2. Specify which authentication methods you plan to use by configuring the `authenticator` behavior
|
|
|
|
in your REST controller classes.
|
|
|
|
3. Implement [[yii\web\IdentityInterface::findIdentityByAccessToken()]] in your [[yii\web\User::identityClass|user identity class]].
|
|
|
|
|
|
|
|
Step 1 is not required but is recommended for RESTful APIs which should be stateless. When [[yii\web\User::enableSession|enableSession]]
|
|
|
|
is false, the user authentication status will NOT be persisted across requests using sessions. Instead, authentication
|
|
|
|
will be performed for every request, which is accomplished by Step 2 and 3.
|
|
|
|
|
|
|
|
> Tip: You may configure [[yii\web\User::enableSession|enableSession]] of the `user` application component
|
|
|
|
in application configurations if you are developing RESTful APIs in terms of an application. If you develop
|
|
|
|
RESTful APIs as a module, you may put the following line in the module's `init()` method, like the following:
|
|
|
|
> ```php
|
|
|
|
public function init()
|
|
|
|
{
|
|
|
|
parent::init();
|
|
|
|
\Yii::$app->user->enableSession = false;
|
|
|
|
}
|
|
|
|
```
|
|
|
|
|
|
|
|
For example, to use HTTP Basic Auth, you may configure the `authenticator` behavior as follows,
|
|
|
|
|
|
|
|
```php
|
|
|
|
use yii\filters\auth\HttpBasicAuth;
|
|
|
|
|
|
|
|
public function behaviors()
|
|
|
|
{
|
|
|
|
$behaviors = parent::behaviors();
|
|
|
|
$behaviors['authenticator'] = [
|
|
|
|
'class' => HttpBasicAuth::className(),
|
|
|
|
];
|
|
|
|
return $behaviors;
|
|
|
|
}
|
|
|
|
```
|
|
|
|
|
|
|
|
If you want to support all three authentication methods explained above, you can use `CompositeAuth` like the following,
|
|
|
|
|
|
|
|
```php
|
|
|
|
use yii\filters\auth\CompositeAuth;
|
|
|
|
use yii\filters\auth\HttpBasicAuth;
|
|
|
|
use yii\filters\auth\HttpBearerAuth;
|
|
|
|
use yii\filters\auth\QueryParamAuth;
|
|
|
|
|
|
|
|
public function behaviors()
|
|
|
|
{
|
|
|
|
$behaviors = parent::behaviors();
|
|
|
|
$behaviors['authenticator'] = [
|
|
|
|
'class' => CompositeAuth::className(),
|
|
|
|
'authMethods' => [
|
|
|
|
HttpBasicAuth::className(),
|
|
|
|
HttpBearerAuth::className(),
|
|
|
|
QueryParamAuth::className(),
|
|
|
|
],
|
|
|
|
];
|
|
|
|
return $behaviors;
|
|
|
|
}
|
|
|
|
```
|
|
|
|
|
|
|
|
Each element in `authMethods` should be an auth method class name or a configuration array.
|
|
|
|
|
|
|
|
|
|
|
|
Implementation of `findIdentityByAccessToken()` is application specific. For example, in simple scenarios
|
|
|
|
when each user can only have one access token, you may store the access token in an `access_token` column
|
|
|
|
in the user table. The method can then be readily implemented in the `User` class as follows,
|
|
|
|
|
|
|
|
```php
|
|
|
|
use yii\db\ActiveRecord;
|
|
|
|
use yii\web\IdentityInterface;
|
|
|
|
|
|
|
|
class User extends ActiveRecord implements IdentityInterface
|
|
|
|
{
|
|
|
|
public static function findIdentityByAccessToken($token, $type = null)
|
|
|
|
{
|
|
|
|
return static::findOne(['access_token' => $token]);
|
|
|
|
}
|
|
|
|
}
|
|
|
|
```
|
|
|
|
|
|
|
|
After authentication is enabled as described above, for every API request, the requested controller
|
|
|
|
will try to authenticate the user in its `beforeAction()` step.
|
|
|
|
|
|
|
|
If authentication succeeds, the controller will perform other checks (such as rate limiting, authorization)
|
|
|
|
and then run the action. The authenticated user identity information can be retrieved via `Yii::$app->user->identity`.
|
|
|
|
|
|
|
|
If authentication fails, a response with HTTP status 401 will be sent back together with other appropriate headers
|
|
|
|
(such as a `WWW-Authenticate` header for HTTP Basic Auth).
|
|
|
|
|
|
|
|
|
|
|
|
## Authorization <a name="authorization"></a>
|
|
|
|
|
|
|
|
After a user is authenticated, you probably want to check if he or she has the permission to perform the requested
|
|
|
|
action for the requested resource. This process is called *authorization* which is covered in detail in
|
|
|
|
the [Authorization section](security-authorization.md).
|
|
|
|
|
|
|
|
If your controllers extend from [[yii\rest\ActiveController]], you may override
|
|
|
|
the [[yii\rest\Controller::checkAccess()|checkAccess()]] method to perform authorization check. The method
|
|
|
|
will be called by the built-in actions provided by [[yii\rest\ActiveController]].
|