Yii - Authentication

The process of verifying the identity of a user is called authentication. It usually uses a username and a password to judge whether the user is one who he claims as.

To use the Yii authentication framework, you need to −

Configure the user apppcation component.

Implement the yiiwebIdentityInterface interface.

The basic apppcation template comes with a built-in authentication system. It uses the user apppcation component as shown in the following code −

<?php
   $params = require(__DIR__ .  /params.php );
   $config = [
       id  =>  basic ,
       basePath  => dirname(__DIR__),
       bootstrap  => [ log ],
       components  => [
          request  => [
            // !!! insert a secret key in the following (if it is empty) - this
               //is required by cookie vapdation
             cookieVapdationKey  =>  ymoaYrebZHa8gURuopoHGlK8fLXCKjO ,
         ],
          cache  => [
             class  =>  yiicachingFileCache ,
         ],
          user  => [
             identityClass  =>  appmodelsUser ,
             enableAutoLogin  => true,
         ],
         //other components...
          db  => require(__DIR__ .  /db.php ),
      ],
       modules  => [
          hello  => [
             class  =>  appmoduleshelloHello ,
         ],
      ],
       params  => $params,
   ];
   if (YII_ENV_DEV) {
      // configuration adjustments for  dev  environment
      $config[ bootstrap ][] =  debug ;
      $config[ modules ][ debug ] = [
          class  =>  yiidebugModule ,
      ];
      $config[ bootstrap ][] =  gii ;
      $config[ modules ][ gii ] = [
          class  =>  yiigiiModule ,
      ];
   }
   return $config;
?>

In the above configuration, the identity class for user is configured to be appmodelsUser.

The identity class must implement the yiiwebIdentityInterface with the following methods −

findIdentity() − Looks for an instance of the identity class using the specified user ID.

findIdentityByAccessToken() − Looks for an instance of the identity class using the specified access token.

getId() − It returns the ID of the user.

getAuthKey() − Returns a key used to verify cookie-based login.

vapdateAuthKey() − Implements the logic for verifying the cookie-based login key.

The User model from the basic apppcation template implements all the above functions. User data is stored in the $users property −

<?php
   namespace appmodels;
   class User extends yiiaseObject implements yiiwebIdentityInterface {
      pubpc $id;
      pubpc $username;
      pubpc $password;
      pubpc $authKey;
      pubpc $accessToken;
      private static $users = [
          100  => [
             id  =>  100 ,
             username  =>  admin ,
             password  =>  admin ,
             authKey  =>  test100key ,
             accessToken  =>  100-token ,
         ],
          101  => [
             id  =>  101 ,
             username  =>  demo ,
             password  =>  demo ,
             authKey  =>  test101key ,
             accessToken  =>  101-token ,
         ],
      ];
      /**
      * @inheritdoc
      */
      pubpc static function findIdentity($id) {
         return isset(self::$users[$id]) ? new static(self::$users[$id]) : null;
      }
      /**
      * @inheritdoc
      */
      pubpc static function findIdentityByAccessToken($token, $type = null) {
         foreach (self::$users as $user) {
            if ($user[ accessToken ] === $token) {
               return new static($user);
            }
         }
         return null;
      }
      /**
      * Finds user by username
      *
      * @param string $username
      * @return static|null
      */
      pubpc static function findByUsername($username) {
         foreach (self::$users as $user) {
            if (strcasecmp($user[ username ], $username) === 0) {
               return new static($user);
            }
         }
         return null;
      }
      /**
      * @inheritdoc
      */
      pubpc function getId() {
         return $this->id;
      }
      /**
      * @inheritdoc
      */
      pubpc function getAuthKey() {
         return $this->authKey;
      }
      /**
      * @inheritdoc
      */
      pubpc function vapdateAuthKey($authKey) {
         return $this->authKey === $authKey;
      }
      /**
      * Vapdates password 
      *
      * @param string $password password to vapdate
      * @return boolean if password provided is vapd for current user
      */
      pubpc function vapdatePassword($password) {
         return $this->password === $password;
      }
   }
?>

Step 1 − Go to the URL http://localhost:8080/index.php?r=site/login and log in into the web site using admin for a login and a password.

Step 2 − Then, add a new function called actionAuth() to the SiteController.

pubpc function actionAuth(){
   // the current user identity. Null if the user is not authenticated.
   $identity = Yii::$app->user->identity;
   var_dump($identity);
   // the ID of the current user. Null if the user not authenticated.
   $id = Yii::$app->user->id;
   var_dump($id);
   // whether the current user is a guest (not authenticated)
   $isGuest = Yii::$app->user->isGuest;
   var_dump($isGuest);
}

Step 3 − Type the address http://localhost:8080/index.php?r=site/auth in the web browser, you will see the detailed information about admin user.

Step 4 − To login and logou,t a user you can use the following code.

pubpc function actionAuth() {
   // whether the current user is a guest (not authenticated)
   var_dump(Yii::$app->user->isGuest);
   // find a user identity with the specified username.
   // note that you may want to check the password if needed
   $identity = User::findByUsername("admin");
   // logs in the user
   Yii::$app->user->login($identity);
   // whether the current user is a guest (not authenticated)
   var_dump(Yii::$app->user->isGuest);
   Yii::$app->user->logout();
   // whether the current user is a guest (not authenticated)
   var_dump(Yii::$app->user->isGuest);
}

At first, we check whether a user is logged in. If the value returns false, then we log in a user via the Yii::$app → user → login() call, and log him out using the Yii::$app → user → logout() method.

Step 5 − Go to the URL http://localhost:8080/index.php?r=site/auth, you will see the following.

The yiiwebUser class raises the following events −

EVENT_BEFORE_LOGIN − Raised at the beginning of yiiwebUser::login()

EVENT_AFTER_LOGIN − Raised after a successful login

EVENT_BEFORE_LOGOUT − Raised at the beginning of yiiwebUser::logout()

EVENT_AFTER_LOGOUT − Raised after a successful logout