Yii 登录的用户资料来自API，我应如何保存用户资料 [ 2.0 版本 ]

我使用的Yii2 basic 2.0.9。登录使用的基础模板的登录，我修改了models\LoginForm.php中的login(),登录的用户资料是从API中请求过来的。因为在site/login()中登录成功之后var_dump(Yii::$app->user);，输出的结果有API返回的user资料，调到site/index之后，再输出var_dump(Yii::$app->user);输出的结果没有user的资料。百度和谷歌之后，很多登录案例是使用db的。

我的问题是：我应该如何正确保存API返回的用户信息保存到session中，在其它页面var_dump(Yii::$app->user);输出也能输出用户资料。

models\LoginForm.php的login()方法。

/**
 * Logs in a user using the provided username and password.
 * @return boolean whether the user is logged in successfully
 */
public function login()
{
    if ($this->validate()) {
        //return Yii::$app->user->login($this->getUser(), $this->rememberMe ? 3600*24*30 : 0);
        try{
            //GuzzleHttp\Client
            $client = new Client(['base_url'=>API_HOST.API_HOST_POSTFIX]);
            $response = $client->get('wp-api-registration/v2/registration',[
                'query'=>['username'=>$this->username,'password'=>$this->password]
            ]);
            $result = $response->json();
            $this->_user = User::getUserIdentity($result);
            return Yii::$app->user->login($this->_user);
        }catch (RequestException $e){
            //当不正确的时候
            if ($e->hasResponse() && $e->getCode() == 400) {
                $responseBody = json_decode($e->getResponse()->getBody());
                if($responseBody->code == 'json_login_error'){
                    $this->addError('username', '用戶名或者密碼不正確.');
                }
            }else{
                echo $e->getResponse();
            }
        }

    }
    return false;
}

models\User.php类:

<?php

namespace app\models;

class User extends \yii\base\Object implements \yii\web\IdentityInterface
{
    public $id;
    public $name;
    public $first_name;
    public $last_name;
    public $email;
    public $url;
    public $description;
    public $link;
    public $nickname;
    public $slug;
    public $registered_date;
    public $roles;
    public $capabilities;
    public $extra_capabilities;
    public $username;
    public $password;
    public $authKey;
    public $accessToken;

    public static function getUserIdentity($data){
        return new static($data);
    }

    /**
     * @inheritdoc
     */
    public static function findIdentity($id)
    {

    }

    /**
     * @inheritdoc
     */
    public static function findIdentityByAccessToken($token, $type = null)
    {

    }

    /**
     * Finds user by username
     *
     * @param string $username
     * @return static|null
     */
    public static function findByUsername($username)
    {

    }


    /**
     * @inheritdoc
     */
    public function getId()
    {
        return $this->id;
    }

    /**
     * @inheritdoc
     */
    public function getAuthKey()
    {

    }

    /**
     * @inheritdoc
     */
    public function validateAuthKey($authKey)
    {

    }

}

API返回结果是:

    {
        "id": 1,
        "username": "admin",
        "name": "admin",
        "first_name": "",
        "last_name": "",
        "email": "test@test.com",
        "url": "",
        "description": "",
        "link": "http://192.168.1.119/wordpress/blog/author/admin/",
        "nickname": "admin",
        "slug": "admin",
        "registered_date": "2016-06-25T02:31:45+00:00",
        "roles":
        [
            "administrator"
        ],
        "capabilities":
        {
            "switch_themes": true,
            "edit_themes": true,
            "activate_plugins": true,
            "edit_plugins": true,
            "edit_users": true,
            "edit_files": true,
            "manage_options": true,
            "moderate_comments": true,
            "manage_categories": true,
            "manage_links": true,
            "upload_files": true,
            "import": true,
            "unfiltered_html": true,
            "edit_posts": true,
            "edit_others_posts": true,
            "edit_published_posts": true,
            "publish_posts": true,
            "edit_pages": true,
            "read": true,
            "level_10": true,
            "level_9": true,
            "level_8": true,
            "level_7": true,
            "level_6": true,
            "level_5": true,
            "level_4": true,
            "level_3": true,
            "level_2": true,
            "level_1": true,
            "level_0": true,
            "edit_others_pages": true,
            "edit_published_pages": true,
            "publish_pages": true,
            "delete_pages": true,
            "delete_others_pages": true,
            "delete_published_pages": true,
            "delete_posts": true,
            "delete_others_posts": true,
            "delete_published_posts": true,
            "delete_private_posts": true,
            "edit_private_posts": true,
            "read_private_posts": true,
            "delete_private_pages": true,
            "edit_private_pages": true,
            "read_private_pages": true,
            "delete_users": true,
            "create_users": true,
            "unfiltered_upload": true,
            "edit_dashboard": true,
            "update_plugins": true,
            "delete_plugins": true,
            "install_plugins": true,
            "update_themes": true,
            "install_themes": true,
            "update_core": true,
            "list_users": true,
            "remove_users": true,
            "promote_users": true,
            "edit_theme_options": true,
            "delete_themes": true,
            "export": true,
            "administrator": true
        },
        "extra_capabilities":
        {
            "administrator": true
        }
    }