Реализован обработчик для смены языка аккаунта

api/controllers/AccountsController.php

@@ -4,6 +4,7 @@ namespace api\controllers;
 use api\models\profile\ChangeEmail\ConfirmNewEmailForm;
 use api\models\profile\ChangeEmail\InitStateForm;
 use api\models\profile\ChangeEmail\NewEmailForm;
+use api\models\profile\ChangeLanguageForm;
 use api\models\profile\ChangePasswordForm;
 use api\models\profile\ChangeUsernameForm;
 use common\models\Account;
@@ -30,6 +31,7 @@ class AccountsController extends Controller {
                             'change-email-initialize',
                             'change-email-submit-new-email',
                             'change-email-confirm-new-email',
+                            'change-lang',
                         ],
                         'allow' => true,
                         'roles' => ['@'],
@@ -52,6 +54,7 @@ class AccountsController extends Controller {
             'change-email-initialize' => ['POST'],
             'change-email-submit-new-email' => ['POST'],
             'change-email-confirm-new-email' => ['POST'],
+            'change-lang' => ['POST'],
         ];
     }
 
@@ -157,4 +160,21 @@ class AccountsController extends Controller {
         ];
     }
 
+    public function actionChangeLang() {
+        /** @var Account $account */
+        $account = Yii::$app->user->identity;
+        $model = new ChangeLanguageForm($account);
+        $model->load(Yii::$app->request->post());
+        if (!$model->applyLanguage()) {
+            return [
+                'success' => false,
+                'errors' => $this->normalizeModelErrors($model->getErrors()),
+            ];
+        }
+
+        return [
+            'success' => true,
+        ];
+    }
+
 }

api/models/profile/ChangeLanguageForm.php

@@ -0,0 +1,45 @@
+<?php
+namespace api\models\profile;
+
+use api\models\base\ApiForm;
+use common\models\Account;
+use common\validators\LanguageValidator;
+use yii\base\ErrorException;
+
+class ChangeLanguageForm extends ApiForm {
+
+    public $lang;
+
+    private $account;
+
+    public function __construct(Account $account, array $config = []) {
+        $this->account = $account;
+        parent::__construct($config);
+    }
+
+    public function rules() {
+        return [
+            ['lang', 'required'],
+            ['lang', LanguageValidator::class],
+        ];
+    }
+
+    public function applyLanguage() : bool {
+        if (!$this->validate()) {
+            return false;
+        }
+
+        $account = $this->getAccount();
+        $account->lang = $this->lang;
+        if (!$account->save()) {
+            throw new ErrorException('Cannot change user language');
+        }
+
+        return true;
+    }
+
+    public function getAccount() : Account {
+        return $this->account;
+    }
+
+}