add some api method

frontend/modules/api/controllers/DocumentFieldValueController.php

@@ -0,0 +1,53 @@
+<?php
+
+namespace frontend\modules\api\controllers;
+
+use common\models\Document;
+use common\models\DocumentFieldValue;
+use Yii;
+use yii\filters\auth\HttpBearerAuth;
+use yii\web\NotFoundHttpException;
+use yii\rest\Controller;
+
+class DocumentFieldValueController extends Controller
+{
+    public function behaviors(): array
+    {
+        $behaviors = parent::behaviors();
+
+        $behaviors['authenticator']['authMethods'] = [
+            HttpBearerAuth::className(),
+        ];
+
+        return $behaviors;
+    }
+
+    public function verbs(): array
+    {
+        return [
+//            'get-task' => ['get'],
+            'document-field-value-list' => ['get'],
+//            'create-task' => ['post'],
+//            'update-task' => ['put', 'patch'],
+        ];
+    }
+
+    public function actionDocumentFieldValueList(): array
+    {
+        $document_id = Yii::$app->request->get('document_id');
+        if(empty($document_id) or !is_numeric($document_id))
+        {
+            throw new NotFoundHttpException('Incorrect document ID');
+        }
+
+        $fieldValues = DocumentFieldValue::find()
+            ->where(['document_id' => $document_id])
+            ->all();
+
+        if(empty($fieldValues)) {
+            throw new NotFoundHttpException('There is no such fields');
+        }
+
+        return $fieldValues;
+    }
+}