guild/frontend/modules/api/controllers/TemplateController.php

<?php

namespace frontend\modules\api\controllers;

use common\models\Document;
use common\models\Template;
use Yii;
use yii\filters\auth\HttpBearerAuth;
use yii\web\NotFoundHttpException;
use yii\rest\Controller;

class TemplateController extends Controller
{
    public function behaviors(): array
    {
        $behaviors = parent::behaviors();

        $behaviors['authenticator']['authMethods'] = [
            HttpBearerAuth::className(),
        ];

        return $behaviors;
    }

    public function verbs(): array
    {
        return [
            'get-template-list' => ['get'],
            'get-template-fields' => ['get'],
        ];
    }

    public function actionGetTemplateList(): array
    {
        $document_type = Yii::$app->request->get('document_type');

        if (!empty($document_type)) {
            $template = Template::find()->where(['document_type' => $document_type])->asArray()->all();
        }
        else {
            $template = Template::find()->asArray()->all();
        }

        if(empty($template)) {
            throw new NotFoundHttpException('Documents are not assigned');
        }

        return $template;
    }

    public function actionGetTemplateFields(): array
    {
        $template_id = Yii::$app->request->get('template_id');
        if(empty($template_id) or !is_numeric($template_id))
        {
            throw new NotFoundHttpException('Incorrect template ID');
        }

        $templates = Template::find()
            ->joinWith('templateDocumentFields.field')
            ->where(['template.id' => $template_id])
            ->asArray()
            ->all();

        if(empty($templates)) {
            throw new NotFoundHttpException('Documents are not assigned');
        }

        return $templates;
    }
}