BaseController.php

<?php
namespace backend\controllers\api;

use Yii;
use yii\web\Controller;

class BaseController extends Controller
{
    protected function readStdIn()
    {
        $data = file_get_contents('php://input');
        return $data;
    }

    protected function readStdInAsJson()
    {
        $data = $this->readStdIn();
        $json = json_decode($data);
        return $json;
    }

    protected function readStdInAsArray()
    {
        $data = $this->readStdIn();
        $json = json_decode($data, true);
        return $json;
    }

    /**
     * @inheritdoc
     */
    public function beforeAction($action)
    {
        $this->enableCsrfValidation = false;
        return parent::beforeAction($action);
    }

    public function sendResponse($data, $message = null, $exception = null)
    {
        \Yii::$app->response->format = 'json';

        $dataStatus = [ 'code' => 0, 'error' => 'OK', 'message' => $message, 'exception' => null ];
        if($exception)
        {
            $dataStatus = [
                'code' => 1,
                'error' => 'ERR_EXCEPTION',
                'message' => $message,
                'exception' => [
                    'message' => $exception->getMessage(),
                    'stackTrace' => $exception->getTraceAsString()
                ]
            ];
        }

        $outData = array_merge([
            'status' => $dataStatus,
        ], $data);

        return $outData;
    }
}