banki.test/controllers/ApiController.php

<?php

namespace app\controllers;
use app\models\Parameter;
use app\models\Image;
use yii\filters\ContentNegotiator;
use yii\web\NotFoundHttpException;
use yii\web\Request;
use yii\web\Response;

class ApiController extends \yii\rest\Controller
{
    public function actionIndex()
    {
        return Parameter::find()->with(['icon', 'iconGray'])->all();
    }

    public function actionImage(Request $request, Response $response)
    {
        $img = Image::find()->where([ 'sha256' => $request->getQueryParam('sha256') ])->one();
        if (!$img) {
            throw new NotFoundHttpException();
        }

        $response->headers->set('Content-Type', $img->mime);
        $response->headers->set('X-Image-Data', json_encode($img->getAttributes()));
        return $response->sendFile(env('UPLOADS_PATH') . '/' . $img->sha256, $img->original_name);
    }

    public function verbs()
    {
        return [
            'index' => [ 'GET' ],
        ];
    }

    public function behaviors()
    {
        return [
            [
                'class' => ContentNegotiator::class,
                'formats' => [
                    'image/*' => Response::FORMAT_RAW,
                    'application/json' => Response::FORMAT_JSON
                ]
            ]
        ];
    }
}