FRONTEND_MVC/modules/manager/controllers/StatsController.php

<?php
namespace manager\controllers;

use  manager\models\News;
use Yii;


class StatsController extends BaseController
{
    public function actionIndex()
    {
		$model = new News();
        return $this->render('index', ['model' => $model]);
    }

// месяц
    public function actionAuthors()
    {
		$model = new News();
        return $this->render('authors', ['model' => $model]);
    }

// по дням
    public function actionAuthorsd()
    {
		$model = new News();
        return $this->render('authorsd', ['model' => $model]);
    }

// по дням csv
    public function actionCsv()
    {

		if (Yii::$app->request->isGet){
			$author = Yii::$app->request->get('author');
			$m = Yii::$app->request->get('m');

			$str = $this->renderpartial('csv', ['author'=>$author, 'm'=>$m]);


			Yii::$app->response->format = \yii\web\Response::FORMAT_RAW;
			Yii::$app->response->headers->set('Content-type', ['text/csv']);
			Yii::$app->response->headers->set('Content-Transfer-Encoding', ['binary']);
			header("Pragma: no-cache");
			header("Expires: 0");
			header('Content-Disposition: attachment; filename="'.basename($author.'.csv').'"');
			header('Content-Length: ' . strlen($str));
			return $str;
		}
		return "Нет данных.";
    }

}