csv file utilities with laravel

CSV.php

<?php
namespace App\Http\Middleware;

use Response;
use Exception;

class CSV
{
    /**
     * downlaod csv file
     * @param  string $csv_text csv-like text
     * @param  string $filename
     * @return \Illuminate\Http\Response
     */
    public static function download($csv_text, $filename = 'document.csv')
    {
        $stream = fopen('php://temp', 'r+b');
        fwrite($stream, $csv_text);
        rewind($stream);
        $csv = str_replace(PHP_EOL, "\r\n", stream_get_contents($stream));
        fclose($stream);
        // $csv = mb_convert_encoding($csv, 'SJIS-win', 'UTF-8');
        $headers = array(
            'Content-Type' => 'text/csv',
            'Content-Disposition' => "attachment; filename=$filename",
        );
        return Response::make($csv, 200, $headers);
    }

    /**
     * parse csv-like text
     * @param  string $csv_text  csv-like text
     * @return \Illuminate\Support\Collection
     */
    public static function parse($csv_text)
    {
        $lines = collect(array_map('trim', explode("\n", $csv_text)));
        $headers = collect(explode(',', $lines->first()));
        $body = $lines
            ->slice(1)
            ->map(function($item) {
                if (!trim($item)) {
                    return [];
                }
                return explode(',', $item);
            })
            ->filter();

        $combined = $body->map(function($item) use ($headers) {
            if ($headers->count() !== count($item)) {
                throw new Exception("Mismatch headers and body size.");
            }
            return $headers->combine($item);
        });

        return $combined;
    }
}