Create a streaming download of a large file with Slim PHP using the build in Stream class

slim-stream-route.php

<?php

use Slim\Http\Request;
use Slim\Http\Response;
use Slim\Http\Stream;

$app->get('/stream', function (Request $request, Response $response, array $args) {
    // a 100mb file
    $path = '../public/files/document.pdf';

    $fh = fopen($path, 'rb');
    $file_stream = new Stream($fh);

    return $response->withBody($file_stream)
        ->withHeader('Content-Disposition', 'attachment; filename=document.pdf;') // Change to 'inline' if you want to see file
        ->withHeader('Content-Type', mime_content_type($path))
        ->withHeader('Content-Length', filesize($path));
})->setOutputBuffering(false);