从Laravel存储下载，而无需将整个文件加载到内存中更新

php laravel

2022-08-30 13:59:22

我正在使用Laravel存储，我想为用户提供一些（大于内存限制）文件。我的代码灵感来自SO中的一篇文章，它是这样的：

$fs = Storage::getDriver();
$stream = $fs->readStream($file->path);

return response()->stream(
    function() use($stream) {
        fpassthru($stream);
    }, 
    200,
    [
        'Content-Type' => $file->mime,
        'Content-disposition' => 'attachment; filename="'.$file->original_name.'"',
    ]);

不幸的是，我遇到了一个大文件的错误：

[2016-04-21 13:37:13] production.ERROR: exception 'Symfony\Component\Debug\Exception\FatalErrorException' with message 'Allowed memory size of 134217728 bytes exhausted (tried to allocate 201740288 bytes)' in /path/app/Http/Controllers/FileController.php:131
Stack trace:
#0 /path/vendor/laravel/framework/src/Illuminate/Foundation/Bootstrap/HandleExceptions.php(133): Symfony\Component\Debug\Exception\FatalErrorException->__construct()
#1 /path/vendor/laravel/framework/src/Illuminate/Foundation/Bootstrap/HandleExceptions.php(118): Illuminate\Foundation\Bootstrap\HandleExceptions->fatalExceptionFromError()
#2 /path/vendor/laravel/framework/src/Illuminate/Foundation/Bootstrap/HandleExceptions.php(0): Illuminate\Foundation\Bootstrap\HandleExceptions->handleShutdown()
#3 /path/app/Http/Controllers/FileController.php(131): fpassthru()
#4 /path/vendor/symfony/http-foundation/StreamedResponse.php(95): App\Http\Controllers\FileController->App\Http\Controllers\{closure}()
#5 /path/vendor/symfony/http-foundation/StreamedResponse.php(95): call_user_func:{/path/vendor/symfony/http-foundation/StreamedResponse.php:95}()
#6 /path/vendor/symfony/http-foundation/Response.php(370): Symfony\Component\HttpFoundation\StreamedResponse->sendContent()
#7 /path/public/index.php(56): Symfony\Component\HttpFoundation\Response->send()
#8 /path/public/index.php(0): {main}()
#9 {main}

它似乎尝试将所有文件加载到内存中。我本来以为使用流和通行证不会这样做......我的代码中是否缺少某些内容？我是否必须以某种方式指定块大小或什么？

我使用的版本是Laravel 5.1和PHP 5.6。

答案 1

似乎输出缓冲仍在内存中积累很多。

尝试在执行 fpassthru 之前禁用 ob：

function() use($stream) {
    while(ob_get_level() > 0) ob_end_flush();
    fpassthru($stream);
},

可能是有多个输出缓冲区处于活动状态，这就是为什么需要 while 的原因。

答案 2

与其一次将整个文件加载到内存中，不如尝试使用 fread 逐块读取并发送它。

这是一篇非常好的文章：http://zinoui.com/blog/download-large-files-with-php

<?php

//disable execution time limit when downloading a big file.
set_time_limit(0);

/** @var \League\Flysystem\Filesystem $fs */
$fs = Storage::disk('local')->getDriver();

$fileName = 'bigfile';

$metaData = $fs->getMetadata($fileName);
$handle = $fs->readStream($fileName);

header('Pragma: public');
header('Expires: 0');
header('Cache-Control: must-revalidate, post-check=0, pre-check=0');
header('Cache-Control: private', false);
header('Content-Transfer-Encoding: binary');
header('Content-Disposition: attachment; filename="' . $metaData['path'] . '";');
header('Content-Type: ' . $metaData['type']);

/*
    I've commented the following line out.
    Because \League\Flysystem\Filesystem uses int for file size
    For file size larger than PHP_INT_MAX (2147483647) bytes
    It may return 0, which results in:

        Content-Length: 0

    and it stops the browser from downloading the file.

    Try to figure out a way to get the file size represented by a string.
    (e.g. using shell command/3rd party plugin?)
*/

//header('Content-Length: ' . $metaData['size']);


$chunkSize = 1024 * 1024;

while (!feof($handle)) {
    $buffer = fread($handle, $chunkSize);
    echo $buffer;
    ob_flush();
    flush();
}

fclose($handle);
exit;
?>

更新

一种更简单的方法：只需调用

if (ob_get_level()) ob_end_clean();

在返回响应之前。

@Christiaan

//disable execution time limit when downloading a big file.
set_time_limit(0);

/** @var \League\Flysystem\Filesystem $fs */
$fs = Storage::disk('local')->getDriver();

$fileName = 'bigfile';

$metaData = $fs->getMetadata($fileName);
$stream = $fs->readStream($fileName);

if (ob_get_level()) ob_end_clean();

return response()->stream(
    function () use ($stream) {
        fpassthru($stream);
    },
    200,
    [
        'Content-Type' => $metaData['type'],
        'Content-disposition' => 'attachment; filename="' . $metaData['path'] . '"',
    ]);