php - Download from Laravel storage without loading whole file in memory

Question

I am using Laravel Storage and I want to serve users some (larger than memory limit) files. My code was inspired from a post in SO and it goes like this:

$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.'"',
    ]);

Unfourtunately, I run into an error for large files:

[2016-04-21 13:37:13] production.ERROR: exception 'SymfonyComponentDebugExceptionFatalErrorException' 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): SymfonyComponentDebugExceptionFatalErrorException->__construct()
#1 /path/vendor/laravel/framework/src/Illuminate/Foundation/Bootstrap/HandleExceptions.php(118): IlluminateFoundationBootstrapHandleExceptions->fatalExceptionFromError()
#2 /path/vendor/laravel/framework/src/Illuminate/Foundation/Bootstrap/HandleExceptions.php(0): IlluminateFoundationBootstrapHandleExceptions->handleShutdown()
#3 /path/app/Http/Controllers/FileController.php(131): fpassthru()
#4 /path/vendor/symfony/http-foundation/StreamedResponse.php(95): AppHttpControllersFileController->AppHttpControllers{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): SymfonyComponentHttpFoundationStreamedResponse->sendContent()
#7 /path/public/index.php(56): SymfonyComponentHttpFoundationResponse->send()
#8 /path/public/index.php(0): {main}()
#9 {main}  

It seems that it tries to load all of the file into memory. I was expecting that usage of stream and passthru would not do this... Is there something missing in my code? Do I have to somehow specify chunk size or what?

The versions I am using are Laravel 5.1 and PHP 5.6.

Answer 1

It seems that output buffering is still building up a lot in memory.

Try disabling ob before doing the fpassthru:

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

It could be that there are multiple output buffers active that is why the while is needed.