BinaryFileResponse doesn't work unless prepare is called

[iluuu1994]

Symfony version(s) affected: 3.4.14

Description

I'm using the HttpFoundation component to stream binary files. I'm using the basic snipped underneath which produces no output. The reason for this is this line.

stream_copy_to_stream has the following signature:

int stream_copy_to_stream(resource $source, resource $dest[, int $maxlength = -1[, int $offset = 0]])

The maxlen and offset properties are only actually ever set in the prepare method. Thus Symfony passes null to both of these parameters unless prepared is called. PHP will not do anything if these properties are null:

https://3v4l.org/MtBl7

How to reproduce

$response = new BinaryFileResponse($filepath);
$response->send();

Possible Solution

The solution is to call prepare on the response. The docs do mention the prepare method but don't say that it's mandatory.

$response = new BinaryFileResponse($filepath);
$response->prepare(Request::createFromGlobals());
$response->send();

Symfony should either:

• Be clearer in the documentation that prepare is necessary
• Throw an error when maxlength or offset are null
• Default to -1 and 0 as the default values

[j4nr6n]

Hey @iluuu1994

I apologize if I'm misunderstanding you. I tried to reproduce your error, but I wasn't able to.

One thing I wasn't clear on, is whether you are using the Symfony framework or just the HttpFoundation component. In the first situation, you can simply return your BinaryFileResponse object instead of calling ->send() on it. The ResponseListener in the HttpKernel component calls prepare() for you.

[j4nr6n]

But the HttpFoundation component docs does mention prepare() a little further up the page.

[iluuu1994]

@WackyMole When using the Symfony kernel Symfony will always calls prepare on the response under the hood:

symfony/src/Symfony/Component/HttpKernel/EventListener/ResponseListener.php

Line 47 in 4e4b216

$response->prepare($event->getRequest());

I'm using the BinaryFileResponse in a non Symfony project. Try just the send but without prepare.

[j4nr6n]

I did, and I do see your error in that case.

[iluuu1994]

@WackyMole Ok 👍 The docs do not mention that prepare needs to be called. That would be a valid solution to this issue.

[j4nr6n]

Well, it wasn't the error I thought it was. This works.

$response = new BinaryFileResponse(__DIR__.'/Test.txt');
$response->setContentDisposition(
    ResponseHeaderBag::DISPOSITION_ATTACHMENT,
    'filename.txt'
);
$response->send();

[iluuu1994]

@WackyMole Can you try it completely without a Symfony kernel? In a standalone .php file with nothing but the lines from the previous comment?

[j4nr6n]

Sure can. This was created as a single index.php and a test.txt with the only dependency being symfony/http-foundation@3.4.14. Setting the content disposition makes it a download rather than open in browser (at least in Chrome). I guess the alternative is to call prepare().

P.S. Do you know how many hello (x).txt files I have in my downloads directory now?

[iluuu1994]

@WackyMole

P.S. Do you know how many hello (x).txt files I have in my downloads directory now?

😂

I can reproduce my problem with your example. The file is downloaded (as the content disposition header is set correctly) but the file is empty because stream_copy_to_stream doesn't work when the 3rd and 4th parameters are null.

[j4nr6n]

Yeah, I noticed that after I commented. Something in prepare() sets those two values based on request headers. Perhaps those properties should have default values.