Symfony2 invalid token with big files

Question

I'm having problem with token and file field form.

The validation of the form is like this:

public function getDefaultOptions(array $options)
{
    $collectionConstraint = new Collection(array(
        'fields' => array(
            'file' => new File(
                array(
                    'maxSize' => '2M',
                    'mimeTypes' => array(
                        'application/pdf', 'application/x-pdf',
                        'image/png', 'image/jpg', 'image/jpeg', 'image/gif',
                    ),
                )
            ),
        )
    ));

    return array(
        'validation_constraint' => $collectionConstraint
}

When I upload a invalid size file(~5MB) I get this error which is what I hope:

The file is too large. Allowed maximum size is 2M bytes

But when I upload a too big file(~30MB) the error changes:

The CSRF token is invalid. Please try to resubmit the form
The uploaded file was too large. Please try to upload a smaller file

The problem is the error token. I've in my form the {{ form_rest(form) }} code. I think the error change is because of this: How to increase the upload limit for files on a Symfony 2 form?

I don't want to increase the upload limit. I want the token error doesn't show.

Answer 1

PHP (not Symfony) rejects the file if it is bigger than your configured values in:

post_max_size
upload_max_filesize

Because of this the csrf-error is thrown.

If you want to avoid this you have to increase the upload limit. It is the only way. If you add your file-constraint this should be no risk.