views.py 文件源码

def download_once(request, ref_key=None):
    cache_key = 'document-ref-{}'.format(ref_key)
    doc_id = cache.get(cache_key)

    if not doc_id:
        raise Http404()

    cache.delete(cache_key)

    doc = get_object_or_404(Document, pk=doc_id)
    response = FileResponse(doc.retrieve(request.user, 'view'),
        content_type=doc.mimetype)

    # Disable browser caching, so the PDF won't end up on the users hard disk.
    response['Cache-Control'] = 'no-cache, no-store, must-revalidate'
    response['Pragma'] = 'no-cache'
    response['Expires'] = '0'
    response['Vary'] = '*'
    return response