创建了允许用户通过链接下载pdf文件的函数。工作正常，唯一的问题是用户保存的是. html。所以所有文件都是file.pdf.html。

def download(request,ticket_id):
    ticket_path = str(Ticket.objects.get(id=ticket_id).upload)
    with open('files/media/' + ticket_path, 'rb') as pdf:
        response = HttpResponse(pdf.read())
        response['content_type'] = 'application/pdf'
        response['Content-Disposition'] = 'attachment;filename="file.pdf"'
        return response

为什么？