def notebook_proxy(request, username):
    """Renders a IPython Notebook frame wrapper.

    Starts or reattachs ot an existing Notebook session.
    """
    security_check(request, username)

    manager = get_notebook_manager(request)
    notebook_info = manager.get_context(username)

    if not notebook_info:
        raise HTTPInternalServerError("Apparently IPython Notebook daemon process is not running for {}".format(username))

    if 'http_port' not in notebook_info:
        raise RuntimeError("Notebook terminated prematurely before managed to tell us its HTTP port")

    return proxy_it(request, notebook_info["http_port"])
Renders a IPython Notebook frame wrapper.

    Starts or reattachs ot an existing Notebook session.