python类get_context()的实例源码

def urlfetch_async(self, url, method='GET', headers=None,
                     payload=None, deadline=None, callback=None,
                     follow_redirects=False):
    """Make an async urlfetch() call.

    This is an async wrapper around urlfetch(). It adds an authentication
    header.

    Args:
      url: the url to fetch.
      method: the method in which to fetch.
      headers: the http headers.
      payload: the data to submit in the fetch.
      deadline: the deadline in which to make the call.
      callback: the call to make once completed.
      follow_redirects: whether or not to follow redirects.

    Yields:
      This returns a Future despite not being decorated with @ndb.tasklet!
    """
    headers = {} if headers is None else dict(headers)
    headers.update(self.user_agent)
    try:
      self.token = yield self.get_token_async()
    except app_identity.InternalError, e:
      if os.environ.get('DATACENTER', '').endswith('sandman'):
        self.token = None
        logging.warning('Could not fetch an authentication token in sandman '
                     'based Appengine devel setup; proceeding without one.')
      else:
        raise e
    if self.token:
      headers['authorization'] = 'OAuth ' + self.token

    deadline = deadline or self.retry_params.urlfetch_timeout

    ctx = ndb.get_context()
    resp = yield ctx.urlfetch(
        url, payload=payload, method=method,
        headers=headers, follow_redirects=follow_redirects,
        deadline=deadline, callback=callback)
    raise ndb.Return(resp)