'Extract necessary query parameters from http request.
:param req: the Request object coming from the wsgi layer
:returns: dictionary of filters to apply to list of images'

def _get_query_params(self, req):

    params = {'filters': self._get_filters(req), 'limit': self._get_limit(req), 'sort_key': [self._get_sort_key(req)], 'sort_dir': [self._get_sort_dir(req)], 'marker': self._get_marker(req)}
    if req.context.is_admin:
        params['is_public'] = self._get_is_public(req)
    items = list(params.items())
    for (key, value) in items:
        if (value is None):
            del params[key]
    params['member_status'] = 'all'
    return params
