daemon.py 文件源码

def __enter__(self):
        self._proxy.__enter__()

        try:
            methods = self._proxy.system.listMethods()
        except ProtocolError as e:
            if e.errcode != 404:
                raise
            # remote daemon returned 404, likely using different rmw impl.
            self._proxy.__exit__()
            # fall back to use direct node
            self._proxy = DirectNode(self._args)
            self._proxy.__enter__()
        else:
            self._methods = [m for m in methods if not m.startswith('system.')]

        return self