rpc.py 文件源码

def on(self, signal, callback, autoremove=True):
        """Register `callback` for `signal`

        signal: 'connecting', 'connected', 'disconnected' or 'error'
        callback: a callable that receives the RPC URL and, for 'error', the
                  exception

        Callbacks are automatically unsubscribed when they are
        garbage-collected.
        """
        try:
            # Attributes with '__' become '_Classname__attribute'
            sig = getattr(self, '_TransmissionRPC__on_' + signal)
        except AttributeError:
            raise ValueError('Unknown signal: {!r}'.format(signal))
        else:
            if not isinstance(sig, Signal):
                raise ValueError('Unknown signal: {!r}'.format(signal))
            else:
                log.debug('Registering %r for %r event', callback, signal)
                sig.connect(callback, weak=autoremove)