我有一个消息总线，一个类订阅了消息总线的很多方法，例如:
class BookingService(object):
def start(self):
self.msg_bus.login(self.user, self.password)
self.msg_bus.subscribe('/broadcast/aliveResponse', self.handleAliveResponse)
self.msg_bus.subscribe('/broadcast/musicInfoUpdated', self.handleMusicInfo)
self.msg_bus.subscribe('/broadcast/radioOnline', self.handleRadioOnline)
self.msg_bus.subscribe('/broadcast/radioOffline', self.handleRadioOffline)
self.msg_bus.subscribe('/broadcast/online', self.handleBroadcastOnline)
self.msg_bus.subscribe('/proxy/aliveResponse', self.handleEvent)
self.msg_bus.subscribe('/proxy/online', self.handleProxyOnline)
self.msg_bus.subscribe('/proxy/radioReady', self.handleEvent)
self.msg_bus.subscribe('/proxy/radioUpdate', self.handleEvent)
self.msg_bus.subscribe('/proxy/radioClosed', self.handleEvent)
self.msg_bus.subscribe('/message_bus/detached', self.handleDetached)
self.msg_bus.run()
它有效，但很难理解每个方法的消息路径是什么，我想要的是使用装饰器来订阅消息总线，它看起来像这样
class BookingService(object):
@subscribe('/broadcast/aliveResponse')
@subscribe('/broadcast/onLine')
def handleEvent(self, dest, data):
print dest, data
@subscribe('/proxy/aliveResponse')
def handleAnotherEvent(self, dest, data):
print dest, data
但是这里有一些难点要解决，首先msg_bus属性是属于instance的，也就是属于self的。我无法在类里面获得 self.msg_bus。为了解决这个问题，我可以这样写:
class BookingService(object):
subscribations = []
def subscribe(dest):
"""Decorator for subscribing function to destination
"""
def callee(func):
subscribations.append((dest, func))
return func
return callee
def subscribe_all(self):
for dest, func in self.subscribations:
self.msg_bus.subscribe(dest, func)
@subscribe('/broadcast/aliveResponse')
def handleEvent(self, dest, data):
print dest, data
def start(self):
self.subscribe_all()
我尝试将订阅收集到 BookingService.subscribations 中，稍后在 subscribe_all 中将它们添加到 msg_bus，但问题来了。我遇到了一个错误
subscribations.append((dest, func))
NameError: global name 'subscribations' is not defined
subscribes好像不在subscribe函数的范围内，请问如何解决？
请您参考如下方法:
与其将其放入实例的列表中，不如将其放入函数或类的列表中。
class BookingService(object):
def subscribe(dest):
"""Decorator for subscribing function to destination
"""
def callee(func):
if not hasattr(func, 'subscriptions'):
func.subscriptions = []
func.subscriptions.append((dest, func))
return func
return callee
def subscribe_all(self):
for classmember in dir(self):
for dest, func in getattr(getattr(self, classmember), 'subscriptions', []):
self.msg_bus.subscribe(dest, func)
@subscribe('/broadcast/aliveResponse')
def handleEvent(self, dest, data):
print dest, data
def start(self):
self.subscribe_all()
然而，您可能仍然遇到未绑定(bind)方法的问题；注意“ self ”的含义。
您可能还想将“subscribe”移到类定义之外，或将其重命名为“_subscribe”，或使其适应被调用为 self.subscribe()(此时 self.subscribe() 会起作用，但不是你期望的那样)
