我正在使用 python 请求库并尝试保持 session 。
由于我的主机上有多个 IP,我创建了以下方法以使 session 绑定(bind)到特定 IP。
class SourceAddressAdapter(HTTPAdapter):
def __init__(self, source_address, **kwargs):
self.source_address = source_address
super(SourceAddressAdapter, self).__init__(**kwargs)
def init_poolmanager(self, connections, maxsize, block=False):
self.poolmanager = PoolManager(num_pools=connections,
maxsize=maxsize,
block=block,
source_address=self.source_address)
下面的代码片段用于调用这个类:
r = requests.Session()
r.mount('http://', SourceAddressAdapter((self.ip,0)))
r.mount('https://', SourceAddressAdapter((self.ip,0)))
在这个适配器上挂载http和https协议(protocol)后,我使用pickle将对象持久化到redis中,如下所示:
session = pickle.dumps(r)
redis.hset('sessions',id,session)
当我试图解开 session 对象时出现问题:
s=redis.hget('sessions', id)
pickle.loads(s)
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "/usr/lib/python2.7/pickle.py", line 1382, in loads
return Unpickler(file).load()
File "/usr/lib/python2.7/pickle.py", line 858, in load
dispatch[key](self)
File "/usr/lib/python2.7/pickle.py", line 1217, in load_build
setstate(state)
File "/usr/local/lib/python2.7/dist-packages/requests/adapters.py", line 114, in __setstate__
block=self._pool_block)
File "network_driver.py", line 158, in init_poolmanager
source_address=self.source_address)
AttributeError: 'SourceAddressAdapter' object has no attribute 'source_address'
它提示 SourceAddressAdapter 没有 source_address 属性。在我将此类 SourceAddressAdapter 添加到我的 session 之前,序列化运行良好。
所以我猜这是自定义类 pickling/unpickling 的问题。
更新:
它在我将 __getstate__
和 __setstate__
方法添加到 SourceAddressAdapter 后起作用
def __getstate__(self):
# it calls HTTPAdapter's __getstate__()
state = super(SourceAddressAdapter, self).__getstate__()
state['source_address'] = self.source_address
return state
def __setstate__(self,state):
self.source_address = state['source_address']
# Call HTTPAdapter's __setstate__ function to pack the attributes in parent class
super(SourceAddressAdapter, self).__setstate__(state)
最佳答案
我认为问题在于 HTTPAdapter
类定义了一个 __setstate__
方法。这个函数在 unpickling 时调用,并将实例恢复到 pickled 状态。但是,HTTPAdapter
对您的 source_address
属性一无所知,因此该属性不会恢复(或者甚至可能一开始就不会被 pickle )。
要解决此问题,您需要覆盖 __setstate__
函数,有点像这样:
def __setstate__(self, state):
self.source_address= state['source_address'] # do this before calling __setstate__
HTTPAdapter.__setstate__(self, state)
并且,如前所述,您可能还必须覆盖 __getstate__
函数,以便对 source_address
进行 pickle。
关于Python unpickle 一个对象里面有一个类实例,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/27711907/