python反序列化的坑

wsjz_01

　　今天遇到python一个坑，调用memcached的get_man报错：

memcache2 get :1:photo:latest:forward:5855687 cost 2857.6438427

转发 <#59066487>

unpickle :1:photo:latest:forward:5855687 FAIL  __import__() argument 1 must be string without null bytes, not str



 　　同样一个key,一个是通过get，一个是通过get_many，结果报错。code如下：

# -*- coding: utf-8 -*-
from django.core.management import setup_environ
import settings
setup_environ(settings)
key = 'photo:latest:forward:5855687'
from django.core.cache import cache
print cache.get(key)
print cache.get_many([key])

　　跟进代码发现问题出在get_man的反序列化上：

def get_multi(self,key):
result = cacheService.getMulti(key)
if result is None:
return []
else:
result_dict = {}
for k,val in result.items():
try:
file = StringIO(val)
_up = unpickler(file)
val = _up.load()
result_dict[k] = val
except Exception,e:
print 'unpickle %s FAIL  %s'%(k,e)
pass
return result_dict

　　尝试把序列化改成：

result_dict[k] = pickle.loads(val)
　　报错信息变了：
　　unpickle :1:photo:latest:forward:5855687 FAIL  must be string, not unicode
　　难道是val的type不是str，是unicode？ 通过print type(val) 打印出来，果然是unicode。