无法从JSON反序列化PyMongo ObjectId

Question

我似乎无法使用BSON json_util反序列化我的MongoDB JSON文档.

json.loads函数在ObjectId()字符串上窒息.我理解json_util能够处理MongoDB的ObjectId格式并转换为可用的JSON.

Python代码:

import json    
from bson import json_util

s = "{u'_id': ObjectId('4ed559abf047050c58000000')}"
u = json.loads(s, object_hook=json_util.object_hook)

我得到解码器异常:

...
    u = json.loads(s, object_hook=json_util.object_hook)
  File "\python27\lib\json\__init__.py", line 339, in loads
    return cls(encoding=encoding, **kw).decode(s)
  File "\python27\lib\json\decoder.py", line 366, in decode
    obj, end = self.raw_decode(s, idx=_w(s, 0).end())
  File "\python27\lib\json\decoder.py", line 382, in raw_decode
    obj, end = self.scan_once(s, idx)
ValueError: Expecting property name: line 1 column 1 (char 1)

我错过了什么吗？

Answer 1

我认为你的字符串形式实际上看起来像python表示...

s = '{"_id": {"$oid": "4edebd262ae5e93b41000000"}}'
u = json.loads(s, object_hook=json_util.object_hook)

print u  # Result:  {u'_id': ObjectId('4edebd262ae5e93b41000000')}

s = json.dumps(u, default=json_util.default)

print s  # Result:  {"_id": {"$oid": "4edebd262ae5e93b41000000"}}

对于在实际的json字符串表示中存在ObjectId(),bson.json_util.object_hook函数似乎没有任何类型的处理.