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jsonpython-2.7datetimeobjectencode

Serialize datetime.datetime object as JSON

Currently working on a quick little project in python and am attempting to encode an object into a JSON string. I've done this several times before without any problem except for now. Usually I just do the following. 

def ClassToEncode :
    def __init__(self, arg1, arg2, ..., argn) :
        self.attr1 = arg1
        self.attr2 = arg2
        ...
        self.attrn = argn

     ...
     def toJSON(self) :
         return json.dumps(self, default=lambda o: o.__dict__)

But the problem is that one of my class attributes is a datetime.datetime object and I am being thrown the following error 

AttributeError: 'datetime.datetime' object has no attribute '__dict__'

Any thoughts or wraparounds that could enable the functionality of including the datetime attribute into the JSON output??

Thanks in advance!

Solution

  • You can use the isoformat() method on a datetime object to convert it to an ISO-8601-formatted time string, then serialize it as JSON just fine. On the other end, call datetime.datetime.strptime() on the formatted string to convert it back into a datetime object:

    >>> from datetime import datetime as dt
>>> now = dt.now()
>>> now
datetime.datetime(2014, 9, 4, 3, 19, 44, 214096)
>>> isonow = now.isoformat()
>>> isonow
'2014-09-04T03:19:44.214096'
>>> fmt = "%Y-%m-%dT%H:%M:%S.%f"
>>> newtime = dt.strptime(isonow, fmt)
>>> newtime
datetime.datetime(2014, 9, 4, 3, 19, 44, 214096)