datetime.datetime is not JSON serializable [duplicate]

Question

I have a class in Python for retrieving all the columns in a table and return a JSON with this data.

The problem is at least one of those columns is a datetime and I can't seem to understand how to serialize the columns so I can generate a valid JSON.

My class is as follows:

class GetTodos(Resource):
    def get(self):
        con = cx_Oracle.connect('brunojs/[email protected]/orcl')
        cur = con.cursor()
        cur.execute("select * from organite_repository")
        r = [dict((cur.description[i][0], value) \
                for i, value in enumerate(row)) for row in cur.fetchall()]
        cur.connection.close()
        return (r[0] if r else None) if None else r 

Any hints on this?

Answer 1

JSON doesn't have a default datetime type, so this is why Python can't handle it automatically. So you need to make the datetime into a string one way or another. I think the best way is to write a custom handler to help the json module.

import datetime
import json

def datetime_handler(x):
    if isinstance(x, datetime.datetime):
        return x.isoformat()
    raise TypeError("Unknown type")

json.dumps(data, default=datetime_handler)

Answer 2

A simple way to do it is to cast your data to string. That way, you will be able to dump with json.

>>> datetime.now()
datetime.datetime(2016, 3, 8, 11, 37, 24, 123639)

>>> str(datetime.now())
'2016-03-08 11:37:27.511053'

But, you could also implement a serializer to transform the data as you want.