Is it possible to dump an enum in json without passing an encoder to json.dumps()?

Question

My problem could be summarised by the following example:

from enum import Enum
import json

class FooBarType(Enum):
    standard = 0
    foo = 1
    bar = 2

dict = {'name': 'test', 'value': 'test', 'type': FooBarType.foo}

json.dumps(dict)

TypeError: <FooBarType.foo: 1> is not JSON serializable

I get a type error, because enums are not JSON serializable.

I primarily though of implementing a JsonEncoder and adding it to the json.dumps() call but I cannot change the line where json.dumps() call is made.

So, my question is : Is it possible to dump an enum in json without passing an encoder to json.dumps(), but instead, by adding class method(s) in FooBarType enum ?

I expect to extract the following json:

{'name': 'test', 'value': 'test', 'type': 'foo'}

or

{'name': 'test', 'value': 'test', 'type': 1}

Answer 1

Try:

from enum import Enum

# class StrEnum(str, Enum):
#     """Enum where members are also (and must be) strs"""

class Color(str, Enum):
    RED = 'red'
    GREEN = 'green'
    BLUE = 'blue'


data = [
    {
        'name': 'car',
        'color': Color.RED,
    },
    {
        'name': 'dog',
        'color': Color.BLUE,
    },
]

import json
print(json.dumps(data))

Result:

[
    {
        "name": "car",
        "color": "red"
    },
    {
        "name": "dog",
        "color": "blue"
    }
]

Answer 2

Sadly, there is no direct support for Enum in JSON.

The closest automatic support is to use IntEnum (which enum34 also supports), and then json will treat your enums as ints; of course, decoding them will give you an int back, but that is as good it gets without specifying your encoder/decoder.