named_tuple_dumping_fail.py

from typing import NamedTuple
import json


class NamedTupleJSONEncoder(json.JSONEncoder):

    def encode(self, o):
        print(f"Encoding {type(o)}")
        return super().encode(o)

    def iterencode(self, o, _one_shot=False):
        print(f"Iterencoding {type(o)}")
        if isinstance(o, tuple):
            try:
                return super().iterencode(o._asdict(), _one_shot=_one_shot)
            except AttributeError:
                return super().iterencode(o, _one_shot=_one_shot)

        return super().iterencode(o,  _one_shot=_one_shot)

    def default(self, o):
        print(f"Defaulted {type(o)}")
        if isinstance(o, tuple):
            try:
                return o._asdict()
            except AttributeError:
                return super().default(o)

        return super().default(o)


class CoolStuff(NamedTuple):
    cool: str
    stuff: int

class NeatGoo(NamedTuple):
    neat: CoolStuff
    goo: CoolStuff

things = CoolStuff("hello", 3)
other_things = CoolStuff("goodbye", 4)
neato = NeatGoo(things, other_things)
print(json.dumps(neato, cls=NamedTupleJSONEncoder))