How to dump a Python dictionary to JSON when keys are non-trivial objects?

Question

import datetime, json
x = {\'alpha\': {datetime.date.today(): \'abcde\'}}
print json.dumps(x)

The above code fails with a TypeError since

Answer 1

If you really need to do it, you can monkeypatch json.encoder:

from _json import encode_basestring_ascii  # used when ensure_ascii=True (which is the default where you want everything to be ascii)
from _json import encode_basestring  # used in any other case

def _patched_encode_basestring(o):
    """
    Monkey-patching Python's json serializer so it can serialize keys that are not string!
    You can monkey patch the ascii one the same way.
    """
    if isinstance(o, MyClass):
        return my_serialize(o)
    return encode_basestring(o)


json.encoder.encode_basestring = _patched_encode_basestring