custom_json_encoder.py

from django.utils import simplejson as json


class SerializeMethod(object):
    def __init__(self):
        self.type = type_
        self.func = func


class CustomJSONEncoder(json.JSONEncoder):
    def __init__(self, methods, *args, **kwargs):
        import collections
        if isinstance(methods, collections.Iterable):
            self._methods = methods
        else:
            self._methods = [methods]
        super(CustomJSONEncoder, self).__init__(*args, **kwargs)

    def default(self, obj):
        print obj
        for method in self._methods:
            type_ = method.type
            func = method.func

            if isinstance(obj, type_):
                ret = func(obj)
                break
        else:
            ret = json.JSONEncoder.default(self, obj)

        return ret