checkio-json-serializer

About

JSON serilizer for more complex objects

Install

pip install checkio-json-serializer

Examples

Standard json module allows you to dump only limit amount of types

from json import dumps

obj = set([5,4,6])

serialized_obj = dumps(obj)

The code above raises an exception

TypeError: Object of type set is not JSON serializable

But if you want to be able to dump and load objects like set or datetype and use JSON format you can use checkio_json_serializer

from checkio_json_serializer import dumps, loads

obj = set([5,4,6])

serialized_obj = dumps(obj)
loaded_obj = loads(serialized_obj)

assert obj == loaded_obj

Explain

In the set example, checkio_json_serializer simply converts set-object to JSON object

serialized_obj variable shows

 {"___checkio___type___": "set", "values": [4, 5, 6]}

https://github.com/CheckiO/checkio-json-serializer/blob/master/tests/test_params.py contails supported datatypes

Custom user types

checkio_json_serializer allows you to dump user-defined objects

class UnexpecrtedClass:
    def __init__(self, name, param):
        self.name = name
        self.param = param

    # __hash__ and __eq__ methods for comparing objects
    # those methods are not required for using dumps or loads
    def __hash__(self):
        return hash((self.name, self.param))
    def __eq__(self, other):
        return hash(self) == hash(other)

In order to dump object of UnexpecrtedClass you need to do extra_cover attribute of dumps

from checkio_json_serializer import dumps, loads

extra_cover = (
    (
        UnexpecrtedClass,
        lambda obj: {"values": [obj.name, obj.param]},
    ),
)

obj = {"45": UnexpecrtedClass("Alex", 200)}
serialized_obj = dumps(obj, extra_cover=extra_cover)

In order to load object you need to use extra_hooks attribute

loads(serialized_obj, extra_uncover={
    "UnexpecrtedClass": lambda obj: UnexpecrtedClass(*obj["values"])
},)