利用Python实现Json序列化库的方法步骤

class A(JsonSerializable):

def __init__(self, a, b):
super().__init__()
self.a = a
self.b = b if b is not None else B(0)

@property
def id(self):
return self.a

def _deserialize_prop(self, name, deserialized):
if name == 'b':
self.b = B.deserialize(deserialized)
return
super()._deserialize_prop(name, deserialized)

class B(JsonSerializable):

def __init__(self, b):
super().__init__()
self.b = b

class JsonSerializableTest(unittest.TestCase):

def test_model_should_serialize_correctly(self):
self.assertEqual(json.dumps({'a': 1, 'b': {'b': 2}}), A(1, B(2)).serialize())

def test_model_should_deserialize_correctly(self):
a = A.deserialize(json.dumps({'a': 1, 'b': {'b': 2}}))
self.assertEqual(1, a.a)
self.assertEqual(2, a.b.b)

def test_model_should_deserialize_with_default_value_correctly(self):
a = A.deserialize(json.dumps({'a': 1}))
self.assertEqual(1, a.a)
self.assertEqual(0, a.b.b)

def is_normal_prop(obj, key):
is_prop = isinstance(getattr(type(obj), key, None), property)
is_func_attr = callable(getattr(obj, key))
is_private_attr = key.startswith('__')
return not (is_func_attr or is_prop or is_private_attr)

def is_basic_type(value):
return value is None or type(value) in [int, float, str, bool]

class JsonSerializable:

def _serialize_prop(self, name):
return getattr(self, name)

def _as_dict(self):
props = {}
for key in dir(self):
if not is_normal_prop(self, key):
continue
value = self._serialize_prop(key)
if not (is_basic_type(value) or isinstance(value, JsonSerializable)):
raise Exception('unknown value to serialize to dict: key={}, value={}'.format(key, value))
props[key] = value if is_basic_type(value) else value._as_dict()
return props

def serialize(self):
return json.dumps(self._as_dict(), ensure_ascii=False)

def _deserialize_prop(self, name, deserialized):
setattr(self, name, deserialized)

@classmethod
def deserialize(cls, json_encoded):
if json_encoded is None:
return None

args = inspect.getfullargspec(cls)
args_without_self = args.args[1:]
obj = cls(*([None] * len(args_without_self)))

data = json.loads(json_encoded, encoding='utf8') if type(json_encoded) is str else json_encoded
for key in dir(obj):
if not is_normal_prop(obj, key):
continue
if key in data:
obj._deserialize_prop(key, data[key])
return obj