jsons 0.2.2

For serializing Python objects to JSON and back

jsons

A Python lib (Python3.5+) for serializing Python objects to dicts or strings and for deserializing dicts or strings to Python objects.

Installation

pip install jsons

Usage

import jsons


some_instance = jsons.load(some_dict, SomeClass)  # Deserialization
some_dict = jsons.dump(some_instance)  # Serialization

API overview

• dump(obj: object) -> dict: serializes an object to a dict.
• load(json_obj: dict, cls: type = None) -> object: deserializes a dict to an object of type cls.
• dumps(obj: object, *args, **kwargs) -> str: serializes an object to a string.
• loads(s: str, cls: type = None, *args, **kwargs) -> object deserializes a string to an object of type cls.
• set_serializer(c: callable, cls: type) -> None: sets a custom serialization function for type cls.
• set_deserializer(c: callable, cls: type) -> None: sets a custom deserialization function for type cls.

Example with dataclasses

from dataclasses import dataclass
from typing import List
import jsons


# You can use dataclasses (since Python3.7). Regular Python classes (Python3.5+) will work as well as long as 
# type hints are present for custom classes.
@dataclass
class Student:
    name: str


@dataclass
class ClassRoom:
    students: List[Student]


c = ClassRoom([Student('John'), Student('Mary'), Student('Greg'), Student('Susan')])
dumped_c = jsons.dump(c)
print(dumped_c)
# Prints:
# {'students': [{'name': 'John'}, {'name': 'Mary'}, {'name': 'Greg'}, {'name': 'Susan'}]}
loaded_c = jsons.load(dumped_c, ClassRoom)
print(loaded_c)
# Prints:
# ClassRoom(students=[Student(name='John'), Student(name='Mary'), Student(name='Greg'), Student(name='Susan')])

Example with regular classes

from typing import List
import jsons


class Student:
    # Since ``name`` is expected to be a string, no type hint is required.
    def __init__(self, name):
        self.name = name


class ClassRoom:
    # Since ``Student`` is a custom class, a type hint must be given.
    def __init__(self, students: List[Student]):
        self.students = students


c = ClassRoom([Student('John'), Student('Mary'), Student('Greg'), Student('Susan')])
dumped_c = jsons.dump(c)
print(dumped_c)
# Prints:
# {'students': [{'name': 'John'}, {'name': 'Mary'}, {'name': 'Greg'}, {'name': 'Susan'}]}
loaded_c = jsons.load(dumped_c, ClassRoom)
print(loaded_c)
# Prints:
# <__main__.ClassRoom object at 0x0337F9B0>

Advanced features

Overriding the default (de)serialization behavior

You may alter the behavior of the serialization and deserialization processes yourself by defining your own custom serialization/deserialization functions.

jsons.set_serializer(custom_serializer, datetime)  # A custom datetime serializer.
jsons.set_deserializer(custom_deserializer, str)  # A custom string deserializer.

Transforming the JSON keys

You can have the keys transformed by the serialization or deserialization process by providing a transformer function that takes a string and returns a string.

result = jsons.dump(some_obj, jsons.KEY_TRANSFORMER_CAMELCASE)
# result could be something like: {'thisIsTransformed': 123}

result = jsons.load(some_dict, SomeClass, jsons.KEY_TRANSFORMER_SNAKECASE)
# result could be something like: {'this_is_transformed': 123}

The following casing styles are supported:

KEY_TRANSFORMER_SNAKECASE   # snake_case
KEY_TRANSFORMER_CAMELCASE   # camelCase
KEY_TRANSFORMER_PASCALCASE  # PascalCase
KEY_TRANSFORMER_LISPCASE    # lisp-case