pyobjson - Python Object JSON Tool

Utility library for serializing/deserializing custom Python objects to/from JSON.

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READ THE DOCS HERE!
Detailed documentation can be found at https://pyobjson.wrencode.dev.

 

Table of Contents


About

The Python Object JSON Tool is a utility library for serializing/deserializing custom Python objects to/from JSON by using pyobjson classes as superclasses/parent classes to your custom Python classes.

Installation

You can install with pip by running:

pip install pyobjson

Note: If you wish to use pyobjson to serialize/deserialize custom Python objects to/from MongoDB, then you have to install with the optional dependencies:

pip install pyobjson[mongo]

Dependencies

The base Python Object JSON Tool does not have any third-party dependencies to run the code. It has several development dependencies, which can be seen in the package pyproject.toml.

If you wish to use pyobjson to serialize/deserialize custom Python objects to/from MongoDB, then there is an additional dependency on the PyMongo package.

Toolchain

The below tools and resources are used as part of pyobjson:

  • uv - package management
  • ruff - code linting
  • bandit - code security
  • make - Makefile build automation
  • MkDocs - package documentation
  • python-dotenv - programmatic access to environment variables defined in a .env file
  • pytest - code testing framework
  • GitHub Actions - CI/CD
  • act - GitHub Actions testing

Usage

The pyobjson package is designed to be used as a base class/parent class/superclass to your own custom Python classes in order to provide built-in, convenient serialization/deserialization functionality. Child classes/subclasses of pyobjson.base.PythonObjectJson will automatically have the following methods:

  • pyobjson.base.PythonObjectJson.serialize(): Create a serializable dictionary from the class instance.
  • pyobjson.base.PythonObjectJson.to_json_str(): Serialize the class instance to a JSON string.
  • pyobjson.base.PythonObjectJson.from_json_str(json_str): Load the class instance from a pyobjson-formatted JSON string.
  • pyobjson.base.PythonObjectJson.save_to_json_file(json_file_path): Save the class instance to a JSON file.
  • pyobjson.base.PythonObjectJson.load_from_json_file(json_file_path): Load the class instance from a pyobjson -formatted JSON file.

Please reference the documentation at https://pyobjson.wrencode.dev for more detailed usage.

JSON Example

from pyobjson.base import PythonObjectJson


class MyOtherClass(PythonObjectJson):

    def __init__(self):
        super().__init__()
        self.message = "Hello, World!"


class MyClass(PythonObjectJson):
    def __init__(self):
        super().__init__()
        self.my_other_classes = [MyOtherClass()]


my_class = MyClass()

print(my_class.to_json_str())

JSON Example Output
{
  "__main__.myclass": {
    "collection::::list::::my_other_classes": [
      {
        "__main__.myotherclass": {
          "message": "Hello, World!"
        }
      }
    ]
  }
}

The above example shows how pyobjson can be used to serialize arbitrary custom Python classes into JSON. Additionally, the above JSON example output JSON can be used to recreate an equivalent class instance by loading the JSON into a custom Python class instance.

Saving and Loading

The pyobjson.base.PythonObjectJson parent class also provides built-in methods to save/load arbitrary custom Python classes to/from JSON in several ways.

JSON Files
  • JSON files (using only Python built-in libraries): Use the PythonObjectJson.save_to_json_file(json_file_path) and PythonObjectJson.load_from_json_file(json_file_path) methods to save/load your custom Python subclasses to JSON files.

JSON File Example
from pathlib import Path

from dotenv import load_dotenv

from pyobjson.base import PythonObjectJson

root_dir = Path(__file__).parent

load_dotenv(root_dir / ".env")


class CustomClassToJsonFile(PythonObjectJson):
    def __init__(self, message: str):
        super().__init__()
        self.message = message


custom_class_to_json_file = CustomClassToJsonFile("Hello, World!")

output_dir = root_dir / "output"
if not output_dir.is_dir():
    output_dir.mkdir(parents=True, exist_ok=True)

custom_class_to_json_file.save_to_json_file(output_dir / "custom_class_to_json_file.json")

custom_class_to_json_file.load_from_json_file(output_dir / "custom_class_to_json_file.json")

JSON File Output
{
  "__main__.customclasstojsonfile": {
    "message": "Hello, World!"
  }
}

MongoDB
  • MongoDB (using pymongo): The pyobjson library includes a class called pyobjson.dao.PythonObjectJsonToMongo, which can be used as a superclass for any custom class you wish to be able to easily serialized/deserialize to/from MongoDB. Use the PythonObjectJsonToMongo.save_to_mongo(mongo_collection) and PythonObjectJsonToMongo.load_from_mongo(mongo_collection, document_id) methods to save/load your custom Python subclasses to MongoDB.

MongoDB Example
import os
from pathlib import Path

from dotenv import load_dotenv

from pyobjson.dao.mongo.base import PythonObjectJsonToMongo

load_dotenv(Path(__file__).parent / ".env")


class CustomClassToMongo(PythonObjectJsonToMongo):
    def __init__(self, mongo_host: str, mongo_port: int, mongo_database: str, mongo_user: str, mongo_password: str):
        super().__init__(mongo_host, mongo_port, mongo_database, mongo_user, mongo_password)
        self.message = "Hello, World!"


custom_class_to_mongo = CustomClassToMongo(
    mongo_host=os.environ.get("MONGO_HOST"),
    mongo_port=int(os.environ.get("MONGO_PORT")),
    mongo_database=os.environ.get("MONGO_DATABASE"),
    mongo_user=os.environ.get("MONGO_ADMIN_USER"),
    mongo_password=os.environ.get("MONGO_ADMIN_PASS"),
)

saved_mongo_document_id = custom_class_to_mongo.save_to_mongo(os.environ.get("MONGO_COLLECTION"))

custom_class_to_mongo.load_from_mongo(os.environ.get("MONGO_COLLECTION"), saved_mongo_document_id)

MongoDB Output

print(custom_class_to_mongo):

{
  "__main__.customclasstomongo": {
    "message": "Hello, World!"
  }
}

print(repr(custom_class_to_mongo)):

__main__.CustomClassToMongo(mongo_host=localhost,mongo_port=27017,mongo_database=pyobjson,mongo_user=<mongodb_user>,mongo_password=<mongodb_password>)

Custom Subclasses

The PythonObjectJson base class in pyobjson is designed to be extended using your own custom subclasses. The built-in PythonObjectJsonToMongo class is an example of this functionality, but it can be adapted to work for additional use cases as well.

Serialization

If you have a custom class with attributes that contain data you wish to exclude from the pyobjson serialized output ( anything from sensitive data like credentials to objects that are not compatible with pyobjson), you can provide a list of attribute names (or a list of valid regular expressions) to the excluded_attributes parameter in the PythonObjectJson.__init__(...), and pyobjson will automatically exclude any attributes that match those provided during serialization.

If you only provide values for excluded_attributes, then pyobjson will exclude those attributes from all custom classes being serialized within the root custom class. However, you can also provide a list of class identifiers (like pyobjson.dao.mongo.base.pythonobjectjsontomongo to the class_keys_for_excluded_attributes parameter in the PythonObjectJson.__init__(...), as derived using the pyobjson.utils.derive_custom_object_key function), in which case pyobjson will only exclude the provided excluded_attributes from the classes in class_keys_for_excluded_attributes.

Deserialization

Similar to the approach for custom subclass serialization, if you have a custom class with extra attributes you wish to include during deserialization, you can provide a list of attribute names (or a list of valid regular expressions) to the extra_attributes parameters in the PythonObjectJson.__init__(...), and pyobjson will attempt to re-apply those attributes during deserialization by pulling the values for those extra attributes from the custom class instance onto which you are deserializing data.

If you only provide values for extra_attributes, then pyobjson will attempt to add those attributes to all custom classes being deserialized onto the root custom class. However, you can also provide a list of class identifiers (like pyobjson.dao.mongo.base.pythonobjectjsontomongo to the class_keys_for_extra_attributes parameter in the PythonObjectJson.__init__(...), as derived using the pyobjson.utils.derive_custom_object_key function), in which case pyobjson will only attempt to add the provided extra_attributes to the classes in class_keys_for_extra_attributes.