json-tag 0.1.7

Python pydantic wrapper for JSON# — the #type convention for cross-language type tagging in JSON.

json-tag

Python support for JSON#.

Configures pydantic to use the JSON# convention.

Install

pip install json-tag

Usage

Define your types:

class Circle(JsonTagModel):
    radius: float

class Rectangle(JsonTagModel):
    width: float
    height: float

Shape = tagged_union(Circle, Rectangle)

Serialize:

circle = Circle(radius=4.0)
circle.to_json()
# {"#type":"Circle","radius":4}

Deserialize:

from pydantic import TypeAdapter

shape = TypeAdapter(Shape).validate_json('{"#type":"Circle","radius":4}')
# Circle(radius=4.0)

Custom tag names via __json_tag_name__ class variable:

class PersonalVehicle(JsonTagModel):
    __json_tag_name__ = "Car"
    make: str

API

Export	Description
JsonTagModel	Base model — subclasses get #type automatically
tagged_union(*types)	Create a discriminated union with #type
TYPE_FIELD	The "#type" constant