ikonst / jschon

A pythonic, extensible JSON Schema implementation.

Welcome to jschon!

jschon is a pythonic and extensible implementation of the JSON Schema specification.

Features

• JSON Schema validator implementation (drafts 2019-09, 2020-12)
  • Schema compilation and indexing
  • $ref loading from local and remote sources
  • Support for custom keywords, vocabularies and meta-schemas
  • Support for format validation
• JSON class implementing the JSON data model
• JSON Pointer (RFC 6901)
• JSON Patch (RFC 6902)
• Relative JSON Pointer (draft)
• JSON document translation (experimental)

Installation

pip install jschon

For remote $ref support, the requests library is required. It may be installed with:

pip install jschon[requests]

Usage

Create a JSON schema:

from jschon import create_catalog, JSON, JSONSchema

create_catalog('2020-12')

demo_schema = JSONSchema({
    "$id": "https://example.com/demo",
    "$schema": "https://json-schema.org/draft/2020-12/schema",
    "type": "array",
    "items": {
        "anyOf": [
            {
                "type": "string",
                "description": "Cool! We got a string here!"
            },
            {
                "type": "integer",
                "description": "Hey! We got an integer here!"
            }
        ]
    }
})

Validate JSON data:

result = demo_schema.evaluate(
    JSON([12, "Monkeys"])
)

Generate JSON Schema-conformant output:

>>> result.output('basic')
{
    "valid": True,
    "annotations": [
        {
            "instanceLocation": "",
            "keywordLocation": "/items",
            "absoluteKeywordLocation": "https://example.com/demo#/items",
            "annotation": True
        },
        {
            "instanceLocation": "/0",
            "keywordLocation": "/items/anyOf/1/description",
            "absoluteKeywordLocation": "https://example.com/demo#/items/anyOf/1/description",
            "annotation": "Hey! We got an integer here!"
        },
        {
            "instanceLocation": "/1",
            "keywordLocation": "/items/anyOf/0/description",
            "absoluteKeywordLocation": "https://example.com/demo#/items/anyOf/0/description",
            "annotation": "Cool! We got a string here!"
        }
    ]
}

Links

• Documentation: https://jschon.readthedocs.io
• GitHub repository: https://github.com/marksparkza/jschon
• PyPI package: https://pypi.org/project/jschon
• Online validator: https://jschon.dev