JSON Schema generate Python types

Tools to generate Python types based on TypedDict from a JSON schema

Quick start

install:

python3 -m pip install --user jsonschema-gentypes

Convert a JSON schema to a Python file contains the types:

jsonschema-gentypes --json-schema=<JSON schema> --python=<destination Python file>

Docker

You can also run it with Docker:

docker run --rm --user=$(id --user) --volume=$(pwd):/src camptocamp/jsonschema-gentypes

Config file

You can also write a config file named jsonschema-gentypes.yaml with:

headers: >
  # Automatically generated file from a JSON schema
# Used to correctly format the generated file
callbacks:
  - - black
  - - isort
generate:
  - # JSON schema file path
    source: jsonschema_gentypes/schema.json
    # Python file path
    destination: jsonschema_gentypes/configuration.py
    # The name of the root element
    root_name: Config
    # Argument passed to the API
    api_arguments:
      additional_properties: Only explicit
    # Rename an element
    name_mapping: {}
    # The minimum Python version that the code should support. By default the
    # currently executing Python version is chosen. Note that the output
    # may require typing_extensions to be installed.
    python_version: '3.11'

And just run:

jsonschema-gentypes

Default

The default values are exported in the Python file, then you can do something like that:

value_with_default = my_object.get('field_name', my_schema.FIELD_DEFAULT)

Validation

This package also provide some validations features for YAML file based on jsonschema.

Additional features:

• Obtain the line and columns number in the errors, if the file is loaded with ruamel.yaml.
• Export the default provided in the JSON schema.

    import ruamel.yaml
    import pkgutil
    import jsonschema_gentypes.validate

    schema_data = pkgutil.get_data("jsonschema_gentypes", "schema.json")
    with open(filename) as data_file:
        yaml = ruamel.yaml.YAML()  # type: ignore
        data = yaml.load(data_file)
    errors, data = jsonschema_gentypes.validate.validate(filename, data, schema)
    if errors:
        print("\n".join(errors))
        sys.exit(1)

The filling of the default value is deprecated because it can produce quite peculiar things, see also the jsonschema documentation.

Limitations

Requires Python 3.8

See the issues with label "limitation".

Pre-commit hooks

This project provides pre-commit hooks to automatically generate the files.

repos:
  - repo: https://github.com/camptocamp/jsonschema-gentypes
    rev: <version> # Use the ref you want to point at
    hools:
      - id: jsonschema-gentypes
        files: |
          (?x)^(
              jsonschema-gentypes\.yaml|
              <schema_path>\.json
          )$

See also the pre_commit section in the configuration to run the pre-commit just after the generation, for example with:

pre_commit:
  enabled: true
  arguments:
    - --color=never

Contributing

Install the pre-commit hooks:

pip install pre-commit
pre-commit install --allow-missing-config

The prospector tests should pass.

The code should be typed.

The code should be tested with pytests.