jinja2-jsonschema 0.1.0

JSON/YAML schema validation within Jinja2 templates

JSON Schema Validation within Jinja2 Templates

A Jinja2 extension providing a Jinja2 filter for validating data against a JSON/YAML schema within Jinja2 templates.

Installation

• With pip:

  pip install jinja2-jsonschema
  
  # ... or with YAML support
  pip install jinja2-jsonschema[yaml]
  

• With poetry:

  poetry add jinja2-jsonschema
  
  # ... or with YAML support
  poetry add jinja2-jsonschema -E yaml
  

• With pdm:

  pdm add jinja2-jsonschema
  
  # ... or with YAML support
  pdm add jinja2-jsonschema[yaml]
  

• With pipx (injected into the pipx-managed virtual env of a package):

  pipx inject PACKAGE jinja2-jsonschema
  
  # ... or with YAML support
  pipx inject PACKAGE jinja2-jsonschema[yaml]
  

Usage

The extension provides a Jinja2 filter which receives a schema file path or schema object as input and returns a jsonschema.ValidationError object when validation fails and an empty string ("") otherwise. The JSON Schema dialect is inferred from the $schema field in the JSON Schema document and, when omitted, defaults to the latest dialect supported by the installed jsonschema library. Both local and remote schemas are supported including schema references and JSON Pointers.

Local schema files are loaded via a Jinja2 loader in which case configuring the Jinja2 environment with a loader is mandatory.

Some example usage of the JSON Schema validation filter is this:

from jinja2 import Environment
from jinja2 import FileSystemLoader


env = Environment(
    # Register a loader (only necessary when using local schema files).
    loader=FileSystemLoader("/path/to/templates"),
    # Register the extension.
    extensions=['jinja2_jsonschema.JsonSchemaExtension'],
)

# Example using an inline schema object.
template = env.from_string("{{ age | jsonschema({'type': 'integer', 'minimum': 0}) }}")
template.render(age=30)  # OK
template.render(age=-1)  # ERROR

# Example using a local schema file.
template = env.from_string("{{ age | jsonschema('age.json') }}")
template.render(age=30)  # OK
template.render(age=-1)  # ERROR

# Example using a remote schema file.
template = env.from_string("{{ age | jsonschema('https://example.com/age.json') }}")
template.render(age=30)  # OK
template.render(age=-1)  # ERROR

Contributions

Contributions are always welcome via filing issues or submitting pull requests. Please check the contribution guide for more details.