Skip to main content

An object wrapper for JSON Schema definitions

Project description

What

python-jsonschema-objects provides an automatic class-based binding to JSON schemas for use in python.

For example, given the following schema:

{
    "title": "Example Schema",
    "type": "object",
    "properties": {
        "firstName": {
            "type": "string"
        },
        "lastName": {
            "type": "string"
        },
        "age": {
            "description": "Age in years",
            "type": "integer",
            "minimum": 0
        },
        "dogs": {
            "type": "array",
            "items": {"type": "string"},
            "maxItems": 4
        }
    },
    "required": ["firstName", "lastName"]
}

jsonschema-objects can generate a class based binding. Assume here that the schema above has been loaded in a variable called schema:

>>> import python_jsonschema_objects as pjs
>>> builder = pjs.ObjectBuilder(schema)
>>> ns = builder.build_classes()
>>> Person = ns.ExampleSchema
>>> james = Person(firstName="James", lastName="Bond")
>>> james.lastName
u'Bond'
>>> james
<example_schema lastName=Bond age=None firstName=James>

Validations will also be applied as the object is manipulated.

>>> james.age = -2
python_jsonschema_objects.validators.ValidationError: -4 was less
or equal to than 0

The object can be serialized out to JSON:

>>> james.serialize()
'{"lastName": "Bond", "age": null, "firstName": "James"}'

Why

Ever struggled with how to define message formats? Been frustrated by the difficulty of keeping documentation and message definition in lockstep? Me too.

There are lots of tools designed to help define JSON object formats, foremost among them JSON Schema. JSON Schema allows you to define JSON object formats, complete with validations.

However, JSON Schema is language agnostic. It validates encoded JSON directly - using it still requires an object binding in whatever language we use. Often writing the binding is just as tedious as writing the schema itself.

This avoids that problem by auto-generating classes, complete with validation, directly from an input JSON schema. These classes can seamlessly encode back and forth to JSON valid according to the schema.

Other Features

The ObjectBuilder can be passed a dictionary specifying ‘memory’ schemas when instantiated. This will allow it to resolve references where the referenced schemas are retrieved out of band and provided at instantiation.

For instance:

{
    "title": "Address",
    "type": "string"
}
{
    "title": "Other",
    "type": "object",
    "properties": {
        "MyAddress": {"$ref": "memory:Address"}
    },
    "additionalProperties": false
}

Installation

pip install python_jsonschema_objects

Tests

Tests are managed using the excellent Tox. Simply pip install tox, then tox.

Changelog

0.0.9 - Added support for ‘memory:’ schema URIs, which can be used to reference externally resolved schemas.

0.0.8 - Fixed bugs that occurred when the same class was read from different locations in the schema, and thus had a different URI

0.0.7 - Required properties containing the ‘@’ symbol no longer cause build_classes() to fail.

0.0.6 - All literals now use a standardized LiteralValue type. Array validation actually coerces element types. as_dict can translate objects to dictionaries seamlessly.

0.0.5 - Improved validation for additionalItems (and tests to match). Provided dictionary-syntax access to object properties and iteration over properties.

0.0.4 - Fixed some bugs that only showed up under specific schema layouts, including one which forced remote lookups for schema-local references.

0.0.3b - Fixed ReStructuredText generation

0.0.3 - Added support for other array validations (minItems, maxItems, uniqueItems).

0.0.2 - Array item type validation now works. Specifying ‘items’, will now enforce types, both in the tuple and list syntaxes.

0.0.1 - Class generation works, including ‘oneOf’ and ‘allOf’ relationships. All basic validations work.

Project details


Release history Release notifications | RSS feed

Download files

Download the file for your platform. If you're not sure which to choose, learn more about installing packages.

Source Distribution

python_jsonschema_objects-0.0.9.tar.gz (16.8 kB view details)

Uploaded Source

Built Distribution

python_jsonschema_objects-0.0.9-py2-none-any.whl (19.3 kB view details)

Uploaded Python 2

File details

Details for the file python_jsonschema_objects-0.0.9.tar.gz.

File metadata

File hashes

Hashes for python_jsonschema_objects-0.0.9.tar.gz
Algorithm Hash digest
SHA256 b521f9a7a02e01b3a0a144d2a241c9bd97c1825c5427449f17b7c831689dcc81
MD5 198ff67fcc1a7721db85b7ec9a206eef
BLAKE2b-256 de51a6877c25e6b74a94221cac9193b2f55d4bdae16a9d5c8cbc99f6adc46356

See more details on using hashes here.

File details

Details for the file python_jsonschema_objects-0.0.9-py2-none-any.whl.

File metadata

File hashes

Hashes for python_jsonschema_objects-0.0.9-py2-none-any.whl
Algorithm Hash digest
SHA256 ac6fd96ae6f05d35d2ced16434014e21d6b601200724eada6d86d9fa1d379fde
MD5 551fed17f0d4f1146f9b9634fc59c046
BLAKE2b-256 ada28b029b7a3803037cd8f2a543685c1390e1362b378d918ad34cd9c44fbb68

See more details on using hashes here.

Supported by

AWS AWS Cloud computing and Security Sponsor Datadog Datadog Monitoring Fastly Fastly CDN Google Google Download Analytics Microsoft Microsoft PSF Sponsor Pingdom Pingdom Monitoring Sentry Sentry Error logging StatusPage StatusPage Status page