Skip to main content

Marshmallow multiplexing schema

Project description

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.

Description: =======================
Marshmallow-OneOfSchema
=======================

.. image:: https://travis-ci.org/maximkulkin/marshmallow-oneofschema.svg?branch=master
:target: https://travis-ci.org/maximkulkin/marshmallow-oneofschema
:alt: Build Status

An extenstion to Marshmallow to support schema (de)multiplexing.

Marshmallow is a fantastic library for serialization and deserialization of data.
For more on that project see its `GitHub <https://github.com/marshmallow-code/marshmallow>`_
page or its `Documentation <http://marshmallow.readthedocs.org/en/latest/>`_.

This library adds a special kind of schema that actually multiplexes other schemas
based on object type. When serializing values, it uses get_obj_type() method
to get object type name. Then it uses `type_schemas` name-to-Schema mapping
to get schema for that particular object type, serializes object using that
schema and adds an extra field with name of object type. Deserialization is reverse.

Installing
----------
::

$ pip install marshmallow-oneofschema

Importing
---------
Here is how to import the necessary field class
::

from marshmallow_oneofschema import OneOfSchema

Example
-------

The code below demonstrates how to setup a schema with a PolyField. For the full context check out the tests.
Once setup the schema should act like any other schema. If it does not then please file an Issue.

.. code:: python

import marshmallow
import marshmallow.fields
from marshmallow_oneofschema import OneOfSchema

class Foo(object):
def __init__(self, foo):
self.foo = foo

class Bar(object):
def __init__(self, bar):
self.bar = bar

class FooSchema(marshmallow.Schema):
foo = marshmallow.fields.String(required=True)

@marshmallow.post_load
def make_foo(self, data):
return Foo(**data)

class BarSchema(marshmallow.Schema):
bar = marshmallow.fields.Integer(required=True)

@marshmallow.post_load
def make_bar(self, data):
return Bar(**data)

class MyUberSchema(OneOfSchema):
type_schemas = {
'foo': FooSchema,
'bar': BarSchema,
}

def get_obj_type(self, obj):
if isinstance(obj, Foo):
return 'foo'
elif isinstance(obj, Bar):
return 'bar'
else:
raise Exception('Unknown object type: %s' % obj.__class__.__name__)

MyUberSchema().dump([Foo(foo='hello'), Bar(bar=123)], many=True).data
# => [{'type': 'foo', 'foo': 'hello'}, {'type': 'bar', 'bar': 123}]

MyUberSchema().load([{'type': 'foo', 'foo': 'hello'},
{'type': 'bar', 'bar': 123}],
many=True).data
# => [Foo('hello'), Bar(123)]

By default get_obj_type() returns obj.__class__.__name__, so you can just reuse that
to save some typing:

.. code:: python

class MyUberSchema(OneOfSchema):
type_schemas = {
'Foo': FooSchema,
'Bar': BarSchema,
}

You can customize type field with `type_field` class property:

.. code:: python

class MyUberSchema(OneOfSchema):
type_field = 'object_type'
type_schemas = {
'Foo': FooSchema,
'Bar': BarSchema,
}

MyUberSchema().dump([Foo(foo='hello'), Bar(bar=123)], many=True).data
# => [{'object_type': 'Foo', 'foo': 'hello'}, {'object_type': 'Bar', 'bar': 123}]

You can use resulting schema everywhere marshmallow.Schema can be used, e.g.

.. code:: python

import marshmallow as m
import marshmallow.fields as f

class MyOtherSchema(m.Schema):
items = f.List(f.Nested(MyUberSchema))

License
-------

MIT licensed. See the bundled `LICENSE <https://github.com/maximkulkin/marshmallow-oneofschema/blob/master/LICENSE>`_ file for more details.

Keywords: serialization,deserialization,json,marshal,marshalling,schema,validation,multiplexing,demultiplexing,polymorphic
Platform: UNKNOWN
Classifier: Intended Audience :: Developers
Classifier: License :: OSI Approved :: MIT License
Classifier: Programming Language :: Python :: 2
Classifier: Programming Language :: Python :: 2.6
Classifier: Programming Language :: Python :: 2.7
Classifier: Programming Language :: Python :: 3
Classifier: Programming Language :: Python :: 3.3
Classifier: Programming Language :: Python :: 3.4
Classifier: Programming Language :: Python :: Implementation :: CPython
Classifier: Programming Language :: Python :: Implementation :: PyPy

Project details


Download files

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

Filename, size & hash SHA256 hash help File type Python version Upload date
marshmallow_oneofschema-1.0.5-py2.py3-none-any.whl (8.2 kB) Copy SHA256 hash SHA256 Wheel py2.py3 Jun 21, 2017
marshmallow-oneofschema-1.0.5.tar.gz (4.9 kB) Copy SHA256 hash SHA256 Source None Jun 21, 2017

Supported by

Elastic Elastic Search Pingdom Pingdom Monitoring Google Google BigQuery Sentry Sentry Error logging AWS AWS Cloud computing DataDog DataDog Monitoring Fastly Fastly CDN DigiCert DigiCert EV certificate StatusPage StatusPage Status page