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Schematics

… rubric:: Python Data Structures for Humans™.

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:alt: Build Status

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:alt: Coverage

About

Project documentation: https://schematics.readthedocs.io/en/latest/

Schematics is a Python library to combine types into structures, validate them, and transform the shapes of your data based on simple descriptions.

The internals are similar to ORM type systems, but there is no database layer in Schematics. Instead, we believe that building a database layer is easily made when Schematics handles everything except for writing the query.

Schematics can be used for tasks where having a database involved is unusual.

Some common use cases:

• Design and document specific data structures <https://schematics.readthedocs.io/en/latest/usage/models.html>_
• Convert structures <https://schematics.readthedocs.io/en/latest/usage/exporting.html#converting-data>_ to and from different formats such as JSON or MsgPack
• Validate <https://schematics.readthedocs.io/en/latest/usage/validation.html>_ API inputs
• Remove fields based on access rights <https://schematics.readthedocs.io/en/latest/usage/exporting.html>_ of some data’s recipient
• Define message formats for communications protocols, like an RPC
• Custom persistence layers <https://schematics.readthedocs.io/en/latest/usage/models.html#model-configuration>_

Example

This is a simple Model.

… code:: python

from schematics.models import Model
from schematics.types import StringType, URLType
class Person(Model):
… name = StringType(required=True)
… website = URLType()
…
person = Person({‘name’: u’Joe Strummer’,
… ‘website’: ‘http://soundcloud.com/joestrummer’})
person.name
u’Joe Strummer’

Serializing the data to JSON.

… code:: python

import json
json.dumps(person.to_primitive())
{“name”: “Joe Strummer”, “website”: “http://soundcloud.com/joestrummer”}

Let’s try validating without a name value, since it’s required.

… code:: python

person = Person()
person.website = ‘http://www.amontobin.com/’
person.validate()
Traceback (most recent call last):
File “”, line 1, in
File “schematics/models.py”, line 231, in validate
raise DataError(e.messages)
schematics.exceptions.DataError: {‘name’: [‘This field is required.’]}

Add the field and validation passes.

… code:: python

person = Person()
person.name = ‘Amon Tobin’
person.website = ‘http://www.amontobin.com/’
person.validate()

… _coverage:

Testing & Coverage support

Run coverage and check the missing statements. ::

$ coverage run --source schematics -m py.test && coverage report