datastore.objects is a
simple object mapper on top of
datastore (not relational). Thanks to
datastore's versatility, it makes it easy to (serialize and) persist custom
classes to any sort of data storage service.
Notice: please familiarize yourself with datastore first.
pip install datastore.objects
datastore.objects uses the default datastore.Key, making significant use
of the type and instance fragments.
>>> from datastore.objects import Key, Model
>>> class Scientist(Model):
>>> pass
>>> Scientist.key
Key('/Scientist')
>>> Scientist('Tesla').key
Key('/Scientist:Tesla')datastore.objects provides a class that you inherit from to define your
models. datastore.objects.Model handles the datastore serializing and
deserializing, attribute validation, etc.
>>> from datastore.objects import Model
>>> class Scientist(Model):
>>> passdatastore.objects uses descriptor Attributes to track the properties you wish
to store. This is heavily based on how other python ORMs (django, app engine)
do it. In short, you define model attributes like this:
>>> from datastore.objects import Attribute, Model
>>> class Scientist(Model):
>>> name = Attribute(required=True)
>>> field = Attribute(default='Physics')
>>> tesla = Scientist('Tesla')
>>> tesla.name = 'Nicola Tesla'
>>> tesla.field
'Physics'
>>> tesla.field = 'Electrical Engineering'
>>> tesla.data
{'name': 'Nicola Tesla', 'field': 'Electrical Engineering'}datastore.objects provides a ShimDatastore that wraps any other datastore.
Thus you can use any of the various datastores to persist your objects.
ObjectDatastore makes sure to serialize (on put) and deserialize (on get)
data properly, and construct your classes.
>>> import datastore
>>> from datastore.objects import Attribute, Model, ObjectDatastore
>>>
>>> class Scientist(Model):
>>> name = Attribute(required=True)
>>> field = Attribute(default='Physics')
>>>
>>> tesla = Scientist('Tesla')
>>> tesla.name = 'Tesla'
>>> tesla.field = 'Electrical Engineering'
>>>
>>> dds = datastore.DictDatastore()
>>> ods = ObjectDatastore(dds, model=Scientist)
>>> ods.put(tesla.key, tesla)
>>> dds.get(tesla.key)
{'name': 'Tesla', 'field': 'Electrical Engineering'}
>>> ods.get(tesla.key)
<Model /Scientist:Tesla>datastore.objects is written by Juan Batiz-Benet,
of Athena.
It is free open-source software, available under the MIT License.
Project webpage: https://github.com/datastore/datastore.objects. Issues: https://github.com/jbenet/object-datastore/issues