https://github.com/thoas/django-metadata

Attach metadata to any Django models using redis
https://github.com/thoas/django-metadata

Last synced: about 2 months ago
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Attach metadata to any Django models using redis

• Host: GitHub
• URL: https://github.com/thoas/django-metadata
• Owner: thoas
• Created: 2013-06-02T20:58:01.000Z (over 11 years ago)
• Default Branch: master
• Last Pushed: 2018-06-15T13:02:17.000Z (over 6 years ago)
• Last Synced: 2024-10-14T14:43:28.276Z (2 months ago)
• Language: Python
• Homepage:
• Size: 23.4 KB
• Stars: 27
• Watchers: 3
• Forks: 1
• Open Issues: 0
• Metadata Files:
  • Readme: README.rst

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README

        
django-metadata

===============

Attach metadata to any Django models using redis.

.. image:: https://secure.travis-ci.org/thoas/django-metadata.png?branch=master

    :alt: Build Status

    :target: http://travis-ci.org/thoas/django-metadata

Installation

------------

Either check out the package from GitHub_ or it pull from a release via PyPI::

       pip install django-metadata

Usage

-----

With ``django-metadata`` you can attach metadata to any Django models, you will

be able to link keys and theirs values to any instances.

Currently only Redis_ is supported with only redis-py_ as backend.

Let's say you have this model:

.. code-block:: python

    # models.py

    from django.db import models

    class User(models.Model):

        username = models.CharField(max_length=150)

Now you have to attach the ``MetadataMixin`` to your model:

.. code-block:: python

    # models.py

    from django.db import models

    from metadata.mixins import MetadataMixin

    class User(MetadataMixin, models.Model):

        username = models.CharField(max_length=150)

You can customize the way ``django-metadata`` is storing your values by providing

a ``metadata_key`` property to your model:

.. code-block:: python

    # models.py

    from django.db import models

    from metadata.mixins import MetadataMixin

    class User(MetadataMixin, models.Model):

        username = models.CharField(max_length=150)

        def metadata_key(self):

            return 'metadata:utilisateur:%d' % self.pk

By default, the schema will be ``metadata:%(lowerclassname)s:%(primary_key)s``.

Now we have connected our model to the mixin we can play with the API.

The API of ``MetadataContainer`` follows the same principes as ``dict``.

Adding keys

...........

.. code-block:: python

    >>> from myapp.models import User

    >>> user = User.objects.create(username='thoas')

    >>> user.metadata['mail_signup_sent'] = 1

    >>> user = User.objects.get(username='thoas')

    >>> user.metadata['mail_signup_sent']

    1

    >>> user.metadata = {'mail_signup_sent': 0}

    >>> user.metadata['mail_signup_sent']

    0

Removing keys

.............

You can either removing a key by setting its value to ``None`` or use the ``del``

operator.

.. code-block:: python

    >>> del user.metadata['key']

    >>> user.metadata['key']

    Traceback (most recent call last):

        ...

    KeyError: 'key'

    >>> user.metadata.get('key', None)

    None

    >>> user.metadata['foo'] = 'bar'

    >>> user.metadata['foo'] = None

    >>> user.metadata['foo']

    Traceback (most recent call last):

        ...

    KeyError: 'foo'

    >>> user.metadata.get('foo', None)

    None

    >>> user.metadata['key'] = 'value'

    >>> user.metadata['foo'] = 'bar'

    >>> user.metadata = {'foo': None}

    >>> user.metadata['foo']

    Traceback (most recent call last):

        ...

    KeyError: 'foo'

    >>> user.metadata['key']

    value

Iterating keys

..............

.. code-block:: python

    >>> 'value' in user.metadata

    True

    >>> user.metadata.values()

    ['value']

    >>> user.metadata.keys()

    ['key']

    >>> user.metadata.items()

    [('key', 'value')]

Incrementing keys

.................

As we are using Redis as storing engine you can use some of its nice features:

.. code-block:: python

    >>> user.metadata.incr('counter')

    >>> user.metadata['counter']

    1

    >>> user.metadata.incr('counter', 2)

    >>> user.metadata['counter']

    3

Inspiration

-----------

``django-metadata`` comes from an original idea of twidi_.

.. _GitHub: https://github.com/thoas/django-metadata

.. _redis-py: https://github.com/andymccurdy/redis-py

.. _Redis: http://redis.io/

.. _twidi: https://github.com/twidi