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Attach metadata to any Django models using redis

Project description

Attach metadata to any Django models using redis.

Build Status

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:

# 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:

# 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:

# 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

>>> 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.

>>> 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

>>> '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:

>>> 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.

Project details


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Filename, size & hash SHA256 hash help File type Python version Upload date
django-metadata-0.2.0.tar.gz (7.7 kB) Copy SHA256 hash SHA256 Source None Oct 10, 2016

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