Attach metadata to any Django models using redis
Project description
Attach metadata to any Django models using redis.
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.pkBy 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']
0Removing 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']
valueIterating 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']
3Inspiration
django-metadata comes from an original idea of twidi.
