django-gen-settings - a Settings Mixin for Django Models

Features:

• Save settings directly to a Instance
• Retrieve settings directly from an Instance
• Settings can be inherited from multiple predecessor fields

When to use:

• if you want to store values to a model, but dont want to create additional fields on the model

And when not:

• if you want to query these stored values
• if you often change this values

Notes

This Version should not be used in full production, since the API will may change in the future

The settings are stored in an json object in the database, some caching is done, but settings a value leads to an write of the whole json object

Installation

pypi package coming soon ...

Add django_gen_settings to your INSTALLED_APPS in your django settings.py:

INSTALLED_APPS = (
    ...,
    'django_gen_settings',
)

Usage

Lets say you have a model Client like this:

class Client(models.Model, SettingsMixin):
    name = models.CharField(max_length=128, db_index=True, verbose_name=_('Name'), help_text=_('Name of the Client')) #Tag Name should be unique

The SettingsMixin adds a additional field with the names 'settings' to your model. Instead of accessing the field directly, use the getsetting and setsetting methods. The setting name will be splitted on the dots ( '.' ), and saved as json dict.

client = Client()
client.name = "Testclient"
client.setsetting("messages.inbox.displaymessages", 5 )
client.save()

nrmsg = client.getsetting("messages.inbox.displaymessages") # nrmsg contains 5

Lets add a second class with also with a SettingsMixin:

class Account(SettingsMixin, AbstractBaseUser, PermissionsMixin):
    client = models.ForeignKey(Client)
    username = models.CharField(max_length=64,  unique=True)
    email = models.EmailField(blank=True)
    is_staff = models.BooleanField(default=False)

    USERNAME_FIELD = 'username'

    class Meta:
        settings_predecessor_field = 'client'
    
    

Note the settings_predecessor_field in the Meta Class of Account. If a setting does not exist in the current instance, the setting of the predecessor field is queried. You can also chain multiple models with a SettingsMixin.

If you create a Account instance linked to the created Client Instance before, you can do the following:

nrmsg = account.getsetting("messages.inbox.displaymessages") # contains 5 from the predecessor field 'client'
account.setsetting("messages.inbox.displaymessages", 2) 

nrmsg = account.getsetting("messages.inbox.displaymessages") # contains now 2, since we overlayed the setting