lambdalisue/django-observer

Watch modification of any type of field in Django's model and call registered callback

django-observer

Author

Alisue <lambdalisue@hashnote.net>

Supported python versions

Python 2.6, 2.7, 3.2, 3.3

Supported django versions

Django 1.2 - 1.6

Observe django model attribute modifications and call the specified callback. django-observer can recognize the modifications of

• Any value type of fields (CharField, IntegerField, etc.)
• Any relational fields (ForeignKey, OneToOneField, ManyToManyField)
• Any reverse relational fields (fields given by related_name)
• Any generic relational fields (GenericForeignKey, GenericRelation)

Documentation

http://django-observer.readthedocs.org/en/latest/

Installation

Use pip like:

$ pip install django-observer

Usage

Configuration

1. Add observer to the INSTALLED_APPS in your settings module

   INSTALLED_APPS = (
       # ...
       'observer',
   )

Example

from django.db import models
from django.contrib.auth.models import User

def status_changed(sender, obj, attr):
    if obj.status == 'draft':
        obj.title = "Draft %s" % obj.title
    else:
        obj.title = obj.title.replace("Draft ")
    obj.save()

# watch status attribute via decorator
from observer.decorators import watch
@watch('status', status_changed, call_on_created=True)
class Entry(models.Model):
    title = models.CharField(max_length=30)
    status = models.CharFiled(max_length=10)

    body = models.TextField('title', max_length=100)
    author = models.ForeignKey(User, null=True, blank=True)


def author_changed(sender, obj, attr):
    if obj.author is None:
        obj.status = "draft"
        obj.save()

# watch author attribute via function
from observer.shortcuts import watch
watch(Entry, 'author', author_changed)