Django Model Change Tracker

change-tracker.py

from django.forms.models import model_to_dict

class ModelChangesMixin(object):
    """
    Mixin to tracks changes to your models.
    """

    def __init__(self, *args, **kwargs):
        super(ModelChangesMixin, self).__init__(*args, **kwargs)
        self.__original = self._data

    @property
    def _data(self):
        return model_to_dict(self, fields=[field.name for field in
                             self._meta.fields])

    @property
    def diff(self):
        original = self.__original
        latest = self._data
        differences = []
        for field_name, value in original.items():
            if value != latest[field_name]:
                differences.append((field_name, (value, latest[field_name],),))
        return dict(differences)

    @property
    def fields_changed(self):
        return self.diff.keys()

    @property
    def has_changed(self):
        return bool(self.diff)

    def save(self, *args, **kwargs):
        super(ModelChangesMixin, self).save(*args, **kwargs)
        self.__original = self._data