Log models

utils.py

#!/usr/bin/env python
# -*- coding: utf-8 -*-
from django.contrib.admin.models import LogEntry, ADDITION, CHANGE, DELETION
from django.contrib.contenttypes.models import ContentType
from django.utils.encoding import force_unicode
from django.forms.models import model_to_dict

def log_addition(request, dbobject, oldobject=None, message=None):
    _log_action(request, dbobject, oldobject, ADDITION, message)

def log_change(request, dbobject, oldobject=None, message=None):
    _log_action(request, dbobject, oldobject, CHANGE, message)

def log_deletion(request, dbobject, oldobject=None, message=None):
    _log_action(request, dbobject, oldobject, DELETION, message)


def _log_action(request, dbobject, oldobject, action, message=None):
    # Helper to get content-type of objects
    def _content_type_id(obj):
        return ContentType.objects.get_for_model(obj).pk
    
    content_type_id = _content_type_id(dbobject)
    
    if message is None:
        messages = []
        # If oldobject is provided, detect which fields were changed
        if oldobject:
            # Check that both object have same type
            assert content_type_id == _content_type_id(oldobject), 'Cannot compare objects fields of different types.'
            # Iterate fields values and compare !
            newvalues = model_to_dict(dbobject)
            for field, oldvalue in model_to_dict(oldobject).items():
                newvalue = newvalues[field]
                if oldvalue != newvalue:
                    messages.append(u"%s → %s" % (oldvalue or "''", newvalue))
        message = u", ".join(messages)
    
    # Use Django admin facility to log actions
    LogEntry.objects.log_action(
        user_id         = request.user.pk, 
        content_type_id = content_type_id,
        object_id       = dbobject.pk,
        object_repr     = force_unicode(dbobject), # Could be customized
        action_flag     = action,
        change_message  = force_unicode(message).decode('unicode_escape'),  #mysql :(
    )