django-concurrency is an optimistic lock¹ implementation for Django.

Tested with: 1.4.x, 1.5.x, 1.6.x, 1.7.x 1.8.x.

It prevents users from doing concurrent editing in Django both from UI and from a django command.

sample code:

from concurrency.fields import IntegerVersionField

class ConcurrentModel( models.Model ):
    version = IntegerVersionField( )

Now if you try:

a = ConcurrentModel.objects.get(pk=1)
b = ConcurrentModel.objects.get(pk=1)
a.save()
b.save()

you will get a RecordModifiedError on b.save()

Other projects that handle concurrent editing are django-optimistic-lock and django-locking anyway concurrency is "a batteries included" optimistic lock management system, here some features not available elsewhere:

• can be applied to any model; not only your code (ie. django.contrib.auth.Group)
• works with django 1.4-1.8
• handle list-editable ChangeList. (handle #11313)
• manage concurrency conflicts in admin's actions
• can intercept changes performend out of the django app (ie using pgAdmin, phpMyAdmin, Toads) (using TriggerVersionField_

Stable
Development
Project home page:	https://github.co	m/saxix/django-	concurrency
Issue tracker:	https://github.co	m/saxix/django-	concurrency/issues?sort
Download:	http://pypi.pytho	n.org/pypi/djan	go-concurrency/
Documentation:	https://django-co	ncurrency.readt	hedocs.org/en/latest/

_list-editable: https://django-concurrency.readthedocs.org/en/latest/admin.html#list-editable