Simple asynchronous messages for django.
What problem does this solve?
Suppose a user instigates an expensive task that you are processing offline (eg using Celery). This library provides a simple mechanism for notifying the user when the task is finished, utilising Django's messaging framework.
What's an example?
You might use Celery to generate a large report and then employ this library to notify the user that their report is ready to be downloaded. The user will see the message you've sent them when they make their next request after the message is submitted.
How does it work?
A cache is used to persist the messages, and middleware is used to pick these up and submit them to Django's messaging framework. All very simple.
Aren't there other libraries that do this?
Yes, there are - but they solve the problem in different ways:
- django-offline-messages - this provides an alternative storage backend that Django's messages framework can use.
What's good about this implementation?
- It's simple, fast and easy to use.
- It works cohesively with existing Django cache and messages framework. It will work no matter what cache backend your are using, and whatever storage backend is used for messages.
- Only one message per user at the moment, lists of messages to come later.
- A user may miss the message if they navigating quickly between pages.
From PyPI (stable):
pip install django-async-messages
From Github (unstable):
pip install git+git://github.com/codeinthehole/django-async-messages#egg=djang-async-messages
'async_messages.middleware.AsyncMiddleware' to your
Ensure it comes after
You need to have
CACHES configured in you settings for this to work. As usual,
memcache is the best choice.
Send a message to a single user:
>>> from async_messages import message_user >>> from django.contrib.auth.models import User >>> barry = User.objects.get(username='barry') >>> message_user(barry, "Barry, your report is ready")
Send a message to lots of users:
>>> from async_messages import message_users >>> staff = User.objects.filter(is_staff=True) >>> message_users(staff, "All budgets must be spent by the end of the day")
Specify message level:
>>> from django.contrib.messages import constants >>> message_users(staff, "Boom!", constants.WARNING)
- Altered dependency on Django to be only 1.2+
- Altered middleware to use
- Better docstrings
- Minimum viable product