papercapp / django-cached_authentication_middleware

A drop in replacement for django's built in AuthenticationMiddleware that utilizes caching.

django-cached_authentication_middleware is a drop in replacement for django.contrib.auth's built in AuthenticationMiddleware. It tries to populate request.user by fetching user data from cache before falling back to the database.

Installation

• Install via pypi:

  pip install django-cached_authentication_middleware
  

• Configure CACHES in django's settings.py:

  CACHES = {
      'default': {
          'BACKEND': 'django.core.cache.backends.memcached.PyLibMCCache',
          'LOCATION': '127.0.0.1:11211',
          'TIMEOUT': 36000,
      }
  }
  

• Replace django.contrib.auth.middleware.AuthenticationMiddleware with cached_auth.Middleware in settings.py:

  MIDDLEWARE_CLASSES = (
      'django.middleware.common.CommonMiddleware',
      'django.contrib.sessions.middleware.SessionMiddleware',
      #'django.contrib.auth.middleware.AuthenticationMiddleware'
      'cached_auth.Middleware',
  )
  

And you're done!

Cached Auth Preprocessor

Sometimes you want to preprocess to User instance before storing it into cache. cached_auth allows you to define settings.CACHED_AUTH_PREPROCESSOR, a callable that takes two arguments, user & request and returns a User instance.

A classic example of this would be to attach Profile data to User object so calling request.user.profile does not incur a database hit. Here's how we can implement it.

def attach_profile(user, request):
    try:
        user.get_profile()
    # Handle exception for user with no profile and AnonymousUser
    except (Profile.DoesNotExist, AttributeError):
        pass
    return user


# In settings.py:
CACHED_AUTH_PREPROCESSOR = 'path.to.module.attach_profile'

Running Tests

To run the test suite:

python tests/runtests.py

To run the test suite with Django custom user (this will run only on Django 1.5):

python tests/runtests_custom_user.py

Changelog

Version 0.2.1

• Better Django 1.8 compatibility.

Version 0.2.0

• Added support for Django 1.5's customer user model
• Added CACHED_AUTH_PREPROCESSOR setting

Version 0.1.1

• Fixed an error where middleware tries to call "get_profile" on AnonymousUser

Version 0.1

• Initial release