middleware.rst

Middleware

.. module:: djem.middleware

MessageMiddleware

.. versionadded:: 0.6

Middleware that handles temporary messages, differentiating between those added as part of an AJAX request vs those that are not. Different storage backends are used for each: the default backend (configurable via MESSAGE_STORAGE) for standard requests and a custom memory-only backend for AJAX requests.

Using a memory-only backend, which does not offer any persistence between requests, prevents simultaneous AJAX requests interfering with each other's message stores, avoiding the documented caveat of Django's out-of-the-box messages framework.

This is a drop-in replacement for Django's own MessageMiddleware:

# before
MIDDLEWARE = [
    ...
    'django.contrib.messages.middleware.MessageMiddleware'
    ...
]

# after
MIDDLEWARE = [
    ...
    'djem.middleware.MessageMiddleware'
    ...
]

Important

MessageMiddleware uses the HttpRequest object's is_ajax() method to differentiate between AJAX and non-AJAX requests. An XMLHttpRequest call must use the appropriate headers in order to be correctly detected.

.. seealso::

    :class:`~djem.ajax.AjaxResponse`
        An extension of Django's ``JsonResponse`` that, among other things, will automatically include any messages that are in the message store as part of the response.