django-user-messages adds offline messaging support to Django's messaging framework. It achieves this by allowing to save messages in the database. The user_messages.api.get_messages utility and the user_messages.context_processors.messages context processor transparently concatenate Django's messages and our own messages in a single list, therefore existing code works without any changes and without causing database writes. django-user-messages' functions have to be used explicitly. I consider this a feature, not a bug.

• Install django-user-messages using pip into your virtualenv.
• Add user_messages to INSTALLED_APPS and run migrate.
• Add the user_messages.context_processors.messages message processor somewhere after the default messages processor. Django's admin app checks for the presence of the latter so you cannot simply remove it (except if you want to silence the "admin.E404" system check).
• Use user_messages.api as you would use django.contrib.messages except that you pass the user model or ID as first parameter, not the current request.

Pretty much the same as Django's messaging framework:

from user_messages import api

api.info(user, 'Hey there')
api.warning(user, 'Stop this')
api.error(user, 'Not nice!')

# Passing the ID is also possible; the user instance does not
# have to be instantiated at all:
api.success(user.id, 'Yay!')

django-user-messages' messages supports two additional features not available in Django's messages framework:

• Messages can be delivered more than once by passing deliver_once=False. These messages have to be acknowledged explicitly. django-user-messages does not contain any code to do this.

• It is possible to attach additional data by passing a dictionary as meta:

  api.debug(user, 'Oww', meta={
      'url': 'http://example.com',
  })
  

For convenience, our messages have the same tags and level_tag properties as Django's messages. Meta properties are also accessible in templates:

{% if messages %}
  <ul class="messages">
  {% for message in messages %}
    <li class="{{ message.tags }}".>
      {% if message.meta.url %}<a href="{{ message.meta.url }}">{% endif %}
      {{ message }}
      {% if message.meta.url %}</a>{% endif %}
    </li>
  {% endfor %}
  </ul>
{% endif %}

django-user-messages' messages are also evaluated lazily.