Messaging a Logged-in User

00:00 Messaging a Logged-in User. Django includes a mechanism for notifying your users. This is tied to their authentication and can be used inside any authorized Django view.

00:13 The messages framework uses middleware to make any outstanding notifications for the user available in any view. By default, messages support five levels: DEBUG, INFO, SUCCESS, WARNING, and ERROR.

00:31 The messages framework is used primarily for asynchronous communication with the user. For example, if a background job goes wrong, then you can inform the user by sending a message with the ERROR level.

00:45 Unfortunately, there is no area in the admin for creating messages. They have to be created in code. To demonstrate this, add the following code to your core/views.py.

01:28 This view adds two messages to the logged-in user’s session, a greeting with the INFO level and an alert with the WARNING level.

01:37 messages.add_message() takes three parameters: the HttpRequest object, the message level, and the message itself. To use messages.add_message(), you need to register the view as a URL.

02:03 You can access messages in your code using get_messages() or directly within a template using the messages value in the template context.

02:12 Add the following code to templates/listing.html to display any messages to the user on the blog listing page.

02:59 This code uses a list of messages in the template context that’s put there by the middleware. If there are messages, then an HTML unordered list is created showing each of them. Visit the /add_messages/ URL to create some messages as seen onscreen here, and then go to the blog listing page at the root of the site to see them.

03:23 If you refresh the page, you’ll notice that the messages are gone. Django automatically recognizes the fact that the notifications have been viewed and removes them from the session.