Class-based views

• Introduction to class-based views
• Using mixins with class-based views

Django provides base view classes which will suit a wide range of applications. All views inherit from the class, which handles linking the view into the URLs, HTTP method dispatching and other common features. RedirectView provides a HTTP redirect, and extends the base class to make it also render a template.

The most direct way to use generic views is to create them directly in your URLconf. If you’re only changing a few attributes on a class-based view, you can pass them into the as_view() method call itself:

The second, more powerful way to use generic views is to inherit from an existing view and override attributes (such as the ) or methods (such as get_context_data) in your subclass to provide new values or methods. Consider, for example, a view that just displays one template, about.html. Django has a generic view to do this - - so we can subclass it, and override the template name:

Then we need to add this new view into our URLconf. TemplateView is a class, not a function, so we point the URL to the class method instead, which provides a function-like entry to class-based views:

Suppose somebody wants to access our book library over HTTP using the views as an API. The API client would connect every now and then and download book data for the books published since last visit. But if no new books appeared since then, it is a waste of CPU time and bandwidth to fetch the books from the database, render a full response and send it to the client. It might be preferable to ask the API when the most recent book was published.

We map the URL to book list view in the URLconf:

If the view is accessed from a request, an object list is returned in the response (using the book_list.html template). But if the client issues a HEAD request, the response has an empty body and the header indicates when the most recent book was published. Based on this information, the client may or may not download the full object list.