python - Django: Generic views based 'as_view()' method

Question

I was working on an application wherein I created a generic ListView. Now, while defining that view in my urls.py, I read from the documentation that I need to use the as_view() method as follows:

from django.conf.urls import patterns, include, url
from .views import BlogIndex

urlpatterns = patterns(
    '',
    url(r'^$', BlogIndex.as_view(), name="index"),
)

Now, I didn't really understood what the documentation had to say about this method. Can someone shed some light into this concept?

Answer 1

In Class-based views, you have to call as_view() function so as to return a callable view that takes a request and returns a response. Its the main entry-point in request-response cycle in case of generic views.

as_view is the function(class method) which will connect my MyView class with its url.

From django docs:

classmethod as_view(**initkwargs)
Returns a callable view that takes a request and returns a response:

You just can't use class-based views like you could in normal function-based views.

BlogIndex(request) # can't do this in case of CBVs

The above code is not valid if you want the CBVs to function properly. For that, you need to provide a view which is callable and then pass request to it. For example:

response = MyView.as_view()(request)  # valid way

By calling the as_view() function on my view class MyView will give me a view which i will call with request parameter to initiate the request-response cycle.

In your case:

my_callable_view = BlogIndex.as_view() # returns a callable view
<function blog.views.BlogIndex>

Now, call this function and pass the request.

 response = my_callable_view(request) # generate proper response