Tutorial :django class view with decorator and sessions



Question:

I'm trying to convert some of my django views over from function based views to class based views and I've run into a small problem.

My OO is kind of weak and I think the problem is that I've lost track of where things are going.

I have a custom login decorator that I need on the views so I have...

First I have the View class from this example http://www.djangosnippets.org/snippets/760/

Then my view class looks like this...

class TopSecretPage(View):      @custom_login      def __call__(self, request, **kwargs):          #bla bla view stuff...          pass  

The problem is that my decorator can't access request.session for some reason...

My decorator looks like this...

def myuser_login_required(f):      def wrap(request, *args, **kwargs):            # this check the session if userid key exist,          # if not it will redirect to login page            if 'field' not in request.session.keys():          return wrap  

I think it's something simple that I'm missing so thanks for your patience everyone!

UPDATE: Ok so here's the error that I get...

"ViewDoesNotExist: Tried TopSecretPage in module projectname.application.views. Error was: type object 'TopSecretPage' has no attribute 'session'"

I simplified the decorator as well to look like this....

def myuser_login_required(request, *args, **kwargs):          # this check the session if userid key exist,      # if not it will redirect to login page        if 'username' not in request.session.keys():          return  HttpResponseRedirect(reverse("login-page"))        return True  


Solution:1

The problem is that your wrapper expects "request" as the first argument, but a method on a class always takes "self" as the first argument. So in your decorator, what it thinks is the request object is actually TopSecretPage itself.

Either Vinay or artran's solutions should work, so I won't repeat them. Just thought a clearer description of the problem might be helpful.


Solution:2

The correct way to do this for any decorator applied to any class-based view method is to use django.utils.decorators.method_decorator(). I'm not sure when method_decorator() was introduced but here is an example/update in the Django 1.2 release notes. Use it like this:

from django.utils.decorators import method_decorator    class TopSecretPage(View):      @method_decorator(custom_login)      def __call__(self, request, **kwargs):          #bla bla view stuff...          pass  


Solution:3

This problem has come up before. A solution is included which might work for you.

Update: Example method with decorator:

class ContentView(View):        # the thing in on_method() is the actual Django decorator      #here are two examples      @on_method(cache_page(60*5))      @on_method(cache_control(max_age=60*5))      def get(self, request, slug): # this is the decorated method          pass #in here, you access request normally  


Solution:4

Instead of using the decorator on the view you could decorate the url.

For example in urls.py:

from my_decorators import myuser_login_required  from my_views import TopSecretPage    urlpatterns = patterns('',       (r'^whatever-the-url-is/$', myuser_login_required(TopSecretPage), {}),  )  

You may need to play with that a little but it's about right.


Solution:5

This is effectively a duplicate of Django - Correct way to pass arguments to CBV decorators? which describes the correct way of addressing this. The correct way of doing this for django 1.9 is as follows:

@method_decorator(myuser_login_required(), name='dispatch')  class TopSecretPage(View):      ..  

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