Authentication decorator

sitefeeds.py

    def basic_authentication(request):
        '''
        Returns LazyUser object if Basic authentication from the GET request can be authenticated.
        Returns None if it cannot.
        '''
        if 'HTTP_AUTHORIZATION' not in request.META and request.user:
            feed_user = request.user
        elif 'HTTP_AUTHORIZATION' in request.META:
            auth_header = request.META.get('HTTP_AUTHORIZATION')
            # Retrieve credentials
            encoded_credentials = auth_header.split(' ')[1]
            username, password = base64.b64decode(encoded_credentials).decode('utf-8').split(':')
            # Verify credentials
            feed_user = authenticate(username=username, password=password)
        else:
            feed_user = None
        return feed_user

    def feed_authorization(authenticated_user, feed_user_username):
        '''
        Checks the authorization of the authenticated user acceessing the feed.

        Args:

            authenticated_user: (User LazyObject) User that is verfied as having credentials
                                for the website

            feed_user_username: (str) The username belonging to the owner of the feed.

        Returns:

            Product_Feed_User:  If the authenticated_user is staff or is otherwise authorized to
                                access this feed. The specified product feed user is returned.

            HttpResponse:       If the authenticated_user is not authorized to access this feed
                                and is not staff.
        '''

        if authenticated_user is not None:
            # Confirmed as site user credentials.
            # Allows staff to access feed.
            if authenticated_user.is_staff or authenticated_user.username == feed_user_username:
                try:
                    product_feed_user = Product_Feed_User.objects \
                        .get(user__username=feed_user_username)
                except:
                    return None
            else:
                return None
        return product_feed_user

    def request_passes_test(test_func):
        """
        Decorator for views that checks that the request passes the given test.
        The test should be a callable that takes the user object and returns True
        or an object if the request passes, and None or False if the request fails.
        """

        def decorator(view_func):
            @wraps(view_func, assigned=available_attrs(view_func))
            def _wrapped_view(request, *args, **kwargs):
                if test_func(request):
                    return view_func(request, *args, **kwargs)
                else:
                    return HttpResponseForbidden()
            return _wrapped_view
        return decorator

@GoogleFeed.request_passes_test(GoogleFeed.basic_authentication)
def local_products_feed(request, feed_user_username):
    '''
    Renders and returns an XML spreadsheet of product data for the declared feed_user.
    The XML and product data conforms to the Google Local Products Inventory Feed Specifications.
    '''
    feed_bot = GoogleFeed.basic_authentication(request)
    authorization_response = GoogleFeed.feed_authorization(feed_bot, feed_user_username)
    if isinstance(authorization_response, HttpResponse):
        return authorization_response  # authorization failed
    else:
        pf_user = authorization_response
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