User passes test in django to check subscription-CodePudding

I have a django application where I need to check if a user has a valid subscription, otherwise it redirects the user to his/her dashboard. I was thinking to use the django decorator user_passes_test but I couldn't find a proper way to create the function to check the user. My models for user and subscription are:

class CustomUser(AbstractUser):
    user_type_data = (
    ('admin', 'admin'),
    ('school_admin', 'school_admin'),
    ('student', 'student'),
)
    user_type = models.CharField(
    max_length=20, choices=user_type_data, default='student')
    address = models.CharField(max_length=500, null=True, blank=True)
    city = models.CharField(max_length=200, null=True, blank=True)
    zip_code = models.CharField(max_length=100, null=True, blank=True)
    country = CountryField(null=True, blank=True)
    phone = models.CharField(max_length=200, null=True, blank=True)
    selected_course = models.ForeignKey(QuizTheoryCourse, on_delete=models.CASCADE, null=True, blank=True)

class Subscription(models.Model):
    user = models.OneToOneField(CustomUser, on_delete=models.CASCADE)
    issue_date = models.DateTimeField(null=True, blank=True)
    duration = models.IntegerField(choices=DURATION_CHOICES)
    expiration_date = models.DateTimeField()


def __str__(self):
    return f'{self.user} - {str(self.expiration_date)}'

def get_expiration(self):
    if self.expiration_date:
        if self.expiration_date > timezone.now():
            expiration_date = self.expiration_date   timedelta(days=int(self.duration))
        else:
            expiration_date = dt.now()   timedelta(days=int(self.duration))
    else:
        expiration_date = dt.now()   timedelta(days=int(self.duration))
    return expiration_date


def is_subscription_valid(self):
    today = timezone.now()
    return today < self.expiration_date

The function I am using to pass in the decorator is:

def subscription_valid(user):
    try:
        superuser = user.is_superuser
        user_valid = user.subscription.is_subscription_valid
        return superuser or user_valid
    except user.DoesNotExist:
        return False

My problem is that, anytime the user doesn't have any kind of subscription (let's say it's just registered) I receive an error:

CustomUser has no subscription.

I suppose I have some kind of if/elif statement in the function, but I couldn't figure out how to get around it.

CodePudding user response：

Your idea is good, but there are some erros in your function. When you try to access to subscription, Django can raise a ObjectDoesNotExist, not a model.DoesNotExist exception. You can check if subscription exist by using hasattr(user, 'subscription') or try an access and catch the exception

from django.core.exceptions import ObjectDoesNotExist
def subscription_valid(user):
    try:
        superuser = user.is_superuser
        user_valid = user.subscription.is_subscription_valid
        return superuser or user_valid
    except ObjectDoesNotExist:
        return False