Group-based permissions in Django - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ component_behavior

intermediate

What is the output of this Django group permission check?

Consider a Django view where a user belongs to a group named 'editors'. The view checks if the user has permission 'blog.change_post' via group membership. What will be the output of the permission check if the group 'editors' has the 'change_post' permission assigned?

Django

from django.contrib.auth.models import Group
user = request.user
has_perm = user.has_perm('blog.change_post')
print(has_perm)

A Raises AttributeError

B False

C True

D None

💡 Hint

Remember that Django checks user permissions including those granted by groups.

If the user belongs to a group that has the 'change_post' permission, user.has_perm('blog.change_post') returns True. Django automatically includes group permissions in this check.

📝 Syntax

intermediate

Identify the correct way to add a user to a group in Django

Which of the following code snippets correctly adds a user to a group named 'managers'?

A

group = Group.objects.get(name='managers')
user.groups.add(group)

B user.add_group('managers')

C Group.add_user(user, 'managers')

D user.groups.append('managers')

💡 Hint

Check the Django documentation for the correct method to add a group to a user's groups.

In Django, to add a user to a group, you first get the group object and then use user.groups.add(group). The other options use invalid methods or attributes.

🔧 Debug

advanced

Why does this permission check always return False?

A developer writes this code to check if a user has permission 'app.delete_item'. The user belongs to a group with this permission, but the check returns False. What is the likely cause?

Django

if request.user.has_perm('app.delete_item'):
    print('Permission granted')
else:
    print('Permission denied')

A User's group permissions are not automatically checked by has_perm

B The permission codename is incorrect or missing app label

C The user is not authenticated

D The permission is assigned to the user directly, not the group

💡 Hint

Check the exact permission string format: it must be '.'.

If the permission string is incorrect or missing the app label, has_perm will always return False even if the user belongs to a group with the correct permission.

❓ state_output

advanced

What is the number of permissions a user has after adding two groups with overlapping permissions?

A user belongs to two groups: 'writers' and 'editors'. Both groups have the permission 'blog.add_post'. The 'writers' group also has 'blog.view_post'. How many unique permissions does the user have?

Django

from django.contrib.auth.models import User
user = User.objects.get(username='alice')
permissions = user.get_all_permissions()
print(len(permissions))

A 4

B 3

C 1

D 2

💡 Hint

Remember that permissions are unique and duplicates from groups count only once.

The user has two unique permissions: 'blog.add_post' (from both groups, counted once) and 'blog.view_post' (from 'writers'). So total is 2.

🧠 Conceptual

expert

Which statement best describes Django's group-based permission inheritance?

Select the statement that correctly explains how Django handles permissions for users assigned to groups.

A Users inherit all permissions assigned to their groups automatically when checking permissions.

B Permissions assigned to groups override user permissions and cannot be combined.

C Group permissions are ignored unless explicitly checked with group.has_perm().

D Users must manually copy group permissions to their user permissions to inherit them.

💡 Hint

Think about how Django's has_perm method works with groups.

Django automatically includes permissions from all groups a user belongs to when checking user.has_perm(). No manual copying or separate checks are needed.