Why advanced DRF features matter in Django - See It in Action

Why advanced DRF features matter

📖 Scenario: You are building a simple API for a bookstore. You want to show how using advanced Django REST Framework (DRF) features can make your API better and easier to maintain.

🎯 Goal: Create a basic DRF API with a book list, then add a filter feature to show only books with more than 300 pages. This shows why advanced DRF features like filtering matter.

📋 What You'll Learn

Create a list of books as Python dictionaries

Add a variable to set the minimum page count filter

Use a list comprehension to filter books with pages greater than the minimum

Return the filtered list in a DRF API view

💡 Why This Matters

🌍 Real World

Filtering data in APIs is common in real-world apps like bookstores, libraries, or any service showing lists of items.

💼 Career

Understanding DRF filtering and API views is essential for backend developers building REST APIs with Django.

1

Create the initial book data

Create a variable called books that is a list of dictionaries. Each dictionary should have these exact entries: {'title': 'Book A', 'pages': 250}, {'title': 'Book B', 'pages': 320}, and {'title': 'Book C', 'pages': 150}.

Django

# Create the books list with 3 dictionaries
# Your code here

Hint

Use a list with three dictionaries exactly as shown.

2

Add a minimum page count filter variable

Create a variable called min_pages and set it to 300.

Django

books = [
    {'title': 'Book A', 'pages': 250},
    {'title': 'Book B', 'pages': 320},
    {'title': 'Book C', 'pages': 150}
]
# Create min_pages variable and set to 300
# Your code here

Hint

Just create a variable named min_pages and assign 300.

3

Filter books with pages greater than min_pages

Create a variable called filtered_books that uses a list comprehension to include only books from books where the pages value is greater than min_pages.

Django

books = [
    {'title': 'Book A', 'pages': 250},
    {'title': 'Book B', 'pages': 320},
    {'title': 'Book C', 'pages': 150}
]
min_pages = 300
# Use list comprehension to filter books with pages > min_pages
# Your code here

Hint

Use a list comprehension with book for book in books if book['pages'] > min_pages.

4

Create a simple DRF API view to return filtered books

Create a DRF API view function called book_list that returns a Response with filtered_books. Import Response from rest_framework.response and api_view from rest_framework.decorators. Use the @api_view(['GET']) decorator.

Django

books = [
    {'title': 'Book A', 'pages': 250},
    {'title': 'Book B', 'pages': 320},
    {'title': 'Book C', 'pages': 150}
]
min_pages = 300
filtered_books = [book for book in books if book['pages'] > min_pages]

# Import Response and api_view
# Create @api_view(['GET']) decorated function book_list returning Response(filtered_books)
# Your code here

Hint

Remember to import Response and api_view, then create a function book_list decorated with @api_view(['GET']) that returns Response(filtered_books).

Practice

1. Why is it important to use advanced features like permissions in Django REST Framework (DRF)?

easy

A. To control who can access or modify API data

B. To speed up the server hardware

C. To change the database schema automatically

D. To make the API look prettier on the frontend

Solution

1. Step 1: Understand the role of permissions in DRF

   Permissions restrict or allow access to API endpoints based on user roles or authentication.

2. Step 2: Identify the purpose of permissions

   Permissions help keep data safe by controlling who can read or change it.

3. Final Answer:

   To control who can access or modify API data -> Option A

4. Quick Check:

   Permissions = Control access [OK]

Hint: Permissions control access rights in APIs [OK]

Common Mistakes:

• Thinking permissions improve server speed
• Confusing permissions with database changes
• Assuming permissions affect frontend design

2. Which of the following is the correct way to add pagination in a DRF viewset?

easy

A. pagination_class = PageNumberPagination

B. paginate = True

C. pagination = 'enabled'

D. page_size = 10

Solution

1. Step 1: Recall DRF pagination syntax

   DRF uses the attribute pagination_class to set pagination behavior in viewsets.

2. Step 2: Match the correct attribute and value

   Assigning PageNumberPagination to pagination_class enables page-based pagination.

3. Final Answer:

   pagination_class = PageNumberPagination -> Option A

4. Quick Check:

   Pagination uses pagination_class = PageNumberPagination [OK]

Hint: Use pagination_class to enable pagination in DRF [OK]

Common Mistakes:

• Using incorrect attribute names like paginate or pagination
• Setting page_size without pagination_class
• Assigning string values instead of classes

3. Given this DRF serializer method:

class MySerializer(serializers.ModelSerializer):
    def create(self, validated_data):
        user = self.context['request'].user
        validated_data['owner'] = user
        return super().create(validated_data)

What does this method do when creating an object?

medium

A. It raises an error because 'owner' is not in validated_data

B. It ignores the user and creates an anonymous object

C. It assigns the current user as the owner of the new object

D. It deletes the user from the request context

Solution

1. Step 1: Analyze the create method override

   The method adds the current user from the request context to the validated data under 'owner'.

2. Step 2: Understand the effect on object creation

   By adding 'owner', the created object will link to the user who made the request.

3. Final Answer:

   It assigns the current user as the owner of the new object -> Option C

4. Quick Check:

   create() adds user as owner [OK]

Hint: create() can add user info from context automatically [OK]

Common Mistakes:

• Assuming it raises error if 'owner' missing
• Thinking it deletes user from context
• Believing it ignores user data

4. You have this DRF viewset snippet:

class MyViewSet(viewsets.ModelViewSet):
    queryset = MyModel.objects.all()
    serializer_class = MySerializer
    permission_classes = [IsAuthenticated]

    def get_queryset(self):
        return MyModel.objects.filter(owner=self.request.user)

What is the main issue with this code?

medium

A. serializer_class must be a list, not a single class

B. permission_classes should be a tuple, not a list

C. get_queryset should not filter by owner

D. The queryset attribute is overridden by get_queryset, so it is redundant

Solution

1. Step 1: Understand get_queryset overriding

   Defining get_queryset replaces the queryset attribute for filtering dynamically.

2. Step 2: Identify redundancy

   Since get_queryset returns a filtered queryset, the class-level queryset is not used and is redundant.

3. Final Answer:

   The queryset attribute is overridden by get_queryset, so it is redundant -> Option D

4. Quick Check:

   get_queryset overrides queryset attribute [OK]

Hint: get_queryset overrides queryset attribute in viewsets [OK]

Common Mistakes:

• Thinking permission_classes must be a tuple
• Believing filtering by owner is wrong here
• Assuming serializer_class must be a list

5. You want to create a DRF API that returns a paginated list of items owned by the logged-in user, and automatically assigns the user as owner when creating new items. Which combination of features should you use?

hard

A. Use pagination_class only, without filtering or permissions

B. Use permission_classes to require login, override get_queryset to filter by user, use pagination_class, and override serializer create() to set owner

C. Use permission_classes to allow all, override get_queryset to return all items, and do not override create()

D. Use no permissions, set queryset to all items, disable pagination, and set owner manually in frontend

Solution

1. Step 1: Identify security and filtering needs

   Require login with permission_classes and filter queryset by logged-in user to show only their items.

2. Step 2: Add pagination and automatic owner assignment

   Use pagination_class to handle large data sets and override serializer create() to assign owner automatically.

3. Final Answer:

   Use permission_classes to require login, override get_queryset to filter by user, use pagination_class, and override serializer create() to set owner -> Option B

4. Quick Check:

   Permissions + filtering + pagination + create() override = D [OK]

Hint: Combine permissions, filtering, pagination, and create() override [OK]

Common Mistakes:

• Ignoring permissions and filtering
• Not using pagination for large data
• Setting owner only on frontend