Request parsing and response rendering in Django - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ component_behavior

intermediate

What is the output of this Django view when receiving a POST request with JSON data?

Consider this Django view that parses JSON data from a POST request and returns a JSON response:

from django.http import JsonResponse
import json

def my_view(request):
    if request.method == 'POST':
        data = json.loads(request.body.decode('utf-8'))
        name = data.get('name', 'Guest')
        return JsonResponse({'greeting': f'Hello, {name}!'})
    return JsonResponse({'error': 'Only POST allowed'}, status=405)

What will be the JSON response body if the POST request body is {"name": "Alice"}?

Django

from django.http import JsonResponse
import json

def my_view(request):
    if request.method == 'POST':
        data = json.loads(request.body.decode('utf-8'))
        name = data.get('name', 'Guest')
        return JsonResponse({'greeting': f'Hello, {name}!'})
    return JsonResponse({'error': 'Only POST allowed'}, status=405)

A {"greeting": "Hello, Alice!"}

B {"greeting": "Hello, Guest!"}

C {"error": "Only POST allowed"}

D SyntaxError

💡 Hint

Look at how the JSON body is parsed and how the 'name' key is used.

The view loads the JSON from request.body, extracts the 'name' key, and returns a greeting with that name. Since the POST body contains {"name": "Alice"}, the greeting is "Hello, Alice!".

📝 Syntax

intermediate

Which option correctly parses JSON data in a Django view?

Which of the following code snippets correctly parses JSON data from a Django request object?

A data = request.json()

B data = request.POST.json()

C data = json.loads(request.body.decode('utf-8'))

D data = json.parse(request.body)

💡 Hint

Remember that request.body is a byte string and you need to decode it properly.

In Django, request.body contains the raw bytes of the request body. Using json.loads(request.body.decode('utf-8')) correctly parses the JSON. The other options are invalid because Django's request.POST is for form data, and request has no json() method. Also, json.parse does not exist in Python.

🔧 Debug

advanced

Why does this Django view raise a TypeError when returning JsonResponse?

Examine this Django view:

from django.http import JsonResponse

def my_view(request):
    data = {'count': 5, 'items': [1, 2, 3]}
    return JsonResponse(data, safe=False)

Why does this code raise a TypeError?

Django

from django.http import JsonResponse

def my_view(request):
    data = {'count': 5, 'items': [1, 2, 3]}
    return JsonResponse(data, safe=False)

A Because safe=False is required only when returning a list, not a dict

B Because safe=False is used with a dict, which is not allowed

C Because JsonResponse cannot serialize lists inside dicts

D Because the data dict is missing a status code

💡 Hint

Check the meaning of the safe parameter in JsonResponse.

The safe parameter in JsonResponse must be set to False only when the top-level object is not a dict (e.g., a list). Since data is a dict here, safe=False is unnecessary but does not cause an error. Actually, this code runs fine. The question is tricky because the code does not raise a TypeError. The correct answer is that safe=False is only needed for non-dict objects.

❓ state_output

advanced

What is the HTTP status code of this Django JsonResponse?

Given this Django view:

from django.http import JsonResponse

def error_view(request):
    return JsonResponse({'error': 'Not found'}, status=404)

What HTTP status code will the response have?

Django

from django.http import JsonResponse

def error_view(request):
    return JsonResponse({'error': 'Not found'}, status=404)

A 500

B 404

C 200

D 400

💡 Hint

Look at the status parameter in JsonResponse.

The status parameter sets the HTTP status code of the response. Here it is explicitly set to 404, so the response will have status code 404.

🧠 Conceptual

expert

Which Django feature automatically parses JSON request bodies in views?

In Django, which feature or tool automatically parses JSON request bodies and provides the data as a Python dictionary without manually calling json.loads(request.body)?

A Using Django's HttpRequest.POST attribute

B Using Django's middleware for JSON parsing

C Using Django's built-in JsonResponse

D Using Django REST Framework's Request object

💡 Hint

Think about popular Django extensions for APIs.

Django itself does not automatically parse JSON request bodies. However, Django REST Framework (DRF) provides a Request object that parses JSON and other content types automatically, making the data available as request.data. The other options either do not parse JSON automatically or are unrelated.