Process request and process response in Django - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ component_behavior

intermediate

What is the output of this Django view when receiving a GET request?

Consider this Django view function. What will be the HTTP response content when a GET request is made to this view?

Django

from django.http import HttpResponse

def my_view(request):
    if request.method == 'GET':
        return HttpResponse('Hello, GET request!')
    else:
        return HttpResponse('Not a GET request')

A Hello, GET request!

B Not a GET request

C Raises an error because request.method is undefined

D Empty response with status 200

💡 Hint

Check the request.method attribute for GET requests.

The view checks if the request method is 'GET'. If yes, it returns 'Hello, GET request!'. Otherwise, it returns 'Not a GET request'.

❓ state_output

intermediate

What is the value of response.status_code after this view runs?

Given this Django view, what will be the HTTP status code of the response object returned?

Django

from django.http import HttpResponse

def status_view(request):
    response = HttpResponse('OK')
    response.status_code = 201
    return response

A 200

B 201

C 404

D 500

💡 Hint

Look at how the status_code attribute is set on the response.

The response status_code is explicitly set to 201 before returning, so the HTTP status code will be 201.

📝 Syntax

advanced

Which option correctly accesses POST data in a Django view?

You want to get the value of the 'username' field sent via POST in a Django view. Which code snippet correctly retrieves it?

Django

def post_view(request):
    # retrieve username from POST data
    pass

A username = request.data['username']

B username = request.GET['username']

C username = request.body['username']

D username = request.POST['username']

💡 Hint

POST data is accessed via request.POST dictionary.

In Django, POST form data is accessed via request.POST dictionary. request.GET is for query parameters. request.body is raw bytes. request.data is not a Django attribute.

🔧 Debug

advanced

What error does this Django view raise when called?

Analyze this Django view code. What error will it raise when a request is made?

Django

from django.http import HttpResponse

def error_view(request):
    return HttpResponse('Hello') + ' World'

A TypeError: unsupported operand type(s) for +: 'HttpResponse' and 'str'

B SyntaxError: invalid syntax

C NameError: name 'HttpResponse' is not defined

D No error, returns 'Hello World'

💡 Hint

Check the types involved in the + operation.

HttpResponse object cannot be concatenated with a string using + operator, causing a TypeError.

🧠 Conceptual

expert

Which option best describes how Django processes a request and returns a response?

Select the option that correctly describes the sequence Django follows when processing an HTTP request and returning a response.

A Django receives request → URL dispatcher selects view → Middleware processes request → View returns HttpResponse → Response sent to client

B Django receives request → View processes request → Middleware processes response → URL dispatcher selects view → Response sent to client

C Django receives request → Middleware processes request → URL dispatcher selects view → View returns HttpResponse → Middleware processes response → Response sent to client

D Django receives request → Middleware processes response → URL dispatcher selects view → View returns HttpResponse → Response sent to client

💡 Hint

Think about the order of middleware and URL routing in Django's request cycle.

Django first passes the request through middleware, then URL dispatcher selects the view, the view returns HttpResponse, then middleware processes the response before sending it back.

Practice

1. What does the request object in a Django view primarily contain?

easy

A. Information sent by the user, like form data and headers

B. The HTML template to render

C. The final content sent back to the user

D. Database connection details

Solution

1. Step 1: Understand the role of the request object

   The request object holds all data sent by the user, such as form inputs, cookies, and headers.

2. Step 2: Differentiate request from response

   The response object is what the server sends back, not the request.

3. Final Answer:

   Information sent by the user, like form data and headers -> Option A

4. Quick Check:

   Request = User data [OK]

Hint: Request holds user input; response sends output [OK]

Common Mistakes:

• Confusing request with response
• Thinking request contains templates
• Assuming request holds server data

2. Which of the following is the correct way to return a simple text response in a Django view?

easy

A. return HttpResponse('Hello World')

B. return render('Hello World')

C. return JsonResponse('Hello World')

D. return redirect('Hello World')

Solution

1. Step 1: Identify the correct response class for text

   HttpResponse is used to send plain text or HTML content back to the user.

2. Step 2: Check other options

   render is for templates, JsonResponse for JSON data, redirect for URL redirects.

3. Final Answer:

   return HttpResponse('Hello World') -> Option A

4. Quick Check:

   Text response uses HttpResponse [OK]

Hint: Use HttpResponse for plain text output [OK]

Common Mistakes:

• Using render without a template
• Using JsonResponse for plain text
• Confusing redirect with response content

3. Given this Django view code, what will be the output when accessed?

from django.http import JsonResponse

def my_view(request):
    data = {'name': 'Alice', 'age': 30}
    return JsonResponse(data)

medium

A. name=Alice&age=30

B. {'name': 'Alice', 'age': 30}

C. {"name": "Alice", "age": 30}

D. An error because JsonResponse needs a string

Solution

1. Step 1: Understand JsonResponse output format

   JsonResponse converts the Python dictionary into a JSON string with double quotes.

2. Step 2: Check the output format

   The output is a JSON string: {"name": "Alice", "age": 30} with double quotes, not Python dict syntax.

3. Final Answer:

   {"name": "Alice", "age": 30} -> Option C

4. Quick Check:

   JsonResponse outputs JSON string [OK]

Hint: JsonResponse outputs JSON with double quotes [OK]

Common Mistakes:

• Expecting Python dict syntax in output
• Confusing URL query string with JSON
• Thinking JsonResponse needs string input

4. What is wrong with this Django view code?

from django.http import HttpResponse

def bad_view(request):
    response = HttpResponse('Hello')
    response.status_code = '404'
    return response

medium

A. HttpResponse cannot have status_code set manually

B. status_code must be an integer, not a string

C. Missing return statement

D. HttpResponse requires a JSON object

Solution

1. Step 1: Check the status_code assignment

   Status codes must be integers like 404, not strings like '404'.

2. Step 2: Confirm HttpResponse usage

   HttpResponse allows setting status_code manually but it must be int.

3. Final Answer:

   status_code must be an integer, not a string -> Option B

4. Quick Check:

   status_code = int, not string [OK]

Hint: status_code must be int, not string [OK]

Common Mistakes:

• Using string for status_code
• Thinking HttpResponse forbids status_code
• Forgetting to return response

5. You want to create a Django view that processes a POST request with JSON data and returns a JSON response with a message and the original data. Which code snippet correctly handles this?

hard

A. def view(request):
data = request.GET
return JsonResponse({'message': 'Received', 'data': data})

B. def view(request):
data = request.POST
return HttpResponse({'message': 'Received', 'data': data})

C. def view(request):
data = request.body
return JsonResponse(data)

D. def view(request):
data = json.loads(request.body)
return JsonResponse({'message': 'Received', 'data': data})

Solution

1. Step 1: Parse JSON from POST request body

   request.body contains raw bytes; json.loads converts it to a Python dict.

2. Step 2: Return JsonResponse with message and data

   JsonResponse correctly serializes the Python dict to JSON for response.

3. Step 3: Check other options

   def view(request): data = request.POST return HttpResponse({'message': 'Received', 'data': data}) wrongly uses HttpResponse with dict, def view(request): data = request.GET return JsonResponse({'message': 'Received', 'data': data}) uses GET instead of POST, def view(request): data = request.body return JsonResponse(data) returns raw bytes without parsing.

4. Final Answer:

   def view(request): data = json.loads(request.body) return JsonResponse({'message': 'Received', 'data': data}) -> Option D

5. Quick Check:

   Parse JSON body, respond with JsonResponse [OK]

Hint: Parse JSON from request.body, respond with JsonResponse [OK]

Common Mistakes:

• Using request.POST for JSON body
• Returning dict in HttpResponse
• Not parsing JSON before response