ASGI vs WSGI in Django - Practice Questions

Challenge - 5 Problems

🧠 Conceptual

intermediate

What is the main difference between ASGI and WSGI?

Choose the option that best describes the key difference between ASGI and WSGI in Django applications.

A ASGI and WSGI both support asynchronous communication but differ in performance optimizations.

B WSGI supports asynchronous communication and WebSockets, while ASGI only supports synchronous HTTP requests.

C ASGI supports asynchronous communication and WebSockets, while WSGI only supports synchronous HTTP requests.

D WSGI is designed for mobile apps, while ASGI is designed only for desktop web apps.

💡 Hint

Think about which interface allows handling multiple connections at the same time.

ASGI (Asynchronous Server Gateway Interface) supports asynchronous features like WebSockets and long-lived connections. WSGI (Web Server Gateway Interface) only handles synchronous HTTP requests.

❓ component_behavior

intermediate

What happens when a Django app using WSGI tries to handle a WebSocket connection?

Select the correct behavior of a Django app configured with WSGI when it receives a WebSocket request.

A The app will reject the connection because WSGI does not support WebSockets.

B The app will handle the WebSocket connection normally using synchronous code.

C The app will convert the WebSocket to a regular HTTP request automatically.

D The app will crash with a syntax error.

💡 Hint

WSGI was designed before WebSockets existed.

WSGI does not support WebSocket connections, so the app will reject or fail to handle them.

📝 Syntax

advanced

Identify the correct ASGI application declaration in Django

Which of the following code snippets correctly declares an ASGI application in Django?

Django

from django.core.asgi import get_asgi_application

application = ???

A application.asgi()

B get_wsgi_application()

C asgi_application()

D get_asgi_application()

💡 Hint

Look for the function that returns an ASGI application instance.

The correct way to get an ASGI application in Django is to call get_asgi_application(). The other options are either WSGI or invalid.

❓ state_output

advanced

What is the output when running an async Django view under WSGI?

Consider an async Django view that returns a simple HTTP response. What happens when this view is run under a WSGI server?

Django

async def my_view(request):
    return HttpResponse('Hello async!')

A Raises a RuntimeWarning and runs the view synchronously, returning 'Hello async!'.

B The server crashes with an AttributeError.

C Raises a SyntaxError because async views are not allowed.

D Runs asynchronously and returns 'Hello async!' without warnings.

💡 Hint

WSGI servers expect synchronous views that return HttpResponse objects directly; async views return coroutines.

Under WSGI, an async view returns a coroutine object instead of an HttpResponse. Django raises an AttributeError (e.g., 'coroutine' object has no attribute 'status_code'). The view body does not execute.

❓ lifecycle

expert

How does ASGI handle multiple simultaneous connections compared to WSGI?

Select the option that best explains how ASGI manages multiple connections differently from WSGI in Django applications.

A ASGI uses an event loop to handle many connections concurrently without blocking, while WSGI handles one request at a time per worker.

B WSGI uses an event loop to handle many connections concurrently, while ASGI processes requests sequentially.

C Both ASGI and WSGI use threading to handle multiple connections simultaneously.

D ASGI queues all requests and processes them one by one, while WSGI uses multiprocessing.

💡 Hint

Think about asynchronous programming and event loops.

ASGI uses asynchronous event loops to handle many connections at once without blocking. WSGI processes one request per worker synchronously.

Practice

1. What is the main difference between WSGI and ASGI in Django?

easy

A. WSGI is faster than ASGI in all cases.

B. WSGI supports WebSocket, ASGI only supports HTTP.

C. WSGI is used for databases, ASGI is used for templates.

D. WSGI handles synchronous requests, ASGI supports asynchronous and real-time features.

Solution

1. Step 1: Understand WSGI's role

   WSGI is designed for synchronous web applications, handling one request at a time.

2. Step 2: Understand ASGI's role

   ASGI supports asynchronous code and real-time features like WebSocket, allowing multiple requests concurrently.

3. Final Answer:

   WSGI handles synchronous requests, ASGI supports asynchronous and real-time features. -> Option D

4. Quick Check:

   WSGI = synchronous, ASGI = asynchronous [OK]

Hint: Remember: ASGI = async and real-time support [OK]

Common Mistakes:

• Thinking WSGI supports WebSocket
• Confusing ASGI with database handling
• Assuming WSGI is always faster

2. Which of the following is the correct way to specify an ASGI application in Django's asgi.py file?

easy

A. application = get_wsgi_application()

B. application = get_application()

C. application = get_asgi_application()

D. application = asgi_application()

Solution

1. Step 1: Recall Django's ASGI setup

   Django provides get_asgi_application() to create the ASGI application instance.

2. Step 2: Compare options

   get_wsgi_application() is for WSGI, others are incorrect function names.

3. Final Answer:

   application = get_asgi_application() -> Option C

4. Quick Check:

   ASGI uses get_asgi_application() [OK]

Hint: ASGI uses get_asgi_application(), WSGI uses get_wsgi_application() [OK]

Common Mistakes:

• Using get_wsgi_application() in asgi.py
• Misspelling function names
• Confusing application variable names

3. Given this Django ASGI consumer code snippet, what will happen when a WebSocket connection is accepted?

from channels.generic.websocket import AsyncWebsocketConsumer

class ChatConsumer(AsyncWebsocketConsumer):
    async def connect(self):
        await self.accept()

medium

A. The server will crash due to missing HTTP response.

B. The WebSocket connection is accepted and ready to receive messages asynchronously.

C. The connection will be rejected because accept() is synchronous.

D. Nothing happens because connect() is not called automatically.

Solution

1. Step 1: Understand AsyncWebsocketConsumer behavior

   The connect method is called automatically on WebSocket connection attempts.

2. Step 2: Analyze the accept() call

   Calling await self.accept() accepts the WebSocket connection asynchronously, enabling message exchange.

3. Final Answer:

   The WebSocket connection is accepted and ready to receive messages asynchronously. -> Option B

4. Quick Check:

   Async accept() means connection accepted [OK]

Hint: Async accept() means WebSocket connection is accepted [OK]

Common Mistakes:

• Thinking accept() is synchronous
• Assuming connect() is not called automatically
• Confusing WebSocket with HTTP requests

4. You wrote this snippet in your Django asgi.py file but get an error:

from django.core.asgi import get_asgi_application

application = get_wsgi_application()

What is the problem?

medium

A. You imported get_asgi_application but called get_wsgi_application, causing a NameError.

B. You must import get_wsgi_application to use it.

C. The application variable name is incorrect.

D. There is no problem; this code works fine.

Solution

1. Step 1: Check imports and function calls

   The code imports get_asgi_application but calls get_wsgi_application(), which is not imported.

2. Step 2: Understand the error cause

   This mismatch causes a NameError because get_wsgi_application is undefined in this context.

3. Final Answer:

   You imported get_asgi_application but called get_wsgi_application, causing a NameError. -> Option A

4. Quick Check:

   Import and call must match [OK]

Hint: Import and function call must match exactly [OK]

Common Mistakes:

• Calling a function not imported
• Mixing ASGI and WSGI functions
• Assuming variable name causes error

5. You want to build a Django app that supports both HTTP requests and WebSocket connections for chat. Which setup should you choose and why?

hard

A. Use ASGI because it supports asynchronous HTTP and WebSocket connections.

B. Use WSGI because it handles HTTP and WebSocket natively.

C. Use WSGI with a separate WebSocket server.

D. Use ASGI but disable asynchronous features for compatibility.

Solution

1. Step 1: Identify requirements

   The app needs to handle HTTP requests and WebSocket connections for chat, which requires async support.

2. Step 2: Match server capabilities

   WSGI only supports synchronous HTTP, no WebSocket support. ASGI supports both async HTTP and WebSocket natively.

3. Step 3: Evaluate options

   Use ASGI because it supports asynchronous HTTP and WebSocket connections. correctly chooses ASGI for full async and WebSocket support in one server.

4. Final Answer:

   Use ASGI because it supports asynchronous HTTP and WebSocket connections. -> Option A

5. Quick Check:

   ASGI supports async HTTP + WebSocket [OK]

Hint: ASGI supports both HTTP and WebSocket asynchronously [OK]

Common Mistakes:

• Assuming WSGI supports WebSocket
• Using separate servers unnecessarily
• Disabling async features in ASGI