Throttling for rate limiting in Django

Introduction

Throttling helps control how many times a user can make requests to your Django app. It stops too many requests in a short time to keep your app safe and fast.

To stop users from sending too many requests and slowing down your site.

To protect your app from accidental or bad behavior like spamming.

To limit API usage so one user doesn't use all resources.

To keep your server stable during high traffic times.

To improve user experience by preventing overload.

Syntax

Django

from rest_framework.throttling import UserRateThrottle

class MyThrottle(UserRateThrottle):
    rate = '5/minute'

# Then add MyThrottle to your view's throttle_classes

The rate is how many requests are allowed per time unit.

You use throttle_classes in your Django REST Framework views to apply throttling.

Examples

This class limits each user to 5 requests per minute.

Django

from rest_framework.throttling import UserRateThrottle

class FivePerMinuteThrottle(UserRateThrottle):
    rate = '5/minute'

This limits anonymous users to 10 requests per hour.

Django

from rest_framework.throttling import AnonRateThrottle

class AnonTenPerHourThrottle(AnonRateThrottle):
    rate = '10/hour'

This view uses the default user throttle settings.

Django

from rest_framework.views import APIView
from rest_framework.response import Response
from rest_framework.throttling import UserRateThrottle

class MyView(APIView):
    throttle_classes = [UserRateThrottle()]

    def get(self, request):
        return Response({'message': 'Hello!'})

Sample Program

This example creates a throttle that allows 5 requests per minute per user. The HelloView uses this throttle to limit how often users can call the GET method.

Django

from rest_framework.views import APIView
from rest_framework.response import Response
from rest_framework.throttling import UserRateThrottle

class FivePerMinuteThrottle(UserRateThrottle):
    rate = '5/minute'

class HelloView(APIView):
    throttle_classes = [FivePerMinuteThrottle()]

    def get(self, request):
        return Response({'message': 'Hello, world!'})

Important Notes

Throttling works best with Django REST Framework views.

You can customize throttle rates per user or anonymous users.

Remember to test throttling by making multiple requests quickly.

Summary

Throttling limits how many requests a user can make in a time period.

Use custom throttle classes with a rate like '5/minute'.

Apply throttling by adding throttle classes to your views.

Practice

1. What is the main purpose of throttling in Django REST Framework?

easy

A. To cache API responses for faster access

B. To limit the number of requests a user can make in a given time period

C. To authenticate users before accessing the API

D. To speed up the response time of the server

Solution

1. Step 1: Understand throttling concept

   Throttling is designed to control how many requests a user can send to the server in a set time.

2. Step 2: Identify purpose in Django REST Framework

   It prevents abuse by limiting request rates, not speeding responses or authentication.

3. Final Answer:

   To limit the number of requests a user can make in a given time period -> Option B

4. Quick Check:

   Throttling = request limit [OK]

Hint: Throttling controls request counts per time [OK]

Common Mistakes:

• Confusing throttling with authentication
• Thinking throttling speeds up responses
• Mixing throttling with caching

2. Which of the following is the correct way to set a throttle rate of 10 requests per minute in a custom throttle class?

easy

A. rate = '10/minute'

B. rate = '10/second'

C. rate = 'minute/10'

D. rate = '10 requests per minute'

Solution

1. Step 1: Recall throttle rate format

   The rate must be a string with number and time unit separated by a slash, e.g., '10/minute'.

2. Step 2: Match correct syntax

   Only '10/minute' matches the required format; others are invalid or incorrect syntax.

3. Final Answer:

   rate = '10/minute' -> Option A

4. Quick Check:

   Throttle rate format = 'number/time' [OK]

Hint: Throttle rate uses 'number/time' string format [OK]

Common Mistakes:

• Using spaces or words instead of slash format
• Swapping number and time units
• Using unsupported time units

3. Given this view with throttling applied:

from rest_framework.throttling import UserRateThrottle

class MyThrottle(UserRateThrottle):
    rate = '3/minute'

class MyView(APIView):
    throttle_classes = [MyThrottle]

    def get(self, request):
        return Response({'message': 'Hello'})

What happens if a user makes 4 GET requests within one minute?

medium

A. The 4th request is delayed but eventually succeeds

B. All 4 requests succeed with status 200

C. The 4th request is blocked with a 429 Too Many Requests error

D. The server crashes due to too many requests

Solution

1. Step 1: Understand throttle rate and behavior

   The throttle allows 3 requests per minute per user; the 4th exceeds the limit.

2. Step 2: Identify response to exceeding limit

   When limit is exceeded, Django REST Framework returns HTTP 429 error blocking the request.

3. Final Answer:

   The 4th request is blocked with a 429 Too Many Requests error -> Option C

4. Quick Check:

   Requests > rate limit = 429 error [OK]

Hint: Requests over limit get 429 error [OK]

Common Mistakes:

• Assuming all requests succeed
• Thinking requests get delayed instead of blocked
• Believing server crashes on too many requests

4. Identify the error in this custom throttle class:

from rest_framework.throttling import SimpleRateThrottle

class CustomThrottle(SimpleRateThrottle):
    scope = 'custom'

    def get_cache_key(self, request, view):
        return request.user.id

# settings.py
REST_FRAMEWORK = {
    'DEFAULT_THROTTLE_RATES': {
        'custom': '5/minute'
    }
}

medium

A. get_cache_key should return a string, but returns an integer

B. scope should be set to 'rate' instead of 'custom'

C. DEFAULT_THROTTLE_RATES key 'custom' is missing a time unit

D. CustomThrottle must inherit from UserRateThrottle, not SimpleRateThrottle

Solution

1. Step 1: Check get_cache_key return type

   The method returns request.user.id, which is an integer, but cache keys must be strings.

2. Step 2: Validate other parts

   Scope 'custom' matches the throttle rate key, and inheritance from SimpleRateThrottle is valid.

3. Final Answer:

   get_cache_key should return a string, but returns an integer -> Option A

4. Quick Check:

   Cache key must be string [OK]

Hint: Cache keys must be strings, not integers [OK]

Common Mistakes:

• Returning non-string cache keys
• Misnaming throttle scope
• Confusing throttle class inheritance

5. You want to apply different throttle rates for authenticated and anonymous users in Django REST Framework. Which approach correctly implements this?

hard

A. Set a single throttle class with rate '10/minute' and check user status inside get_cache_key

B. Use middleware to block anonymous users after 5 requests per minute instead of throttling classes

C. Apply throttling only to authenticated users by setting throttle_classes conditionally in the view

D. Use two throttle classes: one with 'user' scope for authenticated, one with 'anon' scope for anonymous, and add both to the view's throttle_classes

Solution

1. Step 1: Understand throttling for different user types

   Django REST Framework supports multiple throttle classes to handle different user types separately.

2. Step 2: Apply correct method

   Using two throttle classes with 'user' and 'anon' scopes and adding both to throttle_classes is the standard way.

3. Final Answer:

   Use two throttle classes: one with 'user' scope for authenticated, one with 'anon' scope for anonymous, and add both to the view's throttle_classes -> Option D

4. Quick Check:

   Multiple throttle classes handle user types separately [OK]

Hint: Use separate throttle classes for user and anon [OK]

Common Mistakes:

• Trying to handle both user types in one throttle class
• Using middleware instead of throttle classes
• Conditionally setting throttle_classes in the view