DRF installation and setup in Django - Performance & Optimization

Performance: DRF installation and setup

MEDIUM IMPACT

This affects the initial page load speed and backend response time by adding the Django REST Framework to the project.

Setting up Django REST Framework for API development

Django

pip install djangorestframework==3.14.0
INSTALLED_APPS = [
    'django.contrib.admin',
    'django.contrib.auth',
    'rest_framework',
    # other apps
]
REST_FRAMEWORK = {
    'DEFAULT_PAGINATION_CLASS': 'rest_framework.pagination.LimitOffsetPagination',
    'PAGE_SIZE': 10,
    'DEFAULT_THROTTLE_CLASSES': ['rest_framework.throttling.UserRateThrottle'],
    'DEFAULT_THROTTLE_RATES': {'user': '1000/day'},
    'DEFAULT_RENDERER_CLASSES': ['rest_framework.renderers.JSONRenderer'],
    'DEFAULT_PARSER_CLASSES': ['rest_framework.parsers.JSONParser']
}

Pinning DRF version ensures stable dependencies; configuring pagination and throttling reduces server load and response time; limiting renderers and parsers reduces processing overhead.

📈 Performance Gainreduces response time by 30-50ms, lowers memory usage, and avoids unnecessary processing

Setting up Django REST Framework for API development

Django

pip install djangorestframework
# Adding 'rest_framework' to INSTALLED_APPS without version pinning or minimal setup
INSTALLED_APPS = [
    'django.contrib.admin',
    'django.contrib.auth',
    'rest_framework',
    # other apps
]
# No configuration for pagination, throttling, or caching

Installing DRF without version control and without configuring performance-related settings can lead to larger package size and slower API responses.

📉 Performance Costadds ~1MB to backend dependencies, increases response time by 50-100ms due to default settings

Performance Comparison

Pattern	Backend Dependency Size	Response Time Impact	Memory Usage	Verdict
Unpinned DRF with default settings	~1MB added	Adds 50-100ms	Higher memory usage	[X] Bad
Pinned DRF with optimized settings	~1MB added	Adds 20-50ms	Lower memory usage	[OK] Good

Rendering Pipeline

DRF setup affects the backend processing stage before the browser receives data. It influences how fast the API can respond with JSON data, impacting the time until the browser can render content.

→Backend Processing

→Network Transfer

→Browser Rendering

⚠️ BottleneckBackend Processing due to serialization and view handling

Core Web Vital Affected

LCP

This affects the initial page load speed and backend response time by adding the Django REST Framework to the project.

Optimization Tips

1Always pin DRF version to avoid unexpected performance issues.

2Enable pagination to limit data size per API response.

3Use throttling and limit renderers to reduce backend load.

Performance Quiz - 3 Questions

How does pinning the DRF version in requirements affect performance?

A It increases the package size significantly.

B It ensures stable dependencies and avoids unexpected slowdowns.

C It disables pagination by default.

D It automatically caches all API responses.

DevTools: Network

How to check: Open DevTools, go to Network tab, filter API calls, and check the timing breakdown for backend response time.

What to look for: Look for the 'Waiting (TTFB)' time to see backend processing delay; lower times indicate better DRF setup.

Practice

1. What is the first step to add Django REST Framework (DRF) to your Django project?

easy

A. Include DRF URLs in urls.py

B. Add rest_framework to INSTALLED_APPS

C. Install DRF using pip install djangorestframework

D. Run python manage.py migrate

Solution

1. Step 1: Install DRF package

   You must first install the Django REST Framework package using pip to add API features.

2. Step 2: Prepare for configuration

   After installation, you can add it to your Django settings and URLs.

3. Final Answer:

   Install DRF using pip -> Option C

4. Quick Check:

   First step = Install DRF [OK]

Hint: Always install packages before configuring [OK]

Common Mistakes:

• Trying to add to INSTALLED_APPS before installing
• Skipping installation and expecting DRF to work
• Running migrations before installing DRF

2. Which line correctly adds Django REST Framework to your Django settings?

easy

A. 'rest_framework' in INSTALLED_APPS

B. 'rest_framework' in DATABASES

C. 'rest_framework' in TEMPLATES

D. 'rest_framework' in MIDDLEWARE

Solution

1. Step 1: Locate the correct settings list

   Django apps are added to the INSTALLED_APPS list in settings.py.

2. Step 2: Add DRF to INSTALLED_APPS

   Adding 'rest_framework' here enables Django to recognize DRF features.

3. Final Answer:

   'rest_framework' in INSTALLED_APPS -> Option A

4. Quick Check:

   DRF goes in INSTALLED_APPS [OK]

Hint: Apps go in INSTALLED_APPS, not middleware or databases [OK]

Common Mistakes:

• Adding DRF to MIDDLEWARE instead of INSTALLED_APPS
• Placing DRF in TEMPLATES or DATABASES sections
• Forgetting to add DRF to settings after installation

3. Given this urls.py snippet, what does it enable?

from django.urls import path, include

urlpatterns = [
    path('api-auth/', include('rest_framework.urls')),
]

medium

A. It registers all API views automatically

B. It adds API login and logout pages for DRF's browsable API

C. It disables Django admin interface

D. It sets up database migrations for DRF

Solution

1. Step 1: Understand the included URL

   The rest_framework.urls include login and logout views for the browsable API.

2. Step 2: Recognize the effect on API interface

   This enables users to log in and out when using the DRF web interface.

3. Final Answer:

   It adds API login and logout pages for DRF's browsable API -> Option B

4. Quick Check:

   Including rest_framework.urls = API login/logout [OK]

Hint: Including rest_framework.urls adds API login/logout pages [OK]

Common Mistakes:

• Thinking it registers API views automatically
• Confusing it with admin site URLs
• Assuming it runs migrations or database setup

4. You added rest_framework to INSTALLED_APPS but get an error: ModuleNotFoundError: No module named 'rest_framework'. What is the likely cause?

medium

A. You forgot to install DRF with pip

B. You added 'rest_framework' to MIDDLEWARE instead of INSTALLED_APPS

C. You did not include DRF URLs in urls.py

D. You need to run python manage.py migrate first

Solution

1. Step 1: Understand the error meaning

   ModuleNotFoundError means Python cannot find the DRF package installed.

2. Step 2: Check installation status

   This usually happens if you forgot to run pip install djangorestframework.

3. Final Answer:

   You forgot to install DRF with pip -> Option A

4. Quick Check:

   ModuleNotFoundError = Missing pip install [OK]

Hint: ModuleNotFoundError means package not installed [OK]

Common Mistakes:

• Assuming adding to INSTALLED_APPS installs the package
• Thinking missing URLs cause this error
• Running migrate does not fix missing package

5. You want to enable the browsable API login/logout pages and have installed DRF and added it to INSTALLED_APPS. Which is the correct way to update your project's urls.py to achieve this?

hard

A. Add path('api-auth/', include('rest_framework.authentication')) to urlpatterns

B. Add path('api-auth/', include('django.contrib.auth.urls')) to urlpatterns

C. Add path('api-auth/', include('rest_framework.views')) to urlpatterns

D. Add path('api-auth/', include('rest_framework.urls')) to urlpatterns

Solution

1. Step 1: Identify the correct URL include for DRF login/logout

   The DRF package provides rest_framework.urls for login/logout views.

2. Step 2: Add the correct path to urlpatterns

   Use path('api-auth/', include('rest_framework.urls')) to enable these pages.

3. Final Answer:

   Add path('api-auth/', include('rest_framework.urls')) to urlpatterns -> Option D

4. Quick Check:

   DRF login/logout URLs = rest_framework.urls [OK]

Hint: Use rest_framework.urls for API auth URLs [OK]

Common Mistakes:

• Using django.contrib.auth.urls instead of DRF URLs
• Trying to include authentication or views modules directly
• Forgetting to include URLs after installing DRF