Basic authentication in Rest API - Mini Project: Build & Apply

Basic Authentication in a REST API

📖 Scenario: You are building a simple REST API that requires users to log in with a username and password. To keep things safe, the API uses basic authentication, which means the client sends a username and password encoded in a special way with each request.This project will guide you step-by-step to create a basic authentication check in your API.

🎯 Goal: Build a REST API endpoint that checks the username and password sent by the client using basic authentication. If the credentials are correct, the API will respond with a welcome message. If not, it will respond with an error message.

📋 What You'll Learn

Create a dictionary called users with exact username-password pairs

Create a variable called auth_header to hold the incoming authorization header string

Decode the base64 encoded credentials from auth_header and split into username and password

Check if the username and password match the users dictionary and print the correct response

💡 Why This Matters

🌍 Real World

Basic authentication is a simple way to protect API endpoints by requiring users to send their username and password encoded in each request.

💼 Career

Understanding basic authentication helps you build secure APIs and is a foundation for learning more advanced authentication methods used in web development jobs.

1

Create the user credentials dictionary

Create a dictionary called users with these exact entries: 'alice': 'wonderland', 'bob': 'builder', and 'charlie': 'chocolate'.

Rest API

# Create the users dictionary with username-password pairs
# Your code here

Need a hint?

Use curly braces {} to create a dictionary and separate each username and password with a colon.

2

Set the authorization header string

Create a variable called auth_header and set it to the exact string 'Basic YWxpY2U6d29uZGVybGFuZA=='. This string represents the username and password encoded in base64.

Rest API

users = {'alice': 'wonderland', 'bob': 'builder', 'charlie': 'chocolate'}
# Set the auth_header variable to the given base64 encoded string
# Your code here

Need a hint?

Assign the exact string to auth_header including the word Basic and the encoded part.

3

Decode and extract username and password

Import the base64 module. Then decode the base64 part of auth_header (after the space) to get a string like username:password. Split this string by ':' into variables username and password.

Rest API

users = {'alice': 'wonderland', 'bob': 'builder', 'charlie': 'chocolate'}
auth_header = 'Basic YWxpY2U6d29uZGVybGFuZA=='
# Import base64 and decode the credentials
# Your code here

Need a hint?

Use auth_header.split(' ')[1] to get the encoded part. Then use base64.b64decode() and decode to UTF-8 string. Finally, split by ':'.

4

Check credentials and print response

Use an if statement to check if username is in users and if password matches users[username]. If both are true, print f"Welcome, {username}!". Otherwise, print "Authentication failed.".

Rest API

import base64

users = {'alice': 'wonderland', 'bob': 'builder', 'charlie': 'chocolate'}
auth_header = 'Basic YWxpY2U6d29uZGVybGFuZA=='

encoded_credentials = auth_header.split(' ')[1]
decoded_bytes = base64.b64decode(encoded_credentials)
decoded_str = decoded_bytes.decode('utf-8')
username, password = decoded_str.split(':')

# Check credentials and print the correct message
# Your code here

Need a hint?

Use if username in users and users[username] == password: to check credentials.