Bearer token authentication in Rest API - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to add the Authorization header with a bearer token.

Rest API

headers = {"Authorization": "Bearer [1]"}

Drag options to blanks, or click blank then click option'

Amy_token_123

Bauth_token

C12345

Dtoken123

Attempts:

3 left

💡 Hint

Common Mistakes

Forgetting to include the 'Bearer ' prefix.

Using the wrong token string.

The Authorization header must include the word 'Bearer' followed by the token. Here, 'token123' is the token value.

2fill in blank

medium

Complete the code to send a GET request with bearer token authentication using the requests library.

Rest API

response = requests.get(url, headers=[1])

Drag options to blanks, or click blank then click option'

A{"Authorization": "token123"}

B{"Authorization": "Bearer token123"}

C{"Auth": "Bearer token123"}

D{"Authorization": "Bearer"}

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'Auth' instead of 'Authorization' as the header key.

Omitting the 'Bearer ' prefix in the header value.

The headers dictionary must have the key 'Authorization' with the value 'Bearer token123' to authenticate properly.

3fill in blank

hard

Fix the error in the code to correctly extract the bearer token from the Authorization header.

Rest API

token = request.headers.get('Authorization').[1](' ')[1]

Drag options to blanks, or click blank then click option'

Asplit

Bjoin

Creplace

Dstrip

Attempts:

3 left

💡 Hint

Common Mistakes

Using join instead of split.

Trying to strip or replace without splitting.

The Authorization header value is a string like 'Bearer token123'. Using split(' ') divides it into ['Bearer', 'token123'], so index 1 gives the token.

4fill in blank

hard

Fill both blanks to create a dictionary comprehension that extracts tokens from a list of Authorization headers.

Rest API

tokens = {i: header[1](' ')[[2]] for i, header in enumerate(headers)}

Drag options to blanks, or click blank then click option'

Asplit

B1

C0

Dstrip

Attempts:

3 left

💡 Hint

Common Mistakes

Using index 0 which gives 'Bearer' instead of the token.

Using strip instead of split.

Each header string is split by space, and the token is at index 1. The comprehension maps index i to the token.

5fill in blank

hard

Fill all three blanks to create a function that validates a bearer token from headers.

Rest API

def validate_token(headers):
    auth = headers.get([1])
    if auth and auth.startswith([2]):
        return auth.split([3])[1]
    return None

Drag options to blanks, or click blank then click option'

A"Authorization"

B"Bearer "

C" "

D"Token"

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'Token' instead of 'Bearer ' as prefix.

Not including the space in the prefix.

Splitting by wrong character.

The function gets the 'Authorization' header, checks if it starts with 'Bearer ', then splits by space to get the token.

Practice

1. What is the main purpose of a Bearer token in REST API authentication?

easy

A. To prove the identity of the client making the request

B. To encrypt the data sent between client and server

C. To specify the format of the response data

D. To define the API endpoint URL

Solution

1. Step 1: Understand Bearer token role

   A Bearer token is a secret key sent with requests to prove who the client is.

2. Step 2: Identify main purpose

   It helps the server know the client's identity and permissions.

3. Final Answer:

   To prove the identity of the client making the request -> Option A

4. Quick Check:

   Bearer token = client identity proof [OK]

Hint: Bearer tokens prove who you are, not encrypt data [OK]

Common Mistakes:

• Thinking Bearer tokens encrypt data
• Confusing token with API endpoint
• Assuming token defines response format

2. Which of the following is the correct way to include a Bearer token in an HTTP request header?

easy

A. Token: Bearer your_token_here

B. Authorization: Bearer your_token_here

C. Authorization: Token your_token_here

D. Bearer: Authorization your_token_here

Solution

1. Step 1: Recall Bearer token header format

   The standard way is to use the 'Authorization' header with the word 'Bearer' followed by the token.

2. Step 2: Match correct syntax

   Authorization: Bearer your_token_here matches the correct syntax: 'Authorization: Bearer your_token_here'.

3. Final Answer:

   Authorization: Bearer your_token_here -> Option B

4. Quick Check:

   Authorization header + Bearer keyword = correct format [OK]

Hint: Use 'Authorization: Bearer <token>' exactly [OK]

Common Mistakes:

• Using 'Token' instead of 'Bearer'
• Swapping header name and value order
• Omitting 'Bearer' keyword

3. Given this Python code snippet using the requests library, what will be the output if the token is invalid?

import requests
headers = {"Authorization": "Bearer invalid_token"}
response = requests.get("https://api.example.com/data", headers=headers)
print(response.status_code)

medium

A. 200

B. 404

C. 401

D. 500

Solution

1. Step 1: Understand HTTP status codes for authentication

   401 means Unauthorized, which is returned when authentication fails due to invalid token.

2. Step 2: Analyze the code behavior with invalid token

   The server will reject the request and respond with 401 Unauthorized status code.

3. Final Answer:

   401 -> Option C

4. Quick Check:

   Invalid token = 401 Unauthorized [OK]

Hint: Invalid token usually returns 401 status code [OK]

Common Mistakes:

• Assuming 200 means success with invalid token
• Confusing 404 Not Found with authentication error
• Thinking server error 500 occurs for invalid token

4. You wrote this code to send a Bearer token but the server always responds with 401 Unauthorized. What is the likely error?

headers = {"Authorization": "bearer mytoken123"}
response = requests.get(url, headers=headers)

medium

A. The URL is incorrect

B. The token string is missing

C. The header name should be 'Token' instead of 'Authorization'

D. The word 'bearer' should be capitalized as 'Bearer'

Solution

1. Step 1: Check Bearer token header case sensitivity

   The 'Bearer' keyword in the Authorization header is case sensitive and must be capitalized.

2. Step 2: Identify the error in the code

   The code uses 'bearer' in lowercase, causing the server to reject the token and respond 401.

3. Final Answer:

   The word 'bearer' should be capitalized as 'Bearer' -> Option D

4. Quick Check:

   Bearer keyword is case sensitive [OK]

Hint: Capitalize 'Bearer' exactly in Authorization header [OK]

Common Mistakes:

• Using lowercase 'bearer' keyword
• Changing header name from 'Authorization'
• Ignoring token format errors

5. You want to secure an API endpoint so only requests with a valid Bearer token can access it. Which of these is the best approach to implement this in your REST API server?

hard

A. Check the 'Authorization' header for a Bearer token, validate it, and reject requests without valid tokens

B. Allow all requests but log the Bearer token if present

C. Require the token as a URL query parameter instead of header

D. Ignore tokens and rely on IP address filtering

Solution

1. Step 1: Understand secure API access with Bearer tokens

   Secure APIs check the Authorization header for a valid Bearer token to authenticate requests.

2. Step 2: Identify best practice for token validation

   Rejecting requests without valid tokens ensures only authorized clients access the endpoint.

3. Final Answer:

   Check the 'Authorization' header for a Bearer token, validate it, and reject requests without valid tokens -> Option A

4. Quick Check:

   Validate token in Authorization header to secure API [OK]

Hint: Validate Bearer token in Authorization header to secure API [OK]

Common Mistakes:

• Using query parameters for tokens (less secure)
• Allowing requests without token validation
• Relying on IP filtering alone