OAuth 2.0 overview in Rest API - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to specify the OAuth 2.0 grant type for client credentials.

Rest API

grant_type=[1]

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

Aauthorization_code

Brefresh_token

Cclient_credentials

Dpassword

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'authorization_code' when no user is involved.

Confusing 'password' grant type with client credentials.

The client_credentials grant type is used when the client requests an access token to access its own resources, not on behalf of a user.

2fill in blank

medium

Complete the code to include the access token in the HTTP Authorization header.

Rest API

Authorization: Bearer [1]

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

Arefresh_token

Baccess_token

Cclient_id

Dcode

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'client_id' instead of the token.

Sending the refresh token in the Authorization header.

The access_token is sent in the Authorization header using the Bearer scheme to authenticate API requests.

3fill in blank

hard

Fix the error in the OAuth 2.0 token request URL by completing the missing query parameter.

Rest API

https://auth.example.com/token?grant_type=[1]&client_id=abc123

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

Aauthorization_code

Brefresh

Cclient_credentials

Dpassword

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'refresh' instead of 'refresh_token'.

Confusing 'client_credentials' with 'authorization_code'.

The authorization_code grant type is used in the authorization code flow where the client exchanges a code for an access token.

4fill in blank

hard

Fill both blanks to create a dictionary comprehension that maps scopes to their descriptions only if the scope length is greater than 5.

Rest API

scope_descriptions = [1]: descriptions[[2]] for [1] in scopes if len([1]) > 5}

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

Ascope

Bscopes

Cdescription

Dtoken

Attempts:

3 left

💡 Hint

Common Mistakes

Using different variable names for key and value.

Using the list name instead of the loop variable.

We use scope as the variable name to iterate over scopes. The comprehension maps each scope to its description if the scope's length is greater than 5.

5fill in blank

hard

Fill all three blanks to create a dictionary comprehension that maps user IDs to their tokens only if the token is not expired.

Rest API

valid_tokens = [1]: [2] for [1], [2] in user_tokens.items() if not [2].expired

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

Auser_id

Btoken

Duser

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing variable names between key and value.

Using the wrong attribute to check expiration.

The comprehension iterates over user_tokens.items(), unpacking into user_id and token. It includes only tokens that are not expired.

Practice

1. What is the main purpose of OAuth 2.0 in REST APIs?

easy

A. To replace usernames with email addresses

B. To encrypt all data sent between client and server

C. To allow apps to access user data securely without sharing passwords

D. To speed up API response times

Solution

1. Step 1: Understand OAuth 2.0's role

   OAuth 2.0 is designed to let apps access user data safely without needing the user's password.

2. Step 2: Compare options to OAuth 2.0 purpose

   Only To allow apps to access user data securely without sharing passwords correctly describes this purpose. Options A, B, and D describe unrelated functions.

3. Final Answer:

   To allow apps to access user data securely without sharing passwords -> Option C

4. Quick Check:

   OAuth 2.0 = Secure data access without password sharing [OK]

Hint: OAuth 2.0 = safe access without password sharing [OK]

Common Mistakes:

• Confusing OAuth with encryption protocols
• Thinking OAuth replaces usernames
• Assuming OAuth speeds up APIs

2. Which of the following is the correct OAuth 2.0 flow step to get an access token?

easy

A. Client sends password directly to resource server

B. Client sends authorization code to the authorization server

C. Resource server sends access token to client without request

D. Client sends refresh token to user

Solution

1. Step 1: Identify OAuth 2.0 token exchange step

   The client sends the authorization code to the authorization server to exchange it for an access token.

2. Step 2: Eliminate incorrect options

   Client sends password directly to resource server is wrong because passwords are not sent directly. Resource server sends access token to client without request is wrong because tokens are sent after request. Client sends refresh token to user is wrong because refresh tokens are sent to the authorization server, not the user.

3. Final Answer:

   Client sends authorization code to the authorization server -> Option B

4. Quick Check:

   Authorization code sent to server = Step to get access token [OK]

Hint: Authorization code sent to server to get token [OK]

Common Mistakes:

• Sending password instead of authorization code
• Expecting tokens without request
• Confusing refresh token recipient

3. Given this OAuth 2.0 flow snippet:

1. Client requests authorization code
2. User grants permission
3. Client receives authorization code
4. Client sends authorization code to token endpoint
5. Token endpoint returns access token

What is the output after step 5?

medium

A. Client has an access token to access protected resources

B. Client has the user's password

C. Client can directly access user data without token

D. Client must request authorization code again

Solution

1. Step 1: Follow OAuth 2.0 flow steps

   After step 5, the client receives an access token from the token endpoint.

2. Step 2: Understand access token purpose

   The access token lets the client access protected user data securely without needing the password.

3. Final Answer:

   Client has an access token to access protected resources -> Option A

4. Quick Check:

   Access token received = Access to resources [OK]

Hint: Access token means access granted to resources [OK]

Common Mistakes:

• Thinking client gets user password
• Assuming token is not needed for access
• Believing authorization code must be requested again

4. Identify the error in this OAuth 2.0 flow:

Client sends access token directly to user
User sends authorization code to resource server

medium

A. Access token should be sent to resource server, not user

B. Authorization code should be sent to client, not user

C. Client should never send tokens at all

D. User should send access token to authorization server

Solution

1. Step 1: Analyze token flow roles

   Access tokens are meant for the resource server to verify access, not for the user.

2. Step 2: Check authorization code flow

   The authorization code is sent from user to client, not to the resource server.

3. Final Answer:

   Access token should be sent to resource server, not user -> Option A

4. Quick Check:

   Access token destination = Resource server [OK]

Hint: Access token goes to resource server, not user [OK]

Common Mistakes:

• Sending access token to user instead of server
• Confusing authorization code recipient
• Thinking client never sends tokens

5. You want to build an app that accesses user data from a REST API using OAuth 2.0. Which combination correctly describes the roles and tokens involved?

hard

A. Client app sends refresh token to user to renew access token

B. User sends access token to client app, which then sends password to resource server

C. Resource server issues authorization code directly to client app without user consent

D. Client app uses authorization code to get access token from authorization server, then uses access token to access resource server

Solution

1. Step 1: Understand OAuth 2.0 roles

   The client app requests an authorization code from the authorization server after user consent.

2. Step 2: Token exchange and usage

   The client exchanges the authorization code for an access token, then uses it to access the resource server.

3. Final Answer:

   Client app uses authorization code to get access token from authorization server, then uses access token to access resource server -> Option D

4. Quick Check:

   Authorization code -> access token -> resource access [OK]

Hint: Authorization code to token, then token to resource [OK]

Common Mistakes:

• Thinking user sends tokens to client
• Assuming resource server issues codes without user
• Confusing refresh token flow