Why HTTP methods define intent in Rest API - Challenge Your Understanding

Challenge - 5 Problems

❓ Predict Output

intermediate

What is the HTTP method intent in this example?

Consider this REST API call:

POST /users HTTP/1.1
Host: example.com
Content-Type: application/json

{"name": "Alice"}

What is the main intent of the POST method here?

A To retrieve the list of users from the server

B To create a new user resource on the server

C To update an existing user resource

D To delete a user resource from the server

💡 Hint

Think about what POST usually does in REST APIs.

The POST method is used to create new resources on the server. Here, sending user data means the client wants to add a new user.

🧠 Conceptual

intermediate

Why is GET considered safe and idempotent?

Which statement best explains why the GET HTTP method is considered both safe and idempotent?

A GET does not modify server data and multiple identical requests have the same effect

B GET creates new resources without changing existing ones

C GET deletes data safely without side effects

D GET modifies server data but returns the same response each time

💡 Hint

Think about what 'safe' and 'idempotent' mean in HTTP.

GET is safe because it does not change data on the server. It is idempotent because making the same GET request multiple times results in the same server state.

❓ Predict Output

advanced

What is the output status code for this DELETE request?

Given this HTTP DELETE request to remove a user:

DELETE /users/123 HTTP/1.1
Host: example.com

The server successfully deletes the user. What is the most appropriate HTTP status code the server should return?

A 204 No Content

B 201 Created

C 200 OK

D 404 Not Found

💡 Hint

Think about what status code means success with no content returned.

204 No Content means the request was successful but there is no content to return, which fits a successful DELETE.

🔧 Debug

advanced

Identify the HTTP method misuse in this scenario

A client wants to update a user's email but uses this HTTP request:

POST /users/123 HTTP/1.1
Host: example.com
Content-Type: application/json

{"email": "[e-mail]"}

Why is this a misuse of HTTP methods?

A POST requires query parameters for updates

B POST cannot send JSON data in the body

C POST is only for deleting resources

D POST should not be used to update existing resources; PUT or PATCH is correct

💡 Hint

Consider which HTTP methods are intended for updating resources.

POST is generally for creating resources. Updating existing resources should use PUT or PATCH to clearly express intent.

🚀 Application

expert

Determine the correct HTTP method for partial update

You want to change only the phone number of a user resource without affecting other fields. Which HTTP method best expresses this intent?

A POST

B PUT

C PATCH

D GET

💡 Hint

Think about which method is designed for partial updates.

PATCH is used for partial updates to a resource, changing only specified fields without replacing the entire resource.

Practice

1. Which HTTP method is used to retrieve data from a server without changing it?

easy

A. GET

B. POST

C. DELETE

D. PUT

Solution

1. Step 1: Understand the purpose of HTTP methods

   GET is designed to request data without modifying it, making it safe and idempotent.

2. Step 2: Match method to action

   Since the question asks for retrieving data without changes, GET fits perfectly.

3. Final Answer:

   GET -> Option A

4. Quick Check:

   Retrieve data = GET [OK]

Hint: GET is for reading data, no changes made [OK]

Common Mistakes:

• Confusing GET with POST
• Thinking DELETE retrieves data
• Using PUT to fetch data

2. Which of the following is the correct syntax to update a resource using HTTP methods?

easy

A. GET /resource/123

B. DELETE /resource/123

C. POST /resource/123

D. PUT /resource/123

Solution

1. Step 1: Identify the method used for updating

   PUT is the HTTP method used to update or replace a resource at a specific URL.

2. Step 2: Check the syntax correctness

   PUT /resource/123 correctly targets the resource with ID 123 for update.

3. Final Answer:

   PUT /resource/123 -> Option D

4. Quick Check:

   Update resource = PUT [OK]

Hint: PUT updates existing resources fully [OK]

Common Mistakes:

• Using GET to update
• POST is for creating, not updating
• DELETE removes, not updates

3. What will be the expected result of this HTTP request?

POST /users
{
  "name": "Alice",
  "age": 30
}

medium

A. Create a new user named Alice

B. Delete user Alice

C. Update existing user Alice's age

D. Retrieve user data for Alice

Solution

1. Step 1: Identify the HTTP method used

   POST is used to create new resources on the server.

2. Step 2: Analyze the request body

   The JSON data contains user details, indicating creation of a new user named Alice.

3. Final Answer:

   Create a new user named Alice -> Option A

4. Quick Check:

   POST with data = Create new resource [OK]

Hint: POST adds new data, not fetch or delete [OK]

Common Mistakes:

• Thinking POST retrieves data
• Confusing POST with PUT for update
• Assuming POST deletes data

4. You want to remove a user with ID 45 using an HTTP request, but the request POST /users/45 is not working. What is the correct method to use?

medium

A. GET

B. PUT

C. DELETE

D. PATCH

Solution

1. Step 1: Understand the intent of the request

   The goal is to remove (delete) a user, so the method must express deletion.

2. Step 2: Choose the HTTP method for deletion

   DELETE is the standard method to remove a resource identified by a URL.

3. Final Answer:

   DELETE -> Option C

4. Quick Check:

   Remove resource = DELETE [OK]

Hint: DELETE removes resources, POST does not [OK]

Common Mistakes:

• Using POST to delete
• Confusing PATCH with DELETE
• Trying GET to remove data

5. You have an API where PATCH /profile/123 updates only the email field of a user profile, while PUT /profile/123 replaces the entire profile. Why is it important to choose PATCH over PUT when updating just one field?

hard

A. PATCH is faster because it sends less data

B. PUT can accidentally erase other fields if not included

C. PATCH creates a new profile instead of updating

D. PUT is only for deleting resources

Solution

1. Step 1: Understand the difference between PUT and PATCH

   PUT replaces the entire resource, so missing fields get erased. PATCH updates only specified fields.

2. Step 2: Analyze the risk of using PUT for partial updates

   If you use PUT but omit some fields, those fields may be removed unintentionally.

3. Final Answer:

   PUT can accidentally erase other fields if not included -> Option B

4. Quick Check:

   Partial update safe = PATCH, full replace risk = PUT [OK]

Hint: Use PATCH for partial updates to avoid data loss [OK]

Common Mistakes:

• Thinking PATCH creates new resource
• Believing PUT only deletes
• Assuming PATCH sends no data