Activity 29: HTTP Methods HTTP Methods in RESTful APIs

HTTP methods (also known as verbs) define the type of operation to perform on a resource in RESTful APIs. Each method has a specific purpose and is used in different scenarios based on the action required.

1. GET

Purpose

• Used to retrieve data from a server.

• Typically used for fetching resources without making any modifications on the server.

Characteristics

• Idempotent: Multiple identical requests produce the same result.

• Safe: Does not alter server state.

• Cacheable: Responses can often be cached for better performance.

Use Cases

• Fetching a list of resources: /api/products (all products).

• Fetching a specific resource: /api/products/1 (product with ID 1).

Example

Request:

GET /api/users HTTP/1.1
Host: example.com

Response:

[
  { "id": 1, "name": "Alice" },
  { "id": 2, "name": "Bob" }
]

---

2. POST

Purpose

• Used to send data to a server to create a new resource.

Characteristics

• Not Idempotent: Multiple identical requests create multiple resources.

• Safe for creating resources: Can include detailed information in the body.

Use Cases

• Creating a new user: /api/users with details like name, email.

• Submitting forms: Registration, feedback, or data entry forms.

Example

Request:

POST /api/users HTTP/1.1
Content-Type: application/json

{
  "name": "Charlie",
  "email": "charlie@example.com"
}

Response:

{
  "id": 3,
  "name": "Charlie",
  "email": "charlie@example.com"
}

---

3. PUT

Purpose

• Used to update or replace an existing resource on the server.

Characteristics

• Idempotent: Multiple identical requests result in the same state of the resource.

• Typically used when updating entire resources.

Use Cases

• Replacing an entire resource: Updating all details of a user or product.

Example

Request:

PUT /api/users/1 HTTP/1.1
Content-Type: application/json

{
  "name": "Alice",
  "email": "alice_new@example.com"
}

Response:

{
  "id": 1,
  "name": "Alice",
  "email": "alice_new@example.com"
}

---

4. DELETE

Purpose

• Used to remove a resource from the server.

Characteristics

• Idempotent: Multiple identical DELETE requests achieve the same outcome (the resource is removed).

Use Cases

• Deleting a specific resource: /api/users/1 (delete user with ID 1).

• Bulk deletion: Deleting a set of records based on criteria.

Example

Request:

DELETE /api/users/1 HTTP/1.1

Response:

HTTP/1.1 204 No Content

---

5. PATCH

Purpose

• Used to apply partial updates to a resource.

Characteristics

• Not Idempotent by default: Depending on the server implementation, may or may not be idempotent.

• Preferred for updating specific fields instead of the entire resource.

Use Cases

• Updating a single property of a resource: Changing a user's email while keeping other details unchanged.

Example

Request:

PATCH /api/users/1 HTTP/1.1
Content-Type: application/json

{
  "email": "alice_patch@example.com"
}

Response:

  "id": 1,
  "name": "Alice",
  "email": "alice_patch@example.com"
}

Comparison of PUT and PATCH