Activity 29: HTTP Methods

1. GET Method

Purpose: The GET method is used to retrieve data from a server. It is a read-only operation and does not modify any data on the server.

When to Use GET:

• When you want to retrieve data without side effects (i.e., without changing the state of the server).

• For fetching resources, such as retrieving user information, lists of items, or database records.

Example:

Retrieving a list of users from a REST API:

https://api.example.com/users

Retrieving a specific user by ID:

https://api.example.com/users/123

Characteristics:

• Idempotent: Multiple identical GET requests have the same effect as a single request.

• Caching: Responses to GET requests can be cached to improve performance.

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2. POST Method

Purpose: The POST method is used to send data to a server to create a new resource. It often submits data that the server processes and stores.

When to Use POST:

• When you need to create a new resource on the server.

• When submitting data that modifies the state of the server (e.g., creating a new user, adding an item to a shopping cart).

Example:

Creating a new user in a REST API:

https://api.example.com/users
Content-Type: application/json

{
  "name": "John Doe",
  "email": "johndoe@example.com"
}

Use Cases:

• User registration forms

• Uploading files

• Submitting comments or feedback

Characteristics:

• Non-idempotent: Multiple identical POST requests can create multiple resources, each with a unique identifier.

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3. PUT Method

Purpose: The PUT method is used to update an existing resource on a server. It replaces the entire resource with the new data provided in the request.

When to Use PUT:

• When you want to update a specific resource completely.

• When you have the entire representation of the resource and want to replace it.

Example:

Updating a user’s information:

 https://api.example.com/users/123
Content-Type: application/json

{
  "name": "Jane Doe",
  "email": "janedoe@example.com"
}

Characteristics:

• Idempotent: Multiple identical PUT requests have the same effect as a single request (the resource will remain the same).

• The client must send the complete resource representation.

Difference from POST:

• POST creates a new resource, while PUT updates an existing resource.

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4. DELETE Method

Purpose: The DELETE method is used to remove a resource from a server. It requests the server to delete a specific resource identified by a URL.

When to Use DELETE:

• When you want to permanently remove a resource from the server.

Example:

Deleting a user by ID:

https://api.example.com/users/123

Characteristics:

• Idempotent: Sending the same DELETE request multiple times will not change the outcome after the resource has been deleted.

• Often returns a status code indicating success or failure (e.g., 204 No Content for successful deletion).

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5. PATCH Method

Purpose: The PATCH method is used to apply partial updates to a resource. Unlike PUT, which requires the entire resource representation, PATCH only needs the fields to be updated.

When to Use PATCH:

• When you want to update only a few fields of a resource instead of the entire resource.

• For scenarios where sending the complete resource is unnecessary.

Example:

Partially updating a user's email:

https://api.example.com/users/123
Content-Type: application/json

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

Characteristics:

• Non-idempotent: Although multiple identical PATCH requests may not change the outcome, they may have different results based on the server's state.

• It allows for more efficient updates, especially for large resources.

Comparison with PUT:

• PUT requires the full resource representation to replace it, while PATCH only requires the changes (partial updates).

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Summary Table of HTTP Methods