What methods of communication are used in the HTTP protocol?

HTTP protocol uses request methods that define the desired action to be performed on the target resource. The most common ones are:

• GET: Requests a representation of the specified resource. Data is transmitted in the URL. It is idempotent and safe.
• HEAD: Requests the same headers as GET but without the response body. Useful for obtaining resource metadata. It is idempotent and safe.
• POST: Sends data to be processed to a specified resource. Data is included in the request body. It is not idempotent and not safe.
• PUT: Sends data to create or replace the target resource. Data is included in the request body. It is idempotent but not safe.
• DELETE: Deletes the specified resource. It is idempotent but not safe.
• CONNECT: Converts the request connection into a transparent TCP/IP tunnel, usually to support SSL/TLS.
• OPTIONS: Describes the communication methods available for the target resource. It is safe and idempotent.
• TRACE: Performs a diagnostic loop-back test along the path to the target resource. It is safe and idempotent.
• PATCH: Applies partial modifications to a resource. It is not idempotent and not safe.

Terms "safe" and "idempotent" in the context of HTTP methods:

• Safe method: A method that does not alter the server state. GET and HEAD are safe.
• Idempotent method: A method that, when executed multiple times with the same parameters, has the same effect as a single execution. GET, HEAD, PUT, and DELETE are idempotent.

Example of using the GET method:

// Requesting user data with id 123
GET /users/123 HTTP/1.1
Host: api.example.com

Example of using the POST method:

// Sending data for a new user
POST /users HTTP/1.1
Host: api.example.com
Content-Type: application/json

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