Can you explain the main principles of building RESTful services?

Principles of building RESTful services:

• Resource-oriented: all objects and data are represented as resources with unique URIs (e.g., /users/123).

• Use of standard HTTP methods:

  • GET — retrieve a resource
  • POST — create a resource
  • PUT — update a resource
  • DELETE — delete a resource

• HTTP status codes: the service should return correct response codes (e.g., 200 OK, 201 Created, 404 Not Found, 400 Bad Request).

• Statelessness: each client request must contain all necessary information for processing; the server does not store state between requests.

• Use of data formats: usually JSON or XML for data transfer.

• Hypermedia (HATEOAS): responses may contain links to related resources for navigation.

Example of a simple RESTful route in Node.js using Express:

const express = require('express');
const app = express();
app.use(express.json());

// Get user by ID
app.get('/users/:id', (req, res) => {
  const userId = req.params.id;
  // logic to get user
  res.json({ id: userId, name: 'Ivan' });
});

// Create a new user
app.post('/users', (req, res) => {
  const newUser = req.body;
  // logic to create
  res.status(201).json(newUser);
});

app.listen(3000);

This approach provides a standardized and convenient interface for interacting with the service.