Implementing OAuth 2.0 Client Credentials Flow for API Access

// Example using Node.js with 'node-fetch'
const fetch = require('node-fetch'); // or use native fetch in newer Node.js

const TOKEN_URL = 'https://your-auth-server.com/oauth/token';
const CLIENT_ID = 'your_client_id';
const CLIENT_SECRET = 'your_client_secret';
const SCOPE = 'read write'; // Optional, depending on API

async function getAccessToken() {
    try {
        const authHeader = Buffer.from(`${CLIENT_ID}:${CLIENT_SECRET}`).toString('base64');
        const response = await fetch(TOKEN_URL, {
            method: 'POST',
            headers: {
                'Content-Type': 'application/x-www-form-urlencoded',
                'Authorization': `Basic ${authHeader}`
            },
            body: new URLSearchParams({
                grant_type: 'client_credentials',
                scope: SCOPE
            }).toString()
        });

        if (!response.ok) {
            const errorData = await response.json();
            throw new Error(`Failed to get access token: ${response.status} ${response.statusText} - ${JSON.stringify(errorData)}`);
        }

        const data = await response.json();
        return data.access_token;

    } catch (error) {
        console.error('Error fetching OAuth token:', error.message);
        throw error;
    }
}

// Example usage:
// (async () => {
//     try {
//         const token = await getAccessToken();
//         console.log('Access Token:', token);
//         // Use the token to make API calls
//         // const apiResponse = await fetch('https://your-api.com/data', {
//         //     headers: {
//         //         'Authorization': `Bearer ${token}`
//         //     }
//         // });
//         // const apiData = await apiResponse.json();
//         // console.log('API Data:', apiData);
//     } catch (e) {
//         console.error('Application failed:', e);
//     }
// })();