You can implement authentication in the API Gateway by adding middleware to check authentication tokens before proxying the request to backend services.
Example:
app.use((req, res, next) => {
const token = req.headers['authorization'];
if (token === 'valid-token') {
next();
} else {
res.status(401).send('Unauthorized');
}
});
app.use('/service1', createProxyMiddleware({ target: 'http://localhost:3001', changeOrigin: true }));
app.use('/service2', createProxyMiddleware({ target: 'http://localhost:3002', changeOrigin: true }));