How do you implement a reverse proxy with Node.js?

Question

Accepted Answer

**Reverse proxy** — forwards client requests to backend servers.

```javascript
const httpProxy = require("http-proxy");
const http = require("http");

const proxy = httpProxy.createProxyServer({});

const servers = [
    { host: "127.0.0.1", port: 3001, weight: 1 },
    { host: "127.0.0.1", port: 3002, weight: 2 },
    { host: "127.0.0.1", port: 3003, weight: 1 },
];

// Weighted round-robin
let currentWeight = 0;
let maxWeight = Math.max(...servers.map(s => s.weight));
let currentIndex = -1;

http.createServer((req, res) => {
    const server = getServer();
    proxy.web(req, res, {
        target: `http://${server.host}:${server.port}`,
    });
}).listen(80);
```

**Key points:**
- Use Nginx/HAProxy for production.
- Health checking for backends.
- Load balancing strategies.

Node.js: How do you implement a reverse proxy with Node.js?