@cseitz/proxy

Proxy

Facilitates reverse proxying via lite express.js server.

Used as a lightweight NGINX alternative when in development mode.

$3

Note: The rules are in order of precedence.
- Once a request is matched by one of the match functions, its destination is decided and no other matching is attempted.

``ts
import { wasRequestProxied, createReverseProxy } from '@cseitz/proxy';
import { WebSocketServer } from 'ws';
import { createServer } from 'http';
import express from 'express';

const port = 5000;

/* Express app /
export const app = express();


/* Node HTTP Server /
export const server = createServer((req, res) => (
// Only route requests that don't get caught by the proxy
!proxyRequest(req, res) && app(req, res)
));

/* Websocket Server /
export const wss = new WebSocketServer({
noServer: true,
})

/* Define reverse proxies (like NGINX) /
const proxyRequest = createReverseProxy({ server }, {
api: {
/**
* This rule prevents requests to the API from being proxied
* - notice how its missing the server block, meaning it acts as a request trap that ensures requests dont get proxied
/
enabled: true,
match(req, { ws }) {
if (ws) {
if (!req.url?.startsWith('/_next'))
return true; // Matches non-NextJS websockets
} else {
if (req.url?.startsWith('/api'))
return true; // Matches API routes
}
},
},
staff: {
// This rule proxies requests to the staff portal, which runs one port higher than the API
enabled: true,
server: {
ws: true,
target: {
host: 'localhost',
port: port + 1,
},
},
match(req) {
// Proxy requests that are on the staff subdomain, such as staff.localhost
if (req.headers.host?.includes('staff')) {
return true;
}
},
},
web: {
// This catch-all rule forwards any remaining requests to the website running 2 ports higher.
enabled: true,
server: {
ws: true,
target: {
host: 'localhost',
port: port + 2,
},
},
match(req) {
// Match any requests
return true;
},
}
})

/* Upgrade websockets /
server.on('upgrade', (req, socket, head) => {
if (!wasRequestProxied(req)) {
// The request wasn't proxied, so we can do any websocket logic we want
wss.handleUpgrade(req, socket, head, ws => {
wss.emit('connection', ws, req);
})
}
});


/* Close connections when the process is about to exit /
process.on('SIGTERM', () => {
wssHandle.broadcastReconnectNotification();
server.close();
wss.close();
});


/* Start the server on the specified port /
server.listen(port, () => {
console.timeEnd('development proxy ready');
});
``