Proxy target route to invalid url

Question

I am trying to get http-proxy-middleware working, what I am trying to achieve is having multiple nodejs apps running and then having the proxy app as a reverse proxy server.

The problem I encounter is when I press a link on a proxied app, here's my code:

var express = require('express')
var proxy = require('http-proxy-middleware')
var app = express()

var options = {
    target: 'http://localhost:1001', // target host
    changeOrigin: true, // needed for virtual hosted sites
    ws: false, // proxy websockets
    logLevel: "debug",
    pathRewrite: {
        '^/foo': '/', // rewrite path
    }
}
var exampleProxy = proxy(options)

app.use('/foo', exampleProxy)
app.listen(3000)

On the localhost:1001 app I got the routes '/' and '/bar'

app.get('/', function (req, res) {
    res.render('home');
});

app.get('/bar', function (req, res) {
    res.render('bar');
});

If I go to localhost:3000/foo it will reroute me to localhost:1001/ (while showing localhost:3000/ in the browser) and the same with localhost:3000/foo/bar. So this works fine.

The problem happens when I go to localhost:3000/foo and then press the link to 'bar', it will then route me to localhost:3000/bar which is not a route I have defined in my proxy server.

So what I need is that when I press on the link to /bar it will route it to /foo/bar in the proxy.

I have tried coming up with some ways to fix this, but have (obviously) not been succesful:

Add the port (1001) to the response (res.locals.portNo = "1001") and then send that in the request so that the proxy can check where the request is coming from and add /foo (if its 1001). (I have not tried this yet, but maybe this could be achieved by using cookies?)

Answer 1

I got it working but it is a very bad hack... But it works...

I added cookie-parser

var cookieParser = require('cookie-parser')
app.use(cookieParser())

And then I added this ugly middleware

app.use(function (req, res, next) {
    var domainLetter = req.cookies.domainLetter

    switch (req.url.substring(0, 2)) {
        case "/a": {
            domainLetter = 'a'
            res.cookie('domainLetter', 'a')
            break
        }
        case "/b": {
            domainLetter = 'b'
            res.cookie('domainLetter', 'b')
            break
        }
        default: {
            break
        }
    }

    if (req.url.length != 2 || req.url.substring(0, 2) != '/' + domainLetter)
        req.url = '/' + domainLetter + req.url
    next()
})

So what I am doing is when I want to use the proxy for localhost:1001, I go to localhost:3000/a (or localhost:3000/a/****), it will then save a cookie with the property "domainLetter" with the value "a", then whenever I click a link on that website, it will add "/a" to that url (localhost:3000/test becomes localhost:3000/a/test etc)