proxy needs to be last middleware

Perhaps I’m using the library incorrectly, or unaware of its limitations- but I recently found that I’ve had to put http-proxy-middleware as the last middleware in my express config.

Expected behavior

If possible, http-proxy-middleware should call the next() middleware. If not, the behavior should be documented.

Actual behavior

middlewares that follow http-proxy-middleware are not executed

Setup

app.use('*', [
  (req, res, next) => {
    console.log('I do get executed');
    next();
  },

  proxy({ ...proxyOptions }),

  (req, res, next) => {
    console.log('I do not get executed');
    next();
  }
]);

• http-proxy-middleware: 0.17.4
• server: express + 4.16.2

proxy middleware configuration

var apiProxy = proxy({
  target:'http://www.example.org',
  changeOrigin:true,
  secure: false
});

server mounting

const https = require('https');
const express = require('express');
const app = express();
const certs = require('./getCertOptions')();
const middlewares = require('./getExpressMiddlewares')();

app.use('*', middlewares);

https.createServer({ certs }, app).listen(5443);

[PaulMaly]

@aral @hpl002 Hi guys, I’m pretty sure it should work:

    app.use((req, res, next) => {
        createProxyMiddleware(path,  {
            selfHandleResponse: true,
            onProxyRes(proxyRes, req, res) {
                if (proxyRes.statusCode === 404) {
                    return next();
                } else {
                    let body = new Buffer('');
                    proxyRes.on('data', (data) => body = Buffer.concat([body, data]));
                    proxyRes.on('end', () => res.end(body));
                }
            }
        })(req, res, next);
    });

What do you think about this solution? The weak point is that HPM will be created on each request.

[hpl002]

Been a while!

Any updates on this. I too was a bit surprised to see that my subsequent middleware suddenly failed. Would be nice to at least have the argument available in the case of option.selfHandleResponse.

Closing by pending issue provided that there might be more progress here…

One dirty workaround that might work for some is to create a separate express instance which only handles proxying. This instance can then be called in the middleware of the outer instance.

My usecase simply being response validation.