Simple proxy to alter the POST request content that is sent IdP

package.json

{
  "name": "samlproxy",
  "version": "1.0.0",
  "description": "",
  "main": "server.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "author": "Ilyas Türkben",
  "license": "ISC",
  "dependencies": {
    "http-proxy": "^1.15.2"
  }
}

server.js

var httpProxy = require('http-proxy')
var http = require('http')

var proxy = new httpProxy.createProxyServer({
  target: {
    host: 'idp',
    port: 9015
  }
})

proxy.on('proxyReq', function (proxyReq, req, res, options) {
  proxyReq.write("RelayState=https%3A%2F%2Fidp.test&")
})

var proxyServer = http.createServer(function (req, res) {
  proxy.web(req, res)
})

proxyServer.listen(8015)

1. Download package.json and server.js
2. npm install
3. In AEM set the IdP host to this proxy and put the real IdP post & port in server.js (lines 6-7)
4. Modify line 12 for adding new request parameters to IdP
5. npm start