NodeJS proxy router streams implementation example for ExpressJS

var Router = require('express').Router()
var https = require('https')

Router.get('/', function (req, res, next) {

    https.get(req.query.url, (data) => {

        //remove express headers
        Object.keys(res.getHeaders()).forEach((headerName) => {
            res.removeHeader(headerName)
        })

        // write status
        res.status = data.statusCode
        // write headers
        Object.keys(data.headers).forEach((headerName) => {
            res.setHeader(headerName, data.headers[headerName])
        })

         //Pipe data to response stream
         data.pipe(res)

    })

})

module.exports=Router

var router = require('express').Router()
var https = require('https')
// create and prepare stream
var {Readable} = require('stream')
var readStream = Readable()
readStream._read = function () {}

router.get('/', function(req, res, next) {

  https.get(req.query.url, (data) => {

    //remove express headers
    Object.keys(res.getHeaders()).forEach((headerName) => {
      res.removeHeader(headerName)
    })

    // write status
    res.status = data.statusCode
    // write headers
    Object.keys(data.headers).forEach((headerName) => {
      res.setHeader(headerName, data.headers[headerName])
    })

    data.on('data', (chunk) => {

      // transform data here 
      var i = chunk.toString('utf8')

      // UpperCase all letters
      readStream.push(i.toUpperCase())

      console.log(readStream.readableFlowing === true)

    }).on('end', () => {

      // readableStream does not invoke automatic end, whereas data.pipe(res) would do that
      readStream.unpipe(res)
      readStream.destroy()
      console.log('is still flowing?', readStream.readableFlowing === true)
      console.log('is destroyed', readStream.destroyed === true)
      return res.end()
    })

    readStream.pipe(res, {
      end: true
    })
    
  })


})

module.exports = router