http port forward for nodejs,ie access jenkins by http://yourhostname/jenkins,which located at http://yourhostname:8080/jenkins

nodejs_port_forward_by_http.js

'use strict';

/* Sample
 forward :8087/jenkins to :8080/jenkins.

In product,the entityPort can be 80,so u can access jenkins
by http://yourhostname/jenkins
Good Luck! All Done Just By NodeJS!
 */

 const routes = {
   "/jenkins":8080,
 };
 const entityPort = 8087;

forward(entityPort, routes);

/**
 * port forward,base uri and prefix.
 * @param  {number} entityPort port to listen,ie:80,8080.
 * @param  {object} routes     pefix and port pairs,ie:{"/jenkins":8080}.
 * @return {object}            http.Server.
 */
function forward(entityPort,routes){
  const http = require('http');
  const server = http.createServer((reqS,resS) => {
    let path = reqS.url;
    let port = entityPort;
    for (let routePath in routes) {
      if (routes.hasOwnProperty(routePath)) {
        if (path.startsWith(routePath)) {
          port = routes[routePath];
          break;
        }
      }
    }

    /* forward. */
    reqS.pipe(http.request({
      port:port,
      path: reqS.url,
      method: reqS.method,
      headers: reqS.headers,
    }, (resC)=>{
      resS.writeHead(resC.statusCode, resC.headers);
      resC.pipe(resS);
    }));
  }).listen(entityPort);

  return server;
}