A minimalist HTTP proxy using groovy and jetty.

Proxy.groovy

@Grapes([
    @Grab(group='org.eclipse.jetty', module='jetty-server', version='8.1.18.v20150929'),
    @Grab(group='org.eclipse.jetty', module='jetty-servlet', version='8.1.18.v20150929'),
    @Grab(group='org.eclipse.jetty', module='jetty-servlets', version='8.1.18.v20150929')
])

import org.eclipse.jetty.server.Server
import org.eclipse.jetty.servlet.ServletHandler
import org.eclipse.jetty.servlets.ProxyServlet

import javax.servlet.ServletRequest
import javax.servlet.ServletResponse

class Proxy {

    static class MyProxyServlet extends ProxyServlet {
        void service(ServletRequest req, ServletResponse res) {
            println "request = $req"
            super.service(req, res)
        }
    }

    static void main(String[] args) {
        new Server(8000).with { server ->
            server.handler = new ServletHandler()
            server.handler.addServletWithMapping(MyProxyServlet, "/*")
            server.start()
            server.join()
        }
    }
}