[jetty-users] Concurrent Requests in embedded jetty, some responses retu

[Enrico Kern <kern@xxxxxxxxxxx>]

Hello,

i try to create a simple java application with jetty 9 embedded and one 
handler. The application receives status polls every few seconds, but 
some requests can take up to 20 seconds on the server to process.

I figured out that sometimes the longer taking requests return a empty 
body in the response. This only happens if other requests are served by 
the jetty aswell. So i created a little dummy application and have the 
same behavior here. Im pretty new to jetty and just cant figure out what 
i do wrong.  Maybe someone can give me a hint.

The problem is easy to replicate using then curl in one window:

#!/bin/bash
while(true); do
        curl localhost:44999
        sleep 1
done

which is the short request every second. And the long one which will 
wait 2 seconds in the handler (in the real application some command is 
executed here and the handler waits for it to return)

#!/bin/bash
while(true); do
        curl -i 127.0.0.1:44999/MEEEH/whyunotwork
        sleep 1
done

the second curl loop will only return content if the first curl run is 
stopped. Headers are ok. Just the writer.println content is missing.  Im 
pretty sure i do something wrong here.

Thats how i start the server:


         // Jetty
          Server server = new Server(44000);
          server.setHandler(new CheckJettyHandler());
          System.out.println("Starting Jetty on Port 44000");
          server.start();
          server.join();

and the handler:

package jettytest;


import java.io.IOException;
import java.io.PrintWriter;
import java.lang.reflect.Modifier;
import java.util.*;
import java.util.logging.Level;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.log4j.Logger;
import org.eclipse.jetty.server.Request;
import org.eclipse.jetty.server.handler.AbstractHandler;

/**
 *
 * @author teeesting
 */
public class CheckJettyHandler extends AbstractHandler {
    Logger logger = Logger.getRootLogger();
    private HttpServletResponse response;
    private PrintWriter writer;

    public void handle(String target,Request 
baseRequest,HttpServletRequest request,HttpServletResponse p_response)
        throws IOException, ServletException
    {

        if(!target.equals("/favicon.ico"))
        {
            logger.info("Request from ["+baseRequest.getRemoteAddr()+"] 
: " + target);
        }
        response = p_response;
        response.setContentType("text/html;charset=utf-8");
        response.setHeader("Server", "Blabla Test ");
        response.setHeader("Access-Control-Allow-Origin", "*");
        response.setCharacterEncoding("utf-8");
        writer = response.getWriter();

        baseRequest.setHandled(true);

        List l_lTargets = new ArrayList();
        StringTokenizer st = new StringTokenizer(target,"/");
        while (st.hasMoreTokens()) {
            String l_strToken = st.nextToken();
            l_lTargets.add(l_strToken);
            //response.getWriter().println(st.nextToken());
        }

        // multi request?
        if(l_lTargets.size() > 1)
        {
           try {
                Thread.sleep(2000);
            } catch (InterruptedException ex) {
java.util.logging.Logger.getLogger(CheckJettyHandler.class.getName()).log(Level.SEVERE, 
null, ex);
            }
           writer.println("Hello");
        }
        else
        {
           // single requests
           response.setStatus(HttpServletResponse.SC_FORBIDDEN);
           writer.println("invalid authorisation key");
        }

    }

--
[Clavain Technologies GbR]

Gesellschafter: Enrico Kern, Robin Elster
kern@xxxxxxxxxxx
www.clavain.com

Heerstraße 366
13593 Berlin
GERMANY

PHONE: +49 30 89398336