Re: Simultaneous request from same IP

Tim Funk Mon, 16 Dec 2002 10:06:12 -0800

But the same trafficCop instance is being used at the same time for 2 differnt requests.

The trafficCop object has a method called add() which (seems to) acts on instance variables inside of the trafficCop object. This makes the trafficCop object not thread safe.

-Tim

Chris Bick wrote:

Why does that effect the HttpServletRequest object? If you look at the
code it evaluates the header and query string values before I access the
trafficcop object. I will give it a try.

-cb

-----Original Message-----
From: Tim Funk [mailto:[EMAIL PROTECTED]] Sent: Monday, December 16, 2002 12:40 PM
To: Tomcat Users List
Subject: Re: Simultaneous request from same IP

Is TrafficCop.java thread safe?

If not - that is your problem. Both requests are using the same trafficCop instance.

-Tim

Chris Bick wrote:
No offense taken. I still can't believe that this problem may exist.
If you can find a problem with my code, that would be much easy then
getting a fix into tomcat.
Thanks,
-cb



import javax.servlet.*;
import javax.servlet.http.*;
import java.io.*;
import java.util.*;

import java.net.*;


/**
* Title: 
* Description: 
* Copyright: Copyright (c) 2002
* Company: 
* @author not attributable
* @version 1.0
*/

public class TrafficCopServlet extends HttpServlet {
 private static final String CONTENT_TYPE_XML = "text/xml";
 private static final String CONTENT_TYPE_HTML = "text/html";
 /**@todo set DTD*/
 private static final String DOC_TYPE = null;
 //Initialize global variables

 private TrafficCop trafficCop;
 public void init() throws ServletException
 {
 trafficCop = new TrafficCop(false);
 }

 //Process the HTTP Get request
 public void doGet(HttpServletRequest request, HttpServletResponse
response) throws ServletException, IOException {
 PrintWriter out = response.getWriter();

 try
 {
 if (request.getRequestURI().endsWith("/insert"))
 {
 response.setContentType(CONTENT_TYPE_XML);
 out.println("<?xml version=\"1.0\"?>");

 String pcpVersion = request.getHeader("PCP-Client-Version");
 String clientId = request.getHeader("PCP-Client-ID");
 String listenIP = request.getHeader("Listen-IP");
 String behindFirewall = request.getHeader("Behind-Firewall");

 String urn = request.getQueryString();

 synchronized(System.out)
 {
 System.out.println("URN:" + request.getQueryString());
 System.out.println(request.getHeader("Listen-IP"));
 }
 //System.out.println("Listen-IP:" + listenIP);

 if (pcpVersion == null || clientId == null ||
 listenIP == null || behindFirewall == null ||
 urn == null)
 {
 String error = "<error>Bad Headers</error>";
 out.println(error);
 return;
 }

 String xml = trafficCop.add(urn,new
URL(null,"pcp://"+listenIP,new Handler()), new
Boolean(behindFirewall).booleanValue(), 0);

 System.out.println(xml);
 out.println(xml);
 }
 else if (request.getRequestURI().endsWith("/delete"))
 {
 response.setContentType(CONTENT_TYPE_XML);
 out.println("<?xml version=\"1.0\"?>");

 String clientId = request.getHeader("PCP-Client-ID");
 String sessionId = request.getHeader("My-Session-ID");
 String deleteSessionId =
request.getHeader("Delete-Session-ID");
 String listenIP = request.getHeader("Listen-IP");
 String behindFirewall = request.getHeader("Behind-Firewall");

 String completed = request.getHeader("Completed");
 String elapsedTime = request.getHeader("Elapsed-Time");
 String avgDownstream =
request.getHeader("Average-Downstream");
String urn = request.getQueryString();

if (clientId == null || sessionId == null ||
deleteSessionId == null || listenIP == null ||
behindFirewall == null)
{
String error = "<error>Bad Headers</error>";
out.println(error);
return;
}

String xml = trafficCop.remove(urn, deleteSessionId,
sessionId,new URL(null,"pcp://"+listenIP, new Handler()),
new
Boolean(behindFirewall).booleanValue(),0,0);

System.out.println(xml);
out.println(xml);
}
else if (request.getRequestURI().endsWith("/update"))
{
response.setContentType(CONTENT_TYPE_XML);
out.println("<?xml version=\"1.0\"?>");

String clientId = request.getHeader("PCP-Client-ID");
String sessionId = request.getHeader("My-Session-ID");
String listenIP = request.getHeader("Listen-IP");
String behindFirewall = request.getHeader("Behind-Firewall");

String urn = request.getQueryString();

if (clientId == null || sessionId == null ||
listenIP == null || behindFirewall == null)
{
String error = "<error>Bad Headers</error>";
out.println(error);
return;
}

String xml = trafficCop.connectionUpdate(urn, sessionId,new
URL(null,"pcp://"+listenIP,new Handler()),
new
Boolean(behindFirewall).booleanValue(),0,0);

System.out.println(xml);
out.println(xml);
}
}
catch (Exception e)
{
out.println("<error>"+e.getMessage()+"</error>");
e.printStackTrace();
}
}
}

-----Original Message-----
From: Tim Funk [mailto:[EMAIL PROTECTED]] Sent: Monday, December 16, 2002 12:21 PM
To: Tomcat Users List
Subject: Re: Simultaneous request from same IP

Can you post an example servlet (or the real code) that can reproduce this? (No offense but ...) I really think there ios something with

your
code.

-Tim

Chris Bick wrote:
I've reproduced this problem with tomcat 3.2 and every version of 4.1
up
to 4.1.12

I haven't gone any further than all headers being identical and the
query string. I thought maybe tomcat was just passing in the same
reference, but the toString() value of the HttpServletRequest object
are
different.

Let me know if anyone can reproduce this?(If you have the time...)
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