I apologize if this is in the IRC log.

two questions.

1) why does the pluto 1.1 driver (test portal) not exhibit the same problem? Do they do something similar to what your patch does for uPortal? Specifically breaking part of the servlet spec (even though it probably is ok to do so)?

2) Will this change work in other containers? I know that CalPoly uses WebSphere (or did at some point in the past) and Colorado uses Resin.

And a bonus question...
* Does Tomcat 6 implement this optional 'erata' part of the Servlet spec? That is if, someone spent enough time to get uPortal 2.6.0 running in Tomcat 6, are they unlikely to see the same problem?

---- Cris J H

Eric Dalquist wrote:
There is a possible patch for this issue attached to the Jira case: http://www.ja-sig.org/issues/browse/UP-1816

This patch *_HAS NOT_* been extensively tested yet and makes some significant changes in the ChannelRender and related code. The Jira issue also has a link to yesterday's IRC log which I would recommend reading if you are interested in an in-depth discussion about the probably underlying issue causing the session bug.

The high level overview is that due to uPortal's multi-threaded rendering model the Tomcat requestDispatcher is creating incorrectly wrapped HttpServletRequest objects to pass to the portlets for rendering.


A more detailed overview follows, if there are questions about the patch please ask.

Until an errata was recently filed in the servlet 2.4 spec it was against spec to allow multiple threads to access the request or response objects. The errata changed this so that it is no longer against spec but containers can optionally support multi-threaded access to these objects. With this wording it is not specifically a Tomcat bug, just an optional part of the spec that Tomcat does not implement.

The patch involves having the ChannelRenderer.Worker class, which invokes rendering on a channel, create a wrapper around the HttpServletRequest specific for the thread that Worker is running in. The wrapper implements HttpServletRequest directly instead of extending HttpServletRequestWrapper to stop Tomcat from un-wrapping the wrapper. Passing objects back to the servlet container that are not either the original request object or extended from HttpServletRequestWrapper is also against the servlet spec, though breaking spec compliance in this area should fix the session problem and doesn't appear to cause other problems.

The objects, specifically PortalControlStructures, which track the request and response through the rendering pipeline have also been modified to use ThreadLocals. This allows each rendering thread to have its own request and response objects as required by this patch.

This patch is very closely based on code that UW-Madison has been running since going live in June 2006. It was not contributed back earlier due to both the significance of the changes in the rendering pipeline and the thought that the problem being addressed by the change was specific to a special case here at UW.

I would encourage people experiencing the session problem and those who are familiar with the inner workings of the uPortal channel rendering code to try the patch and provide feedback. The patch was created against the 2.5-patches branch. Once some testing has been done on it confirming its viability I will create a patch for the 2.6-patches branch as well.

-Eric

Elliot Metsger wrote:
Yup,

I pulled HEAD of the 2-6-patches branch, and the buggy behavior still exists....

Parker Grimes wrote:
Elliot,

Yes we are using uPortal 2.6.0 GA with no custom patches. getMarkup() in
CPortletAdapter is synchronized.

-Parker

On 9/9/07, Elliot Metsger <[EMAIL PROTECTED]> wrote:

Hi Parker,

Quick question: are you using uPortal 2.6.0 GA?  Have you applied any
custom
patches?

I'm curious if your CPortletAdapter's getMarkup() method is synchronized.


Parker Grimes wrote:
This is sounding very familiar to what we have been experiencing. We use
uPortal 2.6.0 and the Spring Portlet MVC.

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