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2 Replies Latest reply: Aug 6, 2012 12:09 PM by 817264 RSS

IIS, Javascript, Signed Applet and ASP Blank Page Problem

949116 Newbie
Currently Being Moderated
Hi,

I'm having a problem using a Signed Applet in a site that runs in a IIS (Windows Server 2003).

My aspx web page uses the applet to read my smart card and get information from it.
This applet uses an auxiliar dll (stored in a second Signed Jar file) in order to read the information from my smart card.

The way the solution is design:
1) Aspx page is asked from server
2) Internet Explorer recieve the page and asks the server for it content (images, applet, javascripts, etc)
3) After this the JVM runs (console opens)
4) After the Aspx page render fully a javascript register onload fires and call an applet method
5) Applet receive the call and run the logic of the method:
     - reads the smart card;
     - calls Javascript function in order to fill aspx fields with information from smart card
     - calls Javascript function the simulates a click in a botton of aspx page (in order to call server side part sending data readed from smart card to server)
5) The server makes some logic with the information receive and responds to client registering in aspx page a call to another Javascrit function
6) The client received the asnwer from server and runs the Javascript function registered on step 5)
     This Javascript calls another method from applet and runs the following logic:
     - reads more information from smart card;
     - call javascript function in order to fill more fields of aspx page with the information readed
     - calls Javascript function the simulates a click in a botton of aspx page (in order to call server side part sending data readed from smart card to server)
7) The server makes some logic and call another pages with no Applets
8) Client asks for a second page with the same applet and we start with another logic express on steps 1);2);3),4);5) and then 7).

This is all ok, until sometimes the server stop responding correcly for requests regarding this two pages with the Applet.
When this happens the server just responds with a blank page.
     - with fiddler I can seer the request for the aspx page (that uses the applet)
     - but server responds with a blank html page
The JVM doesn't fire.
The IIS log don't show errors.
The eventviewer doesn't show errors.
The problem is solved with an IIS reset or a Application Pool reset.
After a while the problem returns.
This problem occours for other user in another machine, the server just stops responding correcly to request regarding pages with applets, the other pages still continue to work.

If we disable Java Control Panel->Advanced->Java Plug-in->Enable the next-generation Java Plug-in the problem seend to stop, but we can't force all clients to disable this option right?
Or there is a way to force the Applet to run with this option disabled?
As anyone experience similar problem?

Regards,
OF
  • 1. Re: IIS, Javascript, Signed Applet and ASP Blank Page Problem
    949116 Newbie
    Currently Being Moderated
    Anyone?

    Thanks
  • 2. Re: IIS, Javascript, Signed Applet and ASP Blank Page Problem
    817264 Journeyer
    Currently Being Moderated
    This is all ok, until sometimes the server stop responding correcly for requests regarding this two pages with the Applet.
    When this happens the server just responds with a blank page.
    - with fiddler I can seer the request for the aspx page (that uses the applet)
    - but server responds with a blank html page
    Well, if http requests look identical in case of success and failure (pay attention to cookies, etc) then it has to be something on the server side.
    It could be that server gets into this wrong state because of previous requests made by applet but it is hard to tell.
    I am not clear how old/new plugin can make a difference unless your applets run in the legacy mode (i.e. you are actually trying to reuse SAME instance of the applet when
    it is loaded next time).

    I'd start with
    1) carefully comparing good/bad sessions
    2) checking whether server will serve correct response to another client when it serves "bad" page for current client
    3) add debug statements to aspx - it is scripted page, may be some condition is not met and then it returns blank?
    4) record all http requests in one session until you get to "error" state and then use any http server testing tool to "replay" this set of requests.
    You should be able to get server into the same state without use of applet. Then you can try to tweak set of requests to see what makes a difference.

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