HTTP POST and Internet Explorer

Question

Sorry for the cross post, but after reading through this newsgroup, it
          seems that this audience is better suited to answer this question...
          ===========================
          We're running across a very strange bug that is happening only in
          Internet Explorer and only when posting form data. Netscape works
          completely fine every single time.
          The user experience is this:
          Using IE, I get to a JSP that's got a form. I click a button on said
          form that performs either a "Save" or a "Cancel" action and am
          immediately hit with the wonderful "This page cannot be displayed(Cannot
          find server or DNS Error)" IE error message.
          What happens on the server side is this:
          User posts a form to a JSP. The JSP does any processing that it needs
          to, which in the case of "Cancel" is nothing, and issues these commands:
          response.sendRedirect("/some/page.jsp");
          return; //exit program immediately!
          I've verified that the server is executing as expected, sending the
          response and returning out of the program. That's where things seem to
          go awry in Internet Explorer. It's as if IE is not interpreting the
          HTTP response header correctly and just dies not knowing where to go.
          The even stranger thing is that, when running WLS on our internal
          network, this does not happen unless your dialed up. However, when
          hitting our servers that are colocated, this happens on a regular basis.
          One more thing to note is that this does not happen every time. It
          happens more than 90% of the time, but not every time, which is why it's
          very hard for me to recreate.
          Another strange thing is that this error seems to depend on the content
          of the form
          variables, for instance I can have a form with check boxes that errors
          out when the
          check boxes are unchecked, but is fine when the boxes are checked, and
          in both
          cases I'm not doing anything at all with the data that is getting
          posted.
          I've tried everything from changing the http headers to changing the
          post to be
          multipart encoded, and nothing works.
          If you've got a clue or a hint or any suggestions where I should be
          looking, then please let me know. I've got a few more things to check
          out, but I'm running out of ideas.
          Our platform:
          - RedHat Linux 6.0
          - WebLogic Server 4.5.1 Service Pack 5
          - JDK 1.2.2 (Sun/Blackdown)
          These JSPs:
          - Are posting form data ("GET" works for some reason)
          - Are not using any JavaScript
          

Answer 1

Hi Chris/All,
          Following on from this I contacted WebLogic support (Frederic). They
          suggested I downgrade from 4.5.1 sp8 to 4.5.1 sp7. They also suggested I
          use HttpResponse.encodeURL()...
          This did not solve my problem but I went on to discover the following...
          Hi Frederic,
          We tried with sp7
          I thought HttpResponse.encodeURL just encoded session data where no cookie
          support was in the browser, but I tried it anyway.
          Also tried the following to the page I'm redirecting back to (to prevent
          browser cacheing)
          resp.setHeader("Cache-Control","no-cache"); file://HTTP 1.1
          resp.setHeader("Pragma","no-cache"); file://HTTP 1.0
          resp.setDateHeader ("Expires", 0); file://prevents caching at the proxy
          server
          Also added the following to override the standard implementation
          protected long getLastModified(HttpServletRequest req)
          System.out.println("ServletA.getLastModified"); // ensure lastModified is
          always in the future requiring a reload
          return Long.MAX_VALUE;
          The only way I've been able to force this to work is a bit of a cludge and
          is as follows...
          // add time to queryString to fool IE5 into thinking this is a new web page.
          String parentURL = HttpUtils.getRequestURL(req) + "?" + req.getQueryString()
          + "&t=" + System.currentTimeMillis();
          The following is also of interest
          http://forum.java.sun.com/forum?14@@.787c19c1
          HTH, Let me know
          Thanks, Gary
          Gary <[email protected]> wrote in message
          news:[email protected]...
          > This sounds similar to a problem I'm having with straight Servlets.
          >
          > I have a servlet (ServletA) that has a link to another servlet via <a
          href>
          > tags (ServletB). ServletB does some processing and calls ServletA with
          > original parameters to show the user the changed details. This is done as
          > follows...
          >
          > respose.sendRedirect(ServletA?params);
          > return;
          >
          > Once again this is fine in Netscape 4.07 but only works on IE5 machine
          here
          > to date (which unfortunately happens to be mine, leading to my late
          > discovery of this problem).
          >
          > My IE version is 5.00.2314.1003 if that helps.
          >
          >
          > Chris Fraser <[email protected]> wrote in message
          > news:[email protected]...
          > > Sorry for the cross post, but after reading through this newsgroup, it
          > > seems that this audience is better suited to answer this question...
          > > ===========================
          > > We're running across a very strange bug that is happening only in
          > > Internet Explorer and only when posting form data. Netscape works
          > > completely fine every single time.
          > >
          > > The user experience is this:
          > > Using IE, I get to a JSP that's got a form. I click a button on said
          > > form that performs either a "Save" or a "Cancel" action and am
          > > immediately hit with the wonderful "This page cannot be displayed(Cannot
          > >
          > > find server or DNS Error)" IE error message.
          > >
          > > What happens on the server side is this:
          > > User posts a form to a JSP. The JSP does any processing that it needs
          > > to, which in the case of "Cancel" is nothing, and issues these commands:
          > >
          > > response.sendRedirect("/some/page.jsp");
          > > return; file://exit program immediately!
          > >
          > > I've verified that the server is executing as expected, sending the
          > > response and returning out of the program. That's where things seem to
          > > go awry in Internet Explorer. It's as if IE is not interpreting the
          > > HTTP response header correctly and just dies not knowing where to go.
          > >
          > > The even stranger thing is that, when running WLS on our internal
          > > network, this does not happen unless your dialed up. However, when
          > > hitting our servers that are colocated, this happens on a regular basis.
          > >
          > > One more thing to note is that this does not happen every time. It
          > > happens more than 90% of the time, but not every time, which is why it's
          > >
          > > very hard for me to recreate.
          > >
          > > Another strange thing is that this error seems to depend on the content
          > > of the form
          > > variables, for instance I can have a form with check boxes that errors
          > > out when the
          > > check boxes are unchecked, but is fine when the boxes are checked, and
          > > in both
          > > cases I'm not doing anything at all with the data that is getting
          > > posted.
          > >
          > > I've tried everything from changing the http headers to changing the
          > > post to be
          > > multipart encoded, and nothing works.
          > >
          > > If you've got a clue or a hint or any suggestions where I should be
          > > looking, then please let me know. I've got a few more things to check
          > > out, but I'm running out of ideas.
          > >
          > > Our platform:
          > > - RedHat Linux 6.0
          > > - WebLogic Server 4.5.1 Service Pack 5
          > > - JDK 1.2.2 (Sun/Blackdown)
          > >
          > > These JSPs:
          > > - Are posting form data ("GET" works for some reason)
          > > - Are not using any JavaScript
          > >
          >
          >