Re: [Zope] Help with session data and redirects

15 Apr 2003

      Thanks, Chris, for the quick reply.  I tried both of your suggestions: the 
random query string and the setHeader statements in the ZPT.  They both 
improved the situation in that requests after the initial one are now 
returned properly.  However, the very first request still returns the "Problem: no session object (redirectTest)" message.  By the way, instead of a response.redirect, if I return the page 
template directly in the script with a statement like "return 
container['view_session_obj.pt']()", it works perfectly.  Unfortunately, I 
need the redirect because of the way my actual page template works.

Brad

Chris McDonough <chrism@zope.com>
04/15/2003 10:18 AM

        To:     Brad Powell/PPCO@Phillips
        cc:     zope@zope.org
        Subject:        Re: [Zope] Help with session data and redirects

Under Mozilla 1.3 on Linux, when running your test (e.g. when visiting
/createSessionAndRedirect?sessionText=456), I immediately get:

## Page Template "view_session_obj.pt" ##

456

Like you, I suspect this may be a browser issue. 

To verify, cause the createSessionAndRedirect to generate a "random"
query string like this:

session = context.REQUEST.SESSION
sessionObjName = 'redirectTest'
session.set(sessionObjName, sessionText)
return
context.REQUEST.RESPONSE.redirect(context["view_session_obj.pt"].absolute_url() 
+ '?abc=%s' % context.ZopeTime().timeTime())

This should prevent browsers from returning a cached page.  A more
permanent solution would be to set a Pragma: No-Cache or Cache-Control:
No-Cache HTTP header within "view_session_obj.pt".

- C

On Tue, 2003-04-15 at 10:58, Brad Powell wrote:
...
I have a problem where session data does not appear to be updated when 
the 
setting of the session data is followed by a response.redirect in a 
Python 
script.  A browser refresh is required to get the correct data 
displayed. 
This happens on both Zope v2.5.1 and v2.6.1.  It also happens with IE 
and 
Mozilla browsers; but, interestingly, it does not occur with the 
Konqueror 
browser.  This led me to believe it was a browser issue, but no matter 
what options I try in IE, I cannot get it to work.  I thought it might 
be 
an issue with the browser cache settings, but, again, no matter what I 
try 
I get the same result.
I've included a test script and page template that demonstrates this 
problem. When I go to url "sessionCreateAndRedirect?sessionText=123", I 
get the message, "Problem: no session object (redirectTest)."  If I then
...
refresh the browser, I get "123" displayed, which is the correct 
response. 
 Subsequent calls to the url with different values for sessionText 
returns 
the previous session value, until I do a browser refresh.
Any assistance, guidance, wisdom, etc. on this matter would be greatly 
appreciated.
## Script (Python) "sessionCreateAndRedirect"
##parameters=sessionText
##
session = context.REQUEST.SESSION
sessionObjName = 'redirectTest'
session.set(sessionObjName, sessionText)
return
context.REQUEST.RESPONSE.redirect(context["view_session_obj.pt"].absolute_url())
...
## Page Template "view_session_obj.pt"
##
<html>
  <head>
    <title tal:content="template/title">The title</title>
  </head>
  <body>
    <tal:block define="global sesObj request/SESSION/redirectTest | 
nothing"></tal:block>
    <p tal:condition="not:sesObj">Problem: no session object 
(redirectTest).</p>
    <p tal:condition="sesObj" tal:content="sesObj">session obj 
contents</p>
  </body>
</html>
Brad