On first response, Tomcat both set's a cookie JSESSIONID and appends the
same to the page links (when properly coded). If the cookie comes back
on the next request, url rewriting is dropped in favor of the cookie. No
magic, tomcat just covers all it's bases up front.
See HttpServletResponse.encodeURL(String) in the servlet spec for more info.
-- David
Garey Mills wrote:
David -
Tomcat uses cookies to establish a session with the browser. If it
can't use cookies, it uses URL rewriting. So whenever someone uses my app,
Tomcat tries to set a cookie.
If it was the case that Tomcat didn't know whether the browser
accepted cookies until after it tried to set one at the first access,
users of browsers that did not accept cookies would not have a session
that recorded their first access. I don't think that would be considered
acceptable, so I assume that Tomcat knows, before my app is reached,
whether the browser accepts cookies. But is my assumption correct, I don't
know. That is what I am asking.
Garey Mills
Library Systems Office
UC Berkeley
The brain is not where you think
On Wed, 21 Jun 2006, David Kerber wrote:
Why would it try until your app tells it to? AFAIK (admittedly, not
very far; I don't use cookies) think it needs to be handled by your app.
Garey Mills wrote:
David -
Well, okay then, but how can my app find out what Tomcat knows
about whether the browser accepts cookies or not? And when does Tomcat
try? Before control is passed to my app?
Garey Mills
Library Systems Office
UC Berkeley
The brain is not where you think
On Wed, 21 Jun 2006, David Kerber wrote:
I think what he's getting at is that Tomcat (or any other web server)
cannot tell how a browser is set wrt cookies without trying to set one
and then seeing if it's there.
Garey Mills wrote:
Martin -
I guess I'm being obtuse, but WHAT won't work? What I want to know
is how Tomcat detects whether the browser accepts cookies, that is,
whether it is set to accept cookies or not?
Garey Mills
Library Systems Office
UC Berkeley
The brain is not where you think
On Wed, 21 Jun 2006, Martin Gainty wrote:
Garey-
Unfortunately that wont work if your Browser disallows cookies
If its IE
Check out the IE options-
Tools
Internet Options
Privacy
Advanced
look at "switched on Always allow Session Cookies"
HTH,
Martin --
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----- Original Message -----
From: "Garey Mills" <[EMAIL PROTECTED]>
To: "Tomcat Users List" <users@tomcat.apache.org>
Sent: Wednesday, June 21, 2006 12:50 PM
Subject: Re: How does Tomcat detect whether a browser accepts cookies
Leon -
Thank you for your response, but I don't understand it. I have a
key question:
how does Tomcat detect that a browser does not accept cookies?
There are a number of different ways to detect it inside my
application, but all of them seem to need a roundtrip to the browser. If,
as I suspect, Tomcat can tell without the redirect, I would like to use
Tomcat's knowledge. If Tomcat uses a roundtrip, I would still like to use
Tomcat's knowledge, so that I don't have to duplicate the work inside my
app.
Garey Mills
Library Systems Office
UC Berkeley
The brain is not where you think
On Wed, 21 Jun 2006, Leon Rosenberg wrote:
You could check for your cookie in first request and if not present
just set the cookie in the request and redirect to another page which
reads the cookie (btw, it can also be done with javascript without
user-visible-reload). The difference to your approach that each user
will be redirected exactly once, since you are checking for your
cookie in first request and it should remain persistent for next
visits.
regards
Leon
On 6/21/06, Garey Mills <[EMAIL PROTECTED]> wrote:
Hi -
I have an application that does not work correctly when the
browser does not accept cookies. I added some code that rewrites the query
string the first time the app is entered to include a new parameter and
then redirects to the app. I watch for that parameter and if I find it I
check whether the session id is from a cookie. If it isn't I put up a
"Sorry, you need cookies message" and exit.
This solution is not optimal, since I am seeing a blank page the
first time I try to get into the application.
So my question is: Tomcat must ascertain whether the browser
accepts cookies in order to decide whether to use cookies or URL
rewriting. How does it do it? and can I check Tomcat to find out, too?
Garey Mills
Library Systems Office
UC Berkeley
The brain is not where you think
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