David -
Thanks for the clear, concise answer.
Garey Mills
Library Systems Office
UC Berkeley
The brain is not where you think
On Wed, 21 Jun 2006, David Smith wrote:
> 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 --
> >>>>>> *********************************************************************
> >>>>>> This email message and any files transmitted with it contain
> >>>>>> confidential
> >>>>>> information intended only for the person(s) to whom this email message
> >>>>>> is
> >>>>>> addressed. If you have received this email message in error, please
> >>>>>> notify
> >>>>>> the sender immediately by telephone or email and destroy the original
> >>>>>> message without making a copy. Thank you.
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>>> ----- 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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> >>
> >
> >
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