session issue

Hello friends,

i am working on a website using catalyst. Users are required
to fill some forms which are 4-5 pages long. While filling
the form he may opt to go to the previous page to edit
details he has previously filled.if he goes back to the
previous page I need to show him all his details he
chose/filled on the previous page.

I am using session to store all his details he is filling in
the form. When he goes back to the previous pages, i take
the information from the session and i fill them in the
pages.
Now the problem is that if users opens two forms together
and fills some data and then goes back to previous page, the
session shows him the data (he filled in the second form )in
the first form.

I know the problem is that they are using same session. But
how to avoid this? Any help will be highly appreciated!

Thanks!
Gaurav Talwar
"Wisdom begins in wonder" - Socrates, philosopher

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Gaurav Talwar wrote:

> I am using session to store all his details he is
filling in the
> form. When he goes back to the previous pages, i take
the information
> from the session and i fill them in the pages. Now the
problem is
> that if users opens two forms together and fills some
data and then

I suppose you mean the same user opens two instances of the
same form...

> goes back to previous page, the session shows him the
data (he filled
> in the second form )in the first form.
>
> I know the problem is that they are using same session.
But how to
> avoid this? Any help will be highly appreciated!

Actually this isn't a Catalyst issue. You will always have
this problem 
when using sessions that share the same store for multiple
requests.

Two options to avoid the problem:
- Store already received data in hidden fields of the
subsequent forms.
- Use Apache::Session::Counted. This provides a new session
data
  container for every request.
-- 
Bernhard Graf

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On Thu, May 24, 2007 at 05:33:16PM +1000, Gaurav Talwar
wrote:
> i am working on a website using catalyst. Users are
required to fill
> some forms which are 4-5 pages long. While filling the
form he may opt
> to go to the previous page to edit details he has
previously filled.if
> he goes back to the previous page I need to show him
all his details
> he chose/filled on the previous page.
> 
> I am using session to store all his details he is
filling in the form.
> When he goes back to the previous pages, i take the
information from
> the session and i fill them in the pages.  Now the
problem is that if
> users opens two forms together and fills some data and
then goes back
> to previous page, the session shows him the data (he
filled in the
> second form )in the first form.
> 
> I know the problem is that they are using same session.
But how to
> avoid this? Any help will be highly appreciated!

Whether this is a good idea I can't say, but it is an idea
nonetheless.

In the session, instead of just storing an object (hash,
list, whatever)
with the details, store a hash from a random (or sequential)
ID to the
details object. Every time the user enters the form,
generate a new ID
and put it in a hidden element on the form. When you get
some form data,
use the ID to decide where in the session to put it, and
when you
generate the next page of the form, send the same ID in
another hidden
element.

This way, the user can open pages from a form in different
tabs and have
them all edit the same details. He can also open another
form (from a
different entry point) in another tab, or even in the same
window by
pressing 'back' a few times and clicking a different link,
and have
different details. The first details are still in the
session so he can
go back to the first set of forms and finish from where he
left off.

Of course, if your forms are editing some object that is
stored in your
database, it might be a good idea to make the ID depend only
on the
internal ID of the thing the user is editing: that way, if
he clicks
'back' several times and then opens the form from the start
to edit the
same object he was editing before, it uses the same ID
rather than a new
one. It may or may not make sense for you to do this.

The other variation is that you could use a GET parameter
(or an URI
path argument with the ID) rather than a hidden form
element. It
probably interacts better with caches and it is clearer to
the user what
is going on if he cares to look. If you have the ID of the
object
being edited in the URI anyway, and you have the form ID
being the ID of
the object, you don't need to change your templates or URIs
at all: just
make sure you use the ID as a hash key for details objects.

-- 
"I tried snorting coke once, but the bubbles went right
up my nose and I
knocked the glass over."   -- 'Sordid Confessions of a
Teenage Innocent'
http://surreal.istic.org/                              Show, don't tell.

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Bernhard Graf wrote:
> Gaurav Talwar wrote:
> 
>> I am using session to store all his details he is
filling in the
>> form. When he goes back to the previous pages, i
take the information
>> from the session and i fill them in the pages. Now
the problem is
>> that if users opens two forms together and fills
some data and then
> 
> I suppose you mean the same user opens two instances of
the same form...
> 
>> goes back to previous page, the session shows him
the data (he filled
>> in the second form )in the first form.
>>
>> I know the problem is that they are using same
session. But how to
>> avoid this? Any help will be highly appreciated!
> 
> Actually this isn't a Catalyst issue. You will always
have this problem 
> when using sessions that share the same store for
multiple requests.
> 
> Two options to avoid the problem:
> - Store already received data in hidden fields of the
subsequent forms.

This is almost always the best approach, IMO. The state of
the form is
kept with the form, where it belongs. There are no
synchronization 
issues with the session.

Maurice

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mla wrote:

> > Two options to avoid the problem:
> > - Store already received data in hidden fields of
the subsequent
> > forms.
>
> This is almost always the best approach, IMO. The state
of the form
> is kept with the form, where it belongs. There are no
synchronization
> issues with the session.

This applies to the 2nd option, Apache::Session::Counted, as
well.
Instead of storing everything in hidden fields, you only
have to pass a 
session key, that is unique for every new request. With
A:S:C you are 
able to store arbitrary complex data (all that Storable can
handle). 
-- 
Bernhard Graf

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