handling cookies in arrays

[Anon]

This is in response to the Martin's reply for handling arrays in cookies.
I will explain the exact problem.
If the user selects a poll from the list it will pop the window to answer.To answer for the next poll the user has to select from the same list.In this point, i am not once again query the poll details from the database(by filtering with answered one).Simply i want to restrict the user from entering once again for the same poll.
Is it possible to retrieve (or get) the cookie value in the parent window(where all poll lists are displayed) which is set in the child window after the user answers.
The user has to close the child window to move to another pole.In this point how to transwer the cookie value to the parent window.If it is avilable in parent window i can easiy check whether already voted or not.
I am very much confused in this.
I may be wrong in my approach.Please explain in detail.

Many Thanks
Srini.

[Anon]

Hi Srini,

If you open a new window, and set a cookie there, simply closing the window leaving you with the already opened parent window won't do you any good at all.

The cookie will only be active for the next page, e.g.

open page 1
set cookie
redirect to page 2

Then, on page 2 the cookie is active and alive. You can then check.

What you are doing is:

open page 1
user clicks on something in page 1
page 2 opens in a new window
page 2 sets cookie
page 2 closes
still open and unchanged page 1 is supposed to check the cookie that was set in the briefly opened new window.

That will not work, or perhaps I'm wrong, but in my honest opinion, you should bear in mind, that page 1 with your poll links, has already been loaded before any cookie was set, e.g. it was already parsed.

In other words, as far as page 1 is concerned, the cookies are still unset, and the user can revote as much as he likes.

The only thing that will make page 1 understand you cannot vote, e.g. re-read the cookies for being set or not, is to force a reload from your script of page 1 from some other page.

Perhaps there is a nice way to work around this, but I think this will be quite something to do.

What perhaps could work...

Create a javascript to set the cookie and capture the "OnClick" event when the user clicks a link. Before the click is handled, carry out a function to set a cookie for that particular vote, then javascript code to open a new window to display poll.

On the new window, you can php code to check for the cookie and decide to offer the user to vote or not.

Something like this on page 1:

<script language="javascript" type="text/css">
function setcookie(iPollid) {
[set cookie for poll id iPollid]
[open new window]
}
</script>

echo "<a href=\"#\" Onclick=\"setcookie($pollid);\">Click for Poll $pollid</a>";

There are however 2 problems with this:

1. Even if the user decides to not vote after all, his vote is logged and he can no longer vote
2. If the user disables javascript, what then?

Note; the code is not meant for real use, it's just to show you the general idea ;-) I can program but so many hours before my mind starts messing up ;-)

[Anon]

Hi Martin
Many thanks.what you said is correct and it may be the reason for the problem.May be Cookie values are active only on diffrent pages and not on new windows.The cookie value set in the window is not available in page1 if we go back.Is there any other method to do this without having windows.
Meanwhile if you find any other method which could solve the problem,let me know.
Once again many thanks for your help.

srini

[Anon]

Hi Srini,

Glad to have been able to help.

I could think of one way to solve your problem, other than the one supplied before (the javascript way).

Create a page with links to polls, just like you have know. I figure you go through your database with something like while ( $myrow = mysql_fetch_array($result) ) ? In each iteration, you obviously create a link, since on each iteration you have a poll's unique id, and you can dynamically create a link.

Now, you should not only set a cookie but also put the visitor's IP address in your database. There's no real prevention from people voting twice. Cookies can be deleted and IP addresses change on every dialout (usually that is).

Anyway, the visitor clicks a link and you put them through to page 2, where they see the poll. Create a form on that page to submit the vote, and make it go to a page that inserts the results and set a cookie.

Then redirect back to page 1. Not with any new window, same window here.

The page is rebuild and the poll they just took is greyed out, not-active whatever.

That's in my opinion the only way to do this. Of course upon doing your query on page 1 to show the links, not only check for the cookie but also check the database.

There was a talk a few days back about polls. We discussed about the fact you cannot prevent people from voting twice (or more) if they really really want to. Like I said, cookies can be deleted and ip capturing is considered unfriendly as people behind a router usually all get the same IP address and everyone behind it can not vote to that poll.

Also, some ISP's regenerate IP addresses that might incorrectly prevent someone from voting.

I suggested in that thread to only use a cookie and perhaps prevent "bulk" voting, just as you would prevent people from nuking a forum.

This works this way; when your system receives X votes within X minutes, don't count them, but set them aside for the administrator to judge. You can auto e-mail the administrator and say that someone from IP address XXX voted X times within X minutes. With this information you can simply build a query to delete this attack, or not approve them whatever.

For normal websites not getting thousands of visitors, the IP captureing is fine I guess. Because someone would have to log out and re-login at his ISP in order to fake your voting system.

Beware for services like anonimizer.com though ;-)

[Anon]

Hi
Thanks a lot for your help.I will try by submitting the poll details in the second page and set a cookie there and then redirect the control to page 1.Here I will try to list all the polls with links except the voted one(displaying without links).
I will get back to you after trying this.

Many thanks.

srini