Problem with querystring and header.

sijis

I'm working with a product list for a shopping system.

When a user goes to the shop, they get a UID. Once the user adds an item to the cart, i give them a category number (for shipping/discount purposes).

when user first goes to site:
http://domain.com/dir/file.php?UID=12ahdy32124h45

after first item in cart:
http://domain.com/dir/file.php?UID=12ahdy32124h45&CA=1

after subsequent items in cart: (should stay the same)
http://domain.com/dir/file.php?UID=12ahdy32124h45&CA=1

now the problem is, after a user continues to add an items to the cart, they begin to get an URL like so:
http://domain.com/dir/file.php?UID=12ahdy32124h45&CA=1&CA=1&CA=1

What I am attemping to do is

if QUERY_STRING doesn't have CA in it (it doesn't matter its value)
then Add CA=$_POST['CA'] to the querystirng
else
leave URL and querystring alone.

redirect user to refferred page.

here's my code:

// file: order_dvd.php
	echo "<FORM ACTION=\"".RELATIVE_URL."/do_process.php\" METHOD=\"POST\">";
	echo "<INPUT TYPE=\"hidden\" NAME=\"CA\" VALUE=\"1\">";


// file: do_process.php
	if(!$_GET['CA']){
		$Q_STRING = "&CA=$CA";
	}

/* I've also tried:
if(isset($_SERVER['CA'])){
	$Q_STRING = "&CA=$CA";
}
*/

header("Location:". $_SERVER['HTTP_REFERER'] . $Q_STRING);
//Header("Location:$HTTP_REFERER$Q_STRING");
//Header("Location:".RELATIVE_URL."/viewCart.php?CA=$CA&UID=$UID");

Here's an actual example of my problem:
http://www.librarymedia.org/order/order_dvd.php

I'm not sure what is the problem. I've tried several things (as you can see in the code), but none of it works. maybe there could be a different approach for the solution?

thanks for any responses.

veron

Your problem is the $_SERVER['HTTP_REFERER']. This variable includes the query string, resulting in you appending the CA to a URL already include one or more CAs.

sijis

Ahh! i was trying to get the current querystring and see if CA already existed. that way i don't have to add it again the the current querystring.
so is there a way to check if CA exist in HTTP_REFERER?

Rohan_Hill

Yes, use the strstr function to see if the HTTP_REFERER string contains the string "CA":

if (strstr ($_SERVER['HTTP_REFERER'], "CA"))

Weedpacket

...though a safer string to search for would be "&CA=".

sijis

Great! using the strstr() function worked like a charm.
Also thanks for the tip for using "&CA=" as the string to search.

Thanks again.

sijis