how to user header("Location... with dynamic URLs

dancablam and mgh_mgharish,

Which of the two ways above is correct?

Both !

And there is another way.. you can surround the variables in {} as in:

...cmd={$_POST['cmd']}&...

Thanks guys, I'll leave this open a little longer

Ah yes, sorry about that. Or like this:

header("Location: $url");


(You don't need to separate variables when you're using double quotes.)

Another thing you have to note is if $_POST['redirect_cmd'] will be somthing like "text with spaces" then this header will cause an error. So you have to validate all data in according to url's conditions.
If you're using PHP 5 or above then you can use http_build_query(); If not you have to create your own function. Anyway you can create a PHPVersion-Independant function to do this:
<?php
function prepareUrl($dataArray)
{
    // If our server is PHP 5 and higher, then
    // http_build_query() function must exist
    // and we can use it.
    // $dataArray must be an array.
    if (is_array($dataArray) && function_exists("http_build_query")) {
        return http_build_query($dataArray);
    }
    // If http_build_query() is not exist, and
    // $dataArray is array, then do urlencode
    // dor all values of $dataArray
    elseif (is_array($dataArray)) {
        $parsed = array();
        foreach ($dataArray as $k => $v) {
            $parsed[] = $k . "=" . urlencode($v);
        }
        return implode("&", $parsed);
    }
    else {
        trigger_error("First param of prepareUrl must be an array.", E_USER_WARNING);
        return null;
    }
}

$url_data = array(
    "cmd" => $_POST['cmd'],
    "redirect_cmd" => $_POST['redirect_cmd'],
    "business" => $_POST['business'],
    "upload" => $_POST['upload'],
    "item_name_1" => $item1,
    "quantity_1" => $_POST['quantity_1'],
    "amount_1" => $_POST['amount_1']
);

$url_query = prepareUrl($url_data);

header("Location: https://www.paypal.com/cgi-bin/webscr?{$url_query}");
exit();
?>

Why not just use urlencode()?

//  URL stored in variable $url
header('Location: ' . urlencode($url));

<?php
$url = "https://www.paypal.com/cgi-bin/webscr?cmd=test&var2=a lot of text&var3=with\'special chars";
var_dump(urlencode($url));
?>

That's why...

KennyTM, I've wrote about it. But he cannot use http_build_query() on $_POST, because:
1. _POST can conatin data that has not to be inserted in query
2. He need not to put only some _POST values, but $item1

Also his server may not have PHP 5, but PHP4. That's why I've suggested a function.

I got it. I learned a lot from all of your posts. Thanks you guys,

Bob