IF statements and Header redirects.

bostonmacosx

I might just be cross eyed. I'm using PHP 4.3.4. Even though there is a header in the If statement it goes on to complete the rest of the PHP page. If I place a "break;" after the first header line it works. In previous pages I've written as soon as a header was found the rest of the page was not completed(executed)....or at least I think that was the behavior. Any suggestions as to why although it goes to redirect the page to instructors.php that it still querys the database and completes the commands? Shouldn't it just stop at the if statement?

<?
session_start();

$length = strlen($_POST[newcoursenumber]);

if($length != 12){
header("Location:instructors.php?error=coursenum");
}

$db_name = "none";
$table_name = "none";
$connection = @mysql_connect("localhost","none","none") or die("Couldn't Connect.");
$db = @mysql_select_db($db_name, $connection) or die("Couldn't select database.");

$result =mysql_query("SELECT coursenum from co298012004f WHERE email='$_SESSION[username]'") or die (mysql_error());
$coursenums = mysql_fetch_array($result);
$newvar = $_POST[newcoursenumber].':'.$coursenums[0];
mysql_query("UPDATE co298012004f SET coursenum='$newvar' where email='$_SESSION[username]'") or die (mysql_error());

header("Location:instructors.php");
?>

eoghain

No your code shouldn't just stop. Even though you've sent the header everything else on your page is still going to get processed. The header that you are sending is telling the users browser to start loading another page, but you have nothing in your code that tells the server to stop processing. You either have to add an [man]exit/man call inside your if statement or wrap the rest of your code in and else {} block.

if($length != 12){ 
   header("Location:instructors.php?error=coursenum"); 
   exit();
} 

// Or
if($length != 12){ 
header("Location:instructors.php?error=coursenum"); 
} else {
   /// The rest of your code
}

superwormy

Indeed, header() just sends an HTTP header, it DOES NOT guarentee the script will end or anything like that. In fact, the browser doesn't even need to listen to the header() call if it doesn't want to.

Add an exit() call on the line after the header().

Weedpacket

Originally posted by superwormy
Indeed, header() just sends an HTTP header, it DOES NOT guarentee the script will end or anything like that.

After all, you might want to send more than one header - hard to do that if header() stops the script from further processing.