Displaying an Error Message

Funky_Monk

Hi. I'm developing a Mailing List and am building in a feature where the script checks for an e-mail address in the database and displays an error message if that e-mail address is already in it. I can get this to work using the following code, which I have put at the top of the code before the <html> tag:

<?php require_once('../Connections/connMailing.php'); ?>
<?php mysql_select_db($database_connMailing, $connMailing);
$query_rsInsertSubscriber = "SELECT * FROM ml_users ORDER BY user_id ASC";
$rsInsertSubscriber = mysql_query($query_rsInsertSubscriber, $connMailing) or die(mysql_error());
$row_rsInsertSubscriber = mysql_fetch_assoc($rsInsertSubscriber);
$totalRows_rsInsertSubscriber = mysql_num_rows($rsInsertSubscriber);
?>
<?php
function GetSQLValueString($theValue, $theType, $theDefinedValue = "", $theNotDefinedValue = "")
{
$theValue = (!get_magic_quotes_gpc()) ? addslashes($theValue) : $theValue;

switch ($theType) {
case "text":
$theValue = ($theValue != "") ? "'" . $theValue . "'" : "NULL";
break;
case "long":
case "int":
$theValue = ($theValue != "") ? intval($theValue) : "NULL";
break;
case "double":
$theValue = ($theValue != "") ? "'" . doubleval($theValue) . "'" : "NULL";
break;
case "date":
$theValue = ($theValue != "") ? "'" . date("Y-m-d",strtotime($theValue)) . "'" : "NULL";
break;
case "defined":
$theValue = ($theValue != "") ? $theDefinedValue : $theNotDefinedValue;
break;
}
return $theValue;
}

$editFormAction = $SERVER['PHP_SELF'];
if (isset($SERVER['QUERY_STRING'])) {
$editFormAction .= "?" . htmlentities($_SERVER['QUERY_STRING']);
}

if ((isset($POST["MM_insert"])) && ($POST["MM_insert"] == "frmSubscribe")) {
$insertSQL = sprintf("INSERT INTO ml_users (firstname, lastname, email, country, referral) VALUES (%s, %s, %s, %s, %s)",
GetSQLValueString($POST['firstname'], "text"),
GetSQLValueString($POST['lastname'], "text"),
GetSQLValueString($POST['email'], "text"),
GetSQLValueString($POST['Country'], "text"),
GetSQLValueString($_POST['referral'], "text"));

mysql_select_db($database_connMailing, $connMailing);
$email_check=mysql_query("SELECT email FROM ml_users WHERE email='$_POST[email]'");
if(mysql_num_rows($email_check)>=1) {
print("This e-mail address has already been subscribed. Please contact us if you believe this to be incorrect.");
} else {
$Result1 = mysql_query($insertSQL, $connMailing) or die(mysql_error());
header("Location: thank_you.php");
exit;
}
}
?>

This is fine and displays the error message: "This e-mail address has already been subscribed. Please contact us if you believe this to be incorrect." But it displays it at the top of the page. What I want it to do is display it just above the subscribe form. I tried putting the PHP Code above inside the form and it works OK, displays the error message and then you can try again. But when someone actually does sign up with a correct e-mail address it says that the headers have already been sent as it tries to display the 'Thank You' page. It still adds the e-mail address to the database but it just doesn't look very good.

How do I modify this so that the error message displays where I want it to?

Hope someone can help me out.

LarsLai

hi!
you only have to take care that the header is sent before any output to the browser.
so just put your code back to top and change to something like this:

$email_error = "";
mysql_select_db($database_connMailing, $connMailing); 
$email_check=mysql_query("SELECT email FROM ml_users WHERE email='$_POST[email]'"); 
if(mysql_num_rows($email_check)>=1) { 
 $email_error = "This e-mail address has already been subscribed. Please contact us if you believe this to be incorrect."; 
} else { 
 $Result1 = mysql_query($insertSQL, $connMailing) or die(mysql_error()); 
 header("Location: thank_you.php"); 
 exit; 
}

and then at the place you want to display the error message:

if ($email_error != "")
 echo $email_error;

PHPMagician

The reason you get the headers already sent error is because your error message shows up when you add it down further in the code. Why does it show up? Because you are moving it underneath the INSERT of the email address. So, this is how it runs:

User enters correct email
You add it to the database
You check if the email is already in the database

I am not too sure if you realised that was the cause or not, but it does no harm in me explaining.

What to do?

There are many things you can do, here is one way:

mysql_select_db($database_connMailing, $connMailing);
$email_check=mysql_query("SELECT email FROM ml_users WHERE email='$_POST[email]'");
if(mysql_num_rows($email_check)>=1) {
// Lets not print an error message, but make a variable:
$error_msg="This e-mail address has already been subscribed. Please contact us if you believe this to be incorrect.";
} else {
$Result1 = mysql_query($insertSQL, $connMailing) or die(mysql_error());
header("Location: thank_you.php");
exit;
}

Now, just go to the part of the HTML where you want to write the error message and put in:

<?php
echo $error_msg;
?>

$error_msg will be empty if there is no error (and you don't use yourself).

Hope it helps

Good Luck

Funky_Monk

Thanks for all your help. I go it working fine. Thanks for the explanations too.