global mysqli variable?

Twinkie

Twinkie

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Trying some simple testing to form the backbone of a subscription system. Why am I getting this error when I make a subscription?
PHP: 
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>Mail Subscription</title>
</head>
<body>

<?php
function DBCon() {
    global $con;
    $con = mysqli_connect("localhost", "user", "nopass","mtwinkie_testdb");
    if (mysqli_connect_errno()) {
        printf("Connect failed: %s\n", mysqli_connect_error());
        exit();
    }
}

function Validate($email) {
    if(!filter_var($email, FILTER_VALIDATE_EMAIL))
        die("<h1 align=\"center\">Invalid Email.</h1>");
    else if (strlen(email) > 150)
        die("<h1 align=\"center\">Email too long.</h1>");
    $query = "SELECT id FROM Newsletter WHERE email = '" . email ."';";
    $res = mysqli_query($con,$query) or
        die(mysqli_error($con));
    if (mysqli_num_rows($res) < 1)    
        die("<h1 align=\"center\">Your already subscribed.</h1>");
    return true;
}

if (!isset($_REQUEST["do"])) {
?>

<h1>Mail Subscription</h1>
<form action="#" method="post">
<b>Your Email Address:</b><br />
<input type="text" name="email" /><br /><br />
<b>Action:</b><br />
<input type="radio" name="do" value="sub" /> Subscribe
<input type="radio" name="do" value="unsub" /> Unsubscribe
<p><input type="submit" value="Submit Form" /></p>

<?php
} else if ($_REQUEST["do"]=="sub") {
    DBCon();
    if (Validate($_REQUEST["email"])) {
        $query = "INSERT INTO Newsletter (ID, Email) VALUES (\"" . $email . "\");";
        $res = mysqli_query($con,$query) or
            die(mysqli_error($con));
        mysql_close($con);
        die("<h1 align=\"center\">Thank you for signing up!</h1>");
    }
} else if ($_REQUEST["do"]=="unsub") {
    die("<h1 align=\"center\">Not available yet =(</h1>");
} else die("<h1 align=\"center\">Logical Script Error.</h1>");
?>

</body>
</html>
As far as I can tell the global declaration should solve this problem?
 
M

misson

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2 problems:
Twinkie said:
Code: 
function Validate($email) {
    if(!filter_var($email, FILTER_VALIDATE_EMAIL))
        die("<h1 align=\"center\">Invalid Email.</h1>");
    else if (strlen([COLOR="Red"]email[/COLOR]) > 150)
        die("<h1 align=\"center\">Email too long.</h1>");
    $query = "SELECT id FROM Newsletter WHERE email = '" . [COLOR="red"]email[/COLOR] ."';";
    $res = mysqli_query($con,$query) or
        die(mysqli_error($con));
    if (mysqli_num_rows($res) < 1)    
        die("<h1 align=\"center\">[COLOR="red"]Your[/COLOR] already subscribed.</h1>");
    return true;
}
Click to expand...
You left the '$' off of 'email' in 2 lines here. Also, grammar maven says that that should be "You're" ("you are"), not "Your" (possessive).

Twinkie said:
PHP: 
        $query = "INSERT INTO Newsletter (ID, Email) VALUES (\"" . $email . "\");";
Click to expand...

This is the source of the error. You say you're going to provide 2 values, ID and Email, but only provide 1. If the ID column is auto_increment, leave ID out of the insert statement.
 
Twinkie

Twinkie

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Thanks misson, I already the first two errors after I posted, but that's not what the problem was. I got a warning that I did not have a valid mysqli variable supplied in the email validation function. I later fixed it my moving the mysqli portion of the function where the DBCon() was called, but why can't the script posted above read the $con variable in the Validate() function is $con is a global variable?
 
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misson

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Validate() doesn't declare $con as global. I recommend passing $con as a parameter rather than using a global; it's cleaner.
 
Twinkie

Twinkie

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You're probably right, but I declare it as a global variable in the DBCon() function. Shouldn't that make it accessible in the Validate() function?
 
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misson

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Twinkie said:
You're probably right, but I declare it as a global variable in the DBCon() function. Shouldn't that make it accessible in the Validate() function?
Click to expand...

Nope. Each function has its own scope. The "global" declaration imports a global variable into a function's scope (actually, it creates a local variable that holds a reference to the global variable). It doesn't make a variable a superglobal.

In any case, pass the connection around as a parameter and you don't need to worry about globals.
 
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