Question

Fatal error: Call to undefined function sanitize() in general.php on line 5

This is general.php:

include"connect.php"; 
function user_id_from_username($username)
{
$username   =   sanitize($username); //This is line 5/general.php
return mysql_result(mysql_query("SELECT `id` FROM `users` WHERE `username`='$username'"),0, 'id');
}

connect.php contains my database connections, I have a confusion, do I need to include it in the function or functions will do it automatically connect to my database?

I am using the function in user.php As:

if(isset($_GET["username"])===true && empty($_GET["username"])===false)
{
$username   =   $_GET["username"];
$user_id    =   user_id_from_username($username);
echo"$user_id";
}

Answer 1

It means exactly what it says, sanitize isn’t defined in scope. It’s not a standard function so it should be somewhere within your code. You can most likely substitute it directly with mysql_real_escape_string.

$username   =  mysql_real_escape_string(username);

You should of course consider moving to PDO and parameterized queries.