Display a message using msg in PHP - php

Question

I have to redirect a to a page and say x already exist.
I am doing some think like this:
header('location:newcategory.php'?msg=category exists);
I would prefer to do this from PHP, rather than in JavaScript.

Answer 1

On the page doing the redirecting:
header("Location: newcategory.php?msg=" . urlencode('category exists'));
On the newcategory.php page:
echo $_GET['msg'];

Answer 2

header("Location: :newcategory.php?msg=category exists&var=".$x);
in the newcategory.php add this
if(msg == "category exists")
{
echo $var." already exists";
}

Answer 3

It won't be good if you pass whole message in a GET parameter, as it would be probably vulnerable to some sort of XSS. The best way is to store collection of message and their identifiers and produce message on the fly. For example you could have an array:
$messages = array(
'exists' => 'category %s exists',
'failed' => 'query %s failed'
);
And then pass only message identifier in an URL, optional is parameter defining more clearly what happened:
header("Location: newcategory.php?msg=exists&id=2");
In target page you could write something like that:
$msg = '';
switch($_GET['msg'])
{
case 'exists':
{
$msg = sprintf($messages[$_GET['msg']], intval($_GET['id']));
break;
}
}
echo $msg;
It could be also wrapped in some classes, but I'd shown you the idea, hope it helps.