Question

All,

I’m building a front controller in PHP. In it, I say:

if (isset($_GET['action'])){
        $action=$_GET['action'];
    } else {
        $action='';
    }

I follow that with a switch statement than governs which controller is called based on the value of $action:

switch ($action){
        case '':
            require_once('Controller_Welcome.php');
            $command=new controller_Welcome();
            break;
        case 'logon':
            require_once('Controller_Logon.php');
            $command=new controller_Logon();
            break;
        default:
            require_once('Controller_Unknown.php');
            $command=new controller_Unknown();
            break;
    }
$command->execute();

This works fine. When I launch the app, the URL is http://.../Index.php? and the Controller_Welcome.php is called. If I click on the logon menu entry, I get http://.../Index.php?action=logon, and the Controller_Logon.php is called. If I manually edit the URL to set ...?action=... to some unknown value, I get Controller_Unknown.php, which is my error page. So all is well.

What I don’t understand is that if I manually alter the url to show http://.../Index.php?action=, I get the error page rather than the welcome page. Why is it that php doesn’t associate a url ending with ...?action= with the switch case $action='';?

(There’s no logical user case when that would happen, but I still don’t understand it…)

Thanks,

JDelage

PS: Var_dumping $action returns string(0) "".

Answer 1

When you set ?action=, you will get a null return value for $_GET['action']. So in your scenario, the switch statement will use the default case. Like everyone said, you can always use var_dump to see the return value.