404 Errors

It is an inevitability that someone will request a page that does not exist. The Slim application lets you easilydefine a custom Not Found handler with the Slim application’s notFound() method. The Not Found handler will beinvoked when a matching route is not found for the current HTTP request. This method acts as both a getter and a setter.

Set not found handler

If you invoke the Slim application’s notFound() method and specify a callable object as its first and onlyargument, this method will register the callable object as the Not Found handler. However, the registered handlerwill not be invoked.

<?php
$app = new \Slim\Slim();
$app->notFound(function () use ($app) {
    $app->render('404.html');
});

Invoke not found handler

If you invoke the Slim application’s notFound() method without any arguments, this method will invoke thepreviously registered Not Found handler.

<?php
$app = new \Slim\Slim();
$app->get('/hello/:name', function ($name) use ($app) {
    if ( $name === 'Waldo' ) {
        $app->notFound();
    } else {
        echo "Hello, $name";
    }
});