PHP Fatal error: Class 'Slim' not found - php

Question

session_start();
date_default_timezone_set('GMT');
require 'Slim/Slim.php';
use Slim\Slim;
\Slim\Slim::registerAutoloader();
$app = new \Slim\Slim();
require_once 'item.php';
this is code excerpt from index.php and stuck on the said error when it called item.php. Here the contains of the file
$app->put('/getItem', authorize(), 'getItem');
function getItem() {
$sql = "SELECT * FROM item";
$app = Slim::getInstance();
try {
$db = getConnection();
$stmt = $db->query($sql);
$item = $stmt->fetchAll(PDO::FETCH_OBJ);
$db = null;
$response = $app->response();
$response->header('Content-Type', 'application/json');
// Include support for JSONP requests
if (!isset($_GET['callback'])) {
echo json_encode($item);
} else {
echo $_GET['callback'] . '(' . json_encode($item) . ');';
}
} catch(PDOException $e) {
$error = array("error"=> array("text"=>$e->getMessage()));
echo json_encode($error);
}
}
i hit the error on this $app = Slim::getInstance();
What is wrong with my approach?

Answer 1

The Slim class' full name (including namespace) is \Slim\Slim so you'll need to use that, eg
$app = \Slim\Slim::getInstance();
Alternatively, you can import the Slim symbol using the use statement at the top of your item.php script.
use Slim\Slim;

Answer 2

You can use this code for Slim Framework3:
<?php
require "vendor/autoload.php";
use \Slim\App;
$app = new App();
$app->get("/",function(){
echo "Hello World";
});
$app->get("/test",function(){
echo "Hello World";
});
$app->run();
?>