Use the Slim application's get() method to map a callback function to a resource URI that is requested with the HTTP GET method.

<?php
$app = new \Slim\Slim();
$app->get('/books/:id', function ($id) {
    //Show book identified by $id
});

In this example, an HTTP GET request for “/books/1” will invoke the associated callback function, passing “1” as the callback's argument.

The first argument of the Slim application's get() method is the resource URI. The last argument is anything that returns true for is_callable(). Typically, the last argument will be an anonymous function.