On the TutsPlus.com site there's a tutorial recently posted sharing the basics of middleware in Laravel applications - reusable pieces of code that operate on the request and response during the execution of your code.

In this article, we'll dive deep into the Laravel framework to understand the concept of middleware. The first half of the article begins with an introduction to middleware and what it's actually used for.

As we move on, we'll cover how to create custom middleware in a Laravel application. After creation of your custom middleware, we'll explore the options available to register it with Laravel so that it could be actually invoked during the request processing flow.

The tutorial starts by explaining what middleware is and how it functions in the flow of the Laravel application (as well as possible uses). It then starts in on the creation of custom middleware designed to redirect mobile users to the "mobile site" for the service. With the test for that in place the post then shows how to apply the middleware to the application on a route.