Controllers

Controllers are the classes called by the routes when a request is made to your application. They are crucial parts of your application in with server-side rendering, since they are responsible for generating the entire HTML page.

TIP

The use of Graphql with an automatic configuration loader such as Lighthouse and authentication via OAuth makes writing controllers almost unnecessary. We'll briefly address how to implement them here for REST endpoints, as well as OAuth callbacks.

Laravel has support for controllers. There are plenty of libraries that help with a traditional REST endpoint structure, cutting down the amount of controller code you have to write. One example is InertiaJS, which not only has plenty of support on the backend, but has adapters for frontend as well.

What a controller looks like

Controllers are nothing but classes with public methods that are mapped to endpoints by routers. Here's a simple example for rendering a template on the show endpoint, which would be mapped to /user/{id}:

namespace App\Http\Controllers;

use App\Http\Controllers\Controller;
use App\Models\User;

class UserController extends Controller
{
    /**
     * Show the profile for the given user.
     *
     * @param  int  $id
     * @return \Illuminate\View\View
     */
    public function show($id)
    {
        return view('user.profile', ['user' => User::findOrFail($id)]);
    }
}

REST endpoints

Most REST endpoints look the same. They all need CRUDL operations. Laravel provides easy routing for these, which are called resource controllers, defining several endpoints like /posts/create and /posts/{id}:

Route::resources([
    'posts' => PostController::class,
]);

You can scaffold the entire controller class easily:

php artisan make:controller PostController --resource --model=Post

With GraphQL you have just one endpoint, usually at /graphql.

REST is still a common protocol and a good solution for applications that perform non-trivial tasks on CRUDL or that don't use CRUDL. IoT devices often have actions like turning on, off, setting parameters etc, which map very well to GraphQL.

Templates

Templates are fragments of (usually HTML) code that allow you to fill areas with variables. Templates can be powerful and include ifs and loops. Laravel integrates Blade templates. They are extensively used for SSR, but not useful (at least on the backend) for SPAs.

Controllers call the template directly, passing variables to fill its data:

    public function show($id)
    {
        return view('user.profile', ['user' => User::findOrFail($id)]);
    }

We won't get into Blade's syntax on this book.