How to Use Controllers and Middleware in Laravel

Laravel Middleware provides a convenient mechanism for assessing and sifting through HTTP demands that enter your application. All of these middleware are found within the app/Http/Middleware registry.

Laravel Middleware acts as a bridge between a request and a reaction. It is a type of sifting component. Laravel incorporates a middleware that confirms whether or not the client of the application is verified. If the client is confirmed, it diverts to the home page otherwise, it diverts to the login page.

All controllers in Laravel are created in the Controllers folder, located in App/Http/Controllers. All controllers must have the namespace `App\Http\Controllers` and extends from the Controller class.

What Are Controllers in Laravel

Controllers help in maintaining a separation of concerns by encapsulating the request handling logic separate from the routes and views. This enhances the code’s readability, maintainability, and scalability. Controllers in Laravel are typically stored in the app/Http/Controllers directory and follow a specific naming convention.

Basic Controllers

Basic controllers in Laravel are classes that contain methods to handle various HTTP requests. These controllers typically group related request handling logic together. Each method within a controller corresponds to a specific route or endpoint in the application.

Basic controllers often utilize methods like index(), show(), store(), update(), and destroy() to handle CRUD (Create, Read, Update, Delete) operations for resources.

Here is an example of how you can use basic controllers to manage your classes and HTTP requests.

namespace App\Http\Controllers;

use App\Models\User;
use Illuminate\Http\Request;

class UserController extends Controller
{
    public function index()
    {
        // Logic to fetch and display a list of users
    }
    public function show($id)
    {
        // Logic to fetch and display a specific user
    }
    public function store(Request $request)
    {
        // Logic to store a new user
    }
    // Other methods like update() and destroy() would be defined here
}

Single Action Controllers

Single-action controllers are an alternative to traditional controllers when you only need a single action within the controller. Instead of defining multiple methods, you define a single __invoke() method within the controller class.

namespace App\Http\Controllers;

use Illuminate\Http\Request;

class WelcomeController extends Controller
{
    public function __invoke()
    {
        return view('welcome');
    }
}

How to Create a Basic Controller in Laravel

Remember the tables example in the article on routing.

I will now create a controller using a single method which will print the required table on the screen. To define a controller in Laravel, first give it a name. In this example, I will name the controller Table and then add Controller to the name. The full name of the controller class is now TableController. Remember that all the controllers in Laravel must have the word Controller at the end.

You can create controllers in two ways:

• Manually create a file
• Use Artisan to create the controller (this is the easy option!)

I will now demonstrate how you could create a controller using the Laravel Artisan command. I will use the following command:

php artisan make:controller TableController

Once the command is completed, an empty `TableController` class will be generated in the Controllers folder with name `TableController.php`. At this point, the class looks like:

<?php

namespace App\Http\Controllers;
use Illuminate\Http\Request;
class TableController extends Controller
{

   //

}

I will now add the logic for generating the table. Create a new method `create` inside `TableController`:

public function create($number = 2)
{
    for($i =1; $i <= 10 ; $i++){
        echo "$i * $number = ". $i* $number ."<br>";
    }
}

This is the same logic that I used in the rout (refer to the article on Laravel routes). I will now remove this functionality from the route and then bind the controller to it

Route::get('/table/{number?}', 'TableController@create')→where('number', '[0-9]+');

Now whenever the URL is executed, the control action `create` will be called and the table for the number would be generated.

How to Create a Resource Controller

Resource controllers are used to create CRUD options for routes.

Let’s say, I have a model for Books, and now I want to create a controller that will perform its CRUD methods for the route in the controller. Laravel provides an easy way of doing this. Using a single command, I can create a resource controller and define a Model with it (another great feature of Laravel).

I will use the following command for creating a resource controller:

php artisan make:controller BookController --resource

Once the command is executed, you will be asked to create the Book model since it does not exists at the moment. Type yes for now and hit Enter. Once it finishes, a `BookController` will be created along with the model binded in it. You will get the following actions in the `BookController`:

• index() → To view all Book lists
• create() → To load a view to create a new book
• store(Request $request) → To save the newly created book
• show($id) → To view a single book
• edit($id) → To load a view for editing
• update(Request $request, $id) → To update a single book
• destroy($id) → To delete a book

Model binding is important because it reduces the lines of code and streamlines the overall design of the application. Take the example of getting a book by its id. When not using model binding, I would require the following steps to find the book details through the id.

Route::resource('book', 'BookController');

This single declaration will create several routes to handle BooksController requests. The resource route will handle the following actions:

VerbURIActionRoute Name

You can also specify a resource route to handle only certain actions or can exclude the actions that you do not want a route to handle. Here is the syntax of the code snippets for both the situations:.

Route::resource('book', 'BookController', ['only' => [

   'index', 'show'

]]);

Route::resource('book', 'BookController', ['except' => [

   'create', 'store', 'update', 'destroy'

]]);

Once you save the file, only the following routes will be handled:

Controller-Model Binding in Laravel

With Laravel, you can now bind a model(s) to your resource controller by adding `–-model=modelname` to the Artisan command.

php artisan make:controller BookController --resource --model=Book

When you run this command, the following functions will be binded to controllers.

• show(Book $book) → view a single book
• edit(Book $book) → load a view for editing
• update(Request $request, Book $book) → update a single book
• destroy(Book $book) → delete a book

Model binding is important because it reduces the lines of code and streamline the overall design of the application. Take the example of getting a book by its id. When not using model binding, I would require the following steps to find the book details through the id.

public function show($id)
{
    $book = Book::where('id', $id)->get();
    return view('book.book',['book’ => $book]);
}

Now, with model binding, I only have to return the view of that Book and all the rest, i.e. finding the book by the id and error generation will be done by Laravel itself.

public function show(Book $book)
{
    return view('book.book',['book' => $book]);
}

As you could see in this example, I have managed to reduce one line of code. In larger projects, this advantage would become more apparent!.

This is it for controllers. You can learn more about resource routing in Laravel in the official documentation. I will now discuss Middlewares in Laravel.

What Are Middleware in Laravel

Middleware in Laravel is a powerful feature that allows developers to run number of tasks before the request reaches your application’s core logic or after the response is generated.

Middleware can handle a range of functions such as authentication, logging, cross-origin resource sharing (CORS), and even request modification. Essentially, middleware provides an easy way to check or modify the HTTP requests entering your application, without having to clutter your controllers or routes with such logic.

Middleware is typically registered and assigned to routes or route groups. You can create your own custom middleware to suit your application’s specific needs. This is done by generating a new middleware class using Laravel’s artisan command. The middleware class contains a handle method where you define the logic to run before or after the request is processed.

How Middlewares in Laravel Works

When a request is made to the application, it passes through any middleware assigned to the route before reaching the controller. If the request is allowed to continue, it is passed to the application logic; if not, the middleware can interrupt the request, redirecting the user or returning a response, like an error message or access denied. Laravel includes several built-in middleware, such as auth for checking user authentication and throttle for rate limiting requests.

For example, you can create middleware to log request data, validate API tokens, or check user roles. Once created, middleware is then registered in the HTTP kernel, and you can attach it to any route or controller.

How to Create Middleware in Laravel?

Middleware are the easiest way of verifying HTTP requests before they are passed to the controller. All middleware in Laravel are created in the Middleware folder, located inside the `app/HTTP` folder.

Creating a Basic Middleware in Laravel

The process of creating a middleware is very similar in both Laravel 8 or any Laravel higher version.

I will now create a middleware for our Books controller in which the books that correspond to a particular year will not be stored in the database. I will name this middleware CheckYear and use the following Artisan command:

php artisan make:middleware CheckYear

Once the command is finished a middleware will be create with a handle function (to which I will add the logic).

<?php

namespace App\Http\Middleware;

use Closure;

class CheckYear

{

   /**

    * Handle an incoming request.

    *

    * @param  \Illuminate\Http\Request  $request

    * @param  \Closure  $next

    * @return mixed

    */

   public function handle($request, Closure $next)

   {

       $year = ['1956','1970','1972'];

       if (array_has($year,$request->year)) {

           return redirect('home');

       }

       return $next($request);

   }

}

In the above code, I defined the array $year, in which I added the years that I do not want to add to the database. Next, I used the Laravel helpers function array_has to check the input for the year requested. If the year exists in the array, it will be redirected to home. Otherwise, the request will be completed.

Now that I have a middleware, I will now define a controller. The easiest way to define the middleware is in the constructor of the controller. Remember to define the namespace of the middleware in the controller as well. See the following code for defining the middleware in the constructor:

<?php

namespace App\Http\Controllers;

use App\Book;

use Illuminate\Http\Request;

use App\Http\Middleware\CheckYear;

class BookController extends Controller

{

   /**

    * Constructor.

    *

    * @return void

    */

   public function __construct()

   {

       $this->middleware(CheckYear::class);

   }

You can define the middleware in `app/Http/Kernel.php` file, in  `$routemiddleware` array and assign a key to it. Check out the following code:

protected $routeMiddleware = [

       'auth' => \Illuminate\Auth\Middleware\Authenticate::class,

       'auth.basic' => \Illuminate\Auth\Middleware\AuthenticateWithBasicAuth::class,

       'bindings' => \Illuminate\Routing\Middleware\SubstituteBindings::class,

       'can' => \Illuminate\Auth\Middleware\Authorize::class,

       'guest' => \App\Http\Middleware\RedirectIfAuthenticated::class,

       'throttle' => \Illuminate\Routing\Middleware\ThrottleRequests::class,

       'year' => \App\Http\Middleware\CheckYear::class

   ];

This way, I do not need to define the middleware class in the controller. I could just call it by its name (see the following code):

<?php

namespace App\Http\Controllers;

use App\Book;

use Illuminate\Http\Request;

class BookController extends Controller

{

   /**

    * Constructor.

    *

    * @return void

    */

   public function __construct()

   {

       $this->middleware(‘year’);

   }

In addition, you can define the middleware directly to the routes too.Just add the route directly!

Route::post('/books',’BooksController@store’)->middleware('year');

Route::put('/books/{book}',’BooksController@update’)->middleware('year');

Create a Middleware for Controller Without a Separate Class

In a controller, you can define a middleware without writing a separate class for it. The code for the middleware  and the constructor is:

<?php

namespace App\Http\Controllers;

use App\Book;

use Illuminate\Http\Request;

class BookController extends Controller

{

   /**

    * Constructor.

    *

    * @return void

    */

   public function __construct()

   {

       $this->middleware(function($request,$next)

       {

           $year = ['1956','1970','1972'];

           if (array_has($year,$request->year)) {

               return redirect('home');

           }

           return $next($request);

       });

   }

This will work as if you have created a separate class for the middleware. Check out the official documentation for more information on middlewares. Now, it will be as if you have created a separate class for it. You can learn more about middleware in Laravel from the official documentation.

Conclusion

php artisan make:controller

Route::get('/dashboard', function () {
    return view('dashboard');
})->middleware('auth');

Shahzeb Ahmed

Shahzeb is a Digital Marketer with a Software Engineering background, works as a Community Manager — PHP Community at Cloudways. He is growth ambitious and aims to learn & share information about PHP & Laravel Development through practice and experimentation. He loves to travel and explore new ideas whenever he finds time. Get in touch with him at [email protected]

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