Middleware as a Concept

Definition

mid·dle·ware, noun

general term for software that serves to "glue together" separate, often complex and already existing, programs 

bit.ly/middleware-definition

1. receive a thing.
2. change something
   about the thing.
3. send the thing along.

Found in books

bit.ly/middleware-in-books

Found in the wild

Task Automation

1. receive a task.
2. change something
   internal about the task, or write to the file system.
3. send the task along to next pipe.

Message Queues

1. receive a message.
2. change something
   about the message, or conduct some other business with message information.
3. send the message along to next worker.

Halloween

1. receive a trick-or-treater.
2. add candy to trick-or-treater bag.
3. send the trick-or-treater to next house.

Easy, eh?

Let's look at something familiar, yet more complicated.

Web Request

Web Request

1. receive a request.
2. change something about the request.
3. send request to next middleware or application.

1. create response.

1. receive response.
2. change something about the response.
3. send the response to next middleware.

Inbound middleware

Application

Outbound middleware

It's not scary!

It's becoming quite common.

Frameworks with Middleware Support

• Django
• Drupal
• Enterprise JavaBeans
• Laravel
• Node JS
  (gulp, grunt, and many more)
• Ruby on Rails (Rack)

• Silex
• Slim
• Stack PHP
• Symfony
• Yii (extension)
• Zend Framework 3

Let's talk about PHP

PSR 7, Middleware, and You Caring

A Brief History of
PSR 7

(very)

^

Web Request

Web Request

Pre-PSR 7 PHP

Web Request

Pre-PSR 7 PHP

• Request information stored in predefined variables
  • $_SERVER, $_COOKIE, $_FILES, $_GET, $_POST, etc.
• Each framework maintain unique Request and Response objects, different APIs
  • Framework specific adapters required
• Middleware responsible for "transforming" incoming data
  • More code bloat and "not invented here" practices

Whatever shall we do?

Fix it!

Who will fix it?

PHP Framework Interop Group

php-fig.org

How will we fix it?

The Solution

• We like OOP
• We like interfaces
• We like package
  management

Web Request

Post-PSR 7 PHP

• Request information still stored in predefined variables
  • $_SERVER, $_COOKIE, $_FILES, $_GET, $_POST, etc.
• Each framework maintain unique Request and Response objects, same APIs
  • Framework specific adapters no longer required
• Middleware responsible for "manipulating" incoming data
  • Less code bloat

Web Request

Your Middleware

<?php namespace App\Http\Middleware;

use Psr\Http\Message\RequestInterface;

class MyMiddleware
{
    /**
     * Handle request.
     * @param  Psr\Http\Message\RequestInterface $request
     * @return Psr\Http\Message\RequestInterface 
     */  
    public function doThatSweetMagic(RequestInterface $request)
    {
        // Do something awesome to the request        

        return $request;
    }
}

Study PSR 7

• php-fig.org/psr/psr-7
• github.com/php-fig/http-message
• packagist.org/packages/psr/http-message

The Community is Already Adopting Support

Laravel 5 and Middleware!

PSR 7 Middleware Support :(

That's ok!

@todo

• Define middleware
• Describe middleware types
• Register middleware
• Make middleware work

"HTTP middleware provide a convenient mechanism for filtering HTTP requests entering your application."

laravel.com/docs/5.1/middleware

Laravel Middleware is

The handle method

/**
 * @param  Request  $request
 * @param  Closure  $next
 *
 * @return Response
 */
public function handle($request, Closure $next);

Laravel Middleware is

The "next" closure

<?php

namespace App\Http\Middleware;

use Closure;

class MyVeryOwnMiddleware
{
    public function handle($request, Closure $next)
    {
        // Perform action

        return $next($request);
    }
}

@todo

• Define middleware
• Describe middleware types
• Register middleware
• Make middleware work

• Before
• After
• Terminable

Laravel Middleware is

The Before

<?php

namespace App\Http\Middleware;

use Closure;

class BeforeMiddleware
{
    public function handle($request, Closure $next)
    {
        // Perform action

        return $next($request);
    }
}

The After

<?php

namespace App\Http\Middleware;

use Closure;

class AfterMiddleware
{
    public function handle($request, Closure $next)
    {
        $response = $next($request);

        // Perform action

        return $response;
    }
}

Terminable Middleware is

The Terminable

<?php

namespace Illuminate\Session\Middleware;

use Closure;

class StartSession
{
    public function handle($request, Closure $next)
    {
        return $next($request);
    }

    public function terminate($request, $response)
    {
        // Store the session data...
    }
}

Web Request

@todo

• Define middleware
• Describe middleware types
• Register middleware
• Make middleware work

• Global
  (Always on)
• Route
  (Routes/Controllers)

Register Middleware as

Salute the kernel

// app/Http/Kernel.php

<?php 

namespace App\Http;

use Illuminate\Foundation\Http\Kernel as HttpKernel;

class Kernel extends HttpKernel
{
    /**
     * The application's global HTTP middleware stack.
     *
     * @var array
     */
    protected $middleware = [];

    /**
     * The application's route middleware.
     *
     * @var array
     */
    protected $routeMiddleware = [];
}

Global middleware

// Within App\Http\Kernel Class...

protected $middleware = [
    \Illuminate\Foundation\Http\Middleware\CheckForMaintenanceMode::class,
    \App\Http\Middleware\EncryptCookies::class,
    \Illuminate\Cookie\Middleware\AddQueuedCookiesToResponse::class,
    \Illuminate\Session\Middleware\StartSession::class,
    \Illuminate\View\Middleware\ShareErrorsFromSession::class,
    \App\Http\Middleware\VerifyCsrfToken::class,
    \App\Http\Middleware\MyMiddleware::class,
];

Route middleware

// Within App\Http\Kernel Class...

protected $routeMiddleware = [
    'auth' => \App\Http\Middleware\Authenticate::class,
    'auth.basic' => \Illuminate\Auth\Middleware\AuthenticateWithBasicAuth::class,
    'guest' => \App\Http\Middleware\RedirectIfAuthenticated::class,
    'mine' => \App\Http\Middleware\MyMiddleware::class,
];

Requires unique key, used as reference in other parts of application

@todo

• Define middleware
• Describe middleware types
• Register middleware
• Make middleware work

Global Middleware

will always execute and in the order registered within the Kernel

Global middleware execution

// Within app/Http/Kernel.php

protected $middleware = [
    //
    \App\Http\Middleware\MyMiddleware1::class,
    \App\Http\Middleware\MyMiddleware2::class,
    \App\Http\Middleware\MyMiddleware3::class,
    //
];

Multiple middleware executed globally

Global middleware execution

// Within app/Http/Kernel.php

protected $middleware = [
    //
    \App\Http\Middleware\MyMiddleware2::class,
    \App\Http\Middleware\MyMiddleware3::class,
    \App\Http\Middleware\MyMiddleware1::class,
    //
];

Multiple middleware executed globally

Route Middleware

can be assigned to routes, route groups, and controllers, which will control execution order

Route middleware execution

// Within app/Http/Kernel.php

protected $routeMiddleware = [
    //
    'mine' => \App\Http\Middleware\MyMiddleware::class,
    //
];

// Within app/Http/routes.php

Route::get('profile', ['middleware' => 'mine', function () {
    //
}]);

Single middleware executed by route

Route middleware execution

// Within app/Http/Kernel.php

protected $routeMiddleware = [
    //
    'mine.one' => \App\Http\Middleware\MyMiddleware1::class,
    'mine.two' => \App\Http\Middleware\MyMiddleware2::class,
    'mine.three' => \App\Http\Middleware\MyMiddleware3::class,
    //
];

// Within app/Http/routes.php

Route::get('profile', ['middleware' => [
    'mine.one','mine.two','mine.three'], function () {
    //
}]);

Multiple middleware executed by route

Route middleware execution

// Within app/Http/Kernel.php

protected $routeMiddleware = [
    //
    'mine.one' => \App\Http\Middleware\MyMiddleware1::class,
    'mine.two' => \App\Http\Middleware\MyMiddleware2::class,
    'mine.three' => \App\Http\Middleware\MyMiddleware3::class,
    //
];

// Within app/Http/routes.php

Route::get('profile', ['middleware' => [
    'mine.two','mine.three','mine.one'], function () {
    //
}]);

Multiple middleware executed by route

Route middleware execution

// Within app/Http/Kernel.php

protected $routeMiddleware = [
    //
    'mine.one' => \App\Http\Middleware\MyMiddleware1::class,
    'mine.two' => \App\Http\Middleware\MyMiddleware2::class,
    'mine.three' => \App\Http\Middleware\MyMiddleware3::class,
    //
];

// Within app/Http/routes.php

Route::group(['middleware' => ['mine.two','mine.three','mine.one']], function () {
    Route::get('profile', function () {
        //
    });
});

Multiple middleware executed by route group

Route middleware execution

// Within app/Http/Kernel.php

protected $routeMiddleware = [
    //
    'mine.one' => \App\Http\Middleware\MyMiddleware1::class,
    'mine.two' => \App\Http\Middleware\MyMiddleware2::class,
    'mine.three' => \App\Http\Middleware\MyMiddleware3::class,
    //
];

// Within app/Http/routes.php

Route::get('profile', 'MainController@profile');


// Within app/Http/Controllers/MainController.php

public function __construct()
{
    $this->middleware('mine.two');
    $this->middleware('mine.three');
    $this->middleware('mine.one');
}

Multiple middleware executed by controller

Route middleware execution

// Within app/Http/routes.php

Route::get('hello', 'MainController@hello');
Route::get('goodbye', 'MainController@goodbye');

// Within app/Http/Controllers/MainController.php

public function __construct()
{
    $this->middleware('mine.two');
    $this->middleware('mine.three');
    $this->middleware('mine.one');
}

public function hello()
{
    return 'hello';
}

public function goodbye()
{
    return 'goodbye';
}

Multiple middleware executed by controller

Route middleware execution

// Within app/Http/routes.php

Route::get('hello', 'MainController@hello');
Route::get('goodbye', 'MainController@goodbye');

// Within app/Http/Controllers/MainController.php

public function __construct()
{
    $this->middleware('mine.two', ['only' => ['hello']]);
    $this->middleware('mine.three', ['except' => ['hello']]);
    $this->middleware('mine.one');
}

public function hello()
{
    return 'hello';
}

public function goodbye()
{
    return 'goodbye';
}

Multiple middleware executed by controller

Route Middleware

can be passed parameters!

Route middleware parameters

// Within app/Http/Kernel.php

protected $routeMiddleware = [
    //
    'mine' => \App\Http\Middleware\MyMiddleware::class,
    //
];

// Within app/Http/routes.php

Route::get('profile', ['middleware' => 'mine:foo', function () {
    //
}]);

// Within app/Http/Controllers/MainController.php

public function __construct()
{
    $this->middleware('mine:bar');
}

Pass single parameter to route middleware

Route middleware parameters

// Within app/Http/Kernel.php

protected $routeMiddleware = [
    //
    'mine' => \App\Http\Middleware\MyMiddleware::class,
    //
];

// Within app/Http/routes.php

Route::get('profile', ['middleware' => 'mine:foo,bar', function () {
    //
}]);

// Within app/Http/Controllers/MainController.php

public function __construct()
{
    $this->middleware('mine:bar,foo');
}

Pass multiple parameters to route middleware

Route middleware parameters

Receive middleware parameters

// Within app/Http/Middleware/BeforeMiddleware.php

public function handle($request, Closure $next, $param1, $param2)
{
    \Log::info($param1);
    \Log::info($param2);

    // Perform action

    return $next($request);
}

// Within app/Http/routes.php

Route::get('profile', ['middleware' => 'mine:foo,bar', function () { }]);

Route middleware parameters

// Within app/Http/Middleware/BeforeMiddleware.php

public function handle($request, Closure $next, $param1, $param2)
{
    \Log::info($param1);
    \Log::info($param2);

    // Perform action

    return $next($request);
}

// Within app/Http/routes.php

Route::get('profile', ['middleware' => 'mine:foo', function () { }]);

Route middleware parameters

Middleware parameters may be required or optional

// Within app/Http/Middleware/BeforeMiddleware.php

public function handle($request, Closure $next, $param1, $param2 = null)
{
    \Log::info($param1);
    \Log::info($param2);

    // Perform action

    return $next($request);
}

// Within app/Http/routes.php

Route::get('profile', ['middleware' => 'mine:foo', function () { }]);

@todo

• Define middleware
• Describe middleware types
• Register middleware
• Make middleware work