Beyond PSR-7

The magical middleware tour

Marco

Explorer

Avid learner

Chocolate Lover

Steve

Enjoys Travelling

Software Architectures

In a few years...

Software Engineers

Start of the Journey...

Everybody on its own

A Total Mess


$filename = 'log.txt';
$handle = fopen($filename, 'a'));
fwrite($handle, $errorMessage);
fclose($handle);


$filename = 'log.txt';
$handle = fopen($filename, 'a'));
fwrite($handle, $errorMessage);
fclose($handle);

Libraries

Include Hell


include 'config.php';
include_once 'dbcon.php';
include_once 'logger.php';
include 'utils.php';
include 'forms.php';
include 'calculations.php';
include 'graphs.php';
include 'auth.php';

MVC Frameworks

IoC First Wave

Same things, different ways...

Zend Framework


$logger = new Zend_Log();
$writer = new Zend_Log_Writer_Stream('php://output');
$logger->addWriter($writer);
$logger->log('Hello PHPDay People!', Zend_Log::INFO);

Symfony


// YAML Configuration
// [...]
sfContext::getInstance()->getLogger()->info('Hello PHPDay People!');

Reinventing the Wheel

With a little help of...

composer.json

    
                {
    "name": "zendframework/skeleton-application",
    "description": "Skeleton Application for ZF2",
    "license": "BSD-3-Clause",
    "keywords": [
        "framework",
        "zf2"
    ],
    "homepage": "http://framework.zend.com/",
    "require": {
        "php": ">=5.5",
        "zendframework/zendframework": "~2.5"
    }
}

IoC New Wave

Microframeworks

One issue to solve...


namespace Symfony\Component\HttpFoundation;

class Request {
    public static function createFromGlobals(): Request {
        return self::createRequestFromFactory($_GET, $_POST, [], $_COOKIE, $_FILES, $_SERVER);
    }
}


namespace Zend\Http\PhpEnvironment;

class Request extends \Zend\Http\Request {
    public function __construct() {
        $this->setEnv(new Parameters($_ENV));
        $this->setQuery(new Parameters($_GET));
        $this->setPost(new Parameters($_POST));
        $this->setCookies(new Parameters($_COOKIE));
        $this->setFiles(new Parameters($this->mapPhpFiles()));
        $this->setServer(new Parameters($_SERVER));
    }
}

Need for

a good HTTP abstraction

SERVER API

$_SERVER
$_POST
$_GET
header()
setCookie()
echo

CLIENT ADAPTERS

PSR-7

PSR-7 GOALS

Interfaces

Practical applications and usability

No limits

Server and client

PSR-7 NON-GOALS

Conformation

Impose details

A Value object is forever

Pipes and filters

Pizza Example

Decorator


interface Pizza

class Margherita implements Pizza

class CheeseDecoratedPizza implements Pizza
{
    function __construct(Pizza $pizza)
}

class VegetablesDecoratedPizza implements Pizza
{
    function __construct(Pizza $pizza)
}


$myFavouritePizza =

    new VegatablesDecoratedPizza(

        new CheeseDecoratedPizza(

            new Margherita()

        )

    );

Middleware


function (Request request): Response
{
    ...

    response = next(request);

    ...

    return response;
}

Middleware


function (Request): Response

Middleware


function (Request, Response): Response

Middleware


function (

    Request request,

    Response response,

    callable next

): Response

Hot Week

Middleware in Action


class Middleware
{
    function __invoke($request, $response, $next)
    {
        if (!$this->preconditionsExist($request, $response)) {
            throw new RuntimeException();
        }

        $request = $this->doSomethingOnRequest($request);

        $response = $next($request, $response);

        return $this->doSomethingOnResponse($response);
    }
}


class BasicAuthentication
{
    function __invoke($request, $response, $next)
    {
        $authorization = $request->getHeaderLine('Authorization');

        if ($this->checkUserPassword($authorization)) {
            $request = self::setAttribute(
                $request,
                'USERNAME',
                $authorization['username']
            );

            return $next($request, $response);
        }

        return $this->unauthorizedUserResponse($response);
    }
}


class AccessLog
{
    function __invoke($request, $response, $next)
    {
        if (!self::hasAttribute($request, 'CLIENT_IPS')) {
            throw new RuntimeException();
        }

        $response = $next($request, $response);

        $message = $this->createMessage($request, $response);

        $this->logger->log($message);

        return $response;
    }
}

Slim


// src/middleware.php

$app->add(new AccessLog($logger));

$app->add(new Geolocate());

$app->add(new ClientIp());

$app->add(new BasicAuthentication($users));

Radar & Relay


// web/index.php

$adr->middle(new BasicAuthentication($users));

$adr->middle(new ClientIp());

$adr->middle(new Geolocate());

$adr->middle(new AccessLog($logger));

Expressive


// config/autoload/middleware-pipeline.global.php
return [
    'middleware-pipeline' => [
        'basic_authentication' => [
            'middleware' => new BasicAuthentication($users),
            'priority' => 4000
        ],
        'clientip' => [
            'middleware' => ClientIp::class,
            'priority' => 3000
        ],
        'geolocate' => [
            'middleware' => Geolocate::class,
            'priority' => 2000
        ],
        'access-log' => [
            'middleware' => new AccessLog($logger),
            'priority' => 1000
        ]
    ]
];

The magical Expressive tour


// config/autoload/middleware-pipeline.global.php
return [
    'middleware-pipeline' => [
        'always' => [
            'middleware' => [
                Helper\ServerUrlMiddleware::class
            ], 'priority' => 10000
        ],
        'routing' => [
            'middleware' => [
                ApplicationFactory::ROUTING_MIDDLEWARE,
                Helper\UrlHelperMiddleware::class,
                ApplicationFactory::DISPATCH_MIDDLEWARE
            ], 'priority' => 1
        ],
        'error' => [
            'middleware' => [], 'error' => true, 'priority' => -10000
        ]
    ]
];

ReactPhp

Expressive/ReactPhp


// config/autoload/middleware-pipeline.global.php
return [
    'dependencies' => [
        'factories' => [
            React2Psr7\StaticFiles::class => React2Psr7\StaticFilesFactory::class,
        ]
    ],
    'middleware_pipeline' => [
        'static' => [
            'middleware' => React2Psr7\StaticFiles::class,
            'priority' => 100000, // Execute earliest!
        ],
        ...
    ]
];

Use cases

Debug bar


class DebugBar
{
    public function __invoke($request, $response, $next)
    {
        if (!self::hasAttribute($request, FormatNegotiator::KEY)) {
            throw new RuntimeException('Need FormatNegotiator executed before');
        }

        if ($this->isAsset($request)) {
            return $this->responsewithAssetBody($request, $response);
        }
        $response = $next($request, $response);

        if (Utils\Helpers::isRedirect($response)) {
            $this->debugBar->stackData();
        } else if (FormatNegotiator::getFormat($request) === 'html') {
            $response = $this->createHtmlResponse($response);
        } else if (Utils\Helpers::isAjax($request)) {
            $response = $this->createAjaxResponse($response);
        }
        return $response;
    }
}