Build middleware applications with Zend Framework 3
by Enrico Zimuel / @ezimuel
Senior Software Engineer
Zend Technologies, a Rogue Wave Company
About me
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Table of contents
- ZF3: latest news
- Middleware applications in PHP
- PSR-7 standard
- Middleware with zend-expressive
- A skeleton application
Zend Framework 3
ZF3 roadmap
- Performance improvement ✓
- PSR-7 support ✓
- New middleware components: Stratigility, Expressive, MiddlewareListener (MVC) ✓
- Enable forward compatibility with version 3 ✓
- Updated documentation and website
- Code refactor of MVC
Middleware
A function that gets a request and generates a response
function ($request, $response) {
// manipulate $request to generate a $response
return $response;
}
Build a middleware workflow
1) Passing middleware to other middleware:
class Middleware
{
protected $middleware;
public function __construct(callable $middleware) {
$this->middleware = $middleware;
}
public function __invoke($request, $response) {
// do something before
call_user_func($this->middleware, $request, $response);
// do something after
}
}
Build a middleware workflow
2) Use an additional callable during the invoke ($next)
class Middleware
{
public function __invoke($request, $response, callable $next = null) {
// do something before
if ($next) {
$next($request, $response);
}
// do something after
}
}
The Middleware onion
HTTP is the foundation of the web
- A client sends a request
- A server returns a response
HTTP messages
Request
GET /path HTTP/1.1
Host: example.com
Accept: application/json
Response
HTTP/1.1 200 OK
Content-Type: application/json
{"foo":"bar"}
Frameworks model messages
But every framework does it differently.
$method = $request->getMethod();
$method = $request->getRequestMethod();
$method = $request->method;
PSR-7
Shared HTTP Message Interfaces
Request
$method = $request->getMethod();
$accept = $request->getHeader('Accept');
$path = $request->getUri()->getPath();
$controller = $request->getAttribute('controller');
Response
$response->getBody()->write('Hello world!');
$response = $response
->withStatus(200, 'OK')
->withHeader('Content-Type', 'text/plain');
Zend-expressive
- PSR-7 support (using zend-diactoros)
- Middleware using a callable ($next):
function ($request, $response, $next) - Piping workflow (using zend-stratigility)
- Features: routing, container-interop, templating, error handling
- Stable version 1.0 (28 Jan 2016)
Components layer
Flow overview
Basic example
use Zend\Expressive\AppFactory;
chdir(dirname(__DIR__));
require 'vendor/autoload.php';
$app = AppFactory::create();
$app->get('/', function ($request, $response, $next) {
$response->getBody()->write('Hello, world!');
return $response;
});
$app->pipeRoutingMiddleware();
$app->pipeDispatchMiddleware();
$app->run();
Routing
- zend-expressive-router component
- Dynamic routing capabilities using your favorite libraries
- Adapters: Aura.router, FastRoute, Zend-Mvc router
namespace Zend\Expressive\Router;
use Psr\Http\Message\ServerRequestInterface as Request;
interface RouterInterface
{
public function addRoute(Route $route);
public function match(Request $request);
public function generateUri($name, array $substitutions = []);
}
Routing example
// $app is an instance of Zend\Expressive\AppFactory
$app->get('/', function ($request, $response, $next) {
$response->getBody()->write('Hello, world!');
return $response;
});
Piping Middleware
// $app is an instance of Zend\Expressive\AppFactory
// Executed in all the requests
$app->pipe($apiMiddleware);
$app->pipe('middleware service name');
// Pipe to a specific URL
$app->pipe('/api', $apiMiddleware);
$app->pipe('/api', 'middleware service name');
// Error handler
$app->pipeErrorHandler('error handler service name');
$app->pipeErrorHandler('/api', 'error handler service name');
Using a Service Container
use Zend\Expressive\AppFactory;
use Zend\ServiceManager\ServiceManager;
$container = new ServiceManager();
$container->setFactory('HelloWorld', function ($container) {
return function ($req, $res, $next) {
$res->write('Hello, world!');
return $res;
};
});
$app = AppFactory::create($container);
$app->get('/', 'HelloWorld');
We support container-interop
Templating
- While Expressive does not assume templating is being used, it provides a templating abstraction.
- Default adapters: Plates, Twig, Zend-View
namespace Zend\Expressive\Template;
interface TemplateRendererInterface
{
public function render($name, $params = []);
public function addPath($path, $namespace = null);
public function getPaths();
public function addDefaultParam($templateName, $param, $value);
}
Error Handling
- Expressive provides error handling out of the box, via zend-stratigility's FinalHandler
- This pseudo-middleware is executed in the following conditions:
- If the middleware stack is exhausted, and no middleware has returned a response
- If an error has been passed via $next(), but not handled by any error middleware
Templated Errors
use Zend\Expressive\Application;
use Zend\Expressive\Plates\PlatesRenderer;
use Zend\Expressive\TemplatedErrorHandler;
$plates = new PlatesRenderer();
$plates->addPath(__DIR__ . '/templates/error', 'error');
$finalHandler = new TemplatedErrorHandler(
$plates,
'error::404',
'error::500'
);
$app = new Application($router, $container, $finalHandler);
Using Whoops
- whoops is a library for providing a more usable UI around exceptions and PHP errors
- We provide integration with this library through Zend\Express\WhoopsErrorHandler
Skeleton application
- We provide a skeleton app for start with zend-expressive
- On github:
github.com/zendframework/zend-expressive-skeleton
Getting started
$ composer create-project zendframework/zend-expressive-skeleton <path>
Run the skeleton app
$ composer serve
You can browse to http://localhost:8080
Skeleton source code
A brief look at the source code...
Thanks!
Rate this talk at joind.in/talk/f6938
More info: zendframework.github.io/zend-expressive
Contact me: enrico [at] zend.com
Follow me: @ezimuel
This work is licensed under a
Creative Commons Attribution-ShareAlike 3.0 Unported License.
I used reveal.js to make this presentation.