A presentation at PHP MiNDS in in Nottingham, UK by Rob Allen
Rob Allen, March 2020
The C in MVC Rob Allen ~ @akrabat
Slim Framework • • • • Created by Josh Lockhart (phptherightway.com) PSR-7 Request and Response objects PSR-15 Middleware and Request Handlers PSR-11 DI container support Rob Allen ~ @akrabat
Hello world use … $app = AppFactory::create(); $app->get( ‘/ping’, function (Request $request, Response $response) { $response->getBody()->write(json_encode([‘ack’ => time()])); return $response->withHeader(‘Content-Type’, ‘application/json’); }); $app->run(); Rob Allen ~ @akrabat
Hello world use … $app = AppFactory::create(); // Init $app->get( ‘/ping’, function (Request $request, Response $response) { $response->getBody()->write(json_encode([‘ack’ => time()])); return $response->withHeader(‘Content-Type’, ‘application/json’); }); $app->run(); // Run Rob Allen ~ @akrabat
Hello world use … $app = AppFactory::create(); $app->get( // Method ‘/ping’, function (Request $request, Response $response) { $response->getBody()->write(json_encode([‘ack’ => time()])); return $response->withHeader(‘Content-Type’, ‘application/json’); }); $app->run(); Rob Allen ~ @akrabat
Hello world use … $app = AppFactory::create(); $app->get( ‘/ping’, // Pattern function (Request $request, Response $response) { $response->getBody()->write(json_encode([‘ack’ => time()])); return $response->withHeader(‘Content-Type’, ‘application/json’); }); $app->run(); Rob Allen ~ @akrabat
Hello world use … $app = AppFactory::create(); $app->get( ‘/ping’, function (Request $request, Response $response) { // Handler $response->getBody()->write(json_encode([‘ack’ => time()])); return $response->withHeader(‘Content-Type’, ‘application/json’); }); $app->run(); Rob Allen ~ @akrabat
Hello world $ curl -i http://localhost:8888/ping HTTP/1.1 200 OK Host: localhost:8888 Connection: close Content-Type: application/json { “ack”:1570046120 } Rob Allen ~ @akrabat
PSR-7 is the foundation Rob Allen ~ @akrabat
It’s all about HTTP Request: {METHOD} {URI} HTTP/1.1 Header: value1,value2 Another-Header: value Message body Rob Allen ~ @akrabat
It’s all about HTTP Response: HTTP/1.1 {STATUS_CODE} {REASON_PHRASE} Header: value Message body Rob Allen ~ @akrabat
PSR 7 OO interfaces to model HTTP • • • • RequestInterface (& ServerRequestInterface) ResponseInterface UriInterface UploadedFileInterface Rob Allen ~ @akrabat
Key feature 1: Immutability Request, Response, Uri & UploadFile are immutable $uri = new Uri(‘https://api.joind.in/v2.1/events’); $uri2 = $uri->withQuery(‘?filter=upcoming’); $uri3 = $uri->withQuery(‘?filter=cfp’); Rob Allen ~ @akrabat
Key feature 2: Streams Message bodies are streams $body = new Stream(); $body->write(‘<p>Hello’); $body->write(‘World</p>’); $response = (new Response()) ->withStatus(200, ‘OK’) ->withHeader(‘Content-Type’, ‘application/header’) ->withBody($body); Rob Allen ~ @akrabat
I write APIs so let’s talk in that context! Rob Allen ~ @akrabat
A good API framework • Understands HTTP methods • Can receive data in various formats • Has useful error reporting Rob Allen ~ @akrabat
HTTP verbs Rob Allen ~ @akrabat
HTTP methods Method GET PUT DELETE POST PATCH Used for Retrieve data Change data Delete data Change data Update data Idempotent? Yes Yes Yes No No Rob Allen ~ @akrabat
Routing HTTP methods in Slim // specific HTTP methods map to methods on $app $app->get(‘/games’, ListGamesHandler::class); $app->post(‘/games’, CreateGameHandler::class); // routing multiple HTTP methods $app->any(‘/games’, GamesHandler::class); $app->map([‘GET’, ‘POST’], ‘/games’, GamesHandler::class); Rob Allen ~ @akrabat
Dynamic routes $app->get(‘/games/{id}’, function($request, $response) { $id = $request->getAttribute(‘id’); $games = $this->gameRepository->loadById($id); $body = json_encode([‘game’ => $game]); $response->getBody()->write($body); $response = $response->withHeader( ‘Content-Type’, ‘application/json’); return $response; }); Rob Allen ~ @akrabat
It’s just Regex // numbers only $app->get(‘/games/{id:\d+}’, $callable); // optional segments $app->get(‘/games[/{id:\d+}]’, $callable); $app->get(‘/news[/{y:\d{4}}[/{m:\d{2}}]]’, $callable); Rob Allen ~ @akrabat
Invalid HTTP request methods If the HTTP method is not supported, return the 405 status code $ http —json PUT http://localhost:8888/ping HTTP/1.1 405 Method Not Allowed Allow: GET Connection: close Content-Length: 53 Content-type: application/json Host: localhost:8888 { “message”: “Method not allowed. Must be one of: GET” } Rob Allen ~ @akrabat
Incoming data Rob Allen ~ @akrabat
Content-Type handling The Content-Type header specifies the format of the incoming data $ curl http://localhost:8888/games \ -H “Content-Type: application/json” \ -d ‘{“player1”: “Rob”, “player2”: “Jon”}’ Rob Allen ~ @akrabat
Read with getBody() $app->post(‘/games’, function ($request, $response) { $data = $request->getBody(); $response->getBody()->write(print_r($data, true)); return $response; } ); Output: ‘{“player1”: “Rob”, “player2”: “Jon”}’ Rob Allen ~ @akrabat
Read with getParsedBody() Add Slim’s body-parsing middleware to your app: $app->addBodyParsingMiddleware(); Use in your handler: $app->post(‘/games’, function ($request, $response) { $data = $request->getParsedBody(); return $response->write(print_r($data, true)); } ); Rob Allen ~ @akrabat
Read with getParsedBody() $ curl -H “Content-Type: application/json” \ -H “Content-Type: application/json” \ -d ‘{“player1”: “Rob”, “player2”: “Jon”}’ Output: Array ( [player1] => Rob, [player2] => Jon ) Rob Allen ~ @akrabat
This also works with XML $ curl “http://localhost:8888/games” \ -H “Content-Type: application/xml” \ -d “<game><player1>Rob</player1><player2>Jon</player2></game>” Output: Array ( [player1] => Rob, [player2] => Jon ) Rob Allen ~ @akrabat
And form data curl “http://localhost:8888/games” \ -H “Content-Type: application/x-www-form-urlencoded” \ -d “player1=Rob’ -d ‘player2=Jon” Output: Array ( [player1] => Rob, [player2] => Jon ) Rob Allen ~ @akrabat
addBodyParsingMiddleware() ? Rob Allen ~ @akrabat
Middleware Middleware is code that exists between the request and response, and which can take the incoming request, perform actions based on it, and either complete the response or pass delegation on to the next middleware in the queue. Matthew Weier O’Phinney Rob Allen ~ @akrabat
Middleware Take a request, return a response Rob Allen ~ @akrabat
Middleware LIFO stack: $app->add(ValidationMiddleware::class); $app->add(AuthMiddleware::class); $app->add(AuthMiddleware::class); $app->addBodyParsingMiddleware(); $app->addErrorMiddleware(true, true, true); Rob Allen ~ @akrabat
PSR-15 MiddlewareInterface namespace Psr\Http\Server; use Psr\Http\Message\ResponseInterface; use Psr\Http\Message\ServerRequestInterface; interface MiddlewareInterface { public function process( ServerRequestInterface $request, RequestHandlerInterface $handler ) : ResponseInterface; } Rob Allen ~ @akrabat
PSR-15 MiddlewareInterface namespace Psr\Http\Server; use Psr\Http\Message\ResponseInterface; use Psr\Http\Message\ServerRequestInterface; interface MiddlewareInterface { public function process( ServerRequestInterface $request, RequestHandlerInterface $handler ) : ResponseInterface; } Rob Allen ~ @akrabat
PSR-15 MiddlewareInterface namespace Psr\Http\Server; use Psr\Http\Message\ResponseInterface; use Psr\Http\Message\ServerRequestInterface; interface MiddlewareInterface { public function process( ServerRequestInterface $request, RequestHandlerInterface $handler ) : ResponseInterface; } Rob Allen ~ @akrabat
PSR-15 MiddlewareInterface namespace Psr\Http\Server; use Psr\Http\Message\ResponseInterface; use Psr\Http\Message\ServerRequestInterface; interface MiddlewareInterface { public function process( ServerRequestInterface $request, RequestHandlerInterface $handler ) : ResponseInterface; } Rob Allen ~ @akrabat
TimerMiddleware class TimerMiddleware implements MiddlewareInterface { public function process($request, $handler) { $start = microtime(true); $response = $handler->handle($request); $taken = microtime(true) - $start; return $response->withHeader(‘Time-Taken’, $taken); } } Rob Allen ~ @akrabat
TimerMiddleware class TimerMiddleware implements MiddlewareInterface { public function process($request, $handler) { $start = microtime(true); $response = $handler->handle($request); $taken = microtime(true) - $start; return $response->withHeader(‘Time-Taken’, $taken); } } Rob Allen ~ @akrabat
TimerMiddleware class TimerMiddleware implements MiddlewareInterface { public function process($request, $handler) { $start = microtime(true); $response = $handler->handle($request); $taken = microtime(true) - $start; return $response->withHeader(‘Time-Taken’, $taken); } } Rob Allen ~ @akrabat
TimerMiddleware class TimerMiddleware implements MiddlewareInterface { public function process($request, $handler) { $start = microtime(true); $response = $handler->handle($request); $taken = microtime(true) - $start; return $response->withHeader(‘Time-Taken’, $taken); } } Rob Allen ~ @akrabat
TimerMiddleware class TimerMiddleware implements MiddlewareInterface { public function process($request, $handler) { $start = microtime(true); $response = $handler->handle($request); $taken = microtime(true) - $start; return $response->withHeader(‘Time-Taken’, $taken); } } Rob Allen ~ @akrabat
Route Handlers The other half of PSR-15! Rob Allen ~ @akrabat
Route Handlers Any callable! $app->add(‘/’, $app->add(‘/’, $app->add(‘/’, $app->add(‘/’, $app->add(‘/’, function ($request, $response) { … }); [‘RootController’, ‘aStaticFunction’]); [new RootController(), ‘aFunction’]); RootController::class.’:pingAction’); RootHander::class); Rob Allen ~ @akrabat
Use this one $app->add(‘/’, RootHandler::class); Rob Allen ~ @akrabat
PSR-15 RouteHandlerInterface namespace Psr\Http\Server; use Psr\Http\Message\ResponseInterface; use Psr\Http\Message\ServerRequestInterface; interface RequestHandlerInterface { public function handle( ServerRequestInterface $request ): ResponseInterface; } Rob Allen ~ @akrabat
PSR-15 RouteHandlerInterface namespace Psr\Http\Server; use Psr\Http\Message\ResponseInterface; use Psr\Http\Message\ServerRequestInterface; interface RequestHandlerInterface { public function handle( ServerRequestInterface $request ): ResponseInterface; } Rob Allen ~ @akrabat
PSR-15 RouteHandlerInterface namespace Psr\Http\Server; use Psr\Http\Message\ResponseInterface; use Psr\Http\Message\ServerRequestInterface; interface RequestHandlerInterface { public function handle( ServerRequestInterface $request ): ResponseInterface; } Rob Allen ~ @akrabat
PSR-15 RouteHandlerInterface namespace Psr\Http\Server; use Psr\Http\Message\ResponseInterface; use Psr\Http\Message\ServerRequestInterface; interface RequestHandlerInterface { public function handle( ServerRequestInterface $request ): ResponseInterface; } Rob Allen ~ @akrabat
RootHandler use use use use Psr\Http\Message\ResponseInterface; Psr\Http\Message\ServerRequestInterface as Request; Psr\Http\Server\RequestHandlerInterface; Slim\Psr7\Response; class RootHandler implements RequestHandlerInterface { public function handle(Request $request): ResponseInterface { $response = new Response(); $response->getBody()->write(json_encode([‘msg’ => ‘hello world’]); return $response; } } Rob Allen ~ @akrabat
RootHandler use use use use Psr\Http\Message\ResponseInterface; Psr\Http\Message\ServerRequestInterface as Request; Psr\Http\Server\RequestHandlerInterface; Slim\Psr7\Response; class RootHandler implements RequestHandlerInterface { public function handle(Request $request): ResponseInterface { $response = new Response(); $response->getBody()->write(json_encode([‘msg’ => ‘hello world’]); return $response; } } Rob Allen ~ @akrabat
RootHandler use use use use Psr\Http\Message\ResponseInterface; Psr\Http\Message\ServerRequestInterface as Request; Psr\Http\Server\RequestHandlerInterface; Slim\Psr7\Response; class RootHandler implements RequestHandlerInterface { public function handle(Request $request): ResponseInterface { $response = new Response(); $response->getBody()->write(json_encode([‘msg’ => ‘Hello world’]); return $response; } } Rob Allen ~ @akrabat
RootHandler use use use use Psr\Http\Message\ResponseInterface; Psr\Http\Message\ServerRequestInterface as Request; Psr\Http\Server\RequestHandlerInterface; Slim\Psr7\Response; class RootHandler implements RequestHandlerInterface { public function handle(Request $request): ResponseInterface { $response = new Response(); $response->getBody()->write(json_encode([‘msg’ => ‘hello world’]); return $response; } } Rob Allen ~ @akrabat
When things go wrong Rob Allen ~ @akrabat
Error handling • Internal logging • Rendering for output Rob Allen ~ @akrabat
Injecting a logger More PSRs! 11 & 3 Rob Allen ~ @akrabat
Configure PHP-DI $containerBuilder = new ContainerBuilder(); $containerBuilder->addDefinitions([ // Factory for a PSR-3 logger LoggerInterface::class => function (ContainerInterface $c) { $logger = new Logger($settings[‘name’]); $logger->pushHandler(new ErrorLogHandler()); return $logger; }, ]); AppFactory::setContainer($containerBuilder->build()); $app = AppFactory::create(); Rob Allen ~ @akrabat
Configure PHP-DI $containerBuilder = new ContainerBuilder(); $containerBuilder->addDefinitions([ // Factory for a PSR-3 logger LoggerInterface::class => function (ContainerInterface $c) { $logger = new Logger($settings[‘name’]); $logger->pushHandler(new ErrorLogHandler()); return $logger; }, ]); AppFactory::setContainer($containerBuilder->build()); $app = AppFactory::create(); Rob Allen ~ @akrabat
Configure PHP-DI $containerBuilder = new ContainerBuilder(); $containerBuilder->addDefinitions([ // Factory for a PSR-3 logger LoggerInterface::class => function (ContainerInterface $c) { $logger = new Logger($settings[‘name’]); $logger->pushHandler(new ErrorLogHandler()); return $logger; }, ]); AppFactory::setContainer($containerBuilder->build()); $app = AppFactory::create(); Rob Allen ~ @akrabat
Configure PHP-DI $containerBuilder = new ContainerBuilder(); $containerBuilder->addDefinitions([ // Factory for a PSR-3 logger LoggerInterface::class => function (ContainerInterface $c) { $logger = new Logger($settings[‘name’]); $logger->pushHandler(new ErrorLogHandler()); return $logger; }, ]); AppFactory::setContainer($containerBuilder->build()); $app = AppFactory::create(); Rob Allen ~ @akrabat
Configure PHP-DI $containerBuilder = new ContainerBuilder(); $containerBuilder->addDefinitions([ // Factory for a PSR-3 logger LoggerInterface::class => function (ContainerInterface $c) { $logger = new Logger($settings[‘name’]); $logger->pushHandler(new ErrorLogHandler()); return $logger; }, ]); AppFactory::setContainer($containerBuilder->build()); $app = AppFactory::create(); Rob Allen ~ @akrabat
PHP-DI autowiring Just type-hint your constructor! class GetGameHandler implements RequestHandlerInterface { private $logger; public function __construct(LoggerInterface $logger) { $this->logger = $logger; } … Rob Allen ~ @akrabat
Logging class GetGameHandler implements RequestHandlerInterface { public function handle(Request $request): ResponseInterface this->logger->info(“Fetching game”, [‘id’ => $id]); try { $games = $this->gameRepository->loadById($id); } catch (NotFoundException $e) { throw new HttpNotFoundException($request, ‘Game not found’, $e); } … Rob Allen ~ @akrabat
Rendering errors Rob Allen ~ @akrabat
Slim’s error handling Add Slim’s error handling middleware to render exceptions $displayDetails = true; $logErrors = true; $logErrorDetails = true; $app->addErrorMiddleware($displayDetails, $logErrors, $logErrorDetails); Rob Allen ~ @akrabat
Error rendering $ http -j DELETE http://localhost:8888/game HTTP/1.1 405 Method Not Allowed Allow: GET Content-type: application/json { “exception”: [ { “code”: 405, “file”: “…/Slim/Middleware/RoutingMiddleware.php”, “message”: “Method not allowed: Must be one of: GET”, “type”: “Slim\Exception\HttpMethodNotAllowedException” } ], “message”: “Method not allowed: Must be one of: GET” } Rob Allen ~ @akrabat
Raise your own use App\Model\GameNotFoundException; use Slim\Exception\HttpNotFoundException; use Slim\Exception\HttpInternalServerErrorException; public function handle(Request $request): ResponseInterface { $id = $request->getAttribute(‘id’); try { $game = $this->gameRepository->loadById($id); } catch (GameNotFoundException $e) { throw new HttpNotFoundException($request, ‘Game not found’, $e); } catch (\Exception $e) { throw new HttpInternalServerErrorException($request, ‘An unknown error occurred’, $e); } Rob Allen ~ @akrabat
Not found error use App\Model\GameNotFoundException; use Slim\Exception\HttpNotFoundException; use Slim\Exception\HttpInternalServerErrorException; public function handle(Request $request): ResponseInterface { $id = $request->getAttribute(‘id’); try { $games = $this->gameRepository->loadById($id); } catch (GameNotFoundException $e) { throw new HttpNotFoundException($request, ‘Game not found’, $e); } catch (\Exception $e) { throw new HttpInternalServerErrorException($request, ‘An unknown error occurred’, $e); } Rob Allen ~ @akrabat
Not found error $ http -j http://localhost:8888/games/1234 HTTP/1.1 404 Not Found Content-type: application/json { “message”: “Game not found” } (With $displayDetails = false) Rob Allen ~ @akrabat
Generic error use App\Model\GameNotFoundException; use Slim\Exception\HttpNotFoundException; use Slim\Exception\HttpInternalServerErrorException; public function handle(Request $request): ResponseInterface { $id = $request->getAttribute(‘id’); try { $games = $this->gameRepository->loadById($id); } catch (GameNotFoundException $e) { throw new HttpNotFoundException($request, ‘Game not found’, $e); } catch (\Exception $e) { throw new HttpInternalServerErrorException($request, ‘An unknown error occurred’, $e); } Rob Allen ~ @akrabat
Generic error $ http -j http://localhost:8888/games/abcd HTTP/1.1 500 Internal Server Error Content-type: application/json { “exception”: [ { “code”: 500, “file”: “…/src/Handler/GetGameHandler.php”, “line”: 43, “message”: “An unknown error occurred”, “type”: “Slim\Exception\HttpInternalServerErrorException” }, Rob Allen ~ @akrabat
{ “code”: 40, “file”: “…/lib/Assert/Assertion.php”, “line”: 2752, “message”: “Value “abcd” is not a valid integer.”, “type”: “Assert\InvalidArgumentException” } ], “message”: “An unknown error occurred” } (With $displayDetails = true) Rob Allen ~ @akrabat
To sum up Rob Allen ~ @akrabat
Resources • http://slimframework.com • https://akrabat.com/category/slim-framework/ • https://github.com/akrabat/slim4-rps-api • https://github.com/akrabat/slim4-starter Rob Allen ~ @akrabat
Thank you! Rob Allen - http://akrabat.com - @akrabat Rob Allen ~ @akrabat
Photo credits - The Fat Controller: HiT Entertainment - Foundation: https://www.flickr.com/photos/armchairbuilder/6196473431 - APIs: https://www.flickr.com/photos/ebothy/15723500675 - Verbs: https://www.flickr.com/photos/160866001@N07/45904136621/ - Incoming Data: https://www.flickr.com/photos/natspressoffice/13085089605 - Computer code: https://www.flickr.com/photos/n3wjack/3856456237/ - Road sign: https://www.flickr.com/photos/ell-r-brown/6804246004 - Car crash: EuroNCAP - Writing: https://www.flickr.com/photos/froderik/9355085596/ - Error screen: https://www.flickr.com/photos/thirdrail/18126260 - Rocket launch: https://www.flickr.com/photos/gsfc/16495356966 - Stars: https://www.flickr.com/photos/gsfc/19125041621 Rob Allen ~ @akrabat
With support for a host of PSR standards, Slim 4 is the PHP micro framework that enables you to write powerful web applications and APIs that embrace the wider PHP ecosystem and in this talk, I will show how. It takes advantage of many of the FIG group’s PSR standards to allow easy interoperability with a large ecosystem of components. We will look at how Slim’s middleware system leverages the PSR-15 middleware and request handlers to create easily understandable and flexible applications. We will cover application setup, routing and the relationship between actions and middleware. Dependency injection is very useful in a modern PHP application and we’ll look at how to integrate any PSR-11 container with Slim ensuring you can decouple your dependencies. By the end of the session, you will be equipped to use the new Slim 4 to create web applications yourself.
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