Hello, PSR-7. (phpwarks 2016)

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Hello, PSR-7. joind.in/talk/aef0a Beau Simensen beau.io • @beausimensen

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PSR-7 HTTP Message Interface

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The Problem Server-Side Edition

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My background (It is relevant, I promise!)

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PHP ~2005

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Spring Framework ~2008

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class halo_HttpRequest { public function __construct( $method, array $queryParams = null, array $postParams = null, array $fileData = null, array $env = null, $body = null ) { // ... } }

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class halo_DispatcherUtil { public static function MAKE_HTTP_REQUEST() { return new halo_HttpRequest( $_SERVER['REQUEST_METHOD'], $_GET, $_POST, $_FILES, $_SERVER ); } }

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namespace Symfony\Component\HttpFoundation; class Request { public function __construct( array $query = array(), array $request = array(), array $attributes = array(), array $cookies = array(), array $files = array(), array $server = array(), $content = null ) { // ... } }

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namespace Symfony\Component\HttpFoundation; class Request { public static function createFromGlobals() { return self::createRequestFromFactory( $_GET, $_POST, array(), $_COOKIE, $_FILES, $server ); } }

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

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namespace Aura\Web; class WebFactory { public function newRequest() { return new Request( $this->newRequestClient(), $this->newRequestContent(), $this->newRequestGlobals(), $this->newRequestHeaders(), $this->newRequestMethod(), $this->newRequestParams(), $this->newRequestUrl() ); } public function newRequestGlobals() { return new Request\Globals( $this->newRequestCookies(), $this->newRequestEnv(), $this->newRequestFiles(), $this->newRequestPost(), $this->newRequestQuery(), $this->newRequestServer() ); } }

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All define similar Responses

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Abstractions over SAPI

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Impact on Ecosystem

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Symfony 2 HttpFoundation + HttpKernel

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What if we could share code between these applications and frameworks at the HTTP level? — Igor, Beau, and Christoph

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Stack PHP Conventions for writing framework agnostic* middleware stackphp.com

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Framework agnostic my foot. — Imagined People

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The Problem Client-Side Edition

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Guzzle, Buzz, Requests

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The Problem for both server-side and client-side: HTTP Messages abstraction should be a commodity Header: value Another-Header: value Message body

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History of PSR-7

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PHP-FIG PHP Framework Interoperability Group

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March 24th, 2012 HTTP Client interface Benjamin Eberlei

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$client = create_http_client(); // implementation specific $response = $client->request('GET', 'http://www.php.net'); if ($response->getStatusCode() == 200) { $content = $response->getContent(); } $response = $client->request('GET', 'http://api/returning.json'); if ($response->getContentType() == 'application/json') { $json = json_decode($response->getContent()); }

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December 31st, 2012 HTTP Message Chris Wilkinson

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There was a proposal to create a HTTP client interface earlier this year. As was noted at the time, the core HTTP message representation part (ie the request/response objects) is probably of more importance: it's used by both HTTP clients and frameworks. — Chris Wilkinson

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interface MessageInterface { public function __toString(); public function getStartLine(); public function getProtocolVersion(); public function setProtocolVersion($protocolVersion); public function getHeader($header); public function getHeaders(); public function hasHeader($header); public function setHeader($header, $value); public function setHeaders(array $headers); public function addHeaders(array $headers); public function getBody(); public function setBody($body); }

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interface RequestInterface extends MessageInterface { public function __construct( $method, $url, $protocolVersion = '1.1' ); public function getResponse(); public function setResponse(ResponseInterface $response); public function getMethod(); public function setMethod($method); public function getUrl(); public function setUrl($url); }

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interface ResponseInterface extends MessageInterface { public function __construct( $statusCode, $reasonPhrase = null, $protocolVersion = '1.1' ); public function getRequest(); public function setRequest(RequestInterface $request); public function getStatusCode(); public function setStatusCode($statusCode); public function getReasonPhrase(); public function setReasonPhrase($reasonPhrase); }

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January 28th, 2014 PSR-7 HTTP Message - DRAFT Michael Dowling

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August 29th, 2014 PSR-7 HTTP Message - Retracted Michael Dowling

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Matthew Weier O'Phinney

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phly/http http://github.com/phly/http (similar to node's http.Server)

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phly/conduit http://github.com/phly/conduit (a port of Sencha Connect)

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September 26th, 2014 PSR-7 HTTP Message Interfaces Matthew Weier O'Phinney

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accepted May 18th, 2015

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Interfaces & Concepts

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Bloated?

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Immutability Messages and URIs are modeled as value objects

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class Request implements RequestInterface { public function withMethod($method) { $new = clone $this; $new->method = $method; return $new; } }

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use Zend\Diactoros\Request; use Zend\Diactoros\Uri; $request = (new Request()) ->withUri(new Uri('http://example.com')) ->withMethod('GET');

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use Zend\Diactoros\Request; use Zend\Diactoros\Uri; $request = (new Request()) ->withUri(new Uri('http://example.com')) ->withMethod('GET'); // this does nothing to $request. $request->withAddedHeader( 'Content-Type', 'application/json' );

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use Zend\Diactoros\Request; use Zend\Diactoros\Uri; $request = (new Request()) ->withUri(new Uri('http://example.com')) ->withMethod('GET'); // this is probably what you want. $request = $request->withAddedHeader( 'Content-Type', 'application/json' );

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It will take some getting used to, but just try it. — Me

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As somebody who implemented the interfaces, I was able to literally rip out huge swathes of defensive code, as state checks became unnecessary. — Matthew Weier O'Phinney

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Streams cannot be immutable. :(

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Streams Message Bodies & Uploaded Files

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Allows implementations to work with large message bodies

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Strings? php://memory or php://temp $message = $message->withBody(new Stream('php://temp')); $message->getBody()->write('This is my content!');

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REMEMBER Immutability cannot be enforced! Use read-only streams for server-side requests and client-side responses

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Messages

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Header: value Another-Header: value Message body

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Headers

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$message = $message ->withHeader('foo', 'bar') ->withAddedHeader('foo', 'baz'); if ($message->hasHeader('Accept')) { /* ... */ } // 'bar, baz' $header = $message->getHeaderLine('foo'); // ['bar', 'baz'] $header = $message->getHeader('foo'); // [ 'foo' => ['bar', 'baz'] ] foreach ($message->getHeaders() as $header => $values) { }

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Host header Calling $request->withUri() updates Host header Unless you pass true to $preserveHost

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Requests

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URI // https://api.example.com $uri = $uri->withScheme('https')->withHost('api.example.com'); $usersUri = $uri->withPath('/v2/users'); $booksUri = $uri->withPath('/v2/books'); // https://api.example.com/v2/users?limit=10 $getUsersRequest = (new Request()) ->withMethod('GET') ->withUri($usersUri->withQuery('?limit=10')); // https://api.example.com/v2/users $postUsersRequest = (new Request()) ->withMethod('POST') ->withUri($usersUri); // https://api.example.com/v2/books $getBooksRequest = (new Request()) ->withMethod('GET') ->withUri($booksUri);

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Server Requests

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CGI + SAPI $_COOKIE • $_GET • $_POST • $_FILES • $_SERVER

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Attributes

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$country = $this->resolveCountryForRequest($request); if ($country) { $request = $request->withAttribute( 'geocode.country', $country ); } // ... $country = $request->getAttribute('geocode.country'); if ($country) { // }

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Uploaded Files

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Given file input names files[0] and files[1] What you might expect: [ 'files' => [ 0 => [ 'name' => 'file0.txt', 'type' => 'text/plain', /* etc. */ ], 1 => [ 'name' => 'file1.html', 'type' => 'text/html', /* etc. */ ], ], ];

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Given file input names files[0] and files[1] What you actually get: [ 'files' => [ 'name' => [ 0 => 'file0.txt', 1 => 'file1.html', ], 'type' => [ 0 => 'text/plain', 1 => 'text/html', ], /* etc. */ ], ]

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PSR-7 enforces a normalized $_FILES

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$file0 = $request->getUploadedFiles()['files'][0]; $file1 = $request->getUploadedFiles()['files'][1]; printf( "Received the files %s and %s", $file0->getClientFilename(), $file1->getClientFilename() ); // "Received the files file0.txt and file1.html"

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Underlying "filename" is protected // Move a file to an upload directory $filename = sprintf( '%s.%s', create_uuid(), pathinfo($file0->getClientFilename(), PATHINFO_EXTENSION) ); $file0->moveTo(DATA_DIR . '/' . $filename); // Stream a file to Amazon S3. // Assume $s3wrapper is a PHP stream that will write to S3, and that // Psr7StreamWrapper is a class that will decorate a StreamInterface as a PHP // StreamWrapper. $stream = new Psr7StreamWrapper($file1->getStream()); stream_copy_to_stream($stream, $s3wrapper);

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Parsed Body

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application/x-www-form-urlencoded multipart/form-data $_POST

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function ($request, $response, $next) { $contentType = $request->getHeaderLine('Content-Type'); if ('application/json' === $contentType) { $json = json_decode($request->getBody(), true); $request = $request->withParsedBody($json); } return $next( $request, $response ); }

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Middleware In the wild today

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

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function ($request, $response, $next) { $response = $next( $request, $response ); return $response->withAddedHeader( 'X-Clacks-Overhead', 'GNU Terry Pratchett' ); }

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namespace Acme; class ClacksOverhead { public function __invoke($request, $response, $next) { $response = $next( $request, $response ); return $response->withAddedHeader( 'X-Clacks-Overhead', 'GNU Terry Pratchett' ); } }

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Stratigility use Zend\Stratigility\MiddlewarePipe; $app = new MiddlewarePipe(); // ... $app->pipe(new \Acme\ClacksOverhead()); // ...

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Relay use Relay\RelayBuilder; $relayBuilder = new RelayBuilder(); $relay = $relayBuilder->newInstance([ // ... new \Acme\ClacksOverhead(), // ... ]); $response = $relay($request, $response);

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Framework Agnostic HTTP Libraries

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What do we want? Re-use at the web layer! — http://stackphp.com

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What about cookies? — people

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dflydev/fig-cookies

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use Dflydev\FigCookies\FigRequestCookies; // Assume this header is set on $request // Cookie: theme=red; foo=bar $cookie = FigRequestCookies::get($request, 'theme'); $cookie->getValue(); // "red" $request = FigRequestCookies::set($request, $cookie->withValue('blue')); $request = FigRequestCookies::set($request, Cookie::create('name', 'beau')); $request = FigRequestCookies::remove($request, 'foo'); // The $request now has the following header: // Cookie: theme=blue; name=beau

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dflydev/encrypted-fig-cookies WIP

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class EncryptedFigCookiesMiddleware { public function __invoke( RequestInterface $request, ResponseInterface $response, callable $next ) { $request = $this->requestCookieDecryptor->decrypt( $request, $this->cookieNames ); $response = $next($request, $response); return $this->responseCookieEncryptor->encrypt( $response, $this->cookieNames ); } }

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Frameworks

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Slim 3 www.slimframework.com First previously existing framework that intended to implement native support PSR-7

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Zend Expressive github.com/zendframework/zend-expressive Builds on Stratigility to provide a minimalist PSR-7 middleware framework for PHP

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Radar github.com/radarphp Radar is a PSR-7 compliant Action-Domain-Responder (ADR) system

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Nimble monii/nimble-framework A light PSR-7 framework built on top of Laravel's Container, nikic/fastroute, and Relay WIP

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Rolling your own PSR-7 microframework...

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(middleware in the real world)

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NikicFastRoute monii/nikic-fast-route-psr7-middleware WIP

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There were at least two other existing nikic/fast-route middleware implementations jowy/routing-middleware & oscarotero/psr7-middlewares

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class NikicFastRoute { public function __invoke($request, $response, $next) { $routeInfo = $this->dispatcher->dispatch( $request->getMethod(), $request->getUri()->getPath() ); } }

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class NikicFastRoute { public function __invoke($request, $response, $next) { $routeInfo = $this->dispatcher->dispatch( $request->getMethod(), $request->getUri()->getPath() ); switch ($routeInfo[0]) { case FastRoute\Dispatcher::NOT_FOUND: return $response->withStatus(404); case FastRoute\Dispatcher::METHOD_NOT_ALLOWED: return $response->withStatus(405); case FastRoute\Dispatcher::FOUND: $action = $routeInfo[1]; $parameters = $routeInfo[2]; $request = $request ->withAttribute('action', $action) ->withAttribute('parameters', $parameters) ; return $next($request, $response, $next); } } }

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ActionHandler monii/action-handler-psr7-middleware WIP

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class ActionHandler { public function __construct(ActionHandlerResolver $actionResolver) { $this->actionResolver = $actionResolver; } function __invoke($request, $response, $next) { $action = $request->getAttribute('action'); if (is_null($action)) { throw new \RuntimeException('No action specified for request.'); } $handler = $this->actionResolver->resolve($action); return $handler($request, $response, $next); } }

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$container->bind(Relay::class, function (Container $container) { $relayBuilder = $container->make(RelayBuilder::class); return $relayBuilder->newInstance([ $container->make(NikicFastRoute::class), // ... other middleware $container->make(ActionHandler::class), ]); }); $relay = $container->make(Relay::class); $response = $relay( $container->make(ServerRequestInterface::class), $container->make(ResponseInterface::class) ); send_response($response);

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More Middleware In the real world.

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Managed Technical Debt Making a distinction between Managed and Unmanaged Technical Debt. http://verraes.net/2013/07/managed-technical-debt/

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class CorsCompletelyOpenForDevelopment { public function __invoke($request, $response, callable $next) { /** @var ResponseInterface $response */ $response = $next($request, $response); if ($response->hasHeader('Access-Control-Allow-Origin')) { // If the response already has an expected header we will // assume that CORS has been handled successfully. return $response; } // This is unsafe and not what people will want in production // unless they really know what they are doing. return $response ->withHeader('Access-Control-Allow-Origin', '*') ->withHeader( 'X-Completely-Open-Cors-For-Development', 'unsafe' ) ; } }

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$container->bind(Relay::class, function (Container $container) { $relayBuilder = $container->make(RelayBuilder::class); return $relayBuilder->newInstance([ $container->make(NikicFastRoute::class), $container->make(CorsCompletelyOpenForDevelopment::class), // ... other middleware $container->make(ActionHandler::class), ]); });

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Quick Win

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Minimal Impact

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neomerx/cors-psr7 https://github.com/neomerx/cors-psr7 Managed technical debt paid off by someone else!

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Server, Middleware, and Client interfaces are missing Some of us are still working on that...

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Problem: No standard way to write PSR-7 middleware.

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PSR-15 HTTP Middleware

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PSR-7 + PSR-15 = Stack's Vision. Realized.

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Problem: In many cases it is hard to write PSR-7 code that is not tied to an implementation.

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PSR-17 HTTP Factories

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With PSR-7, PSR-15 and PSR-17 combined we can truly start writing Framework Agnostic HTTP applications.

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Implementations zend/diactoros (phly/http), Slim, Guzzle, phpixie/http

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Want to start using PSR-7 today in your existing Symfony, Laravel, Lumen, or Drupal 8 app?

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Symfony Bridge https://github.com/symfony/psr-http-message-bridge

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Thanks! joind.in/talk/aef0a beau.io • @beausimensen monii.io • @moniidev thatpodcast.io • @thatpodcast