API Create HTTPMiddleware and standardise middleware for request handling

main.php

@@ -15,5 +15,5 @@ $request = HTTPRequest::createFromEnvironment();
 $kernel = new AppKernel();
 $app = new HTTPApplication($kernel);
 $app->addMiddleware(new OutputMiddleware());
-$app->addMiddleware(new ErrorControlChainMiddleware($app, $request));
+$app->addMiddleware(new ErrorControlChainMiddleware($app));
 $app->handle($request);

src/Control/HTTPRequest.php

@@ -316,7 +316,7 @@ class HTTPRequest implements ArrayAccess
         }
 
         // Initiate an empty session - doesn't initialize an actual PHP session (see HTTPApplication)
-        $session = new Session($variables['_SESSION']);
+        $session = new Session(isset($variables['_SESSION']) ? $variables['_SESSION'] : null);
         $request->setSession($session);
 
         return $request;

src/Core/Application.php

@@ -13,13 +13,4 @@ interface Application
      * @return Kernel
      */
     public function getKernel();
-
-    /**
-     * Invoke the application control chain
-     *
-     * @param callable $callback
-     * @param bool $flush
-     * @return mixed
-     */
-    public function execute(callable $callback, $flush = false);
 }

src/Core/HTTPApplication.php

@@ -12,12 +12,12 @@ use SilverStripe\Control\HTTPResponse;
 class HTTPApplication implements Application
 {
     /**
-     * @var callable[]
+     * @var HTTPMiddleware[]
      */
     protected $middlewares = [];
 
     /**
-     * @return callable[]
+     * @return HTTPMiddleware[]
      */
     public function getMiddlewares()
     {
@@ -25,7 +25,7 @@ class HTTPApplication implements Application
     }
 
     /**
-     * @param callable[] $middlewares
+     * @param HTTPMiddleware[] $middlewares
      * @return $this
      */
     public function setMiddlewares($middlewares)
@@ -35,10 +35,10 @@ class HTTPApplication implements Application
     }
 
     /**
-     * @param callable $middleware
+     * @param HTTPMiddleware $middleware
      * @return $this
      */
-    public function addMiddleware($middleware)
+    public function addMiddleware(HTTPMiddleware $middleware)
     {
         $this->middlewares[] = $middleware;
         return $this;
@@ -47,19 +47,21 @@ class HTTPApplication implements Application
     /**
      * Call middleware
      *
+     * @param HTTPRequest $request
      * @param callable $last Last config to call
      * @return HTTPResponse
      */
-    protected function callMiddleware($last)
+    protected function callMiddleware(HTTPRequest $request, $last)
     {
         // Reverse middlewares
         $next = $last;
+        /** @var HTTPMiddleware $middleware */
         foreach (array_reverse($this->getMiddlewares()) as $middleware) {
-            $next = function () use ($middleware, $next) {
-                return call_user_func($middleware, $next);
+            $next = function ($request) use ($middleware, $next) {
+                return $middleware->process($request, $next);
             };
         }
-        return call_user_func($next);
+        return call_user_func($next, $request);
     }
 
     /**
@@ -93,7 +95,7 @@ class HTTPApplication implements Application
         $flush = $request->getVar('flush') || strpos($request->getURL(), 'dev/build') === 0;
 
         // Ensure boot is invoked
-        return $this->execute(function () use ($request) {
+        return $this->execute($request, function (HTTPRequest $request) {
             // Start session and execute
             $request->getSession()->init();
             return Director::direct($request);
@@ -103,17 +105,18 @@ class HTTPApplication implements Application
     /**
      * Safely boot the application and execute the given main action
      *
+     * @param HTTPRequest $request
      * @param callable $callback
      * @param bool $flush
      * @return HTTPResponse
      */
-    public function execute(callable $callback, $flush = false)
+    public function execute(HTTPRequest $request, callable $callback, $flush = false)
     {
         try {
-            return $this->callMiddleware(function () use ($callback, $flush) {
+            return $this->callMiddleware($request, function ($request) use ($callback, $flush) {
                 // Pre-request boot
                 $this->getKernel()->boot($flush);
-                return call_user_func($callback);
+                return call_user_func($callback, $request);
             });
         } finally {
             $this->getKernel()->shutdown();

src/Core/HTTPMiddleware.php

@@ -0,0 +1,22 @@
+<?php
+
+namespace SilverStripe\Core;
+
+use SilverStripe\Control\HTTPRequest;
+use SilverStripe\Control\HTTPResponse;
+
+/**
+ * HTTP Request middleware
+ * Based on https://github.com/php-fig/fig-standards/blob/master/proposed/http-middleware/middleware.md#21-psrhttpservermiddlewaremiddlewareinterface
+ */
+interface HTTPMiddleware
+{
+    /**
+     * Generate response for the given request
+     *
+     * @param HTTPRequest $request
+     * @param callable $delegate
+     * @return HTTPResponse
+     */
+    public function process(HTTPRequest $request, callable $delegate);
+}

src/Core/Startup/ErrorControlChainMiddleware.php

@@ -7,52 +7,42 @@ use SilverStripe\Control\HTTPRequest;
 use SilverStripe\Control\HTTPResponse;
 use SilverStripe\Control\HTTPResponse_Exception;
 use SilverStripe\Core\Application;
+use SilverStripe\Core\HTTPMiddleware;
 use SilverStripe\Security\Permission;
 use SilverStripe\Security\Security;
 
 /**
  * Decorates application bootstrapping with errorcontrolchain
  */
-class ErrorControlChainMiddleware
+class ErrorControlChainMiddleware implements HTTPMiddleware
 {
     /**
      * @var Application
      */
     protected $application = null;
 
-    /**
-     * @var HTTPRequest
-     */
-    protected $request = null;
-
     /**
      * Build error control chain for an application
      *
      * @param Application $application
-     * @param HTTPRequest $request
      */
-    public function __construct(Application $application, HTTPRequest $request)
+    public function __construct(Application $application)
     {
         $this->application = $application;
-        $this->request = $request;
     }
 
-    /**
-     * @param callable $next
-     * @return HTTPResponse
-     */
-    public function __invoke(callable $next)
+    public function process(HTTPRequest $request, callable $next)
     {
         $result = null;
 
         // Prepare tokens and execute chain
         $reloadToken = ParameterConfirmationToken::prepare_tokens(
             ['isTest', 'isDev', 'flush'],
-            $this->getRequest()
+            $request
         );
         $chain = new ErrorControlChain();
         $chain
-            ->then(function () use ($chain, $reloadToken, $next, &$result) {
+            ->then(function () use ($request, $chain, $reloadToken, $next, &$result) {
                 // If no redirection is necessary then we can disable error supression
                 if (!$reloadToken) {
                     $chain->setSuppression(false);
@@ -61,10 +51,10 @@ class ErrorControlChainMiddleware
                 try {
                     // Check if a token is requesting a redirect
                     if ($reloadToken) {
-                        $result = $this->safeReloadWithToken($reloadToken);
+                        $result = $this->safeReloadWithToken($request, $reloadToken);
                     } else {
                         // If no reload necessary, process application
-                        $result = call_user_func($next);
+                        $result = call_user_func($next, $request);
                     }
                 } catch (HTTPResponse_Exception $exception) {
                     $result = $exception->getResponse();
@@ -84,16 +74,17 @@ class ErrorControlChainMiddleware
      * Reload application with the given token, but only if either the user is authenticated,
      * or authentication is impossible.
      *
+     * @param HTTPRequest $request
      * @param ParameterConfirmationToken $reloadToken
      * @return HTTPResponse
      */
-    protected function safeReloadWithToken($reloadToken)
+    protected function safeReloadWithToken(HTTPRequest $request, $reloadToken)
     {
         // Safe reload requires manual boot
         $this->getApplication()->getKernel()->boot(false);
 
         // Ensure session is started
-        $this->getRequest()->getSession()->init();
+        $request->getSession()->init();
 
         // Next, check if we're in dev mode, or the database doesn't have any security data, or we are admin
         if (Director::isDev() || !Security::database_is_ready() || Permission::check('ADMIN')) {
@@ -102,7 +93,7 @@ class ErrorControlChainMiddleware
 
         // Fail and redirect the user to the login page
         $loginPage = Director::absoluteURL(Security::config()->get('login_url'));
-        $loginPage .= "?BackURL=" . urlencode($this->getRequest()->getURL());
+        $loginPage .= "?BackURL=" . urlencode($request->getURL());
         $result = new HTTPResponse();
         $result->redirect($loginPage);
         return $result;
@@ -125,22 +116,4 @@ class ErrorControlChainMiddleware
         $this->application = $application;
         return $this;
     }
-
-    /**
-     * @return HTTPRequest
-     */
-    public function getRequest()
-    {
-        return $this->request;
-    }
-
-    /**
-     * @param HTTPRequest $request
-     * @return $this
-     */
-    public function setRequest(HTTPRequest $request)
-    {
-        $this->request = $request;
-        return $this;
-    }
 }

src/Core/Startup/OutputMiddleware.php

@@ -2,13 +2,15 @@
 
 namespace SilverStripe\Core\Startup;
 
+use SilverStripe\Control\HTTPRequest;
 use SilverStripe\Control\HTTPResponse;
 use SilverStripe\Control\HTTPResponse_Exception;
+use SilverStripe\Core\HTTPMiddleware;
 
 /**
  * Emits response to the browser
  */
-class OutputMiddleware
+class OutputMiddleware implements HTTPMiddleware
 {
     protected $defaultResponse = null;
 
@@ -24,11 +26,11 @@ class OutputMiddleware
         $this->defaultResponse = $defaultResponse;
     }
 
-    public function __invoke(callable $next)
+    public function process(HTTPRequest $request, callable $delegate)
     {
         /** @var HTTPResponse $response */
         try {
-            $response = call_user_func($next);
+            $response = call_user_func($delegate, $request);
         } catch (HTTPResponse_Exception $exception) {
             $response = $exception->getResponse();
         }

src/Dev/SapphireTest.php

@@ -898,7 +898,7 @@ class SapphireTest extends PHPUnit_Framework_TestCase
         $app = new HTTPApplication($kernel);
 
         // Custom application
-        $app->execute(function () use ($request) {
+        $app->execute($request, function (HTTPRequest $request) {
             // Start session and execute
             $request->getSession()->init();