Imports the ApplicationRunner from zend-expressive as RequestHandlerRunner

Imports the (still in development) `ApplicationRunner` from
zend-expressive as the class `RequestHandlerRunner`.

Author: weierophinney

src/RequestHandlerRunner.php

@@ -0,0 +1,96 @@
+<?php
+/**
+ * @see       https://github.com/zendframework/zend-serverhandler-runner for the canonical source repository
+ * @copyright Copyright (c) 2018 Zend Technologies USA Inc. (https://www.zend.com)
+ * @license   https://github.com/zendframework/zend-serverhandler-runner/blob/master/LICENSE.md New BSD License
+ */
+
+declare(strict_types=1);
+
+namespace Zend\ServerHandler\Runner;
+
+use Psr\Http\Message\ServerRequestInterface;
+use Psr\Http\Server\RequestHandlerInterface;
+use Throwable;
+
+/**
+ * "Run" a request handler.
+ *
+ * The RequestHandlerRunner will marshal a request using the composed factory, and
+ * then pass the request to the composed handler. Finally, it emits the response
+ * returned by the handler using the composed emitter.
+ *
+ * If the factory for generating the request raises an exception or throwable,
+ * then the runner will use the composed error response generator to generate a
+ * response, based on the exception or throwable raised.
+ */
+class RequestHandlerRunner
+{
+    /**
+     * @var Emitter\EmitterInterface
+     */
+    private $emitter;
+
+    /**
+     * A request handler to run as the application.
+     *
+     * @var RequestHandlerInterface
+     */
+    private $handler;
+
+    /**
+     * A factory capable of generating an error response in the scenario that
+     * the $serverRequestFactory raises an exception during generation of the
+     * request instance.
+     *
+     * The factory will receive the Throwable or Exception that caused the error,
+     * and must return a Psr\Http\Message\ResponseInterface instance.
+     *
+     * @var callable
+     */
+    private $serverRequestErrorResponseGenerator;
+
+    /**
+     * A factory capable of generating a Psr\Http\Message\ServerRequestInterface instance.
+     * The factory will not receive any arguments.
+     *
+     * @var callable
+     */
+    private $serverRequestFactory;
+
+    public function __construct(
+        RequestHandlerInterface $handler,
+        Emitter\EmitterInterface $emitter,
+        callable $serverRequestFactory,
+        callable $serverRequestErrorResponseGenerator
+    ) {
+        $this->handler = $handler;
+        $this->emitter = $emitter;
+        $this->serverRequestFactory = $serverRequestFactory;
+        $this->serverRequestErrorResponseGenerator = $serverRequestErrorResponseGenerator;
+    }
+
+    /**
+     * Run the application
+     */
+    public function run(ServerRequestInterface $request = null) : void
+    {
+        try {
+            $request = $request ?: ($this->serverRequestFactory)();
+        } catch (Throwable $e) {
+            // Error in generating the request
+            $this->emitMarshalServerRequestException($e);
+            return;
+        }
+
+        $response = $this->handler->handle($request);
+
+        $this->emitter->emit($response);
+    }
+
+    private function emitMarshalServerRequestException(Throwable $exception) : void
+    {
+        $response = ($this->serverRequestErrorResponseGenerator)($exception);
+        $this->emitter->emit($response);
+    }
+}

test/RequestHandlerRunnerTest.php

@@ -0,0 +1,113 @@
+<?php
+/**
+ * @see       https://github.com/zendframework/zend-serverhandler-runner for the canonical source repository
+ * @copyright Copyright (c) 2018 Zend Technologies USA Inc. (https://www.zend.com)
+ * @license   https://github.com/zendframework/zend-serverhandler-runner/blob/master/LICENSE.md New BSD License
+ */
+
+declare(strict_types=1);
+
+namespace ZendTest\ServerHandler\Runner;
+
+use Exception;
+use PHPUnit\Framework\Assert;
+use PHPUnit\Framework\TestCase;
+use Prophecy\Argument;
+use Psr\Http\Message\ResponseInterface;
+use Psr\Http\Message\ServerRequestInterface;
+use Psr\Http\Server\RequestHandlerInterface;
+use Zend\ServerHandler\Runner\Emitter\EmitterInterface;
+use Zend\ServerHandler\Runner\RequestHandlerRunner;
+
+class RequestHandlerRunnerTest extends TestCase
+{
+    public function testUsesErrorResponseGeneratorToGenerateResponseWhenRequestFactoryRaisesException()
+    {
+        $exception = new Exception();
+        $serverRequestFactory = function () use ($exception) {
+            throw $exception;
+        };
+
+        $response = $this->prophesize(ResponseInterface::class)->reveal();
+
+        $errorResponseGenerator = function ($e) use ($exception, $response) {
+            Assert::assertSame($exception, $e);
+            return $response;
+        };
+
+        $emitter = $this->prophesize(EmitterInterface::class);
+        $emitter->emit($response)->shouldBeCalled();
+
+        $handler = $this->prophesize(RequestHandlerInterface::class);
+        $handler->handle(Argument::any())->shouldNotBeCalled();
+
+        $runner = new RequestHandlerRunner(
+            $handler->reveal(),
+            $emitter->reveal(),
+            $serverRequestFactory,
+            $errorResponseGenerator
+        );
+
+        $this->assertNull($runner->run());
+    }
+
+    public function testRunPassesRequestGeneratedByRequestFactoryToHandleWhenNoRequestPassedToRun()
+    {
+        $request = $this->prophesize(ServerRequestInterface::class)->reveal();
+
+        $serverRequestFactory = function () use ($request) {
+            return $request;
+        };
+
+        $errorResponseGenerator = function ($e) {
+            Assert::fail('Should never hit error response generator');
+        };
+
+        $response = $this->prophesize(ResponseInterface::class)->reveal();
+
+        $handler = $this->prophesize(RequestHandlerInterface::class);
+        $handler->handle($request)->willReturn($response);
+
+        $emitter = $this->prophesize(EmitterInterface::class);
+        $emitter->emit($response)->shouldBeCalled();
+
+        $runner = new RequestHandlerRunner(
+            $handler->reveal(),
+            $emitter->reveal(),
+            $serverRequestFactory,
+            $errorResponseGenerator
+        );
+
+        $this->assertNull($runner->run());
+    }
+
+    public function testRunPassesRequestPassedDuringInvocationToHandler()
+    {
+        $request = $this->prophesize(ServerRequestInterface::class)->reveal();
+
+        $serverRequestFactory = function () {
+            Assert::fail('Should never hit server request factory');
+        };
+
+        $errorResponseGenerator = function ($e) {
+            Assert::fail('Should never hit error response generator');
+        };
+
+        $response = $this->prophesize(ResponseInterface::class)->reveal();
+
+        $handler = $this->prophesize(RequestHandlerInterface::class);
+        $handler->handle($request)->willReturn($response);
+
+        $emitter = $this->prophesize(EmitterInterface::class);
+        $emitter->emit($response)->shouldBeCalled();
+
+        $runner = new RequestHandlerRunner(
+            $handler->reveal(),
+            $emitter->reveal(),
+            $serverRequestFactory,
+            $errorResponseGenerator
+        );
+
+        $this->assertNull($runner->run($request));
+    }
+}