Delay middleware

Author: WyriHaximus

src/DelayMiddleware.php

@@ -0,0 +1,59 @@
+<?php declare(strict_types=1);
+
+namespace ApiClients\Middleware\Delay;
+
+use ApiClients\Foundation\Middleware\MiddlewareInterface;
+use ApiClients\Foundation\Middleware\PostTrait;
+use ApiClients\Foundation\Middleware\Priority;
+use Psr\Http\Message\RequestInterface;
+use React\EventLoop\LoopInterface;
+use React\Promise\CancellablePromiseInterface;
+use function React\Promise\resolve;
+use function WyriHaximus\React\timedPromise;
+
+final class DelayMiddleware implements MiddlewareInterface
+{
+    use PostTrait;
+
+    /**
+     * @var LoopInterface
+     */
+    private $loop;
+
+    /**
+     * DelayMiddleware constructor.
+     * @param LoopInterface $loop
+     */
+    public function __construct(LoopInterface $loop)
+    {
+        $this->loop = $loop;
+    }
+
+    /**
+     * @param RequestInterface $request
+     * @param array $options
+     * @return CancellablePromiseInterface
+     */
+    public function pre(RequestInterface $request, array $options = []): CancellablePromiseInterface
+    {
+        if (!isset($options[self::class][Options::DELAY])) {
+            return resolve($request);
+        }
+
+        return timedPromise(
+            $this->loop,
+            $options[self::class][Options::DELAY],
+            $request
+        )->then(function (RequestInterface $request) {
+            return resolve($request);
+        });
+    }
+
+    /**
+     * @return int
+     */
+    public function priority(): int
+    {
+        return Priority::FIRST - 1;
+    }
+}

src/Options.php

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+<?php declare(strict_types=1);
+
+namespace ApiClients\Middleware\Delay;
+
+final class Options
+{
+    const DELAY = 'delay';
+}

tests/DelayMiddlewareTest.php

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+<?php
+
+namespace ApiClients\Tests\Middleware\Delay;
+
+use ApiClients\Middleware\Delay\DelayMiddleware;
+use ApiClients\Middleware\Delay\Options;
+use ApiClients\Tools\TestUtilities\TestCase;
+use Prophecy\Argument;
+use Psr\Http\Message\RequestInterface;
+use React\EventLoop\Factory;
+use function Clue\React\Block\await;
+use function React\Promise\resolve;
+
+final class DelayMiddlewareTest extends TestCase
+{
+    public function testRequest()
+    {
+        $loop = Factory::create();
+
+        $request = $this->prophesize(RequestInterface::class);
+
+        $options = [
+            DelayMiddleware::class => [
+                Options::DELAY => 3,
+            ],
+        ];
+        $middleware = new DelayMiddleware($loop);
+        $preCalled = false;
+        $middleware->pre($request->reveal(), $options)->then(function () use (&$preCalled) {
+            $preCalled = true;
+        });
+
+        self::assertFalse($preCalled);
+
+        $start = microtime(true);
+
+        $loop->run();
+
+        $stop = microtime(true);
+
+        self::assertNotSame($start + 3, $stop);
+        self::assertTrue($start + 3 < $stop, $start + 3 . ' vs ' . $stop);
+
+        self::assertTrue($preCalled);
+    }
+
+    public function testRequestNoDelay()
+    {
+        $request = $this->prophesize(RequestInterface::class);
+
+        $options = [];
+        $middleware = new DelayMiddleware(Factory::create());
+        $preCalled = false;
+        $middleware->pre($request->reveal(), $options)->then(function () use (&$preCalled) {
+            $preCalled = true;
+        });
+
+        self::assertTrue($preCalled);
+    }
+}