[Plugin] Add a plugin to record and replay responses

composer.json

@@ -22,7 +22,9 @@
         "guzzlehttp/psr7": "^1.4",
         "phpspec/phpspec": "^5.1",
         "phpspec/prophecy": "^1.8",
-        "sebastian/comparator": "^3.0"
+        "sebastian/comparator": "^3.0",
+        "symfony/filesystem": " ^3.4.20 || ^4.0.15 || ^4.1.9 || ^4.2.1",
+        "symfony/phpunit-bridge": "*"
     },
     "suggest": {
         "ext-json": "To detect JSON responses with the ContentTypePlugin",
@@ -38,7 +40,8 @@
     },
     "autoload-dev": {
         "psr-4": {
-            "spec\\Http\\Client\\Common\\": "spec/"
+            "spec\\Http\\Client\\Common\\": "spec/",
+            "tests\\Http\\Client\\Common\\": "tests/"
         }
     },
     "scripts": {

src/Plugin/NamingStrategyInterface.php

@@ -0,0 +1,17 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Http\Client\Common\Plugin;
+
+use Psr\Http\Message\RequestInterface;
+
+/**
+ * Provides a unique name to identify a request.
+ *
+ * @author Gary PEGEOT <garypegeot@gmail.com>
+ */
+interface NamingStrategyInterface
+{
+    public function name(RequestInterface $request): string;
+}

src/Plugin/RecordAndReplayPlugin.php

@@ -0,0 +1,73 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Http\Client\Common\Plugin;
+
+use GuzzleHttp\Psr7;
+use Http\Client\Common\Plugin;
+use Http\Promise\FulfilledPromise;
+use Http\Promise\Promise;
+use Psr\Http\Message\RequestInterface;
+use Psr\Http\Message\ResponseInterface;
+use Symfony\Component\Filesystem\Filesystem;
+
+/**
+ * Record successful responses into the filesystem and replay the response when a similar request is performed (VCR-like).
+ *
+ * @author Gary PEGEOT <garypegeot@gmail.com>
+ */
+final class RecordAndReplayPlugin implements Plugin
+{
+    /**
+     * Return a unique name to identify a given request.
+     *
+     * @var NamingStrategyInterface
+     */
+    private $namingStrategy;
+
+    /**
+     * The directory containing your fixtures (Must be writable).
+     *
+     * @var string
+     */
+    private $directory;
+
+    /**
+     * @var Filesystem
+     */
+    private $fs;
+
+    public function __construct(NamingStrategyInterface $namingStrategy, string $directory, ?Filesystem $fs = null)
+    {
+        $this->namingStrategy = $namingStrategy;
+        $this->directory = $directory;
+        $this->fs = $fs ?? new Filesystem();
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function handleRequest(RequestInterface $request, callable $next, callable $first): Promise
+    {
+        if (!$this->fs->exists($this->directory)) {
+            $this->fs->mkdir($this->directory);
+        }
+
+        $directory = realpath($this->directory);
+        $name = $this->namingStrategy->name($request);
+        $filename = "$directory/$name.txt";
+
+        if ($this->fs->exists($filename)) {
+            return new FulfilledPromise(Psr7\parse_response(file_get_contents($filename)));
+        }
+
+        return $next($request)->then(function (ResponseInterface $response) use ($filename) {
+            if ($response->getStatusCode() < 300) {
+                $this->fs->dumpFile($filename, Psr7\str($response));
+            }
+
+            return $response;
+        });
+    }
+}

tests/Plugin/RecordAndReplayPluginTest.php

@@ -0,0 +1,83 @@
+<?php
+
+declare(strict_types=1);
+
+namespace tests\Http\Client\Common\Plugin;
+
+use GuzzleHttp\Psr7\Response;
+use function GuzzleHttp\Psr7\str;
+use Http\Client\Common\Plugin\NamingStrategyInterface;
+use Http\Client\Common\Plugin\RecordAndReplayPlugin;
+use Http\Promise\FulfilledPromise;
+use Http\Promise\Promise;
+use PHPUnit\Framework\MockObject\MockObject;
+use PHPUnit\Framework\TestCase;
+use Psr\Http\Message\RequestInterface;
+use spec\Http\Client\Common\Plugin\PluginStub;
+use Symfony\Component\Filesystem\Filesystem;
+
+/**
+ * @author Gary PEGEOT <garypegeot@gmail.com>
+ *
+ * @internal
+ */
+final class RecordAndReplayPluginTest extends TestCase
+{
+    /**
+     * @var NamingStrategyInterface|MockObject
+     */
+    private $strategy;
+
+    private $directory;
+
+    /**
+     * @var Filesystem
+     */
+    private $fs;
+
+    /**
+     * @var RecordAndReplayPlugin
+     */
+    private $plugin;
+
+    protected function setUp(): void
+    {
+        $this->strategy = $this->createMock(NamingStrategyInterface::class);
+        $this->directory = sys_get_temp_dir().\DIRECTORY_SEPARATOR.md5(random_bytes(10));
+        $this->fs = new Filesystem();
+        $this->plugin = new RecordAndReplayPlugin($this->strategy, $this->directory, $this->fs);
+    }
+
+    protected function tearDown(): void
+    {
+        if ($this->fs->exists($this->directory)) {
+            $this->fs->remove($this->directory);
+        }
+    }
+
+    public function testHandleRequest(): void
+    {
+        /** @var RequestInterface $request */
+        $request = $this->createMock(RequestInterface::class);
+        $next = function (): Promise {
+            return new FulfilledPromise(new Response(200, ['X-Foo' => 'Bar'], '{"baz": true}'));
+        };
+        $filename = "$this->directory/foo.txt";
+        $first = PluginStub::first();
+
+        $this->assertFileNotExists($filename, 'File should not exists yet');
+
+        $this->strategy->expects($this->any())->method('name')->with($request)->willReturn('foo');
+
+        $response = $this->plugin->handleRequest($request, $next, $first)->wait();
+
+        $this->assertInstanceOf(Response::class, $response);
+        $this->assertFileExists($filename, 'File should be created');
+        $this->assertStringEqualsFile($filename, str($response));
+
+        $next = function (): void {
+            $this->fail('Next should not be called when the fixture file exists');
+        };
+        $this->assertSame(str($response), str($this->plugin->handleRequest($request, $next, $first)->wait()));
+    }
+}