Created action to return preview images

module/Common/src/Util/ResponseUtilsTrait.php

@@ -0,0 +1,35 @@
+<?php
+namespace Shlinkio\Shlink\Common\Util;
+
+use Zend\Diactoros\Response;
+use Zend\Diactoros\Stream;
+use Zend\Stdlib\ArrayUtils;
+
+trait ResponseUtilsTrait
+{
+    protected function generateDownloadFileResponse($filePath)
+    {
+        return $this->generateBinaryResponse($filePath, [
+            'Content-Disposition' => 'attachment; filename=' . basename($filePath),
+            'Content-Transfer-Encoding' => 'Binary',
+            'Content-Description' => 'File Transfer',
+            'Pragma' => 'public',
+            'Expires' => '0',
+            'Cache-Control' => 'must-revalidate',
+        ]);
+    }
+
+    protected function generateImageResponse($imagePath)
+    {
+        return $this->generateBinaryResponse($imagePath);
+    }
+
+    protected function generateBinaryResponse($path, $extraHeaders = [])
+    {
+        $body = new Stream($path);
+        return new Response($body, 200, ArrayUtils::merge([
+            'Content-Type' => (new \finfo(FILEINFO_MIME))->file($path),
+            'Content-Length' => (string) $body->getSize(),
+        ], $extraHeaders));
+    }
+}

module/Core/config/dependencies.config.php

@@ -20,6 +20,7 @@ return [
             // Middleware
             Action\RedirectAction::class => AnnotatedFactory::class,
             Action\QrCodeAction::class => AnnotatedFactory::class,
+            Action\PreviewAction::class => AnnotatedFactory::class,
             Middleware\QrCodeCacheMiddleware::class => AnnotatedFactory::class,
         ],
     ],

module/Core/config/routes.config.php

@@ -20,6 +20,12 @@ return [
             ],
             'allowed_methods' => ['GET'],
         ],
+        [
+            'name' => 'short-url-preview',
+            'path' => '/{shortCode}/preview',
+            'middleware' => Action\PreviewAction::class,
+            'allowed_methods' => ['GET'],
+        ],
     ],
 
 ];

module/Core/src/Action/PreviewAction.php

@@ -0,0 +1,82 @@
+<?php
+namespace Shlinkio\Shlink\Core\Action;
+
+use Acelaya\ZsmAnnotatedServices\Annotation\Inject;
+use Psr\Http\Message\ResponseInterface as Response;
+use Psr\Http\Message\ServerRequestInterface as Request;
+use Shlinkio\Shlink\Common\Service\PreviewGenerator;
+use Shlinkio\Shlink\Common\Service\PreviewGeneratorInterface;
+use Shlinkio\Shlink\Common\Util\ResponseUtilsTrait;
+use Shlinkio\Shlink\Core\Exception\InvalidShortCodeException;
+use Shlinkio\Shlink\Core\Service\UrlShortener;
+use Shlinkio\Shlink\Core\Service\UrlShortenerInterface;
+use Zend\Stratigility\MiddlewareInterface;
+
+class PreviewAction implements MiddlewareInterface
+{
+    use ResponseUtilsTrait;
+
+    /**
+     * @var PreviewGeneratorInterface
+     */
+    private $previewGenerator;
+    /**
+     * @var UrlShortenerInterface
+     */
+    private $urlShortener;
+
+    /**
+     * PreviewAction constructor.
+     * @param PreviewGeneratorInterface $previewGenerator
+     * @param UrlShortenerInterface $urlShortener
+     *
+     * @Inject({PreviewGenerator::class, UrlShortener::class})
+     */
+    public function __construct(PreviewGeneratorInterface $previewGenerator, UrlShortenerInterface $urlShortener)
+    {
+        $this->previewGenerator = $previewGenerator;
+        $this->urlShortener = $urlShortener;
+    }
+
+    /**
+     * Process an incoming request and/or response.
+     *
+     * Accepts a server-side request and a response instance, and does
+     * something with them.
+     *
+     * If the response is not complete and/or further processing would not
+     * interfere with the work done in the middleware, or if the middleware
+     * wants to delegate to another process, it can use the `$out` callable
+     * if present.
+     *
+     * If the middleware does not return a value, execution of the current
+     * request is considered complete, and the response instance provided will
+     * be considered the response to return.
+     *
+     * Alternately, the middleware may return a response instance.
+     *
+     * Often, middleware will `return $out();`, with the assumption that a
+     * later middleware will return a response.
+     *
+     * @param Request $request
+     * @param Response $response
+     * @param null|callable $out
+     * @return null|Response
+     */
+    public function __invoke(Request $request, Response $response, callable $out = null)
+    {
+        $shortCode = $request->getAttribute('shortCode');
+
+        try {
+            $url = $this->urlShortener->shortCodeToUrl($shortCode);
+            if (! isset($url)) {
+                return $out($request, $response->withStatus(404), 'Not found');
+            }
+
+            $imagePath = $this->previewGenerator->generatePreview($url);
+            return $this->generateImageResponse($imagePath);
+        } catch (InvalidShortCodeException $e) {
+            return $out($request, $response->withStatus(404), 'Not found');
+        }
+    }
+}