Merge pull request #3 from acelaya/feature/7

Feature/7

composer.json

@@ -28,10 +28,12 @@
         "guzzlehttp/guzzle": "^6.2",
         "symfony/console": "^3.0",
         "symfony/process": "^3.0",
+        "symfony/filesystem": "^3.0",
         "firebase/php-jwt": "^4.0",
         "monolog/monolog": "^1.21",
         "theorchard/monolog-cascade": "^0.4",
-        "endroid/qrcode": "^1.7"
+        "endroid/qrcode": "^1.7",
+        "mikehaertl/phpwkhtmltopdf": "^2.2"
     },
     "require-dev": {
         "phpunit/phpunit": "^5.0",

config/autoload/phpwkhtmltopdf.global.php

@@ -0,0 +1,11 @@
+<?php
+return [
+
+    'phpwkhtmltopdf' => [
+        'images' => [
+            'binary' => 'bin/wkhtmltoimage',
+            'type' => 'jpg',
+        ],
+    ],
+
+];

config/autoload/preview-generation.global.php

@@ -0,0 +1,8 @@
+<?php
+return [
+
+    'preview_generation' => [
+        'files_location' => 'data/cache',
+    ],
+
+];

module/CLI/config/cli.config.php

@@ -10,6 +10,7 @@ return [
             Command\Shortcode\ResolveUrlCommand::class,
             Command\Shortcode\ListShortcodesCommand::class,
             Command\Shortcode\GetVisitsCommand::class,
+            Command\Shortcode\GeneratePreviewCommand::class,
             Command\Visit\ProcessVisitsCommand::class,
             Command\Config\GenerateCharsetCommand::class,
             Command\Config\GenerateSecretCommand::class,

module/CLI/config/dependencies.config.php

@@ -14,6 +14,7 @@ return [
             Command\Shortcode\ResolveUrlCommand::class => AnnotatedFactory::class,
             Command\Shortcode\ListShortcodesCommand::class => AnnotatedFactory::class,
             Command\Shortcode\GetVisitsCommand::class => AnnotatedFactory::class,
+            Command\Shortcode\GeneratePreviewCommand::class => AnnotatedFactory::class,
             Command\Visit\ProcessVisitsCommand::class => AnnotatedFactory::class,
             Command\Config\GenerateCharsetCommand::class => AnnotatedFactory::class,
             Command\Config\GenerateSecretCommand::class => AnnotatedFactory::class,

module/CLI/lang/es.po

@@ -1,8 +1,8 @@
 msgid ""
 msgstr ""
 "Project-Id-Version: Shlink 1.0\n"
-"POT-Creation-Date: 2016-08-07 20:16+0200\n"
-"PO-Revision-Date: 2016-08-07 20:18+0200\n"
+"POT-Creation-Date: 2016-08-18 17:24+0200\n"
+"PO-Revision-Date: 2016-08-18 17:26+0200\n"
 "Last-Translator: Alejandro Celaya <alejandro@alejandrocelaya.com>\n"
 "Language-Team: \n"
 "Language: es_ES\n"
@@ -68,7 +68,35 @@ msgstr ""
 msgid "Character set:"
 msgstr "Grupo de caracteres:"
 
-#, fuzzy
+msgid ""
+"Generates a random secret string that can be used for JWT token encryption"
+msgstr ""
+"Genera una cadena de caracteres aleatoria que puede ser usada para cifrar "
+"tokens JWT"
+
+msgid "Secret key:"
+msgstr "Clave secreta:"
+
+msgid ""
+"Processes and generates the previews for every URL, improving performance "
+"for later web requests."
+msgstr ""
+"Procesa y genera las vistas previas para cada URL, mejorando el rendimiento "
+"para peticiones web posteriores."
+
+msgid "Finished processing all URLs"
+msgstr "Finalizado el procesado de todas las URLs"
+
+#, php-format
+msgid "Processing URL %s..."
+msgstr "Procesando URL %s..."
+
+msgid " <info>Success!</info>"
+msgstr "<info>¡Correcto!</info>"
+
+msgid "Error"
+msgstr "Error"
+
 msgid "Generates a short code for provided URL and returns the short URL"
 msgstr ""
 "Genera un código corto para la URL proporcionada y devuelve la URL acortada"
@@ -149,22 +177,6 @@ msgstr "Has alcanzado la última página"
 msgid "Continue with page"
 msgstr "Continuar con la página"
 
-msgid "Processes visits where location is not set yet"
-msgstr "Procesa las visitas donde la localización no ha sido establecida aún"
-
-msgid "Processing IP"
-msgstr "Procesando IP"
-
-msgid "Ignored localhost address"
-msgstr "Ignorada IP de localhost"
-
-#, php-format
-msgid "Address located at \"%s\""
-msgstr "Dirección localizada en \"%s\""
-
-msgid "Finished processing all IPs"
-msgstr "Finalizado el procesado de todas las IPs"
-
 msgid "Returns the long URL behind a short code"
 msgstr "Devuelve la URL larga detrás de un código corto"
 
@@ -185,3 +197,19 @@ msgstr "URL larga:"
 #, php-format
 msgid "Provided short code \"%s\" has an invalid format."
 msgstr "El código corto proporcionado \"%s\" tiene un formato inválido."
+
+msgid "Processes visits where location is not set yet"
+msgstr "Procesa las visitas donde la localización no ha sido establecida aún"
+
+msgid "Processing IP"
+msgstr "Procesando IP"
+
+msgid "Ignored localhost address"
+msgstr "Ignorada IP de localhost"
+
+#, php-format
+msgid "Address located at \"%s\""
+msgstr "Dirección localizada en \"%s\""
+
+msgid "Finished processing all IPs"
+msgstr "Finalizado el procesado de todas las IPs"

module/CLI/src/Command/Shortcode/GeneratePreviewCommand.php

@@ -0,0 +1,89 @@
+<?php
+namespace Shlinkio\Shlink\CLI\Command\Shortcode;
+
+use Acelaya\ZsmAnnotatedServices\Annotation\Inject;
+use Shlinkio\Shlink\Common\Exception\PreviewGenerationException;
+use Shlinkio\Shlink\Common\Service\PreviewGenerator;
+use Shlinkio\Shlink\Common\Service\PreviewGeneratorInterface;
+use Shlinkio\Shlink\Core\Service\ShortUrlService;
+use Shlinkio\Shlink\Core\Service\ShortUrlServiceInterface;
+use Symfony\Component\Console\Command\Command;
+use Symfony\Component\Console\Input\InputInterface;
+use Symfony\Component\Console\Output\OutputInterface;
+use Zend\I18n\Translator\TranslatorInterface;
+
+class GeneratePreviewCommand extends Command
+{
+    /**
+     * @var PreviewGeneratorInterface
+     */
+    private $previewGenerator;
+    /**
+     * @var TranslatorInterface
+     */
+    private $translator;
+    /**
+     * @var ShortUrlServiceInterface
+     */
+    private $shortUrlService;
+
+    /**
+     * GeneratePreviewCommand constructor.
+     * @param ShortUrlServiceInterface $shortUrlService
+     * @param PreviewGeneratorInterface $previewGenerator
+     * @param TranslatorInterface $translator
+     *
+     * @Inject({ShortUrlService::class, PreviewGenerator::class, "translator"})
+     */
+    public function __construct(
+        ShortUrlServiceInterface $shortUrlService,
+        PreviewGeneratorInterface $previewGenerator,
+        TranslatorInterface $translator
+    ) {
+        $this->shortUrlService = $shortUrlService;
+        $this->previewGenerator = $previewGenerator;
+        $this->translator = $translator;
+        parent::__construct(null);
+    }
+
+    public function configure()
+    {
+        $this->setName('shortcode:process-previews')
+             ->setDescription(
+                 $this->translator->translate(
+                     'Processes and generates the previews for every URL, improving performance for later web requests.'
+                 )
+             );
+    }
+
+    public function execute(InputInterface $input, OutputInterface $output)
+    {
+        $page = 1;
+        do {
+            $shortUrls = $this->shortUrlService->listShortUrls($page);
+            $page += 1;
+
+            foreach ($shortUrls as $shortUrl) {
+                $this->processUrl($shortUrl->getOriginalUrl(), $output);
+            }
+        } while ($page <= $shortUrls->count());
+
+        $output->writeln('<info>' . $this->translator->translate('Finished processing all URLs') . '</info>');
+    }
+
+    protected function processUrl($url, OutputInterface $output)
+    {
+        try {
+            $output->write(sprintf($this->translator->translate('Processing URL %s...'), $url));
+            $this->previewGenerator->generatePreview($url);
+            $output->writeln($this->translator->translate(' <info>Success!</info>'));
+        } catch (PreviewGenerationException $e) {
+            $messages = [' <error>' . $this->translator->translate('Error') . '</error>'];
+            if ($output->isVerbose()) {
+                $messages[] = '<error>' . $e->__toString() . '</error>';
+            }
+
+            $output->writeln($messages);
+        }
+    }
+}

module/CLI/test/Command/Shortcode/GeneratePreviewCommandTest.php

@@ -0,0 +1,99 @@
+<?php
+namespace ShlinkioTest\Shlink\CLI\Command\Shortcode;
+
+use PHPUnit_Framework_TestCase as TestCase;
+use Prophecy\Argument;
+use Prophecy\Prophecy\ObjectProphecy;
+use Shlinkio\Shlink\CLI\Command\Shortcode\GeneratePreviewCommand;
+use Shlinkio\Shlink\Common\Exception\PreviewGenerationException;
+use Shlinkio\Shlink\Common\Service\PreviewGenerator;
+use Shlinkio\Shlink\Core\Entity\ShortUrl;
+use Shlinkio\Shlink\Core\Service\ShortUrlService;
+use Symfony\Component\Console\Application;
+use Symfony\Component\Console\Tester\CommandTester;
+use Zend\I18n\Translator\Translator;
+use Zend\Paginator\Adapter\ArrayAdapter;
+use Zend\Paginator\Paginator;
+
+class GeneratePreviewCommandTest extends TestCase
+{
+    /**
+     * @var CommandTester
+     */
+    protected $commandTester;
+    /**
+     * @var ObjectProphecy
+     */
+    private $previewGenerator;
+    /**
+     * @var ObjectProphecy
+     */
+    private $shortUrlService;
+
+    public function setUp()
+    {
+        $this->previewGenerator = $this->prophesize(PreviewGenerator::class);
+        $this->shortUrlService = $this->prophesize(ShortUrlService::class);
+
+        $command = new GeneratePreviewCommand(
+            $this->shortUrlService->reveal(),
+            $this->previewGenerator->reveal(),
+            Translator::factory([])
+        );
+        $app = new Application();
+        $app->add($command);
+
+        $this->commandTester = new CommandTester($command);
+    }
+
+    /**
+     * @test
+     */
+    public function previewsForEveryUrlAreGenerated()
+    {
+        $paginator = $this->createPaginator([
+            (new ShortUrl())->setOriginalUrl('http://foo.com'),
+            (new ShortUrl())->setOriginalUrl('https://bar.com'),
+            (new ShortUrl())->setOriginalUrl('http://baz.com/something'),
+        ]);
+        $this->shortUrlService->listShortUrls(1)->willReturn($paginator)->shouldBeCalledTimes(1);
+
+        $this->previewGenerator->generatePreview('http://foo.com')->shouldBeCalledTimes(1);
+        $this->previewGenerator->generatePreview('https://bar.com')->shouldBeCalledTimes(1);
+        $this->previewGenerator->generatePreview('http://baz.com/something')->shouldBeCalledTimes(1);
+
+        $this->commandTester->execute([
+            'command' => 'shortcode:process-previews'
+        ]);
+    }
+
+    /**
+     * @test
+     */
+    public function exceptionWillOutputError()
+    {
+        $items = [
+            (new ShortUrl())->setOriginalUrl('http://foo.com'),
+            (new ShortUrl())->setOriginalUrl('https://bar.com'),
+            (new ShortUrl())->setOriginalUrl('http://baz.com/something'),
+        ];
+        $paginator = $this->createPaginator($items);
+        $this->shortUrlService->listShortUrls(1)->willReturn($paginator)->shouldBeCalledTimes(1);
+        $this->previewGenerator->generatePreview(Argument::any())->willThrow(PreviewGenerationException::class)
+                                                                 ->shouldBeCalledTimes(count($items));
+
+        $this->commandTester->execute([
+            'command' => 'shortcode:process-previews'
+        ]);
+        $output = $this->commandTester->getDisplay();
+        $this->assertEquals(count($items), substr_count($output, 'Error'));
+    }
+
+    protected function createPaginator(array $items)
+    {
+        $paginator = new Paginator(new ArrayAdapter($items));
+        $paginator->setItemCountPerPage(count($items));
+
+        return $paginator;
+    }
+}

module/Common/config/dependencies.config.php

@@ -4,30 +4,35 @@ use Doctrine\Common\Cache\Cache;
 use Doctrine\ORM\EntityManager;
 use Monolog\Logger;
 use Psr\Log\LoggerInterface;
-use Shlinkio\Shlink\Common\Factory\CacheFactory;
-use Shlinkio\Shlink\Common\Factory\EntityManagerFactory;
-use Shlinkio\Shlink\Common\Factory\LoggerFactory;
-use Shlinkio\Shlink\Common\Factory\TranslatorFactory;
+use Shlinkio\Shlink\Common\Factory;
+use Shlinkio\Shlink\Common\Image;
 use Shlinkio\Shlink\Common\Middleware\LocaleMiddleware;
-use Shlinkio\Shlink\Common\Service\IpLocationResolver;
+use Shlinkio\Shlink\Common\Service;
 use Shlinkio\Shlink\Common\Twig\Extension\TranslatorExtension;
+use Symfony\Component\Filesystem\Filesystem;
 use Zend\I18n\Translator\Translator;
 use Zend\ServiceManager\Factory\InvokableFactory;
 
 return [
 
     'dependencies' => [
+        'invokables' => [
+            Filesystem::class => Filesystem::class,
+        ],
         'factories' => [
-            EntityManager::class => EntityManagerFactory::class,
+            EntityManager::class => Factory\EntityManagerFactory::class,
             GuzzleHttp\Client::class => InvokableFactory::class,
-            Cache::class => CacheFactory::class,
-            'Logger_Shlink' => LoggerFactory::class,
+            Cache::class => Factory\CacheFactory::class,
+            'Logger_Shlink' => Factory\LoggerFactory::class,
 
-            Translator::class => TranslatorFactory::class,
+            Translator::class => Factory\TranslatorFactory::class,
             TranslatorExtension::class => AnnotatedFactory::class,
             LocaleMiddleware::class => AnnotatedFactory::class,
 
-            IpLocationResolver::class => AnnotatedFactory::class,
+            Image\ImageBuilder::class => Image\ImageBuilderFactory::class,
+
+            Service\IpLocationResolver::class => AnnotatedFactory::class,
+            Service\PreviewGenerator::class => AnnotatedFactory::class,
         ],
         'aliases' => [
             'em' => EntityManager::class,

module/Common/src/Exception/PreviewGenerationException.php

@@ -0,0 +1,10 @@
+<?php
+namespace Shlinkio\Shlink\Common\Exception;
+
+class PreviewGenerationException extends RuntimeException
+{
+    public static function fromImageError($error)
+    {
+        return new self(sprintf('Error generating a preview image with error: %s', $error));
+    }
+}

module/Common/src/Image/ImageBuilder.php

@@ -0,0 +1,10 @@
+<?php
+namespace Shlinkio\Shlink\Common\Image;
+
+use mikehaertl\wkhtmlto\Image;
+use Zend\ServiceManager\AbstractPluginManager;
+
+class ImageBuilder extends AbstractPluginManager implements ImageBuilderInterface
+{
+    protected $instanceOf = Image::class;
+}

module/Common/src/Image/ImageBuilderFactory.php

@@ -0,0 +1,31 @@
+<?php
+namespace Shlinkio\Shlink\Common\Image;
+
+use Interop\Container\ContainerInterface;
+use Interop\Container\Exception\ContainerException;
+use mikehaertl\wkhtmlto\Image;
+use Zend\ServiceManager\Exception\ServiceNotCreatedException;
+use Zend\ServiceManager\Exception\ServiceNotFoundException;
+use Zend\ServiceManager\Factory\FactoryInterface;
+
+class ImageBuilderFactory implements FactoryInterface
+{
+    /**
+     * Create an object
+     *
+     * @param  ContainerInterface $container
+     * @param  string $requestedName
+     * @param  null|array $options
+     * @return object
+     * @throws ServiceNotFoundException if unable to resolve the service.
+     * @throws ServiceNotCreatedException if an exception is raised when
+     *     creating a service.
+     * @throws ContainerException if any other error occurs
+     */
+    public function __invoke(ContainerInterface $container, $requestedName, array $options = null)
+    {
+        return new ImageBuilder($container, ['factories' => [
+            Image::class => ImageFactory::class,
+        ]]);
+    }
+}

module/Common/src/Image/ImageBuilderInterface.php

@@ -0,0 +1,8 @@
+<?php
+namespace Shlinkio\Shlink\Common\Image;
+
+use Zend\ServiceManager\ServiceLocatorInterface;
+
+interface ImageBuilderInterface extends ServiceLocatorInterface
+{
+}

module/Common/src/Image/ImageFactory.php

@@ -0,0 +1,36 @@
+<?php
+namespace Shlinkio\Shlink\Common\Image;
+
+use Interop\Container\ContainerInterface;
+use Interop\Container\Exception\ContainerException;
+use mikehaertl\wkhtmlto\Image;
+use Zend\ServiceManager\Exception\ServiceNotCreatedException;
+use Zend\ServiceManager\Exception\ServiceNotFoundException;
+use Zend\ServiceManager\Factory\FactoryInterface;
+
+class ImageFactory implements FactoryInterface
+{
+    /**
+     * Create an object
+     *
+     * @param  ContainerInterface $container
+     * @param  string $requestedName
+     * @param  null|array $options
+     * @return object
+     * @throws ServiceNotFoundException if unable to resolve the service.
+     * @throws ServiceNotCreatedException if an exception is raised when
+     *     creating a service.
+     * @throws ContainerException if any other error occurs
+     */
+    public function __invoke(ContainerInterface $container, $requestedName, array $options = null)
+    {
+        $config = $container->get('config')['phpwkhtmltopdf'];
+        $image = new Image(isset($config['images']) ? $config['images'] : null);
+
+        if (isset($options) && isset($options['url'])) {
+            $image->setPage($options['url']);
+        }
+
+        return $image;
+    }
+}

module/Common/src/Service/PreviewGenerator.php

@@ -0,0 +1,70 @@
+<?php
+namespace Shlinkio\Shlink\Common\Service;
+
+use Acelaya\ZsmAnnotatedServices\Annotation\Inject;
+use mikehaertl\wkhtmlto\Image;
+use Shlinkio\Shlink\Common\Exception\PreviewGenerationException;
+use Shlinkio\Shlink\Common\Image\ImageBuilder;
+use Shlinkio\Shlink\Common\Image\ImageBuilderInterface;
+use Symfony\Component\Filesystem\Filesystem;
+
+class PreviewGenerator implements PreviewGeneratorInterface
+{
+    /**
+     * @var string
+     */
+    private $location;
+    /**
+     * @var ImageBuilderInterface
+     */
+    private $imageBuilder;
+    /**
+     * @var Filesystem
+     */
+    private $filesystem;
+
+    /**
+     * PreviewGenerator constructor.
+     * @param ImageBuilderInterface $imageBuilder
+     * @param Filesystem $filesystem
+     * @param string $location
+     *
+     * @Inject({ImageBuilder::class, Filesystem::class, "config.preview_generation.files_location"})
+     */
+    public function __construct(ImageBuilderInterface $imageBuilder, Filesystem $filesystem, $location)
+    {
+        $this->location = $location;
+        $this->imageBuilder = $imageBuilder;
+        $this->filesystem = $filesystem;
+    }
+
+    /**
+     * Generates and stores preview for provided website and returns the path to the image file
+     *
+     * @param string $url
+     * @return string
+     * @throws PreviewGenerationException
+     */
+    public function generatePreview($url)
+    {
+        /** @var Image $image */
+        $image = $this->imageBuilder->build(Image::class, ['url' => $url]);
+
+        // If the file already exists, return its path
+        $cacheId = sprintf('preview_%s.%s', urlencode($url), $image->type);
+        $path = $this->location . '/' . $cacheId;
+        if ($this->filesystem->exists($path)) {
+            return $path;
+        }
+
+        // Save and check if an error occurred
+        $image->saveAs($path);
+        $error = $image->getError();
+        if (! empty($error)) {
+            throw PreviewGenerationException::fromImageError($error);
+        }
+
+        // Cache the path and return it
+        return $path;
+    }
+}

module/Common/src/Service/PreviewGeneratorInterface.php

@@ -0,0 +1,16 @@
+<?php
+namespace Shlinkio\Shlink\Common\Service;
+
+use Shlinkio\Shlink\Common\Exception\PreviewGenerationException;
+
+interface PreviewGeneratorInterface
+{
+    /**
+     * Generates and stores preview for provided website and returns the path to the image file
+     *
+     * @param string $url
+     * @return string
+     * @throws PreviewGenerationException
+     */
+    public function generatePreview($url);
+}

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/Common/test/Image/ImageBuilderFactoryTest.php

@@ -0,0 +1,29 @@
+<?php
+namespace ShlinkioTest\Shlink\Common\Image;
+
+use PHPUnit_Framework_TestCase as TestCase;
+use Shlinkio\Shlink\Common\Image\ImageBuilder;
+use Shlinkio\Shlink\Common\Image\ImageBuilderFactory;
+use Zend\ServiceManager\ServiceManager;
+
+class ImageBuilderFactoryTest extends TestCase
+{
+    /**
+     * @var ImageBuilderFactory
+     */
+    protected $factory;
+
+    public function setUp()
+    {
+        $this->factory = new ImageBuilderFactory();
+    }
+
+    /**
+     * @test
+     */
+    public function serviceIsCreated()
+    {
+        $instance = $this->factory->__invoke(new ServiceManager(), '');
+        $this->assertInstanceOf(ImageBuilder::class, $instance);
+    }
+}

module/Common/test/Image/ImageFactoryTest.php

@@ -0,0 +1,56 @@
+<?php
+namespace ShlinkioTest\Shlink\Common\Image;
+
+use mikehaertl\wkhtmlto\Image;
+use PHPUnit_Framework_TestCase as TestCase;
+use Shlinkio\Shlink\Common\Image\ImageFactory;
+use Zend\ServiceManager\ServiceManager;
+
+class ImageFactoryTest extends TestCase
+{
+    /**
+     * @var ImageFactory
+     */
+    protected $factory;
+
+    public function setUp()
+    {
+        $this->factory = new ImageFactory();
+    }
+
+    /**
+     * @test
+     */
+    public function noPageIsSetWhenOptionsAreNotProvided()
+    {
+        /** @var Image $image */
+        $image = $this->factory->__invoke(new ServiceManager(['services' => [
+            'config' => ['phpwkhtmltopdf' => []],
+        ]]), '');
+        $this->assertInstanceOf(Image::class, $image);
+
+        $ref = new \ReflectionObject($image);
+        $page = $ref->getProperty('_page');
+        $page->setAccessible(true);
+        $this->assertNull($page->getValue($image));
+    }
+
+    /**
+     * @test
+     */
+    public function aPageIsSetWhenOptionsIncludeTheUrl()
+    {
+        $expectedPage = 'foo/bar.html';
+
+        /** @var Image $image */
+        $image = $this->factory->__invoke(new ServiceManager(['services' => [
+            'config' => ['phpwkhtmltopdf' => []],
+        ]]), '', ['url' => $expectedPage]);
+        $this->assertInstanceOf(Image::class, $image);
+
+        $ref = new \ReflectionObject($image);
+        $page = $ref->getProperty('_page');
+        $page->setAccessible(true);
+        $this->assertEquals($expectedPage, $page->getValue($image));
+    }
+}

module/Common/test/Service/PreviewGeneratorTest.php

@@ -0,0 +1,89 @@
+<?php
+namespace ShlinkioTest\Shlink\Common\Service;
+
+use mikehaertl\wkhtmlto\Image;
+use PHPUnit_Framework_TestCase as TestCase;
+use Prophecy\Argument;
+use Prophecy\Prophecy\ObjectProphecy;
+use Shlinkio\Shlink\Common\Image\ImageBuilder;
+use Shlinkio\Shlink\Common\Service\PreviewGenerator;
+use Symfony\Component\Filesystem\Filesystem;
+use Zend\ServiceManager\ServiceManager;
+
+class PreviewGeneratorTest extends TestCase
+{
+    /**
+     * @var PreviewGenerator
+     */
+    protected $generator;
+    /**
+     * @var ObjectProphecy
+     */
+    protected $image;
+    /**
+     * @var ObjectProphecy
+     */
+    protected $filesystem;
+
+    public function setUp()
+    {
+        $this->image = $this->prophesize(Image::class);
+        $this->filesystem = $this->prophesize(Filesystem::class);
+
+        $this->generator = new PreviewGenerator(new ImageBuilder(new ServiceManager(), [
+            'factories' => [
+                Image::class => function () {
+                    return $this->image->reveal();
+                },
+            ]
+        ]), $this->filesystem->reveal(), 'dir');
+    }
+
+    /**
+     * @test
+     */
+    public function alreadyProcessedElementsAreNotProcessed()
+    {
+        $url = 'http://foo.com';
+        $this->filesystem->exists(sprintf('dir/preview_%s.png', urlencode($url)))->willReturn(true)
+                                                                                 ->shouldBeCalledTimes(1);
+        $this->image->saveAs(Argument::cetera())->shouldBeCalledTimes(0);
+        $this->assertEquals(sprintf('dir/preview_%s.png', urlencode($url)), $this->generator->generatePreview($url));
+    }
+
+    /**
+     * @test
+     */
+    public function nonProcessedElementsAreProcessed()
+    {
+        $url = 'http://foo.com';
+        $cacheId = sprintf('preview_%s.png', urlencode($url));
+        $expectedPath = 'dir/' . $cacheId;
+
+        $this->filesystem->exists(sprintf('dir/preview_%s.png', urlencode($url)))->willReturn(false)
+                                                                                 ->shouldBeCalledTimes(1);
+
+        $this->image->saveAs($expectedPath)->shouldBeCalledTimes(1);
+        $this->image->getError()->willReturn('')->shouldBeCalledTimes(1);
+        $this->assertEquals($expectedPath, $this->generator->generatePreview($url));
+    }
+
+    /**
+     * @test
+     * @expectedException \Shlinkio\Shlink\Common\Exception\PreviewGenerationException
+     */
+    public function errorWhileGeneratingPreviewThrowsException()
+    {
+        $url = 'http://foo.com';
+        $cacheId = sprintf('preview_%s.png', urlencode($url));
+        $expectedPath = 'dir/' . $cacheId;
+
+        $this->filesystem->exists(sprintf('dir/preview_%s.png', urlencode($url)))->willReturn(false)
+                                                                                 ->shouldBeCalledTimes(1);
+
+        $this->image->saveAs($expectedPath)->shouldBeCalledTimes(1);
+        $this->image->getError()->willReturn('Error!!')->shouldBeCalledTimes(1);
+
+        $this->generator->generatePreview($url);
+    }
+}

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

@@ -13,6 +13,23 @@ return [
         ],
         [
             'name' => 'short-url-qr-code',
+            'path' => '/{shortCode}/qr-code[/{size:[0-9]+}]',
+            'middleware' => [
+                Middleware\QrCodeCacheMiddleware::class,
+                Action\QrCodeAction::class,
+            ],
+            'allowed_methods' => ['GET'],
+        ],
+        [
+            'name' => 'short-url-preview',
+            'path' => '/{shortCode}/preview',
+            'middleware' => Action\PreviewAction::class,
+            'allowed_methods' => ['GET'],
+        ],
+
+        // Old QR code route. Deprecated
+        [
+            'name' => 'short-url-qr-code-old',
             'path' => '/qr/{shortCode}[/{size:[0-9]+}]',
             'middleware' => [
                 Middleware\QrCodeCacheMiddleware::class,

module/Core/src/Action/PreviewAction.php

@@ -0,0 +1,85 @@
+<?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\Exception\PreviewGenerationException;
+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');
+        } catch (PreviewGenerationException $e) {
+            return $out($request, $response->withStatus(500), 'Preview generation error');
+        }
+    }
+}

module/Core/test/Action/PreviewActionTest.php

@@ -0,0 +1,114 @@
+<?php
+namespace ShlinkioTest\Shlink\Core\Action;
+
+use PHPUnit_Framework_TestCase as TestCase;
+use Prophecy\Prophecy\ObjectProphecy;
+use Shlinkio\Shlink\Common\Exception\PreviewGenerationException;
+use Shlinkio\Shlink\Common\Service\PreviewGenerator;
+use Shlinkio\Shlink\Core\Action\PreviewAction;
+use Shlinkio\Shlink\Core\Exception\InvalidShortCodeException;
+use Shlinkio\Shlink\Core\Service\UrlShortener;
+use Zend\Diactoros\Response;
+use Zend\Diactoros\ServerRequestFactory;
+
+class PreviewActionTest extends TestCase
+{
+    /**
+     * @var PreviewAction
+     */
+    protected $action;
+    /**
+     * @var ObjectProphecy
+     */
+    private $previewGenerator;
+    /**
+     * @var ObjectProphecy
+     */
+    private $urlShortener;
+
+    public function setUp()
+    {
+        $this->previewGenerator = $this->prophesize(PreviewGenerator::class);
+        $this->urlShortener = $this->prophesize(UrlShortener::class);
+        $this->action = new PreviewAction($this->previewGenerator->reveal(), $this->urlShortener->reveal());
+    }
+
+    /**
+     * @test
+     */
+    public function invalidShortCodeFallbacksToNextMiddlewareWithStatusNotFound()
+    {
+        $shortCode = 'abc123';
+        $this->urlShortener->shortCodeToUrl($shortCode)->willReturn(null)->shouldBeCalledTimes(1);
+
+        $resp = $this->action->__invoke(
+            ServerRequestFactory::fromGlobals()->withAttribute('shortCode', $shortCode),
+            new Response(),
+            function ($req, $resp) {
+                return $resp;
+            }
+        );
+
+        $this->assertEquals(404, $resp->getStatusCode());
+    }
+
+    /**
+     * @test
+     */
+    public function correctShortCodeReturnsImageResponse()
+    {
+        $shortCode = 'abc123';
+        $url = 'foobar.com';
+        $path = __FILE__;
+        $this->urlShortener->shortCodeToUrl($shortCode)->willReturn($url)->shouldBeCalledTimes(1);
+        $this->previewGenerator->generatePreview($url)->willReturn($path)->shouldBeCalledTimes(1);
+
+        $resp = $this->action->__invoke(
+            ServerRequestFactory::fromGlobals()->withAttribute('shortCode', $shortCode),
+            new Response()
+        );
+
+        $this->assertEquals(filesize($path), $resp->getHeaderLine('Content-length'));
+        $this->assertEquals((new \finfo(FILEINFO_MIME))->file($path), $resp->getHeaderLine('Content-type'));
+    }
+
+    /**
+     * @test
+     */
+    public function invalidShortcodeExceptionReturnsNotFound()
+    {
+        $shortCode = 'abc123';
+        $this->urlShortener->shortCodeToUrl($shortCode)->willThrow(InvalidShortCodeException::class)
+                                                       ->shouldBeCalledTimes(1);
+
+        $resp = $this->action->__invoke(
+            ServerRequestFactory::fromGlobals()->withAttribute('shortCode', $shortCode),
+            new Response(),
+            function ($req, $resp) {
+                return $resp;
+            }
+        );
+
+        $this->assertEquals(404, $resp->getStatusCode());
+    }
+
+    /**
+     * @test
+     */
+    public function previewExceptionReturnsNotFound()
+    {
+        $shortCode = 'abc123';
+        $this->urlShortener->shortCodeToUrl($shortCode)->willThrow(PreviewGenerationException::class)
+                                                       ->shouldBeCalledTimes(1);
+
+        $resp = $this->action->__invoke(
+            ServerRequestFactory::fromGlobals()->withAttribute('shortCode', $shortCode),
+            new Response(),
+            function ($req, $resp) {
+                return $resp;
+            }
+        );
+
+        $this->assertEquals(500, $resp->getStatusCode());
+    }
+}

module/Rest/lang/es.po

@@ -1,8 +1,8 @@
 msgid ""
 msgstr ""
 "Project-Id-Version: Shlink 1.0\n"
-"POT-Creation-Date: 2016-08-07 20:19+0200\n"
-"PO-Revision-Date: 2016-08-07 20:21+0200\n"
+"POT-Creation-Date: 2016-08-18 17:27+0200\n"
+"PO-Revision-Date: 2016-08-18 17:27+0200\n"
 "Last-Translator: Alejandro Celaya <alejandro@alejandrocelaya.com>\n"
 "Language-Team: \n"
 "Language: es_ES\n"
@@ -29,21 +29,19 @@ msgid "A URL was not provided"
 msgstr "No se ha proporcionado una URL"
 
 #, php-format
-msgid "Provided URL \"%s\" is invalid. Try with a different one."
-msgstr ""
-"La URL \"%s\" proporcionada es inválida. Inténtalo de nuevo con una "
-"diferente."
+msgid "Provided URL %s is invalid. Try with a different one."
+msgstr "La URL proporcionada \"%s\" es inválida. Prueba con una diferente."
 
 msgid "Unexpected error occurred"
 msgstr "Ocurrió un error inesperado"
 
 #, php-format
-msgid "Provided short code \"%s\" is invalid"
-msgstr "El código corto \"%s\" proporcionado es inválido"
+msgid "Provided short code %s does not exist"
+msgstr "El código corto \"%s\" proporcionado no existe"
 
 #, php-format
-msgid "No URL found for shortcode \"%s\""
-msgstr "No se ha encontrado una URL para el código corto \"%s\""
+msgid "No URL found for short code \"%s\""
+msgstr "No se ha encontrado ninguna URL para el código corto \"%s\""
 
 #, php-format
 msgid "Provided short code \"%s\" has an invalid format"

phpcs.xml

@@ -16,6 +16,7 @@
     </rule>
 
     <!-- Paths to check -->
+    <file>bin</file>
     <file>module</file>
     <file>config</file>
     <file>public/index.php</file>