Added wkhtmltopdf stuff and created preview generator service

module/Common/config/dependencies.config.php

@@ -2,14 +2,16 @@
 use Acelaya\ZsmAnnotatedServices\Factory\V3\AnnotatedFactory;
 use Doctrine\Common\Cache\Cache;
 use Doctrine\ORM\EntityManager;
+use mikehaertl\wkhtmlto\Image;
 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\Image\ImageFactory;
 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 Zend\I18n\Translator\Translator;
 use Zend\ServiceManager\Factory\InvokableFactory;
@@ -22,12 +24,14 @@ return [
             GuzzleHttp\Client::class => InvokableFactory::class,
             Cache::class => CacheFactory::class,
             'Logger_Shlink' => LoggerFactory::class,
+            Image::class => ImageFactory::class,
 
             Translator::class => TranslatorFactory::class,
             TranslatorExtension::class => AnnotatedFactory::class,
             LocaleMiddleware::class => AnnotatedFactory::class,
 
-            IpLocationResolver::class => AnnotatedFactory::class,
+            Service\IpLocationResolver::class => AnnotatedFactory::class,
+            Service\PreviewGenerator::class => AnnotatedFactory::class,
         ],
         'aliases' => [
             'em' => EntityManager::class,

module/Common/src/Image/ImageFactory.php

@@ -0,0 +1,30 @@
+<?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 = $container->get('config')['phpwkhtmltopdf'];
+        return new Image(isset($config['images']) ? $config['images'] : null);
+    }
+}

module/Common/src/Service/PreviewGenerator.php

@@ -0,0 +1,58 @@
+<?php
+namespace Shlinkio\Shlink\Common\Service;
+
+use Acelaya\ZsmAnnotatedServices\Annotation\Inject;
+use Doctrine\Common\Cache\Cache;
+use mikehaertl\wkhtmlto\Image;
+
+class PreviewGenerator implements PreviewGeneratorInterface
+{
+    /**
+     * @var Image
+     */
+    private $image;
+    /**
+     * @var Cache
+     */
+    private $cache;
+    /**
+     * @var string
+     */
+    private $location;
+
+    /**
+     * PreviewGenerator constructor.
+     * @param Image $image
+     * @param Cache $cache
+     * @param string $location
+     *
+     * @Inject({Image::class, Cache::class, "config.phpwkhtmltopdf.images.files_location"})
+     */
+    public function __construct(Image $image, Cache $cache, $location)
+    {
+        $this->image = $image;
+        $this->cache = $cache;
+        $this->location = $location;
+    }
+
+    /**
+     * Generates and stores preview for provided website and returns the path to the image file
+     *
+     * @param string $url
+     * @return string
+     */
+    public function generatePreview($url)
+    {
+        $cacheId = sprintf('preview_%s.png', urlencode($url));
+        if ($this->cache->contains($cacheId)) {
+            return $this->cache->fetch($cacheId);
+        }
+
+        $path = $this->location . '/' . $cacheId;
+        $this->image->setPage($url);
+        $this->image->saveAs($path);
+        $this->cache->save($cacheId, $path);
+
+        return $path;
+    }
+}

module/Common/src/Service/PreviewGeneratorInterface.php

@@ -0,0 +1,13 @@
+<?php
+namespace Shlinkio\Shlink\Common\Service;
+
+interface PreviewGeneratorInterface
+{
+    /**
+     * Generates and stores preview for provided website and returns the path to the image file
+     *
+     * @param string $url
+     * @return string
+     */
+    public function generatePreview($url);
+}

module/Common/test/Service/PreviewGeneratorTest.php

@@ -0,0 +1,60 @@
+<?php
+namespace ShlinkioTest\Shlink\Common\Service;
+
+use Doctrine\Common\Cache\ArrayCache;
+use mikehaertl\wkhtmlto\Image;
+use PHPUnit_Framework_TestCase as TestCase;
+use Prophecy\Argument;
+use Prophecy\Prophecy\ObjectProphecy;
+use Shlinkio\Shlink\Common\Service\PreviewGenerator;
+
+class PreviewGeneratorTest extends TestCase
+{
+    /**
+     * @var PreviewGenerator
+     */
+    protected $generator;
+    /**
+     * @var ObjectProphecy
+     */
+    protected $image;
+    /**
+     * @var ArrayCache
+     */
+    protected $cache;
+
+    public function setUp()
+    {
+        $this->image = $this->prophesize(Image::class);
+        $this->cache = new ArrayCache();
+        $this->generator = new PreviewGenerator($this->image->reveal(), $this->cache, 'dir');
+    }
+
+    /**
+     * @test
+     */
+    public function alreadyCachedElementsAreNotProcessed()
+    {
+        $url = 'http://foo.com';
+        $this->cache->save(sprintf('preview_%s.png', urlencode($url)), 'dir/foo.png');
+        $this->image->saveAs(Argument::cetera())->shouldBeCalledTimes(0);
+        $this->assertEquals('dir/foo.png', $this->generator->generatePreview($url));
+    }
+
+    /**
+     * @test
+     */
+    public function nonCachedElementsAreProcessedAndThenCached()
+    {
+        $url = 'http://foo.com';
+        $cacheId = sprintf('preview_%s.png', urlencode($url));
+        $expectedPath = 'dir/' . $cacheId;
+
+        $this->image->setPage($url)->shouldBeCalledTimes(1);
+        $this->image->saveAs($expectedPath)->shouldBeCalledTimes(1);
+
+        $this->assertFalse($this->cache->contains($cacheId));
+        $this->assertEquals($expectedPath, $this->generator->generatePreview($url));
+        $this->assertTrue($this->cache->contains($cacheId));
+    }
+}