Improved PreviewGenerator by composing an ImageBuilder that creates new Image objects fore each URL

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

@@ -25,6 +25,12 @@ class ImageFactory implements FactoryInterface
     public function __invoke(ContainerInterface $container, $requestedName, array $options = null)
     {
         $config = $container->get('config')['phpwkhtmltopdf'];
-        return new Image(isset($config['images']) ? $config['images'] : null);
+        $image = new Image(isset($config['images']) ? $config['images'] : null);
+
+        if (isset($options['url'])) {
+            $image->setPage($options['url']);
+        }
+
+        return $image;
     }
 }