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

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

@@ -0,0 +1,87 @@
+<?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->previewGenerator = $previewGenerator;
+        $this->translator = $translator;
+        $this->shortUrlService = $shortUrlService;
+        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) {
+            $output->writeln([
+                ' <error>' . $this->translator->translate('Error') . '</error>',
+                '<error>' . $e->__toString() . '</error>',
+            ]);
+        }
+    }
+}