Validate language & preview picture fields

Instead of saving the value of each field right into the content without any validation, it seems better to validate them.
This might sounds obvious now we say that.

src/Wallabag/CoreBundle/Helper/ContentProxy.php

@@ -7,6 +7,9 @@ use Psr\Log\LoggerInterface;
 use Wallabag\CoreBundle\Entity\Entry;
 use Wallabag\CoreBundle\Tools\Utils;
 use Symfony\Component\HttpFoundation\File\MimeType\MimeTypeExtensionGuesser;
+use Symfony\Component\Validator\Constraints\Language as LanguageConstraint;
+use Symfony\Component\Validator\Constraints\Url as UrlConstraint;
+use Symfony\Component\Validator\Validator\ValidatorInterface;
 
 /**
  * This kind of proxy class take care of getting the content from an url
@@ -21,10 +24,11 @@ class ContentProxy
     protected $fetchingErrorMessage;
     protected $eventDispatcher;
 
-    public function __construct(Graby $graby, RuleBasedTagger $tagger, LoggerInterface $logger, $fetchingErrorMessage)
+    public function __construct(Graby $graby, RuleBasedTagger $tagger, ValidatorInterface $validator, LoggerInterface $logger, $fetchingErrorMessage)
     {
         $this->graby = $graby;
         $this->tagger = $tagger;
+        $this->validator = $validator;
         $this->logger = $logger;
         $this->mimeGuesser = new MimeTypeExtensionGuesser();
         $this->fetchingErrorMessage = $fetchingErrorMessage;
@@ -113,7 +117,24 @@ class ContentProxy
             $entry->setHeaders($content['all_headers']);
         }
 
-        $entry->setLanguage(isset($content['language']) ? $content['language'] : '');
+        $this->validateAndSetLanguage(
+            $entry,
+            isset($content['language']) ? $content['language'] : ''
+        );
+
+        $this->validateAndSetPreviewPicture(
+            $entry,
+            isset($content['open_graph']['og_image']) ? $content['open_graph']['og_image'] : ''
+        );
+
+        // if content is an image define as a preview too
+        if (!empty($content['content_type']) && in_array($this->mimeGuesser->guess($content['content_type']), ['jpeg', 'jpg', 'gif', 'png'], true)) {
+            $this->validateAndSetPreviewPicture(
+                $entry,
+                $content['url']
+            );
+        }
+
         $entry->setMimetype(isset($content['content_type']) ? $content['content_type'] : '');
         $entry->setReadingTime(Utils::getReadingTime($html));
 
@@ -122,15 +143,6 @@ class ContentProxy
             $entry->setDomainName($domainName);
         }
 
-        if (!empty($content['open_graph']['og_image'])) {
-            $entry->setPreviewPicture($content['open_graph']['og_image']);
-        }
-
-        // if content is an image define as a preview too
-        if (!empty($content['content_type']) && in_array($this->mimeGuesser->guess($content['content_type']), ['jpeg', 'jpg', 'gif', 'png'], true)) {
-            $entry->setPreviewPicture($content['url']);
-        }
-
         try {
             $this->tagger->tag($entry);
         } catch (\Exception $e) {
@@ -152,4 +164,48 @@ class ContentProxy
     {
         return !empty($content['title']) && !empty($content['html']) && !empty($content['url']);
     }
+
+    /**
+     * Use a Symfony validator to ensure the language is well formatted.
+     *
+     * @param Entry  $entry
+     * @param string $value Language to validate
+     */
+    private function validateAndSetLanguage($entry, $value)
+    {
+        $errors = $this->validator->validate(
+            $value,
+            (new LanguageConstraint())
+        );
+
+        if (0 === count($errors)) {
+            $entry->setLanguage($value);
+
+            return;
+        }
+
+        $this->logger->warning('Language validation failed. '.(string) $errors);
+    }
+
+    /**
+     * Use a Symfony validator to ensure the preview picture is a real url.
+     *
+     * @param Entry  $entry
+     * @param string $value URL to validate
+     */
+    private function validateAndSetPreviewPicture($entry, $value)
+    {
+        $errors = $this->validator->validate(
+            $value,
+            (new UrlConstraint())
+        );
+
+        if (0 === count($errors)) {
+            $entry->setPreviewPicture($value);
+
+            return;
+        }
+
+        $this->logger->warning('PreviewPicture validation failed. '.(string) $errors);
+    }
 }

src/Wallabag/CoreBundle/Resources/config/services.yml

@@ -90,6 +90,7 @@ services:
         arguments:
             - "@wallabag_core.graby"
             - "@wallabag_core.rule_based_tagger"
+            - "@validator"
             - "@logger"
             - '%wallabag_core.fetching_error_message%'