Convert encoding of resolved titles based on page encoding

CHANGELOG.md

@@ -21,6 +21,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com), and this
 
 ### Fixed
 * [#2111](https://github.com/shlinkio/shlink/issues/2111) Fix typo in OAS docs examples where redirect rules with `query-param` condition type were defined as `query`.
+* [#2129](https://github.com/shlinkio/shlink/issues/2129) Fix error when resolving title for sites not using UTF-8 charset (detected with Japanese charsets).
 
 
 ## [4.1.0] - 2024-04-14

composer.json

@@ -16,6 +16,7 @@
         "ext-curl": "*",
         "ext-gd": "*",
         "ext-json": "*",
+        "ext-mbstring": "*",
         "ext-pdo": "*",
         "akrabat/ip-address-middleware": "^2.1",
         "cakephp/chronos": "^3.0.2",

config/constants.php

@@ -12,7 +12,6 @@
 const DEFAULT_REDIRECT_STATUS_CODE = RedirectStatus::STATUS_302;
 const DEFAULT_REDIRECT_CACHE_LIFETIME = 30;
 const LOCAL_LOCK_FACTORY = 'Shlinkio\Shlink\LocalLockFactory';
-const TITLE_TAG_VALUE = '/<title[^>]*>(.*?)<\/title>/i'; // Matches the value inside a html title tag
 const LOOSE_URI_MATCHER = '/(.+)\:(.+)/i'; // Matches anything starting with a schema.
 const DEFAULT_QR_CODE_SIZE = 300;
 const DEFAULT_QR_CODE_MARGIN = 0;

module/Core/src/ShortUrl/Helper/ShortUrlTitleResolutionHelper.php

@@ -12,20 +12,24 @@
 use Throwable;
 
 use function html_entity_decode;
+use function mb_convert_encoding;
 use function preg_match;
 use function str_contains;
 use function str_starts_with;
 use function strtolower;
 use function trim;
 
-use const Shlinkio\Shlink\TITLE_TAG_VALUE;
-
 readonly class ShortUrlTitleResolutionHelper implements ShortUrlTitleResolutionHelperInterface
 {
     public const MAX_REDIRECTS = 15;
     public const CHROME_USER_AGENT = 'Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) '
         . 'Chrome/121.0.0.0 Safari/537.36';
 
+    // Matches the value inside a html title tag
+    private const TITLE_TAG_VALUE = '/<title[^>]*>(.*?)<\/title>/i';
+    // Matches the charset inside a Content-Type header
+    private const CHARSET_VALUE = '/charset=([^;]+)/i';
+
     public function __construct(
         private ClientInterface $httpClient,
         private UrlShortenerOptions $options,
@@ -53,7 +57,7 @@ public function processTitle(TitleResolutionModelInterface $data): TitleResoluti
             return $data;
         }
 
-        $title = $this->tryToResolveTitle($response);
+        $title = $this->tryToResolveTitle($response, $contentType);
         return $title !== null ? $data->withResolvedTitle($title) : $data;
     }
 
@@ -76,20 +80,27 @@ private function fetchUrl(string $url): ?ResponseInterface
         }
     }
 
-    private function tryToResolveTitle(ResponseInterface $response): ?string
+    private function tryToResolveTitle(ResponseInterface $response, string $contentType): ?string
     {
         $collectedBody = '';
         $body = $response->getBody();
         // With streaming enabled, we can walk the body until the </title> tag is found, and then stop
         while (! str_contains($collectedBody, '</title>') && ! $body->eof()) {
             $collectedBody .= $body->read(1024);
         }
-        preg_match(TITLE_TAG_VALUE, $collectedBody, $matches);
-        return isset($matches[1]) ? $this->normalizeTitle($matches[1]) : null;
-    }
 
-    private function normalizeTitle(string $title): string
-    {
+        // Try to match the title from the <title /> tag
+        preg_match(self::TITLE_TAG_VALUE, $collectedBody, $titleMatches);
+        if (! isset($titleMatches[1])) {
+            return null;
+        }
+
+        // Get the page's charset from Content-Type header
+        preg_match(self::CHARSET_VALUE, $contentType, $charsetMatches);
+
+        $title = isset($charsetMatches[1])
+            ? mb_convert_encoding($titleMatches[1], 'utf8', $charsetMatches[1])
+            : $titleMatches[1];
         return html_entity_decode(trim($title));
     }
 }

module/Core/test/ShortUrl/Helper/ShortUrlTitleResolutionHelperTest.php

@@ -12,6 +12,7 @@
 use Laminas\Diactoros\Response\JsonResponse;
 use Laminas\Diactoros\Stream;
 use PHPUnit\Framework\Attributes\Test;
+use PHPUnit\Framework\Attributes\TestWith;
 use PHPUnit\Framework\MockObject\Builder\InvocationMocker;
 use PHPUnit\Framework\MockObject\MockObject;
 use PHPUnit\Framework\TestCase;
@@ -89,10 +90,12 @@ public function dataIsReturnedAsIsWhenTitleCannotBeResolvedFromResponse(): void
     }
 
     #[Test]
-    public function titleIsUpdatedWhenItCanBeResolvedFromResponse(): void
+    #[TestWith(['TEXT/html; charset=utf-8'], name: 'charset')]
+    #[TestWith(['TEXT/html'], name: 'no charset')]
+    public function titleIsUpdatedWhenItCanBeResolvedFromResponse(string $contentType): void
     {
         $data = ShortUrlCreation::fromRawData(['longUrl' => self::LONG_URL]);
-        $this->expectRequestToBeCalled()->willReturn($this->respWithTitle());
+        $this->expectRequestToBeCalled()->willReturn($this->respWithTitle($contentType));
 
         $result = $this->helper(autoResolveTitles: true)->processTitle($data);
 
@@ -122,10 +125,10 @@ private function respWithoutTitle(): Response
         return new Response($body, 200, ['Content-Type' => 'text/html']);
     }
 
-    private function respWithTitle(): Response
+    private function respWithTitle(string $contentType): Response
     {
         $body = $this->createStreamWithContent('<title data-foo="bar">  Resolved &quot;title&quot; </title>');
-        return new Response($body, 200, ['Content-Type' => 'TEXT/html; charset=utf-8']);
+        return new Response($body, 200, ['Content-Type' => $contentType]);
     }
 
     private function createStreamWithContent(string $content): Stream