Use Dom\HTMLDocument to generate link previews

1 files changed, 17 insertions, 25 deletions

diff --git a/Digitigrade/LinkPreview.php b/Digitigrade/LinkPreview.php
index 4716cc8..706c3c7 100644
--- a/Digitigrade/LinkPreview.php
+++ b/Digitigrade/LinkPreview.php
@@ -29,38 +29,30 @@ class LinkPreview implements \JsonSerializable {
             return false;
         }
 
-        $d = new \DOMDocument();
+        // TODO: Respect Content-Type header from response, maybe set an Accept header in the request?
+        // I was able to find a URL serving SHIFT-JIS, but they do not specify a charset in the Content-Type header.
+        //    https://www2d.biglobe.ne.jp/~msyk/charcode/cp932/Windows-31J-charset.html
         $c = @file_get_contents($this->url);
         if (!$c)
             return false;
-        @$d->loadHTML($c);
+        $d = \Dom\HTMLDocument::createFromString($c, LIBXML_NOERROR);
 
         $url = $this->url;
         $siteName = hostname_from_uri($this->url);
         $style = 'text';
-        $title = $d->getElementsByTagName('title')->item(0)?->textContent;
-        $metas = $d->getElementsByTagName('meta');
-        foreach ($metas as $tag) {
-            if ($tag->attributes->getNamedItem('name')?->textContent == 'description') {
-                // <meta name="description" content="...">
-                $description = $tag->attributes->getNamedItem('content')?->textContent;
-            } elseif ($prop = $tag->attributes->getNamedItem('property')) {
-                // <meta property="og:..." content="...">
-                $content = $tag->attributes->getNamedItem('content')?->textContent;
-                match ($prop->textContent) {
-                    'og:title' => $title = $content,
-                    'og:description' => $description = $content,
-                    'og:url' => $url = $content,
-                    'og:site_name' => $siteName = $content,
-                    'og:image' => $imageUrl = $content,
-                    default => null
-                };
 
-            } elseif ($tag->attributes->getNamedItem('name')?->textContent == 'twitter:card'
-                && $tag->attributes->getNamedItem("content")?->textContent == 'summary_large_image') {
-                // <meta name="twitter:card" content="summary_large_image">
-                $style = 'largeImage';
-            }
+        // opengraph
+        $title       = $d->querySelector("meta[property='og:title']")?->getAttribute('content');
+        $description = $d->querySelector("meta[property='og:description']")?->getAttribute('content');
+        $url         = $d->querySelector("meta[property='og:url']")?->getAttribute('content');
+        $siteName    = $d->querySelector("meta[property='og:site_name']")?->getAttribute('content');
+        $imageUrl    = $d->querySelector("meta[property='og:image']")?->getAttribute('content');
+        // fallbacks
+        $title = $title ?? $d->querySelector('title')?->textContent;
+        $description = $description ?? $d->querySelector('meta[name=description]')?->getAttribute('content');
+
+        if ($d->querySelector("meta[name='twitter:card'][content=summary_large_image]") != null) {
+            $style = 'largeImage';
         }
         // turn text into smallImage if an image is present
         $style = ($style == 'text' && isset($imageUrl)) ? 'smallImage' : $style;
@@ -88,4 +80,4 @@ class LinkPreview implements \JsonSerializable {
             'imageUrl' => $this->imageUrl
         ];
     }
-}
\ No newline at end of file
+}