Add support for multiple Link as urls of Images in ActivityPub\Receiver

- Address https://github.com/friendica/friendica/issues/8676#issuecomment-650554955

diff --git a/src/Protocol/ActivityPub/Receiver.php b/src/Protocol/ActivityPub/Receiver.php
index 7a0a9c1f78e838a85ae8ca056db03c26fbe50be9..aa59b9eb9e722e0455adbe9017f026f2ecf1e8f9 100644 (file)
--- a/src/Protocol/ActivityPub/Receiver.php
+++ b/src/Protocol/ActivityPub/Receiver.php
@@ -877,7 +877,7 @@ class Receiver
         *
         * @param array $attachments Attachments in JSON-LD format
         *
-        * @return array with attachmants in a simplified format
+        * @return array Attachments in a simplified format
         */
        private static function processAttachments(array $attachments)
        {
@@ -925,6 +925,62 @@ class Receiver
                                                'url' => JsonLD::fetchElement($attachment, 'as:href', '@id')
                                        ];
                                        break;
+                               case 'as:Image':
+                                       $mediaType = JsonLD::fetchElement($attachment, 'as:mediaType', '@value');
+                                       $imageFullUrl = JsonLD::fetchElement($attachment, 'as:url', '@id');
+                                       $imagePreviewUrl = null;
+                                       // Multiple URLs?
+                                       if (!$imageFullUrl && ($urls = JsonLD::fetchElementArray($attachment, 'as:url'))) {
+                                               $imageVariants = [];
+                                               $previewVariants = [];
+                                               foreach ($urls as $url) {
+                                                       // Scalar URL, no discrimination possible
+                                                       if (is_string($url)) {
+                                                               $imageFullUrl = $url;
+                                                               continue;
+                                                       }
+
+                                                       // Not sure what to do with a different Link media type than the base Image, we skip
+                                                       if ($mediaType != JsonLD::fetchElement($url, 'as:mediaType', '@value')) {
+                                                               continue;
+                                                       }
+
+                                                       $href = JsonLD::fetchElement($url, 'as:href', '@id');
+
+                                                       // Default URL choice if no discriminating width is provided
+                                                       $imageFullUrl = $href ?? $imageFullUrl;
+
+                                                       $width = intval(JsonLD::fetchElement($url, 'as:width', '@value') ?? 1);
+
+                                                       if ($href && $width) {
+                                                               $imageVariants[$width] = $href;
+                                                               // 632 is the ideal width for full screen frio posts, we compute the absolute distance to it
+                                                               $previewVariants[abs(632 - $width)] = $href;
+                                                       }
+                                               }
+
+                                               if ($imageVariants) {
+                                                       // Taking the maximum size image
+                                                       ksort($imageVariants);
+                                                       $imageFullUrl = array_pop($imageVariants);
+
+                                                       // Taking the minimum number distance to the target distance
+                                                       ksort($previewVariants);
+                                                       $imagePreviewUrl = array_shift($previewVariants);
+                                               }
+
+                                               unset($imageVariants);
+                                               unset($previewVariants);
+                                       }
+
+                                       $attachlist[] = [
+                                               'type' => str_replace('as:', '', JsonLD::fetchElement($attachment, '@type')),
+                                               'mediaType' => $mediaType,
+                                               'name'  => JsonLD::fetchElement($attachment, 'as:name', '@value'),
+                                               'url'   => $imageFullUrl,
+                                               'image' => $imagePreviewUrl !== $imageFullUrl ? $imagePreviewUrl : null,
+                                       ];
+                                       break;
                                default:
                                        $attachlist[] = [
                                                'type' => str_replace('as:', '', JsonLD::fetchElement($attachment, '@type')),