Improve the compatibility with Lemmy

diff --git a/src/Protocol/ActivityPub/Transmitter.php b/src/Protocol/ActivityPub/Transmitter.php
index 2cab827bb1afd937468687e1e542c0bf9988f897..553993edca300717b225bcf6a232e2c9ba7f5063 100644 (file)
--- a/src/Protocol/ActivityPub/Transmitter.php
+++ b/src/Protocol/ActivityPub/Transmitter.php
@@ -1467,10 +1467,28 @@ class Transmitter
                        return [];
                }
 
+               // We are treating posts differently when they are directed to a community.
+               // This is done to better support Lemmy. Most of the changes should work with other systems as well.
+               // But to not risk compatibility issues we currently perform the changes only for communities.
+               if ($item['gravity'] == GRAVITY_PARENT) {
+                       $isCommunityPost = !empty(Tag::getByURIId($item['uri-id'], [Tag::EXCLUSIVE_MENTION]));
+                       $links = Post\Media::getByURIId($item['uri-id'], [Post\Media::HTML]);
+                       if ($isCommunityPost && (count($links) == 1)) {
+                               $link = $links[0]['url'];
+                       }
+               } else {
+                       $isCommunityPost = false;
+               }
+
                if ($item['event-type'] == 'event') {
                        $type = 'Event';
                } elseif (!empty($item['title'])) {
-                       $type = 'Article';
+                       if (!$isCommunityPost || empty($link)) {
+                               $type = 'Article';
+                       } else {
+                               // "Page" is used by Lemmy for posts that contain an external link
+                               $type = 'Page';
+                       }
                } else {
                        $type = 'Note';
                }
@@ -1502,7 +1520,7 @@ class Transmitter
                        $data['updated'] = DateTimeFormat::utc($item['edited'] . '+00:00', DateTimeFormat::ATOM);
                }
 
-               $data['url'] = $item['plink'];
+               $data['url'] = $link ?? $item['plink'];
                $data['attributedTo'] = $item['author-link'];
                $data['sensitive'] = self::isSensitive($item['uri-id']);
                $data['context'] = self::fetchContextURLForItem($item);
@@ -1539,6 +1557,19 @@ class Transmitter
                if ($type == 'Event') {
                        $data = array_merge($data, self::createEvent($item));
                } else {
+                       if ($isCommunityPost) {
+                               // For community posts we remove the visible "!user@domain.tld".
+                               // This improves the look at systems like Lemmy.
+                               // Also in the future we should control the community delivery via other methods.
+                               $body = preg_replace("/!\[url\=[^\[\]]*\][^\[\]]*\[\/url\]/ism", '', $body);
+                       }
+
+                       if ($type == 'Page') {
+                               // When we transmit "Page" posts we have to remove the attachment.
+                               // The attachment contains the link that we already transmit in the "url" field.
+                               $body = preg_replace("/\s*\[attachment .*?\].*?\[\/attachment\]\s*/ism", '', $body);
+                       }
+
                        $body = BBCode::setMentionsToNicknames($body);
 
                        $data['content'] = BBCode::convertForUriId($item['uri-id'], $body, BBCode::ACTIVITYPUB);