[danbooru] extract uploader metadata (if metadata is set)

docs/configuration.rst

@@ -999,7 +999,8 @@ Type
 Default
     ``false``
 Description
-    Extract additional metadata (notes, artist commentary, parent, children)
+    Extract additional metadata
+    (notes, artist commentary, parent, children, uploader)
 
     Note: This requires 1 additional HTTP request for each post.
 

gallery_dl/extractor/danbooru.py

@@ -101,8 +101,8 @@ class DanbooruExtractor(BaseExtractor):
 
             if self.extended_metadata:
                 template = (
-                    "{}/posts/{}.json"
-                    "?only=artist_commentary,children,notes,parent"
+                    "{}/posts/{}.json?only=artist_commentary,children,notes,"
+                    "parent,uploader"
                 )
                 resp = self.request(template.format(self.root, post["id"]))
                 post.update(resp.json())