Finer Peertube fix.

activitypub.c

@@ -392,8 +392,12 @@ xs_list *get_attachments(const xs_dict *msg)
                     }
                     else
                     if (xs_is_string(mtype) && strcmp(mtype, "video/mp4") == 0) {
-                        href = xs_dict_get(v, "href");
-                        type = mtype;
+                        const char *h = xs_dict_get(v, "href");
+
+                        if (xs_is_string(h)) {
+                            href = xs_dict_get(v, "href");
+                            type = mtype;
+                        }
                     }
                 }
             }