Can now serve track from remote library

api/funkwhale_api/music/permissions.py

@@ -0,0 +1,23 @@
+from django.conf import settings
+
+from rest_framework.permissions import BasePermission
+
+from funkwhale_api.federation import actors
+
+
+class Listen(BasePermission):
+
+    def has_permission(self, request, view):
+        if not settings.PROTECT_AUDIO_FILES:
+            return True
+
+        user = getattr(request, 'user', None)
+        if user and user.is_authenticated:
+            return True
+
+        actor = getattr(request, 'actor', None)
+        if actor is None:
+            return False
+
+        library = actors.SYSTEM_ACTORS['library'].get_actor_instance()
+        return library.followers.filter(url=actor.url).exists()