From 665b7f58476c6a0a84a1eea38d0a016e0d843213 Mon Sep 17 00:00:00 2001
From: Thomas Sileo <t@a4.io>
Date: Tue, 5 Jul 2022 21:09:49 +0200
Subject: [PATCH] Support actors update

---
 app/activitypub.py | 19 ++++++++++++++++---
 app/boxes.py       | 30 +++++++++++++++++++++++++++++-
 2 files changed, 45 insertions(+), 4 deletions(-)

diff --git a/app/activitypub.py b/app/activitypub.py
index 8bebc26..e9822a2 100644
--- a/app/activitypub.py
+++ b/app/activitypub.py
@@ -103,7 +103,7 @@ class NotAnObjectError(Exception):
         self.resp = resp
 
 
-async def fetch(url: str, params: dict[str, Any] | None = None) -> dict[str, Any]:
+async def fetch(url: str, params: dict[str, Any] | None = None) -> RawObject:
     async with httpx.AsyncClient() as client:
         resp = await client.get(
             url,
@@ -223,6 +223,19 @@ def get_actor_id(activity: RawObject) -> str:
         return get_id(activity["actor"])
 
 
+async def get_object(activity: RawObject) -> RawObject:
+    if "object" not in activity:
+        raise ValueError(f"No object in {activity}")
+
+    raw_activity_object = activity["object"]
+    if isinstance(raw_activity_object, dict):
+        return raw_activity_object
+    elif isinstance(raw_activity_object, str):
+        return await fetch(raw_activity_object)
+    else:
+        raise ValueError(f"Unexpected object {raw_activity_object}")
+
+
 def wrap_object(activity: RawObject) -> RawObject:
     return {
         "@context": AS_EXTENDED_CTX,
@@ -244,8 +257,8 @@ def wrap_object_if_needed(raw_object: RawObject) -> RawObject:
 
 
 def unwrap_activity(activity: RawObject) -> RawObject:
-    # FIXME(ts): other types to unwrap?
-    if activity["type"] == "Create":
+    # FIXME(ts): deprecate this
+    if activity["type"] in ["Create", "Update"]:
         unwrapped_object = activity["object"]
 
         # Sanity check, ensure the wrapped object actor matches the activity
diff --git a/app/boxes.py b/app/boxes.py
index a0b0aca..daad780 100644
--- a/app/boxes.py
+++ b/app/boxes.py
@@ -590,6 +590,34 @@ async def _handle_undo_activity(
     # commit will be perfomed in save_to_inbox
 
 
+async def _handle_update_activity(
+    db_session: AsyncSession,
+    from_actor: models.Actor,
+    update_activity: models.InboxObject,
+) -> None:
+    logger.info("Processing Update activity")
+    wrapped_object = await ap.get_object(update_activity.ap_object)
+    if wrapped_object["type"] in ap.ACTOR_TYPES:
+        logger.info("Updating actor")
+
+        updated_actor = RemoteActor(wrapped_object)
+        if (
+            from_actor.ap_id != updated_actor.ap_id
+            or from_actor.ap_type != updated_actor.ap_type
+            or from_actor.handle != updated_actor.handle
+        ):
+            raise ValueError(
+                f"Invalid Update activity {from_actor.ap_actor}/"
+                f"{updated_actor.ap_actor}"
+            )
+
+        # Update the actor
+        from_actor.ap_actor = updated_actor.ap_actor
+    else:
+        # TODO(ts): support updating objects
+        logger.info(f'Cannot update {wrapped_object["type"]}')
+
+
 async def _handle_create_activity(
     db_session: AsyncSession,
     from_actor: models.Actor,
@@ -742,7 +770,7 @@ async def save_to_inbox(
     if activity_ro.ap_type == "Create":
         await _handle_create_activity(db_session, actor, inbox_object)
     elif activity_ro.ap_type == "Update":
-        pass
+        await _handle_update_activity(db_session, actor, inbox_object)
     elif activity_ro.ap_type == "Delete":
         if relates_to_inbox_object:
             await _handle_delete_activity(db_session, actor, relates_to_inbox_object)