component AP gateway: convert Delete AP activities to corresponding Pubsub retract:

when a `Delete` actity is received, the item is removed from cache, and the corresponding
item `retract` is sent to local XMPP subscribers.

rel 367

sat/plugins/plugin_comp_ap_gateway/__init__.py

@@ -1792,3 +1792,43 @@ class APGateway:
                 [(subscription.subscriber, None, [item_elt])]
             )
 
+    async def newAPDeleteItem(
+        self,
+        client: SatXMPPEntity,
+        destinee: Optional[jid.JID],
+        node: str,
+        item: dict,
+    ) -> None:
+        """Analyse, cache and send notification for received AP item
+
+        @param destinee: jid of the destinee,
+        @param node: XMPP pubsub node
+        @param item: AP object payload
+        """
+        item_id = item.get("id")
+        if not item_id:
+            raise exceptions.DataError('"id" attribute is missing in item')
+        if self.isLocalURL(item_id):
+            raise ValueError("Local IDs should not be used")
+
+        cached_node = await self.host.memory.storage.getPubsubNode(
+            client, client.jid, node, with_subscriptions=True
+        )
+        if cached_node is None:
+            log.warning(
+                f"Received an item retract for node {node!r} at {client.jid} which is "
+                "not cached"
+            )
+        else:
+            await self.host.memory.storage.deletePubsubItems(cached_node, [item_id])
+            # notifyRetract is expecting domish.Element instances
+            item_elt = domish.Element((None, "item"))
+            item_elt["id"] = item_id
+            for subscription in cached_node.subscriptions:
+                if subscription.state != SubscriptionState.SUBSCRIBED:
+                    continue
+                self.pubsub_service.notifyRetract(
+                    client.jid,
+                    node,
+                    [(subscription.subscriber, None, [item_elt])]
+                )

sat/plugins/plugin_comp_ap_gateway/constants.py

@@ -69,7 +69,8 @@ ACTIVITY_OBJECT_MANDATORY = (
     "Create", "Update", "Delete", "Follow", "Add", "Remove", "Like", "Block", "Undo"
 )
 ACTIVITY_TARGET_MANDATORY = ("Add", "Remove")
-# activities which can be used with Shared Inbox (i.e. with not account specified)
-ACTIVIY_NO_ACCOUNT_ALLOWED = ("create",)
+# activities which can be used with Shared Inbox (i.e. with no account specified)
+# must be lowercase
+ACTIVIY_NO_ACCOUNT_ALLOWED = ("create", "delete")
 # maximum number of parents to retrieve when comments_max_depth option is set
 COMMENTS_MAX_PARENTS = 100

sat/plugins/plugin_comp_ap_gateway/http_server.py

@@ -232,6 +232,28 @@ class HTTPAPGServer(web_resource.Resource):
             else:
                 log.warning(f"Unmanaged accept type: {type_!r}")
 
+    async def handleDeleteActivity(
+        self,
+        request: "HTTPRequest",
+        data: dict,
+        account_jid: Optional[jid.JID],
+        node: Optional[str],
+        ap_account: Optional[str],
+        ap_url: str,
+        signing_actor: str
+    ):
+        digest = request.getHeader("digest")
+        if digest in self._seen_digest:
+            log.debug(f"Ignoring duplicated request (digest: {digest!r})")
+            return
+        self._seen_digest.append(digest)
+        if node is None:
+            node = self.apg._m.namespace
+        client = await self.apg.getVirtualClient(signing_actor)
+        objects = await self.apg.apGetList(data, "object")
+        for obj in objects:
+            await self.apg.newAPDeleteItem(client, account_jid, node, obj)
+
     async def handleCreateActivity(
         self,
         request: "HTTPRequest",