refactor: Represent route auth information in the type system

src/api/server/backfill.rs

@@ -28,7 +28,7 @@ pub(crate) async fn get_backfill_route(
 ) -> Result<get_backfill::v1::Response> {
 	AccessCheck {
 		services: &services,
-		origin: body.origin(),
+		origin: &body.identity,
 		room_id: &body.room_id,
 		event_id: None,
 	}
@@ -41,7 +41,7 @@ pub(crate) async fn get_backfill_route(
 		.await
 	{
 		info!(
-			origin = body.origin().as_str(),
+			origin = body.identity.as_str(),
 			"Refusing to serve backfill for room we aren't participating in"
 		);
 		return Err!(Request(NotFound("This server is not participating in that room.")));
@@ -76,7 +76,7 @@ pub(crate) async fn get_backfill_route(
 			Ok(services
 				.rooms
 				.state_accessor
-				.server_can_see_event(body.origin(), &pdu.room_id_or_hash(), &pdu.event_id)
+				.server_can_see_event(&body.identity, &pdu.room_id_or_hash(), &pdu.event_id)
 				.await
 				.then_some(pdu))
 		})