feat: Add stable mutual rooms endpoint

src/api/client/mutual_rooms.rs

@@ -1,7 +1,7 @@
 use axum::extract::State;
 use conduwuit::{Err, Result};
 use futures::StreamExt;
-use ruma::api::client::membership::mutual_rooms;
+use ruma::{OwnedRoomId, api::client::membership::mutual_rooms};
 
 use crate::Ruma;
 
@@ -11,14 +11,14 @@ use crate::Ruma;
 ///
 /// An implementation of [MSC2666](https://github.com/matrix-org/matrix-spec-proposals/pull/2666)
 #[tracing::instrument(skip_all, name = "mutual_rooms", level = "info")]
-pub(crate) async fn get_mutual_rooms_route(
+pub(crate) async fn get_mutual_rooms_unstable_route(
 	State(services): State<crate::State>,
 	body: Ruma<mutual_rooms::unstable::Request>,
 ) -> Result<mutual_rooms::unstable::Response> {
 	let sender_user = body.identity.expect_sender_user()?;
 
 	if sender_user == body.user_id {
-		return Err!(Request(Unknown("You cannot request rooms in common with yourself.")));
+		return Err!(Request(InvalidParam("You cannot request rooms in common with yourself.")));
 	}
 
 	let mutual_rooms = services
@@ -30,3 +30,33 @@ pub(crate) async fn get_mutual_rooms_route(
 
 	Ok(mutual_rooms::unstable::Response::new(mutual_rooms))
 }
+
+/// # `GET /_matrix/client/v1/mutual_rooms`
+///
+/// Gets all the rooms the sender shares with the specified user.
+#[tracing::instrument(skip_all, name = "mutual_rooms", level = "info")]
+pub(crate) async fn get_mutual_rooms_route(
+	State(services): State<crate::State>,
+	body: Ruma<mutual_rooms::v1::Request>,
+) -> Result<mutual_rooms::v1::Response> {
+	let sender_user = body.identity.expect_sender_user()?;
+
+	if sender_user == body.user_id {
+		return Err!(Request(InvalidParam("You cannot request rooms in common with yourself.")));
+	}
+
+	let mutual_rooms: Vec<OwnedRoomId> = services
+		.rooms
+		.state_cache
+		.get_shared_rooms(sender_user, &body.user_id)
+		.collect()
+		.await;
+
+	Ok(mutual_rooms::v1::Response::new(
+		mutual_rooms
+			.len()
+			.try_into()
+			.expect("user should be in fewer than 9.1 quadrillion rooms"),
+		mutual_rooms,
+	))
+}