Room: Add a method to set your own user's display name within a room

bindings/matrix-sdk-ffi/src/room/mod.rs

@@ -343,6 +343,14 @@ impl Room {
         Ok(avatar_url_string)
     }
 
+    pub async fn set_own_member_display_name(
+        &self,
+        display_name: Option<String>,
+    ) -> Result<(), ClientError> {
+        self.inner.set_own_member_display_name(display_name).await?;
+        Ok(())
+    }
+
     /// Get the membership details for the current user.
     ///
     /// Returns:

crates/matrix-sdk/CHANGELOG.md

@@ -8,6 +8,9 @@ All notable changes to this project will be documented in this file.
 
 ### Features
 
+- Add `Room::set_own_member_display_name` to set the current user's display name
+  within only the one single room (can be used for /myroomnick functionality).
+  [#5981](https://github.com/matrix-org/matrix-rust-sdk/pull/5981)
 - Sending `MessageLike` and `RawMessageLike` events through a `Room` now returns
   the used `EncryptionInfo`, if any.
   ([#5936](https://github.com/matrix-org/matrix-rust-sdk/pull/5936))

crates/matrix-sdk/src/room/mod.rs

@@ -114,7 +114,7 @@ use ruma::{
             avatar::{self, RoomAvatarEventContent},
             encryption::RoomEncryptionEventContent,
             history_visibility::HistoryVisibility,
-            member::{MembershipChange, SyncRoomMemberEvent},
+            member::{MembershipChange, RoomMemberEventContent, SyncRoomMemberEvent},
             message::{
                 AudioInfo, AudioMessageEventContent, FileInfo, FileMessageEventContent,
                 ImageMessageEventContent, MessageType, RoomMessageEventContent,
@@ -1109,6 +1109,37 @@ impl Room {
             .collect())
     }
 
+    /// Sets the display name of the current user within this room.
+    ///
+    /// *Note*: This is different to [`crate::Account::set_display_name`] which
+    /// updates the user's display name across all of their rooms.
+    pub async fn set_own_member_display_name(
+        &self,
+        display_name: Option<String>,
+    ) -> Result<send_state_event::v3::Response> {
+        let user_id = self.own_user_id();
+        let member_event =
+            self.get_state_event_static_for_key::<RoomMemberEventContent, _>(user_id).await?;
+
+        let Some(member_event) = member_event else {
+            return Err(Error::InsufficientData);
+        };
+
+        let RawSyncOrStrippedState::Sync(raw_event) = member_event else {
+            return Err(Error::InsufficientData);
+        };
+
+        let event = raw_event.deserialize()?;
+
+        let SyncStateEvent::Original(ev) = event else {
+            return Err(Error::InsufficientData);
+        };
+
+        let mut content = ev.content;
+        content.displayname = display_name;
+        self.send_state_event_for_key(user_id, content).await
+    }
+
     /// Get all state events of a given type in this room.
     pub async fn get_state_events(
         &self,

crates/matrix-sdk/tests/integration/room/joined.rs

@@ -1456,3 +1456,50 @@ async fn test_report_room() {
 
     room.report_room(reason.to_owned()).await.unwrap();
 }
+
+#[async_test]
+async fn test_set_own_member_display_name() {
+    // Given a room with an existing member event for the current user.
+    let (client, server) = logged_in_client_with_server().await;
+    let mut sync_builder = SyncResponseBuilder::new();
+    let sync_settings = SyncSettings::new().timeout(Duration::from_millis(3000));
+    let room_id = &DEFAULT_TEST_ROOM_ID;
+    let user_id = client.user_id().unwrap();
+
+    let existing_name = "Old Name";
+    let existing_avatar_url = mxc_uri!("mxc://example.org/avA7ar");
+
+    let member_event = EventFactory::new()
+        .member(user_id)
+        .display_name(existing_name.to_owned())
+        .avatar_url(existing_avatar_url)
+        .membership(MembershipState::Join);
+
+    let response = sync_builder
+        .add_joined_room(JoinedRoomBuilder::new(room_id).add_state_event(member_event))
+        .build_json_sync_response();
+
+    mock_sync(&server, response, None).await;
+    client.sync_once(sync_settings).await.unwrap();
+
+    let room = client.get_room(room_id).unwrap();
+
+    // When setting a new display name.
+    let new_name = "New Name";
+
+    // Then the user's display name is updated without changing the avatar URL.
+    Mock::given(method("PUT"))
+        .and(path_regex(format!(r"^/_matrix/client/r0/rooms/.*/state/m.room.member/{user_id}")))
+        .and(header("authorization", "Bearer 1234"))
+        .and(body_partial_json(json!({
+            "displayname": new_name,
+            "avatar_url": existing_avatar_url.to_string(),
+            "membership": "join"
+        })))
+        .respond_with(ResponseTemplate::new(200).set_body_json(&*test_json::EVENT_ID))
+        .expect(1)
+        .mount(&server)
+        .await;
+
+    room.set_own_member_display_name(Some(new_name.to_owned())).await.unwrap();
+}