enhancement(realtime): send metadata update on revision save

When the frontend is notified about metadata updates, it refreshes the
data and therefore refreshes information like the timestamp of the last
revision save in the sidebar.
This commit adds such a notification from the backend to all clients on
each revision save, so that the "last saved at" value in the frontend is
correct.

Signed-off-by: Erik Michelson <github@erik.michelson.eu>

backend/src/realtime/realtime-note/realtime-note.service.ts

@@ -1,5 +1,5 @@
 /*
- * SPDX-FileCopyrightText: 2022 The HedgeDoc developers (see AUTHORS file)
+ * SPDX-FileCopyrightText: 2024 The HedgeDoc developers (see AUTHORS file)
  *
  * SPDX-License-Identifier: AGPL-3.0-only
  */
@@ -49,6 +49,9 @@ export class RealtimeNoteService implements BeforeApplicationShutdown {
         realtimeNote.getRealtimeDoc().getCurrentContent(),
         realtimeNote.getRealtimeDoc().encodeStateAsUpdate(),
       )
+      .then(() => {
+        realtimeNote.announceMetadataUpdate();
+      })
       .catch((reason) => this.logger.error(reason));
   }
 
@@ -117,7 +120,7 @@ export class RealtimeNoteService implements BeforeApplicationShutdown {
     const realtimeNote = this.realtimeNoteStore.find(note.id);
     if (!realtimeNote) return;
 
-    realtimeNote.announcePermissionChange();
+    realtimeNote.announceMetadataUpdate();
     const allConnections = realtimeNote.getConnections();
     await this.updateOrCloseConnection(allConnections, note);
   }

backend/src/realtime/realtime-note/realtime-note.spec.ts

@@ -1,5 +1,5 @@
 /*
- * SPDX-FileCopyrightText: 2023 The HedgeDoc developers (see AUTHORS file)
+ * SPDX-FileCopyrightText: 2024 The HedgeDoc developers (see AUTHORS file)
  *
  * SPDX-License-Identifier: AGPL-3.0-only
  */
@@ -82,11 +82,11 @@ describe('realtime note', () => {
     const sendMessage2Spy = jest.spyOn(client2.getTransporter(), 'sendMessage');
 
     const metadataMessage = { type: MessageType.METADATA_UPDATED };
-    sut.announcePermissionChange();
+    sut.announceMetadataUpdate();
     expect(sendMessage1Spy).toHaveBeenCalledWith(metadataMessage);
     expect(sendMessage2Spy).toHaveBeenCalledWith(metadataMessage);
     sut.removeClient(client2);
-    sut.announcePermissionChange();
+    sut.announceMetadataUpdate();
     expect(sendMessage1Spy).toHaveBeenCalledTimes(2);
     expect(sendMessage2Spy).toHaveBeenCalledTimes(1);
   });

backend/src/realtime/realtime-note/realtime-note.ts

@@ -1,5 +1,5 @@
 /*
- * SPDX-FileCopyrightText: 2022 The HedgeDoc developers (see AUTHORS file)
+ * SPDX-FileCopyrightText: 2024 The HedgeDoc developers (see AUTHORS file)
  *
  * SPDX-License-Identifier: AGPL-3.0-only
  */
@@ -149,9 +149,10 @@ export class RealtimeNote extends EventEmitter2<RealtimeNoteEventMap> {
   }
 
   /**
-   * Announce to all clients that the permissions of the note have been changed.
+   * Announce to all clients that the metadata of the note have been changed.
+   * This could for example be a permission change or a revision being saved.
    */
-  public announcePermissionChange(): void {
+  public announceMetadataUpdate(): void {
     this.sendToAllClients({ type: MessageType.METADATA_UPDATED });
   }