userlog: send only one SSEEvent per language

Signed-off-by: jkoberg <jkoberg@owncloud.com>

services/userlog/pkg/service/service.go

@@ -190,16 +190,18 @@ func (ul *UserlogService) processEvent(event events.Event) {
 
 	// III) store the eventID for each user
 	for _, id := range users {
-		if !ul.cfg.DisableSSE {
-			if err := ul.sendSSE(ctx, id, event, gwc); err != nil {
-				ul.log.Error().Err(err).Str("userid", id).Str("eventid", event.ID).Msg("cannot create sse event")
-			}
-		}
-		if err := ul.addEventToUser(ctx, id, event); err != nil {
+		if err := ul.addEventToUser(id, event); err != nil {
 			ul.log.Error().Err(err).Str("userID", id).Str("eventid", event.ID).Msg("failed to store event for user")
 			return
 		}
 	}
+
+	// IV) send sses
+	if !ul.cfg.DisableSSE {
+		if err := ul.sendSSE(ctx, users, event, gwc); err != nil {
+			ul.log.Error().Err(err).Interface("userid", users).Str("eventid", event.ID).Msg("cannot create sse event")
+		}
+	}
 }
 
 // GetEvents allows retrieving events from the eventhistory by userid
@@ -230,12 +232,12 @@ func (ul *UserlogService) GetEvents(ctx context.Context, userid string) ([]*ehms
 
 	// remove expired events from list asynchronously
 	go func() {
-		if err := ul.removeExpiredEvents(userid, eventIDs, resp.Events); err != nil {
+		if err := ul.removeExpiredEvents(userid, eventIDs, resp.GetEvents()); err != nil {
 			ul.log.Error().Err(err).Str("userid", userid).Msg("could not remove expired events from user")
 		}
 	}()
 
-	return resp.Events, nil
+	return resp.GetEvents(), nil
 }
 
 // DeleteEvents will delete the specified events
@@ -248,7 +250,7 @@ func (ul *UserlogService) DeleteEvents(userid string, evids []string) error {
 	return ul.alterUserEventList(userid, func(ids []string) []string {
 		var newids []string
 		for _, id := range ids {
-			if _, delete := toDelete[id]; delete {
+			if _, del := toDelete[id]; del {
 				continue
 			}
 
@@ -331,28 +333,52 @@ func (ul *UserlogService) DeleteGlobalEvents(ctx context.Context, evnames []stri
 	})
 }
 
-func (ul *UserlogService) addEventToUser(ctx context.Context, userid string, event events.Event) error {
+func (ul *UserlogService) addEventToUser(userid string, event events.Event) error {
 	return ul.alterUserEventList(userid, func(ids []string) []string {
 		return append(ids, event.ID)
 	})
 }
 
-func (ul *UserlogService) sendSSE(ctx context.Context, userid string, event events.Event, gwc gateway.GatewayAPIClient) error {
-	ev, err := NewConverter(ctx, ul.getUserLocale(userid), gwc, ul.cfg.Service.Name, ul.cfg.TranslationPath, ul.cfg.DefaultLanguage).ConvertEvent(event.ID, event.Event)
-	if err != nil {
-		return err
+func (ul *UserlogService) sendSSE(ctx context.Context, userIDs []string, event events.Event, gwc gateway.GatewayAPIClient) error {
+	m := make(map[string]events.SendSSE)
+
+	for _, userid := range userIDs {
+		loc := ul.getUserLocale(userid)
+		if ev, ok := m[loc]; ok {
+			ev.UserIDs = append(m[loc].UserIDs, userid)
+			m[loc] = ev
+			continue
+		}
+
+		ev, err := NewConverter(ctx, loc, gwc, ul.cfg.Service.Name, ul.cfg.TranslationPath, ul.cfg.DefaultLanguage).ConvertEvent(event.ID, event.Event)
+		if err != nil {
+			if utils.IsErrNotFound(err) || utils.IsErrPermissionDenied(err) {
+				// the resource was not found, we assume it is deleted
+				continue
+			}
+			return err
+		}
+
+		b, err := json.Marshal(ev)
+		if err != nil {
+			return err
+		}
+
+		m[loc] = events.SendSSE{
+			UserIDs: []string{userid},
+			Type:    "userlog-notification",
+			Message: b,
+		}
+
 	}
 
-	b, err := json.Marshal(ev)
-	if err != nil {
-		return err
+	for _, ev := range m {
+		if err := events.Publish(ctx, ul.publisher, ev); err != nil {
+			return err
+		}
 	}
 
-	return events.Publish(context.Background(), ul.publisher, events.SendSSE{
-		UserIDs: []string{userid},
-		Type:    "userlog-notification",
-		Message: b,
-	})
+	return nil
 }
 
 func (ul *UserlogService) removeExpiredEvents(userid string, all []string, received []*ehmsg.Event) error {