Slightly improve performance of sidebar update APIs (#31061)

server/channels/api4/channel_category.go

@@ -236,7 +236,7 @@ func validateSidebarCategory(c *Context, teamId, userId string, category *model.
 		return model.NewAppError("validateSidebarCategory", "api.invalid_channel", nil, "", http.StatusBadRequest).Wrap(appErr)
 	}
 
-	category.Channels = validateSidebarCategoryChannels(c, userId, category.Channels, channels)
+	category.Channels = validateSidebarCategoryChannels(c, userId, category.Channels, channelListToMap(channels))
 
 	return nil
 }
@@ -250,28 +250,30 @@ func validateSidebarCategories(c *Context, teamId, userId string, categories []*
 		return model.NewAppError("validateSidebarCategory", "api.invalid_channel", nil, "", http.StatusBadRequest).Wrap(err)
 	}
 
+	channelMap := channelListToMap(channels)
+
 	for _, category := range categories {
-		category.Channels = validateSidebarCategoryChannels(c, userId, category.Channels, channels)
+		category.Channels = validateSidebarCategoryChannels(c, userId, category.Channels, channelMap)
 	}
 
 	return nil
 }
 
+func channelListToMap(channelList model.ChannelList) map[string]*model.Channel {
+	channelMap := make(map[string]*model.Channel, len(channelList))
+	for _, channel := range channelList {
+		channelMap[channel.Id] = channel
+	}
+	return channelMap
+}
+
 // validateSidebarCategoryChannels returns a normalized slice of channel IDs by removing duplicates from it and
-// ensuring that it only contains IDs of channels in the given ChannelList.
+// ensuring that it only contains IDs of channels in the given map of Channels by IDs.
-func validateSidebarCategoryChannels(c *Context, userId string, channelIds []string, channels model.ChannelList) []string {
+func validateSidebarCategoryChannels(c *Context, userId string, channelIds []string, channelMap map[string]*model.Channel) []string {
 	var filtered []string
 
 	for _, channelId := range channelIds {
-		found := false
+		if _, ok := channelMap[channelId]; ok {
-		for _, channel := range channels {
-			if channel.Id == channelId {
-				found = true
-				break
-			}
-		}
-
-		if found {
 			filtered = append(filtered, channelId)
 		} else {
 			c.Logger.Info("Stopping user from adding channel to their sidebar when they are not a member", mlog.String("user_id", userId), mlog.String("channel_id", channelId))

server/channels/api4/channel_category_test.go

@@ -1007,11 +1007,11 @@ func TestValidateSidebarCategoryChannels(t *testing.T) {
 	}
 
 	t.Run("should filter valid channels", func(t *testing.T) {
-		// Create test channels
+		// Create test channelMap
-		channels := model.ChannelList{
+		channelMap := channelListToMap(model.ChannelList{
 			th.BasicChannel,
 			th.BasicChannel2,
-		}
+		})
 
 		// Test with valid channel IDs
 		channelIds := []string{
@@ -1019,42 +1019,42 @@ func TestValidateSidebarCategoryChannels(t *testing.T) {
 			th.BasicChannel2.Id,
 		}
 
-		filtered := validateSidebarCategoryChannels(c, th.BasicUser.Id, channelIds, channels)
+		filtered := validateSidebarCategoryChannels(c, th.BasicUser.Id, channelIds, channelMap)
 		require.Len(t, filtered, 2)
 		require.ElementsMatch(t, channelIds, filtered)
 	})
 
 	t.Run("should filter out invalid channels", func(t *testing.T) {
-		channels := model.ChannelList{
+		channelMap := channelListToMap(model.ChannelList{
 			th.BasicChannel,
-		}
+		})
 
 		channelIds := []string{
 			th.BasicChannel.Id,
 			"invalid_channel_id",
 		}
 
-		filtered := validateSidebarCategoryChannels(c, th.BasicUser.Id, channelIds, channels)
+		filtered := validateSidebarCategoryChannels(c, th.BasicUser.Id, channelIds, channelMap)
 		require.Len(t, filtered, 1)
 		require.Contains(t, filtered, th.BasicChannel.Id)
 		require.NotContains(t, filtered, "invalid_channel_id")
 	})
 
 	t.Run("should handle empty channel list", func(t *testing.T) {
-		channels := model.ChannelList{}
+		channelMap := channelListToMap(model.ChannelList{})
 		channelIds := []string{th.BasicChannel.Id}
 
-		filtered := validateSidebarCategoryChannels(c, th.BasicUser.Id, channelIds, channels)
+		filtered := validateSidebarCategoryChannels(c, th.BasicUser.Id, channelIds, channelMap)
 		require.Empty(t, filtered)
 	})
 
 	t.Run("should handle empty channelIds", func(t *testing.T) {
-		channels := model.ChannelList{
+		channelMap := channelListToMap(model.ChannelList{
 			th.BasicChannel,
 			th.BasicChannel2,
-		}
+		})
 
-		filtered := validateSidebarCategoryChannels(c, th.BasicUser.Id, []string{}, channels)
+		filtered := validateSidebarCategoryChannels(c, th.BasicUser.Id, []string{}, channelMap)
 		require.Empty(t, filtered)
 	})
 
@@ -1064,9 +1064,9 @@ func TestValidateSidebarCategoryChannels(t *testing.T) {
 	})
 
 	t.Run("should prevent duplicate channel IDs", func(t *testing.T) {
-		channels := model.ChannelList{
+		channelMap := channelListToMap(model.ChannelList{
 			th.BasicChannel,
-		}
+		})
 
 		// Include duplicate channel IDs
 		channelIds := []string{
@@ -1074,7 +1074,7 @@ func TestValidateSidebarCategoryChannels(t *testing.T) {
 			th.BasicChannel.Id,
 		}
 
-		filtered := validateSidebarCategoryChannels(c, th.BasicUser.Id, channelIds, channels)
+		filtered := validateSidebarCategoryChannels(c, th.BasicUser.Id, channelIds, channelMap)
 		require.Len(t, filtered, 1)
 		require.Equal(t, []string{th.BasicChannel.Id}, filtered)
 	})