snapshot of https://github.com/mattermost/mattermost.git (master, 2026-09-16; blobs > 131072B omitted)

server/channels/app/post_membership_messages.go

@@ -0,0 +1,148 @@
+// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
+// See LICENSE.txt for license information.
+
+package app
+
+import (
+	"net/http"
+
+	"github.com/mattermost/mattermost/server/public/model"
+	"github.com/mattermost/mattermost/server/public/shared/request"
+)
+
+func (a *App) channelExcludeMembershipSystemPostsByID(rctx request.CTX, channelID string) (bool, *model.AppError) {
+	channel, appErr := a.GetChannel(rctx, channelID)
+	if appErr != nil {
+		if appErr.StatusCode == http.StatusNotFound {
+			return false, nil
+		}
+		return false, appErr
+	}
+	return model.ShouldChannelExcludeMembershipSystemPosts(channel), nil
+}
+
+func (a *App) populateGetPostsOptionsMembershipFilter(rctx request.CTX, options *model.GetPostsOptions) *model.AppError {
+	if options == nil || options.ChannelId == "" {
+		return nil
+	}
+
+	exclude, appErr := a.channelExcludeMembershipSystemPostsByID(rctx, options.ChannelId)
+	if appErr != nil {
+		return appErr
+	}
+	options.ExcludeMembershipSystemPosts = exclude
+	return nil
+}
+
+func (a *App) populateGetPostsSinceOptionsMembershipFilter(rctx request.CTX, options *model.GetPostsSinceOptions) *model.AppError {
+	if options == nil || options.ChannelId == "" {
+		return nil
+	}
+
+	exclude, appErr := a.channelExcludeMembershipSystemPostsByID(rctx, options.ChannelId)
+	if appErr != nil {
+		return appErr
+	}
+	options.ExcludeMembershipSystemPosts = exclude
+	return nil
+}
+
+// shouldSuppressMembershipSystemPost reports whether push and email notifications
+// for a membership system post should be dropped. It uses the caller-supplied
+// channel object, which may be milliseconds stale if an admin toggled
+// DisableJoinLeaveMessages concurrently. This is acceptable: the feature is
+// best-effort for notification delivery; the DB read-path always reflects the
+// current setting.
+//
+// Add-type posts (system_add_to_channel, system_add_guest_to_chan,
+// system_add_to_team) are excluded from suppression so that the added user
+// still receives push/email/desktop notifications even when join/leave messages
+// are hidden in the channel. The WS posted event always fires; the webapp
+// filters the post out of postsInChannel so it does not appear in the timeline.
+func (a *App) shouldSuppressMembershipSystemPost(rctx request.CTX, channel *model.Channel, post *model.Post) bool {
+	if !model.IsMembershipSystemPost(post) {
+		return false
+	}
+	if model.IsAddMembershipSystemPost(post) {
+		return false
+	}
+	return model.ShouldChannelExcludeMembershipSystemPosts(channel)
+}
+
+func (a *App) filterSuppressedMembershipPosts(rctx request.CTX, postList *model.PostList) *model.AppError {
+	if postList == nil || len(postList.Posts) == 0 {
+		return nil
+	}
+
+	channelExclude := map[string]bool{}
+	channelCache := map[string]*model.Channel{}
+
+	for postID, post := range postList.Posts {
+		if !model.IsMembershipSystemPost(post) {
+			continue
+		}
+
+		exclude, ok := channelExclude[post.ChannelId]
+		if !ok {
+			channel, cached := channelCache[post.ChannelId]
+			if !cached {
+				var appErr *model.AppError
+				channel, appErr = a.GetChannel(rctx, post.ChannelId)
+				if appErr != nil {
+					return appErr
+				}
+				channelCache[post.ChannelId] = channel
+			}
+
+			exclude = model.ShouldChannelExcludeMembershipSystemPosts(channel)
+			channelExclude[post.ChannelId] = exclude
+		}
+
+		if exclude {
+			delete(postList.Posts, postID)
+			postList.Order = removePostIDFromOrder(postList.Order, postID)
+		}
+	}
+
+	return nil
+}
+
+func (a *App) filterSuppressedMembershipPostsFromSlice(rctx request.CTX, posts []*model.Post) ([]*model.Post, *model.AppError) {
+	if len(posts) == 0 {
+		return posts, nil
+	}
+
+	postList := model.NewPostList()
+	for _, post := range posts {
+		if post != nil {
+			postList.AddPost(post)
+			postList.Order = append(postList.Order, post.Id)
+		}
+	}
+
+	if appErr := a.filterSuppressedMembershipPosts(rctx, postList); appErr != nil {
+		return nil, appErr
+	}
+
+	filtered := make([]*model.Post, 0, len(postList.Posts))
+	for _, postID := range postList.Order {
+		if post, ok := postList.Posts[postID]; ok {
+			filtered = append(filtered, post)
+		}
+	}
+
+	return filtered, nil
+}
+
+func removePostIDFromOrder(order []string, postID string) []string {
+	if len(order) == 0 {
+		return order
+	}
+	filtered := make([]string, 0, len(order))
+	for _, id := range order {
+		if id != postID {
+			filtered = append(filtered, id)
+		}
+	}
+	return filtered
+}