Comment System with Replies
Overview
A threaded comment system that allows users to post comments and reply to existing comments, creating nested conversation threads. The system includes real-time updates, spam prevention, moderation tools, and notifications for comment replies.
User Stories
- As a user, I want to post comments on content, so that I can share my thoughts
- As a user, I want to reply to specific comments, so that I can have focused discussions
- As a user, I want to see new comments appear in real-time, so that conversations feel live
- As a user, I want to edit or delete my own comments, so that I can correct mistakes
- As a moderator, I want to remove inappropriate comments, so that I can maintain community standards
Acceptance Criteria
- [ ] Comment form displays below content with character count (max 1000 chars)
- [ ] Submitted comments appear immediately (optimistic UI)
- [ ] Users can reply to comments (nested up to 3 levels deep)
- [ ] Reply button shows inline reply form
- [ ] Edit and delete buttons visible only on user's own comments
- [ ] Deleted comments show "[deleted]" placeholder if they have replies
- [ ] Comments display author name, avatar, and timestamp
- [ ] Moderators see "Remove" button on all comments
- [ ] Real-time updates when new comments posted (WebSocket or polling)
Technical Requirements
- Store comments in database with parent_id for threading
- Implement recursive query to fetch nested comments efficiently
- Use optimistic UI updates for instant feedback
- WebSocket connection for real-time comment updates (or poll every 10 seconds)
- Rate limit comment posting (max 10 per minute per user)
- Sanitize comment HTML to prevent XSS attacks
- Soft delete comments (mark as deleted, preserve thread structure)
- Send email notification when someone replies to user's comment
Edge Cases
- User deletes comment with replies → Keep comment as placeholder "[deleted by user]"
- Comment posted while offline → Show error, allow retry when connection restored
- Very long thread (100+ comments) → Paginate or "Load more" button
- User edits comment multiple times rapidly → Debounce save, show "Saving..." indicator
- Spam/abuse reported on comment → Flag for review, hide from view pending moderation
Out of Scope
- Upvoting/downvoting comments
- Sorting comments (by date, popularity)
- @mentions or tagging users
- Rich text formatting (bold, italic, links)
- Image attachments in comments