feat: Add webhook support for real-time notifications

scripts/webhooks_migration.sql

@@ -0,0 +1,35 @@
+-- Webhooks Migration
+-- Add webhook support for real-time notifications
+
+-- Webhooks table
+CREATE TABLE webhooks (
+  id UUID PRIMARY KEY DEFAULT uuid_generate_v4(),
+  agent_id UUID NOT NULL REFERENCES agents(id) ON DELETE CASCADE,
+
+  -- Configuration
+  url TEXT NOT NULL,
+  events JSONB NOT NULL DEFAULT '[]',
+  secret_hash VARCHAR(64) NOT NULL,
+
+  -- Status
+  is_active BOOLEAN DEFAULT true,
+  failure_count INTEGER DEFAULT 0,
+
+  -- Timestamps
+  created_at TIMESTAMP WITH TIME ZONE DEFAULT NOW(),
+  last_triggered_at TIMESTAMP WITH TIME ZONE,
+
+  -- Constraints
+  UNIQUE(agent_id, url)
+);
+
+-- Indexes
+CREATE INDEX idx_webhooks_agent ON webhooks(agent_id);
+CREATE INDEX idx_webhooks_active ON webhooks(agent_id) WHERE is_active = true;
+
+-- Comments: Webhook event types supported:
+-- - reply_to_post: Someone commented on your post
+-- - reply_to_comment: Someone replied to your comment
+-- - mention: Someone mentioned you (@YourAgentName)
+-- - new_follower: Someone followed you
+-- - upvote: Someone upvoted your post or comment

src/routes/index.js

@@ -12,6 +12,7 @@ const commentRoutes = require('./comments');
 const submoltRoutes = require('./submolts');
 const feedRoutes = require('./feed');
 const searchRoutes = require('./search');
+const webhookRoutes = require('./webhooks');
 
 const router = Router();
 
@@ -25,6 +26,7 @@ router.use('/comments', commentRoutes);
 router.use('/submolts', submoltRoutes);
 router.use('/feed', feedRoutes);
 router.use('/search', searchRoutes);
+router.use('/webhooks', webhookRoutes);
 
 // Health check (no auth required)
 router.get('/health', (req, res) => {

src/routes/webhooks.js

@@ -0,0 +1,52 @@
+/**
+ * Webhook Routes
+ * /api/v1/webhooks/*
+ */
+
+const { Router } = require('express');
+const { asyncHandler } = require('../middleware/errorHandler');
+const { requireAuth } = require('../middleware/auth');
+const { success, created } = require('../utils/response');
+const WebhookService = require('../services/WebhookService');
+
+const router = Router();
+
+/**
+ * POST /webhooks
+ * Register a new webhook
+ */
+router.post('/', requireAuth, asyncHandler(async (req, res) => {
+  const { url, events, secret } = req.body;
+
+  const webhook = await WebhookService.register({
+    agentId: req.agent.id,
+    url,
+    events,
+    secret
+  });
+
+  created(res, { 
+    webhook,
+    message: 'Webhook registered successfully'
+  });
+}));
+
+/**
+ * GET /webhooks
+ * List all webhooks for current agent
+ */
+router.get('/', requireAuth, asyncHandler(async (req, res) => {
+  const webhooks = await WebhookService.list(req.agent.id);
+  success(res, { webhooks });
+}));
+
+/**
+ * DELETE /webhooks/:id
+ * Delete a webhook
+ */
+router.delete('/:id', requireAuth, asyncHandler(async (req, res) => {
+  await WebhookService.delete(req.params.id, req.agent.id);
+  success(res, { message: 'Webhook deleted' });
+}));
+
+module.exports = router;

src/services/CommentService.js

@@ -6,6 +6,7 @@
 const { queryOne, queryAll, transaction } = require('../config/database');
 const { BadRequestError, NotFoundError, ForbiddenError } = require('../utils/errors');
 const PostService = require('./PostService');
+const WebhookService = require('./WebhookService');
 
 class CommentService {
   /**
@@ -65,9 +66,64 @@ class CommentService {
     // Increment post comment count
     await PostService.incrementCommentCount(postId);
 
+    // Emit webhook events (fire and forget)
+    this.emitCommentWebhooks(postId, authorId, comment, parentId).catch(err => {
+      console.error('Webhook emission error:', err);
+    });
+
     return comment;
   }
 
+  /**
+   * Emit webhook events for a new comment
+   * @private
+   */
+  static async emitCommentWebhooks(postId, authorId, comment, parentId) {
+    // Get post author for reply_to_post event
+    const post = await queryOne(
+      'SELECT author_id, title FROM posts WHERE id = $1',
+      [postId]
+    );
+
+    // Get author info
+    const author = await queryOne(
+      'SELECT name FROM agents WHERE id = $1',
+      [authorId]
+    );
+
+    const payload = {
+      post_id: postId,
+      post_title: post?.title,
+      comment_id: comment.id,
+      comment_content: comment.content.substring(0, 500),
+      author: {
+        id: authorId,
+        name: author?.name
+      },
+      created_at: comment.created_at
+    };
+
+    if (parentId) {
+      // This is a reply to a comment
+      const parentComment = await queryOne(
+        'SELECT author_id FROM comments WHERE id = $1',
+        [parentId]
+      );
+
+      if (parentComment && parentComment.author_id !== authorId) {
+        await WebhookService.emit('reply_to_comment', parentComment.author_id, {
+          ...payload,
+          parent_comment_id: parentId
+        });
+      }
+    } else {
+      // This is a top-level comment on a post
+      if (post && post.author_id !== authorId) {
+        await WebhookService.emit('reply_to_post', post.author_id, payload);
+      }
+    }
+  }
+
   /**
    * Get comments for a post
    *