refresh redesign

backend/server.js

@@ -70,6 +70,87 @@ const dbPath = path.join(__dirname, 'data', 'tracker.db');
 const db = new Database(dbPath);
 db.pragma('foreign_keys = ON');
 
+const SSE_RETRY_INTERVAL_MS = 5000;
+const SSE_HEARTBEAT_INTERVAL_MS = 30000;
+const sseClients = new Map();
+let nextSseClientId = 1;
+
+function scheduleAsync(fn) {
+  if (typeof setImmediate === 'function') {
+    setImmediate(fn);
+  } else {
+    setTimeout(fn, 0);
+  }
+}
+
+function removeSseClient(clientId) {
+  const client = sseClients.get(clientId);
+  if (!client) {
+    return;
+  }
+  sseClients.delete(clientId);
+  if (client.heartbeat) {
+    clearInterval(client.heartbeat);
+  }
+}
+
+function addSseClient(res) {
+  const clientId = nextSseClientId++;
+  const client = {
+    id: clientId,
+    res,
+    heartbeat: setInterval(() => {
+      if (res.writableEnded) {
+        removeSseClient(clientId);
+        return;
+      }
+      try {
+        res.write('event: heartbeat\ndata: {}\n\n');
+      } catch (error) {
+        removeSseClient(clientId);
+      }
+    }, SSE_HEARTBEAT_INTERVAL_MS)
+  };
+  sseClients.set(clientId, client);
+  return client;
+}
+
+function broadcastSseEvent(payload) {
+  if (!payload) {
+    return;
+  }
+
+  let serialized;
+  try {
+    serialized = JSON.stringify(payload);
+  } catch (error) {
+    console.warn('Failed to serialize SSE payload:', error.message);
+    return;
+  }
+
+  const message = `data: ${serialized}\n\n`;
+
+  for (const [clientId, client] of sseClients.entries()) {
+    const target = client && client.res;
+    if (!target || target.writableEnded) {
+      removeSseClient(clientId);
+      continue;
+    }
+    try {
+      target.write(message);
+    } catch (error) {
+      removeSseClient(clientId);
+    }
+  }
+}
+
+function queuePostBroadcast(postId, options = {}) {
+  if (!postId) {
+    return;
+  }
+  scheduleAsync(() => broadcastPostChangeById(postId, options));
+}
+
 function ensureColumn(table, column, definition) {
   const info = db.prepare(`PRAGMA table_info(${table})`).all();
   if (!info.some((row) => row.name === column)) {
@@ -833,7 +914,7 @@ db.prepare(`
   WHERE last_change IS NULL
 `).run();
 
-function touchPost(postId) {
+function touchPost(postId, reason = null) {
   if (!postId) {
     return;
   }
@@ -842,6 +923,7 @@ function touchPost(postId) {
   } catch (error) {
     console.warn(`Failed to update last_change for post ${postId}:`, error.message);
   }
+  queuePostBroadcast(postId, { reason: reason || 'touch' });
 }
 
 function normalizeExistingPostUrls() {
@@ -1816,6 +1898,56 @@ function mapPostRow(post) {
   };
 }
 
+function broadcastPostChange(post, options = {}) {
+  if (!post || !post.id) {
+    return;
+  }
+
+  const payload = {
+    type: 'post-upsert',
+    post
+  };
+
+  if (options && options.reason) {
+    payload.reason = options.reason;
+  }
+
+  broadcastSseEvent(payload);
+}
+
+function broadcastPostChangeById(postId, options = {}) {
+  if (!postId) {
+    return;
+  }
+  try {
+    const row = db.prepare('SELECT * FROM posts WHERE id = ?').get(postId);
+    if (!row) {
+      return;
+    }
+    const postPayload = mapPostRow(row);
+    broadcastPostChange(postPayload, options);
+  } catch (error) {
+    console.warn(`Failed to broadcast post ${postId}:`, error.message);
+  }
+}
+
+function broadcastPostDeletion(postId, options = {}) {
+  if (!postId) {
+    return;
+  }
+
+  const payload = {
+    type: 'post-deleted',
+    postId
+  };
+
+  if (options && options.reason) {
+    payload.reason = options.reason;
+  }
+
+  broadcastSseEvent(payload);
+}
+
 app.get('/api/bookmarks', (req, res) => {
   try {
     const rows = listBookmarksStmt.all();
@@ -1890,6 +2022,34 @@ app.delete('/api/bookmarks/:bookmarkId', (req, res) => {
 });
 
 // Get all posts
+app.get('/api/events', (req, res) => {
+  res.setHeader('Content-Type', 'text/event-stream');
+  res.setHeader('Cache-Control', 'no-cache, no-transform');
+  res.setHeader('Connection', 'keep-alive');
+  res.setHeader('X-Accel-Buffering', 'no');
+  if (typeof res.flushHeaders === 'function') {
+    res.flushHeaders();
+  } else {
+    res.write('\n');
+  }
+
+  res.write(`retry: ${SSE_RETRY_INTERVAL_MS}\n\n`);
+
+  const client = addSseClient(res);
+  const initialPayload = {
+    type: 'connected',
+    clientId: client.id
+  };
+  res.write(`data: ${JSON.stringify(initialPayload)}\n\n`);
+
+  const cleanup = () => {
+    removeSseClient(client.id);
+  };
+
+  req.on('close', cleanup);
+  res.on('close', cleanup);
+});
+
 app.get('/api/posts', (req, res) => {
   try {
     const posts = db.prepare(`
@@ -1925,6 +2085,7 @@ app.get('/api/posts/by-url', (req, res) => {
     const alternates = collectPostAlternateUrls(post.url, [normalizedUrl]);
     if (alternates.length) {
       storePostUrls(post.id, post.url, alternates);
+      touchPost(post.id, 'alternate-urls');
     }
 
     res.json(mapPostRow(post));
@@ -1957,6 +2118,9 @@ app.post('/api/search-posts', (req, res) => {
       const alternateUrls = collectPostAlternateUrls(trackedPost.url, normalizedUrls);
       storePostUrls(trackedPost.id, trackedPost.url, alternateUrls);
       removeSearchSeenEntries([trackedPost.url, ...alternateUrls]);
+      if (alternateUrls.length) {
+        touchPost(trackedPost.id, 'alternate-urls');
+      }
       return res.json({ seen_count: 0, should_hide: false, tracked: true });
     }
 
@@ -2104,7 +2268,9 @@ app.post('/api/posts/:postId/screenshot', (req, res) => {
     db.prepare('UPDATE posts SET screenshot_path = ?, last_change = CURRENT_TIMESTAMP WHERE id = ?').run(fileName, postId);
 
     const updatedPost = db.prepare('SELECT * FROM posts WHERE id = ?').get(postId);
-    res.json(mapPostRow(updatedPost));
+    const formattedPost = mapPostRow(updatedPost);
+    res.json(formattedPost);
+    broadcastPostChange(formattedPost, { reason: 'screenshot-updated' });
   } catch (error) {
     res.status(500).json({ error: error.message });
   }
@@ -2121,9 +2287,10 @@ app.get('/api/posts/:postId/screenshot', (req, res) => {
     if (!post || !post.screenshot_path) {
       // Return placeholder image
       if (fs.existsSync(placeholderPath)) {
-        res.set('Cache-Control', 'public, max-age=86400');
+        res.set('Cache-Control', 'no-store');
         return res.sendFile(placeholderPath);
       }
+      res.set('Cache-Control', 'no-store');
       return res.status(404).json({ error: 'Screenshot not found' });
     }
 
@@ -2131,9 +2298,10 @@ app.get('/api/posts/:postId/screenshot', (req, res) => {
     if (!fs.existsSync(filePath)) {
       // Return placeholder image
       if (fs.existsSync(placeholderPath)) {
-        res.set('Cache-Control', 'public, max-age=86400');
+        res.set('Cache-Control', 'no-store');
         return res.sendFile(placeholderPath);
       }
+      res.set('Cache-Control', 'no-store');
       return res.status(404).json({ error: 'Screenshot not found' });
     }
 
@@ -2190,7 +2358,7 @@ app.post('/api/posts', (req, res) => {
 
         if (normalizedPostText && (!existingByHash.post_text || !existingByHash.post_text.trim())) {
           updatePostTextColumnsStmt.run(normalizedPostText, postTextHash, existingByHash.id);
-          touchPost(existingByHash.id);
+          touchPost(existingByHash.id, 'post-text-normalized');
           existingByHash = db.prepare('SELECT * FROM posts WHERE id = ?').get(existingByHash.id);
         }
 
@@ -2250,7 +2418,9 @@ app.post('/api/posts', (req, res) => {
     storePostUrls(id, normalizedUrl, alternateUrls);
     removeSearchSeenEntries([normalizedUrl, ...alternateUrls]);
 
-    res.json(mapPostRow(post));
+    const formattedPost = mapPostRow(post);
+    res.json(formattedPost);
+    broadcastPostChange(formattedPost, { reason: 'created' });
   } catch (error) {
     if (error.message.includes('UNIQUE constraint failed')) {
       res.status(409).json({ error: 'Post with this URL already exists' });
@@ -2385,7 +2555,9 @@ app.put('/api/posts/:postId', (req, res) => {
     }
     removeSearchSeenEntries(Array.from(cleanupUrls));
 
-    res.json(mapPostRow(updatedPost));
+    const formattedPost = mapPostRow(updatedPost);
+    res.json(formattedPost);
+    broadcastPostChange(formattedPost, { reason: 'updated' });
   } catch (error) {
     res.status(500).json({ error: error.message });
   }
@@ -2465,7 +2637,7 @@ app.post('/api/posts/:postId/check', (req, res) => {
     didChange = true;
     recalcCheckedCount(postId);
     if (didChange) {
-      touchPost(postId);
+      touchPost(postId, 'profile-status-update');
     }
 
     const updatedPost = db.prepare('SELECT * FROM posts WHERE id = ?').get(postId);
@@ -2492,6 +2664,9 @@ app.post('/api/posts/:postId/urls', (req, res) => {
     removeSearchSeenEntries([post.url, ...alternateUrls]);
 
     const storedAlternates = selectAlternateUrlsForPostStmt.all(post.id).map(row => row.url);
+    if (alternateUrls.length) {
+      touchPost(post.id, 'alternate-urls');
+    }
     res.json({
       success: true,
       primary_url: post.url,
@@ -2587,7 +2762,7 @@ app.post('/api/check-by-url', (req, res) => {
     didChange = true;
     recalcCheckedCount(post.id);
     if (didChange) {
-      touchPost(post.id);
+      touchPost(post.id, 'check-by-url');
     }
 
     const updatedPost = db.prepare('SELECT * FROM posts WHERE id = ?').get(post.id);
@@ -2674,7 +2849,7 @@ app.post('/api/posts/:postId/profile-status', (req, res) => {
 
     recalcCheckedCount(postId);
     if (didChange) {
-      touchPost(postId);
+      touchPost(postId, 'profile-status-update');
     }
 
     const updatedPost = db.prepare('SELECT * FROM posts WHERE id = ?').get(postId);
@@ -2710,7 +2885,7 @@ app.patch('/api/posts/:postId', (req, res) => {
 
       const contentKey = extractFacebookContentKey(normalizedUrl);
       // Update URL
-      db.prepare('UPDATE posts SET url = ?, content_key = ? WHERE id = ?').run(normalizedUrl, contentKey || null, postId);
+      db.prepare('UPDATE posts SET url = ?, content_key = ?, last_change = CURRENT_TIMESTAMP WHERE id = ?').run(normalizedUrl, contentKey || null, postId);
 
       const alternateCandidates = [];
       if (existingPost.url && existingPost.url !== normalizedUrl) {
@@ -2720,15 +2895,19 @@ app.patch('/api/posts/:postId', (req, res) => {
       const alternateUrls = collectPostAlternateUrls(normalizedUrl, alternateCandidates);
       storePostUrls(postId, normalizedUrl, alternateUrls);
       removeSearchSeenEntries([normalizedUrl, ...alternateUrls]);
+      queuePostBroadcast(postId, { reason: 'url-updated' });
       return res.json({ success: true, url: normalizedUrl });
     }
 
     if (is_successful !== undefined) {
       const successValue = is_successful ? 1 : 0;
-      db.prepare('UPDATE posts SET is_successful = ? WHERE id = ?').run(successValue, postId);
+      db.prepare('UPDATE posts SET is_successful = ?, last_change = CURRENT_TIMESTAMP WHERE id = ?').run(successValue, postId);
 
       const updatedPost = db.prepare('SELECT * FROM posts WHERE id = ?').get(postId);
-      return res.json(mapPostRow(updatedPost));
+      const formattedPost = mapPostRow(updatedPost);
+      res.json(formattedPost);
+      broadcastPostChange(formattedPost, { reason: 'success-flag' });
+      return;
     }
 
     return res.status(400).json({ error: 'No valid update parameter provided' });
@@ -2763,6 +2942,7 @@ app.delete('/api/posts/:postId', (req, res) => {
     }
 
     res.json({ success: true });
+    broadcastPostDeletion(postId, { reason: 'deleted' });
   } catch (error) {
     res.status(500).json({ error: error.message });
   }