fix: code update

server/index.js

@@ -55,19 +55,42 @@ wss.on('connection', (ws) => {
   ws.send(JSON.stringify({ type: 'situation', data: getSituation(), stats: getStats() }))
 })
 
-function broadcastSituation() {
+// 仅用 situation.updated_at + situation_update 条数做“版本”，避免无变更时重复查库和推送
+function getBroadcastVersion() {
+  try {
+    const meta = db.prepare('SELECT updated_at FROM situation WHERE id = 1').get()
+    const row = db.prepare('SELECT COUNT(*) as c FROM situation_update').get()
+    return `${meta?.updated_at || ''}_${row?.c ?? 0}`
+  } catch (_) {
+    return ''
+  }
+}
+
+let lastBroadcastVersion = null
+
+function broadcastSituation(force = false) {
+  if (!force && wss.clients.size === 0) return
+  const version = getBroadcastVersion()
+  if (!force && version === lastBroadcastVersion) return
   try {
     const data = JSON.stringify({ type: 'situation', data: getSituation(), stats: getStats() })
     wss.clients.forEach((c) => {
       if (c.readyState === 1) c.send(data)
     })
+    lastBroadcastVersion = version
   } catch (_) {}
 }
-app.set('broadcastSituation', broadcastSituation)
+
+app.set('broadcastSituation', () => broadcastSituation(true))
+
 if (typeof routes.setBroadcastSituation === 'function') {
-  routes.setBroadcastSituation(broadcastSituation)
+  routes.setBroadcastSituation(() => broadcastSituation(true))
+}
+
+const BROADCAST_INTERVAL_MS = Math.max(0, parseInt(process.env.BROADCAST_INTERVAL_MS, 10) || 30000)
+if (BROADCAST_INTERVAL_MS > 0) {
+  setInterval(() => broadcastSituation(false), BROADCAST_INTERVAL_MS)
 }
-setInterval(broadcastSituation, 3000)
 
 // 供爬虫调用：先从磁盘重载 DB（纳入爬虫写入），再更新 updated_at 并立即广播
 function notifyCrawlerUpdate() {