fix: 通知 SSE 长连接被 Nginx 60s 超时掐断

apps/server/src/notifications/notifications.controller.ts

@@ -9,7 +9,7 @@ import {
   UseGuards,
 } from '@nestjs/common';
 import { Request } from 'express';
-import { Observable, map } from 'rxjs';
+import { Observable, interval, map, merge } from 'rxjs';
 import { NotificationsService } from './notifications.service';
 import { NotificationQueryDto } from './dto/notification.dto';
 import { JwtAuthGuard } from '../auth/guards/jwt-auth.guard';
@@ -53,17 +53,22 @@ export class NotificationsController {
     req.on('close', () => {
       this.service.unsubscribe(userId);
     });
-    return this.service.subscribe(userId).pipe(
-      map((notification) => ({
-        data: JSON.stringify({
-          id: notification.id,
-          type: notification.type,
-          title: notification.title,
-          content: notification.content,
-          link: notification.link,
-          createdAt: notification.createdAt,
-        }),
-      } as MessageEvent)),
+    // 每 25s 发送一次空消息作为心跳，避免空闲连接被 Nginx 等中间层超时掐断。
+    // 空 data 会被前端 EventSource 收到并忽略（JSON.parse 失败）。
+    return merge(
+      this.service.subscribe(userId).pipe(
+        map((notification) => ({
+          data: JSON.stringify({
+            id: notification.id,
+            type: notification.type,
+            title: notification.title,
+            content: notification.content,
+            link: notification.link,
+            createdAt: notification.createdAt,
+          }),
+        } as MessageEvent)),
+      ),
+      interval(25_000).pipe(map(() => ({ data: '' } as MessageEvent))),
     );
   }