firebase 建立与数据库的连接缓慢

Question

我有一个使用 Google Firebase 身份验证的网络应用程序，最近我注意到当您在 Android 设备上将该应用程序后台运行然后返回到该应用程序时，需要很长时间才能重新建立网络套接字连接到数据库。

我启用了日志记录，这就是发生的事情。从日志记录的时间可以看出，重新连接需要将近 5 分钟 - 为什么？

logger.ts:80 [2020-07-11T10:26:54.376Z]  @firebase/database: p:0: from server: {"r":80,"b":{"s":"ok","d":""}} 
logger.ts:80 [2020-07-11T10:32:34.296Z]  @firebase/database: c:0:0:0 Websocket connection was disconnected. 
logger.ts:80 [2020-07-11T10:32:34.297Z]  @firebase/database: c:0:0:0 WebSocket is closing itself 
logger.ts:80 [2020-07-11T10:32:34.298Z]  @firebase/database: c:0:0: Realtime connection lost. 
logger.ts:80 [2020-07-11T10:32:34.300Z]  @firebase/database: c:0:0: Closing realtime connection. 
logger.ts:80 [2020-07-11T10:32:34.300Z]  @firebase/database: c:0:0: Shutting down all connections 
logger.ts:80 [2020-07-11T10:32:34.302Z]  @firebase/database: p:0: data client disconnected 
logger.ts:80 [2020-07-11T10:32:34.304Z]  @firebase/database: p:0: Window isn't visible.  Delaying reconnect. 
logger.ts:80 [2020-07-11T10:32:34.305Z]  @firebase/database: p:0: Trying to reconnect in 297779.38668296754ms 
logger.ts:80 [2020-07-11T10:32:34.309Z]  @firebase/database: 0: onDisconnectEvents 
logger.ts:80 [2020-07-11T10:32:36.069Z]  @firebase/database: p:0: Listen called for /NEWLADDER/2020 default 
logger.ts:80 [2020-07-11T10:37:32.088Z]  @firebase/database: p:0: Making a connection attempt 
logger.ts:80 [2020-07-11T10:37:32.096Z]  @firebase/database: getToken() completed. Creating connection. 
logger.ts:80 [2020-07-11T10:37:32.099Z]  @firebase/database: c:0:1: Connection created 
logger.ts:80 [2020-07-11T10:37:32.105Z]  @firebase/database: c:0:1:0 Websocket connecting to ********
logger.ts:80 [2020-07-11T10:37:32.764Z]  @firebase/database: c:0:1:0 Websocket connected. 
logger.ts:80 [2020-07-11T10:37:32.767Z]  @firebase/database: c:0:1: Realtime connection established. 
logger.ts:80 [2020-07-11T10:37:32.768Z]  @firebase/database: p:0: connection ready 

Answer 1

Firebase 客户端尝试使用指数回退自动重新连接。很难说为什么在您的情况下这需要 5 分钟，但鉴于上述情况，您的应用程序在后台运行的时间越长，重新连接所需的时间就越长，这是有道理的。

如果这是一个常见问题，我建议在应用再次进入前台时明确断开并重新连接客户端。所以：

FirebaseDatabase.getInstance().goOffline();
FirebaseDatabase.getInstance().goOnline();