Websocket S2S: ping every 55s to keep alive.

server/lib/prosody/config/content.ts

@@ -296,6 +296,9 @@ class ProsodyConfigContent {
     this.global.set('peertubelivechat_instance_url', publicServerUrl)
 
     this.global.add('modules_enabled', 'websocket_s2s_peertubelivechat')
+    // Nginx closes the websockets connection after a timeout. Seems the default is 60s.
+    // So we will ping on outgoing websocket s2s connection every 55s.
+    this.global.set('websocket_s2s_ping_interval', 55)
     // FIXME: seems to be necessary to add the module on the muc host, so that dialback can trigger route/remote.
     this.muc.add('modules_enabled', 'websocket_s2s_peertubelivechat')