In my Expo (React Native) project, I am working on implementing a protocol to manage stale websocket connections on both the client and server sides. The 'ws' package offers built-in callback handling for the 'pong' event (and sending pings), making server-side management in NodeJS relatively straightforward.
However, I'm encountering difficulties with the client side. The native WebSocket object does not provide a callback function for responding to pings from the server. Although it does respond correctly to server pings with opcode 0x9, these messages are not captured by the WebSocket.onmessage handler.
Below is my current attempt at a client-side ping handler:
const heartbeat = () => {
console.log("heartbeat");
clearTimeout(pingTimeout!);
pingTimeout = setTimeout(() => {
socket.close();
setResetConnection(rc => !rc);
}, HEARTBEAT_INTERVAL + HEARTBEAT_LATENCY);
};
socket.onmessage = (event) => {
console.log("message");
if (event.data instanceof Blob) {
console.log("received ping");
heartbeat();
const response = new ArrayBuffer(1);
const view = new Uint8Array(response);
view[0] = 0x9;
socket.send(view);
return;
}
[...remaining onmessage code...]
}
The socket is initialized as
var socket = new WebSocket("ws://ipaddr:8080");As noted, the pong is sent back to the server automatically without giving the client any opportunity for additional logic. I am currently looking for a way to override this default behavior without having to create my own ping/pong protocol.