使用node.js和socket.io向客户端发送信息时出现延迟

Question

I have an application written in node.js with a timer function. Whenever a second has passed, the server sends the new time value to every connected client. While this works perfectly fine on localhost, it's very choppy when hosted online. Clients won't update immediately and the value will sometimes jump two or three seconds at a time.

I discovered, however, if I repeatedly send the timer data to the clients (using setInterval), it runs perfectly without any delay from anywhere.

Does anyone have any idea why this might be the case? It doesn't make sense to me why sending the same data more often would fix the issue. If anything, shouldn't this be more slow? I was thinking I could use this approach and have the client notify the server when it has updated but this seems unnecessary and inefficient.

I'm very new to node.js but this has got me stumped. Any insight would be greatly appreciated.

Answer 1

Where are you hosting it? Does it support websockets? Some hosts do not support/allow them. My guess is that your host is not allowing websockets and socket.io is falling back to the polling transport.

In your browser, you can find the websocket connection and inspect it in developer tools: How do you inspect websocket traffic with Chrome Developer Tools?

If it does not undergo the 101 Switching Protocols http status to successfully upgrade the first request to a websocket, you'll see the polling requests recur in the developer tools.