main.rs

async fn eval_with_event(webview: Webview, event_name: &str, script: &str, timeout: Duration) -> anyhow::Result<Value> {
	let (sender, receiver): (Sender<String>, Receiver<String>) = channel();
	let id = webview.listen(event_name, move |event| {
		let value = event.payload().to_string();
		let result = sender.send(value);
		if let Err(err) = result {
			log::error!("failed to get result from callback {}", err);
		}
	});
	let result = webview.eval(&script);
	if let Err(err) = result {
		log::error!("failed to eval {}", err);
	}
	log::debug!("waiting for eval result from webview");

	let mut final_value: Value = serde_json::Value::Object(Default::default());
	let start = Instant::now();
	while start.elapsed() < timeout {
		match receiver.try_recv() {
			Ok(json_value) => {

				let value: Result<Value, serde_json::Error> = serde_json::from_str(&json_value);
				if let Ok(value) = value {
					final_value = value;
				}
				break;
			}
			Err(TryRecvError::Empty) => {
				// No HTML received yet, sleep for a bit before trying again
				tokio::time::sleep(Duration::from_millis(100)).await;
			}
			Err(TryRecvError::Disconnected) => {
				// The sender has disconnected, handle the error
				log::error!("sender disconnected while waiting for eval result");
				break;
			}
		}
	}
	// here wait for payload to receive and then unlisten
	webview.unlisten(id);
	Ok(final_value)
}