码:
subscription = source
// close websocket eventually
.Finally(() => webSocket.CloseAsync(WebSocketCloseStatus.Empty, String.Empty, CancellationToken.None).Wait())
.Subscribe(
data =>
{
if (webSocket.State != WebSocketState.Open)
{
_logger.LogWarning("Websocket closed by client!");
// TODO: End subscription
}
try
{
webSocket.SendAsync(data.ToString(),
WebSocketMessageType.Text, true, CancellationToken.None).Wait();
}
catch (WebSocketException e)
{
_logger.LogWarning(e, "problem with websocket!");
// TODO: End subscription
}
});
说明:
实现这一目标的一种方法是让异常不被处理,这将使观察者停止观察并“最终”调用,但问题是它然后崩溃我的整个服务器,因为异常在某个后台线程上重新抛出并且未处理。
要在回调中结束订阅,您只需在订阅上调用Dispose()
:
IDisposable subscription = null;
...
subscription = source
// close websocket eventually
.Finally(() => webSocket.CloseAsync(WebSocketCloseStatus.Empty, String.Empty, CancellationToken.None).Wait())
.Subscribe(
data =>
{
if (webSocket.State != WebSocketState.Open)
{
_logger.LogWarning("Websocket closed by client!");
subscription.Dispose(); // End subscription
}
try
{
webSocket.SendAsync(data.ToString(),
WebSocketMessageType.Text, true, CancellationToken.None).Wait();
}
catch (WebSocketException e)
{
_logger.LogWarning(e, "problem with websocket!");
subscription.Dispose(); // End subscription
}
});
另见http://www.introtorx.com/content/v1.0.10621.0/03_LifetimeManagement.html#Unsubscribing
你真的应该尝试像这样定义你的observable:
var subscription =
source
.TakeWhile(data => webSocket.State == WebSocketState.Open)
.SelectMany(data =>
Observable.FromAsync(() =>
webSocket.SendAsync(data.ToString(), WebSocketMessageType.Text, true, CancellationToken.None)))
.Catch<WebSocketException>(ex =>
Observable.FromAsync(() =>
webSocket.CloseAsync(WebSocketCloseStatus.Empty, String.Empty, CancellationToken.None)))
.Subscribe();
它最终会自动取消订阅。
即使你可以,你也应该避免在观察者中取消订阅。