protected override async Task ExecuteAsync(HttpContext context, WebSocket socket)
{
await Task.Yield();
SemaphoreSlim socketSemaphore = new SemaphoreSlim(1, 1);
async void handler(object sender, object e)
{
await socketSemaphore.WaitAsync(context.RequestAborted);
try
{
if (socket.State != WebSocketState.Open)
{
return;
}
await socket.SendObjectAsync(e, context.RequestAborted).ConfigureAwait(false);
}
catch
{
// Ignored.
}
finally
{
socketSemaphore.Release();
}
}
var subscription = Guid.NewGuid().ToString("n");
using (var subscriptions = new JoinedDisposable())
{
subscriptions.Add(string.Empty, _messenger.Subscribe($"WebSocket.{subscription}", handler));
await socket.SendObjectAsync(new {
@event = "Connected",
data = null as object
});
while (socket.State == WebSocketState.Open)
{
var result = await socket.ReadObjectAsync <JObject>(context.RequestAborted);
if (result == null)
{
continue;
}
if (result.TryGetValue("subscribe", StringComparison.OrdinalIgnoreCase, out var subscribeTo))
{
HandleSubscribes(subscribeTo, subscription, subscriptions);
}
if (result.TryGetValue("unsubscribe", StringComparison.OrdinalIgnoreCase, out var unsubscribeFrom))
{
HandleUnsubscribes(unsubscribeFrom, subscription, subscriptions);
}
}
}
}
private void HandleSubscribe(string item, string subscription, JoinedDisposable subscriptions)
{
void handler(object sender, object data) => _messenger.Publish($"WebSocket.{subscription}", sender, new
{
@event = item,
data
});
subscriptions.Add(item, _messenger.Subscribe($"Public.{item}", handler));
}
private void HandleSubscribes(JToken subscribeTo, string subscription, JoinedDisposable subscriptions)
{
if (subscribeTo.Type == JTokenType.String)
{
HandleSubscribe(subscribeTo.ToObject <string>(), subscription, subscriptions);
}
else if (subscribeTo.Type == JTokenType.Array)
{
var jarray = (JArray)subscribeTo;
foreach (var item in jarray.Children().OfType <JValue>().Where(i => i.Type == JTokenType.String).Select(x => x.ToObject <string>()))
{
HandleSubscribe(item, subscription, subscriptions);
}
}
}
void HandleUnsubscribe(string unsubscribeFrom, string subscription, JoinedDisposable subscriptions)
{
subscriptions.Remove(unsubscribeFrom);
}
