private async Task DataReceiver(ClientMetadata client, CancellationToken?cancelToken = null)
{
var clientId = client.IpPort();
try
{
#region Wait-for-Data
while (true)
{
cancelToken?.ThrowIfCancellationRequested();
byte[] data = await MessageReadAsync(client);
if (data != null)
{
if (MessageReceived != null)
{
var _ = Task.Run(() => MessageReceived?.Invoke(client.IpPort(), data), CancellationToken.None);
}
}
else
{
// no message available
await Task.Delay(30, cancelToken.GetValueOrDefault());
}
}
#endregion
}
catch (OperationCanceledException oce)
{
Log("DataReceiver client " + clientId + " disconnected (canceled): " + oce.Message);
}
catch (WebSocketException wse)
{
Log("DataReceiver client " + clientId + " disconnected (websocket exception): " + wse.Message);
}
finally
{
if (RemoveClient(client))
{
// must only fire disconnected event if the client was previously connected. Note that
// multithreading gives multiple disconnection events from the socket, the reader and the writer
ClientDisconnected?.Invoke(clientId);
client.Ws.Dispose();
Log("DataReceiver client " + clientId + " disconnected (now " + _Clients.Count + " clients active)");
}
}
}
private async Task <bool> MessageWriteAsync(ClientMetadata client, byte[] data, WebSocketMessageType messageType)
{
try
{
#region Send-Message
// Cannot have two simultaneous SendAsync calls so use a
// semaphore to block the second until the first has completed
await client.SendAsyncLock.WaitAsync(client.KillToken.Token);
try
{
await client.Ws.SendAsync(new ArraySegment <byte>(data, 0, data.Length),
messageType, true, client.KillToken.Token);
}
finally
{
client.SendAsyncLock.Release();
}
return(true);
#endregion
}
catch (Exception e)
{
Log("*** MessageWriteAsync " + client.IpPort() + " disconnected due to exception " + e);
return(false);
}
}
private bool RemoveClient(ClientMetadata client)
{
return(_Clients.TryRemove(client.IpPort(), out var removedClient));
}
private bool AddClient(ClientMetadata client)
{
_Clients.TryRemove(client.IpPort(), out var removedClient);
return(_Clients.TryAdd(client.IpPort(), client));
}
