/// <summary>Write client messages.</summary>
/// <param name="webSocket"> The web socket.</param>
/// <param name="clientGuid"> Unique identifier for the client.</param>
/// <param name="cancelToken">A token that allows processing to be canceled.</param>
/// <returns>An asynchronous result.</returns>
private async Task WriteClientMessages(
WebSocket webSocket,
Guid clientGuid,
CancellationToken cancelToken)
{
// get the client object
if (!WebsocketManager.TryGetClient(clientGuid, out WebsocketClientInformation client))
{
// nothing to do here (will cancel on exit)
return;
}
// loop until cancelled
while (!cancelToken.IsCancellationRequested)
{
// do not bubble errors here
try
{
// **** check for a message ***
if (!client.MessageQ.TryDequeue(out string message))
{
// wait and prevent exceptions
await Task.Delay(_sendSleepDelayMs, cancelToken)
.ContinueWith(_ => Task.CompletedTask);
// go to next loop
continue;
}
// grab a byte buffer of our data
byte[] buffer = Encoding.UTF8.GetBytes(message);
// send this message
await webSocket.SendAsync(
buffer,
WebSocketMessageType.Text,
true,
cancelToken).ConfigureAwait(false);
WebsocketManager.UpdateTimeoutForSentMessage(clientGuid);
}
// keep looping
catch (Exception ex)
{
Console.WriteLine($"SubscriptionWebsocketHandler.WriteClientMessages" +
$" <<< client: {clientGuid} caught exception: {ex.Message}");
// this socket is borked, exit
break;
}
}
}
/// <summary>Keepalive thread function.</summary>
private void KeepaliveThreadFunc()
{
List <Guid> clientsToRemove = new List <Guid>();
try
{
// loop while there are clients
while (!_clientMessageTimeoutDict.IsEmpty)
{
long currentTicks = DateTime.Now.Ticks;
string keepaliveTime = string.Format(CultureInfo.InvariantCulture, "{0:o}", DateTime.Now.ToUniversalTime());
// traverse the dictionary looking for clients we need to send messages to
foreach (KeyValuePair <Guid, long> kvp in _clientMessageTimeoutDict)
{
// check timeout
if (currentTicks > kvp.Value)
{
// enqueue a message for this client
if (WebsocketManager.TryGetClient(kvp.Key, out WebsocketClientInformation client))
{
// enqueue a keepalive message
client.MessageQ.Enqueue($"keepalive {keepaliveTime}");
}
else
{
// client is gone, stop sending (cannot remove inside iterator)
clientsToRemove.Add(kvp.Key);
}
}
}
// remove any clients we need to remove
foreach (Guid clientGuid in clientsToRemove)
{
_clientMessageTimeoutDict.TryRemove(clientGuid, out _);
}
clientsToRemove.Clear();
Thread.Sleep(1000);
}
}
catch (Exception ex)
{
Console.WriteLine($"SubscriptionWebsocketHandler.KeepaliveThreadFunc <<< exception: {ex.Message}");
}
}
/// <summary>Tests queueing messages.</summary>
/// <param name="clientGuid">Unique identifier for the client.</param>
private void TestQueueingMessages(Guid clientGuid)
{
bool done = false;
long messageNumber = 0;
while (!done)
{
// check for no client
if (!WebsocketManager.TryGetClient(clientGuid, out WebsocketClientInformation client))
{
// done
done = true;
continue;
}
// queue a message for this client
client.MessageQ.Enqueue($"Test message: {messageNumber++}, {DateTime.Now}");
// wait a couple of seconds
Thread.Sleep(2000);
}
}
/// <summary>Reads client messages.</summary>
/// <param name="webSocket"> The web socket.</param>
/// <param name="clientGuid"> Unique identifier for the client.</param>
/// <param name="cancelToken">A token that allows processing to be cancelled.</param>
/// <returns>An asynchronous result.</returns>
private async Task ReadClientMessages(
WebSocket webSocket,
Guid clientGuid,
CancellationToken cancelToken)
{
// get the client object
if (!WebsocketManager.TryGetClient(clientGuid, out WebsocketClientInformation client))
{
// nothing to do here (will cancel on exit)
return;
}
// create our receive buffer
byte[] buffer = new byte[_messageBufferSize];
int count;
int messageLength = 0;
WebSocketReceiveResult result;
// loop until cancelled
while (!cancelToken.IsCancellationRequested)
{
// reset buffer offset
messageLength = 0;
// do not bubble errors here
try
{
// read a message
do
{
count = _messageBufferSize - messageLength;
result = await webSocket.ReceiveAsync(
new ArraySegment <byte>(
buffer,
messageLength,
count),
cancelToken).ConfigureAwait(false);
messageLength += result.Count;
}while (!result.EndOfMessage);
// process this message
if (result.MessageType == WebSocketMessageType.Close)
{
break;
}
// check for a bind request
string message = Encoding.UTF8.GetString(buffer).Substring(0, messageLength);
if (message.StartsWith("bind ", StringComparison.Ordinal))
{
// grab the rest of the content
message = message.Replace("bind ", string.Empty, StringComparison.Ordinal);
string[] ids = message.Split(',');
// traverse the requested ids
foreach (string id in ids)
{
string subscriptionId = id.StartsWith("Subscription/", StringComparison.Ordinal)
? id.Replace("Subscription/", string.Empty, StringComparison.Ordinal)
: id;
// make sure this subscription exists
if ((!SubscriptionManagerR4.Exists(subscriptionId)) &&
(!SubscriptionManagerR5.Exists(subscriptionId)))
{
continue;
}
// register this subscription to this client
WebsocketManager.AddSubscriptionToClient(subscriptionId, clientGuid);
}
}
if (message.StartsWith("bind-with-token ", StringComparison.Ordinal))
{
// grab the rest of the content
message = message.Replace("bind-with-token ", string.Empty, StringComparison.Ordinal);
if (!Guid.TryParse(message, out Guid tokenGuid))
{
continue;
}
// register this token to this client
WebsocketManager.BindClientWithToken(tokenGuid, clientGuid);
}
if (message.StartsWith("unbind ", StringComparison.Ordinal))
{
// grab the rest of the content
message = message.Replace("unbind ", string.Empty, StringComparison.Ordinal);
string[] ids = message.Split(',');
// traverse the requested ids
foreach (string id in ids)
{
string subscriptionId = id.StartsWith("Subscription/", StringComparison.Ordinal)
? id.Replace("Subscription/", string.Empty, StringComparison.Ordinal)
: id;
// remove this subscription from this client
WebsocketManager.RemoveSubscriptionFromClient(subscriptionId, clientGuid);
}
}
}
// keep looping
catch (Exception ex)
{
Console.WriteLine($"SubscriptionWebsocketHandler.ReadClientMessages" +
$" <<< client: {clientGuid} caught exception: {ex.Message}");
// this socket is borked, exit
break;
}
}
}
