/// <summary>
/// Reads the socket.
/// </summary>
/// <returns>Task<System.String>.</returns>
private async Task <string> ReadSocketAsync()
{
var segment = new ArraySegment <byte>(new byte[8192]); // 8Kb
using (var stream = new MemoryStream())
{
WebSocketReceiveResult result;
do
{
result = await ClientWs.ReceiveAsync(segment, CancellationToken.None);
switch (result.MessageType)
{
case WebSocketMessageType.Text:
stream.Write(segment.Array, segment.Offset, result.Count);
break;
case WebSocketMessageType.Close:
await ClientWs.CloseAsync(WebSocketCloseStatus.NormalClosure, DONE, CancellationToken.None);
break;
case WebSocketMessageType.Binary:
Debug.WriteLine("Received Unsupported Binary Websocket message: " + segment.ToString());
break;
}
}while (ClientWs.State == WebSocketState.Open && !result.EndOfMessage);
stream.Seek(0, SeekOrigin.Begin);
using (var reader = new StreamReader(stream)) return(reader.ReadToEnd());
}
}
/// <summary>
/// Opens the websocket connection and sends the CONNECT message.
/// </summary>
/// <returns><System.Boolean> true if successful.</returns>
public async Task <bool> ConnectAsync(Action <string> errorsEventHandler)
{
const string WEBSOCKETPATH = "/w/messages/websocket"; // Based on https://docs.nem.io/en/nem-dev-basics-docker/blockchain-monitoring
await ClientWs.ConnectAsync(new Uri(string.Concat("ws://", Domain, ":", Port, WEBSOCKETPATH)), CancellationToken.None);
if (ClientWs.State != WebSocketState.Open)
{
return(false);
}
// Send CONNECT
StompMessage connect = new StompMessage(StompMessage.ClientCommands.CONNECT);
// Set message headers, might not be needed
//connect["accept-version"] = "1.1,1.0";
//connect["heart-beat"] = "10000, 10000"; // out, in
await SendAsync(connect);
// Read the answer from the server
StompMessage connectedMsg = StompMessage.Deserialize(await ReadSocketAsync());
if (connectedMsg.Command != StompMessage.ServerResponses.CONNECTED)
{
return(false);
}
// Subscribe to errors channel
await SubscribeToErrorsAsync(errorsEventHandler);
// Start the Loop to read answers
Task loop = LoopReadStompMsgsAsync(); // Explicitely not using await, to allow the Loop to run asynchronously without waiting for it to complete!
return(true);
}
/// <summary>
/// Sends the DISCONNECT message and Closes the websocket connection.
/// </summary>
/// <returns><System.Boolean>.</returns>
public async Task <bool> DisconnectAsync()
{
//// Send DISCONNECT, does not seem to be needed
//StompMessage disconnect = new StompMessage(StompMessage.ClientCommands.DISCONNECT);
//await SendAsync(disconnect);
// Close the Websocket
await ClientWs.CloseAsync(WebSocketCloseStatus.NormalClosure, DONE, CancellationToken.None);
if (ClientWs.State != WebSocketState.Open)
{
return(true);
}
return(false);
}
/// <summary>
/// Sends the StompMessage Asynchronously. Call LoopReadStompMsgsAsync to process answers from the server.
/// </summary>
/// <param name="stompMsg"></param>
async Task SendAsync(StompMessage stompMsg)
{
byte[] encoded = Encoding.UTF8.GetBytes(stompMsg.Serialize());
ArraySegment <byte> segment = new ArraySegment <byte>(encoded, 0, encoded.Length);
await ClientWs.SendAsync(segment, WebSocketMessageType.Text, true, CancellationToken.None);
}