Ooui-tws-port/Ooui/WebSocketSession.cs

158 lines
6.4 KiB
C#

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading;
using System.Threading.Tasks;
using System.Net;
using System.Net.WebSockets;
namespace Ooui
{
public class WebSocketSession : Session
{
readonly WebSocket webSocket;
readonly Action<Message> handleElementMessageSent;
readonly CancellationTokenSource sessionCts = new CancellationTokenSource ();
readonly CancellationTokenSource linkedCts;
readonly CancellationToken token;
readonly System.Timers.Timer sendThrottle;
DateTime lastTransmitTime = DateTime.MinValue;
readonly TimeSpan throttleInterval = TimeSpan.FromSeconds (1.0 / UI.MaxFps);
public WebSocketSession (WebSocket webSocket, Element element, double initialWidth, double initialHeight, CancellationToken serverToken)
: base (element, initialWidth, initialHeight)
{
this.webSocket = webSocket;
//
// Create a new session cancellation token that will trigger
// automatically if the server shutsdown or the session shutsdown.
//
linkedCts = CancellationTokenSource.CreateLinkedTokenSource (serverToken, sessionCts.Token);
token = linkedCts.Token;
//
// Preparse handlers for the element
//
handleElementMessageSent = QueueMessage;
//
// Create a timer to use as a throttle when sending messages
//
sendThrottle = new System.Timers.Timer (throttleInterval.TotalMilliseconds);
sendThrottle.Elapsed += (s, e) => {
// System.Console.WriteLine ("TICK SEND THROTTLE FOR {0}", element);
if ((e.SignalTime - lastTransmitTime) >= throttleInterval) {
sendThrottle.Enabled = false;
lastTransmitTime = e.SignalTime;
TransmitQueuedMessages ();
}
};
}
public async Task RunAsync ()
{
//
// Start watching for changes in the element
//
element.MessageSent += handleElementMessageSent;
try {
//
// Add it to the document body
//
if (element.WantsFullScreen) {
element.Style.Width = initialWidth;
element.Style.Height = initialHeight;
}
QueueMessage (Message.Call ("document.body", "appendChild", element));
//
// Start the Read Loop
//
var receiveBuffer = new byte[64 * 1024];
while (webSocket.State == WebSocketState.Open && !token.IsCancellationRequested) {
var receiveResult = await webSocket.ReceiveAsync (new ArraySegment<byte> (receiveBuffer), token).ConfigureAwait (false);
if (receiveResult.MessageType == WebSocketMessageType.Close) {
await webSocket.CloseAsync (WebSocketCloseStatus.NormalClosure, "", token).ConfigureAwait (false);
sessionCts.Cancel ();
}
else if (receiveResult.MessageType == WebSocketMessageType.Binary) {
await webSocket.CloseAsync (WebSocketCloseStatus.InvalidMessageType, "Cannot accept binary frame", token).ConfigureAwait (false);
sessionCts.Cancel ();
}
else {
var size = receiveResult.Count;
while (!receiveResult.EndOfMessage) {
if (size >= receiveBuffer.Length) {
await webSocket.CloseAsync (WebSocketCloseStatus.MessageTooBig, "Message too big", token).ConfigureAwait (false);
return;
}
receiveResult = await webSocket.ReceiveAsync (new ArraySegment<byte> (receiveBuffer, size, receiveBuffer.Length - size), token).ConfigureAwait (false);
size += receiveResult.Count;
}
var receivedString = Encoding.UTF8.GetString (receiveBuffer, 0, size);
try {
// Console.WriteLine ("RECEIVED: {0}", receivedString);
var message = Newtonsoft.Json.JsonConvert.DeserializeObject<Message> (receivedString);
element.Receive (message);
}
catch (Exception ex) {
Error ("Failed to process received message", ex);
}
}
}
}
finally {
element.MessageSent -= handleElementMessageSent;
}
}
protected override void QueueMessage (Message message)
{
base.QueueMessage (message);
sendThrottle.Enabled = true;
}
async void TransmitQueuedMessages ()
{
try {
//
// Dequeue as many messages as we can
//
var messagesToSend = new List<Message> ();
System.Runtime.CompilerServices.ConfiguredTaskAwaitable task;
lock (queuedMessages) {
messagesToSend.AddRange (queuedMessages);
queuedMessages.Clear ();
if (messagesToSend.Count == 0)
return;
//
// Now actually send this message
// Do this while locked to make sure SendAsync is called in the right order
//
var json = Newtonsoft.Json.JsonConvert.SerializeObject (messagesToSend);
var outputBuffer = new ArraySegment<byte> (Encoding.UTF8.GetBytes (json));
//Console.WriteLine ("TRANSMIT " + json);
task = webSocket.SendAsync (outputBuffer, WebSocketMessageType.Text, true, token).ConfigureAwait (false);
}
await task;
}
catch (Exception ex) {
Error ("Failed to send queued messages, aborting session", ex);
element.MessageSent -= handleElementMessageSent;
sessionCts.Cancel ();
}
}
}
}