Cancel aborted sessions

This commit is contained in:
Frank A. Krueger 2017-06-15 21:21:38 -07:00
parent 096c42adbc
commit a8b227ec1c
1 changed files with 114 additions and 76 deletions

View File

@ -179,7 +179,7 @@ namespace Ooui
response.Close (); response.Close ();
} }
static async void ProcessWebSocketRequest (HttpListenerContext listenerContext, CancellationToken token) static async void ProcessWebSocketRequest (HttpListenerContext listenerContext, CancellationToken serverToken)
{ {
// //
// Find the element // Find the element
@ -225,82 +225,11 @@ namespace Ooui
} }
// //
// Keep a list of all the elements for which we've transmitted the initial state // Create a new session and let it handle everything from here
//
var createdIds = new HashSet<string> {
"window",
"document",
"document.body",
};
//
// Preparse handlers for the element
//
Action<Message> onElementMessage = async m => {
if (webSocket == null) return;
try {
await SendMessageAsync (webSocket, m, element, createdIds, token).ConfigureAwait (false);
}
catch (Exception ex) {
Error ("Failed to handled element message", ex);
}
};
//
// Communicate!
// //
try { try {
// var session = new Session (webSocket, element);
// Start watching for changes in the element await session.RunAsync (serverToken).ConfigureAwait (false);
//
element.MessageSent += onElementMessage;
//
// Add it to the document body
//
await SendMessageAsync (webSocket, new Message {
TargetId = "document.body",
MessageType = MessageType.Call,
Key = "appendChild",
Value = new[] { element },
}, element, createdIds, token).ConfigureAwait (false);
//
// Listen for events
//
var receiveBuffer = new byte[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);
}
else if (receiveResult.MessageType == WebSocketMessageType.Binary) {
await webSocket.CloseAsync (WebSocketCloseStatus.InvalidMessageType, "Cannot accept binary frame", token).ConfigureAwait (false);
}
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);
}
}
}
} }
catch (WebSocketException ex) when (ex.WebSocketErrorCode == WebSocketError.ConnectionClosedPrematurely) { catch (WebSocketException ex) when (ex.WebSocketErrorCode == WebSocketError.ConnectionClosedPrematurely) {
// The remote party closed the WebSocket connection without completing the close handshake. // The remote party closed the WebSocket connection without completing the close handshake.
@ -309,7 +238,6 @@ namespace Ooui
Error ("Web socket failed", ex); Error ("Web socket failed", ex);
} }
finally { finally {
element.MessageSent -= onElementMessage;
webSocket?.Dispose (); webSocket?.Dispose ();
} }
} }
@ -364,5 +292,115 @@ namespace Ooui
Console.WriteLine ("{0}: {1}", message, ex); Console.WriteLine ("{0}: {1}", message, ex);
Console.ResetColor (); Console.ResetColor ();
} }
class Session
{
readonly WebSocket webSocket;
readonly Element element;
public Session (WebSocket webSocket, Element element)
{
this.webSocket = webSocket;
this.element = element;
}
public async Task RunAsync (CancellationToken serverToken)
{
//
// Create a new session cancellation token that will trigger
// automatically if the server shutsdown or the session shutsdown.
//
var sessionCts = new CancellationTokenSource ();
var linkedCts = CancellationTokenSource.CreateLinkedTokenSource (serverToken, sessionCts.Token);
var token = linkedCts.Token;
//
// Keep a list of all the elements for which we've transmitted the initial state
//
var createdIds = new HashSet<string> {
"window",
"document",
"document.body",
};
//
// Preparse handlers for the element
//
Action<Message> onElementMessage = null;
onElementMessage = async m => {
if (webSocket == null) return;
try {
await SendMessageAsync (webSocket, m, element, createdIds, token).ConfigureAwait (false);
}
catch (Exception ex) {
if (webSocket.State == WebSocketState.Aborted) {
Error ("WebSocket is aborted, cancelling session", ex);
element.MessageSent -= onElementMessage;
sessionCts.Cancel ();
}
else {
Error ("Failed to handle element message", ex);
}
}
};
//
// Start watching for changes in the element
//
element.MessageSent += onElementMessage;
try {
//
// Add it to the document body
//
await SendMessageAsync (webSocket, new Message {
TargetId = "document.body",
MessageType = MessageType.Call,
Key = "appendChild",
Value = new[] { element },
}, element, createdIds, token).ConfigureAwait (false);
//
// Listen for events
//
var receiveBuffer = new byte[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);
}
else if (receiveResult.MessageType == WebSocketMessageType.Binary) {
await webSocket.CloseAsync (WebSocketCloseStatus.InvalidMessageType, "Cannot accept binary frame", token).ConfigureAwait (false);
}
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 -= onElementMessage;
}
}
}
} }
} }