RPC-JSON over WebSockets

src/WebSocketServer/WalletSession.cs

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+using Neo.Wallets;
+using System;
+
+namespace Neo.Plugins
+{
+    public class WalletSession
+    {
+        public Wallet Wallet { get; private init; }
+        public DateTime Expires { get; private set; }
+
+        public WalletSession(
+            Wallet wallet)
+        {
+            Wallet = wallet;
+            ResetExpiration();
+        }
+
+        public void ResetExpiration() =>
+            Expires = DateTime.Now.AddSeconds(WebSocketServerSettings.Current?.WalletSessionTimeout ?? WebSocketServerSettings.Default.WalletSessionTimeout);
+    }
+}

src/WebSocketServer/WalletSessionManager.cs

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+using System;
+using System.Collections.Concurrent;
+using System.Linq;
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace Neo.Plugins
+{
+    public class WalletSessionManager : ConcurrentDictionary<Guid, WalletSession>
+    {
+        private readonly PeriodicTimer _timer;
+
+        public WalletSessionManager()
+        {
+            _timer = new(TimeSpan.FromSeconds(1));
+            _ = Task.Run(SessionTimeoutAsync);
+        }
+
+        private async Task SessionTimeoutAsync()
+        {
+            while (await _timer.WaitForNextTickAsync())
+            {
+                var killAll = this.Where(w => w.Value.Expires <= DateTime.Now)
+                    .Select(s => Task.Run(() =>
+                    {
+                        TryRemove(s);
+                    }));
+                await Task.WhenAll(killAll);
+            }
+        }
+    }
+}

src/WebSocketServer/WebSocketClient.cs

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+using Neo.Json;
+using System;
+using System.Net.WebSockets;
+using System.Text;
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace Neo.Plugins
+{
+    internal class WebSocketClient : IDisposable, IEquatable<WebSocketClient>
+    {
+        public WebSocket Socket { get; init; }
+
+        public bool IsConnected =>
+            Socket != null &&
+            Socket.State == WebSocketState.Open;
+
+        public void Dispose()
+        {
+            Socket?.Dispose();
+            GC.SuppressFinalize(this);
+        }
+
+        public async Task SendJsonAsync(JToken message)
+        {
+            if (IsConnected)
+            {
+                await Socket!.SendAsync(
+                    new(Encoding.UTF8.GetBytes(message.ToString())),
+                    WebSocketMessageType.Text,
+                    true,
+                    CancellationToken.None).ConfigureAwait(false);
+            }
+        }
+
+        public async Task CloseAsync(WebSocketCloseStatus status)
+        {
+            if (Socket == null)
+                return;
+            switch (Socket.State)
+            {
+                case WebSocketState.Connecting:
+                case WebSocketState.Open:
+                    await Socket.CloseOutputAsync(status, string.Empty, CancellationToken.None).ConfigureAwait(false);
+                    break;
+                default:
+                    break;
+            }
+        }
+
+        #region IEquatable
+
+        public bool Equals(WebSocketClient other) =>
+            ReferenceEquals(Socket, other?.Socket);
+
+        public override int GetHashCode() =>
+            HashCode.Combine(this, Socket);
+
+        public override bool Equals(object obj)
+        {
+            if (ReferenceEquals(obj, this))
+                return true;
+            if (obj == null)
+                return false;
+            if (obj is not WebSocketClient wsObj)
+                return false;
+            return Equals(wsObj);
+        }
+
+        public static bool operator ==(WebSocketClient left, WebSocketClient right)
+        {
+            if (left as object is null || right as object is null)
+                return Equals(left, right);
+            return left.Equals(right);
+        }
+
+        public static bool operator !=(WebSocketClient left, WebSocketClient right)
+        {
+            if (left as object is null || right as object is null)
+                return Equals(left, right) == false;
+            return left.Equals(right) == false;
+        }
+
+        #endregion
+    }
+}