RPC-JSON over WebSockets

src/WebSocketServer/WebSocketClient.cs

@@ -9,7 +9,7 @@ namespace Neo.Plugins
 {
     internal class WebSocketClient : IDisposable, IEquatable<WebSocketClient>
     {
-        public WebSocket Socket { get; init; }
+        public WebSocket? Socket { get; init; }
 
         public bool IsConnected =>
             Socket != null &&
@@ -25,7 +25,7 @@ public async Task SendJsonAsync(JToken message)
         {
             if (IsConnected)
             {
-                await Socket.SendAsync(
+                await Socket!.SendAsync(
                     new(Encoding.UTF8.GetBytes(message.ToString())),
                     WebSocketMessageType.Text,
                     true,
@@ -50,13 +50,13 @@ public async Task CloseAsync(WebSocketCloseStatus status)
 
         #region IEquatable
 
-        public bool Equals(WebSocketClient other) =>
+        public bool Equals(WebSocketClient? other) =>
             ReferenceEquals(Socket, other?.Socket);
 
         public override int GetHashCode() =>
             HashCode.Combine(this, Socket);
 
-        public override bool Equals(object obj)
+        public override bool Equals(object? obj)
         {
             if (ReferenceEquals(obj, this))
                 return true;

src/WebSocketServer/WebSocketConnection.cs

@@ -18,10 +18,10 @@ internal class WebSocketConnection<TClient> : IDictionary<Guid, TClient>, IDispo
     {
         private readonly ConcurrentDictionary<Guid, TClient> _clients;
 
-        public static event WebSocketMessageSent OnMessageSent;
-        public static event WebSocketMessageReceived OnMessageReceived;
-        public static event WebSocketConnect OnConnect;
-        public static event WebSocketDisconnect OnDisconnect;
+        public static event WebSocketMessageSent? OnMessageSent;
+        public static event WebSocketMessageReceived? OnMessageReceived;
+        public static event WebSocketConnect? OnConnect;
+        public static event WebSocketDisconnect? OnDisconnect;
 
         public WebSocketConnection()
         {
@@ -125,10 +125,10 @@ public async Task ProcessClientAsync(WebSocket client, TaskCompletionSource tcs)
                         {
                             requestId = message.RequestId;
 
-                            if (WebSocketServerPlugin.Methods.TryGetValue(message.Method, out var callMethod) == false)
+                            if (WebSocketServerPlugin.Methods.TryGetValue(message.Method!, out var callMethod) == false)
                                 throw new WebSocketException(-32601, "Method not found");
 
-                            var obj = callMethod(message.Params);
+                            var obj = callMethod(message.Params!);
 
                             if (obj is Task<JToken> responseTask)
                                 obj = await responseTask.ConfigureAwait(false);
@@ -173,8 +173,8 @@ private async Task SendJsonAndCleanUpAsync(KeyValuePair<Guid, TClient> kvp, JTok
 
         private static async Task<WebSocketRequestMessage> ReceiveMessageAsync(Guid clientId, WebSocket client)
         {
-            var buffer = new byte[WebSocketServerSettings.Current.MessageSize]; // 4096 bytes
-            WebSocketReceiveResult receiveResult = null;
+            var buffer = new byte[WebSocketServerSettings.Current?.MessageSize ?? WebSocketServerSettings.Default.MessageSize]; // 4096 bytes
+            WebSocketReceiveResult? receiveResult = null;
 
             using var ms = new MemoryStream();
             while (receiveResult == null || receiveResult.EndOfMessage == false)

src/WebSocketServer/WebSocketErrorResult.cs

@@ -6,9 +6,9 @@ namespace Neo.Plugins
     internal class WebSocketErrorResult
     {
         public int Code { get; init; }
-        public string Message { get; init; }
+        public string Message { get; init; } = string.Empty;
 #if DEBUG
-        public string StackTrace { get; init; }
+        public string? StackTrace { get; init; }
 #endif
 
         public static WebSocketErrorResult Create(Exception exception) =>

src/WebSocketServer/WebSocketExtensions.cs

@@ -14,7 +14,9 @@ public static JToken ToJson(this NotifyEventArgs args, bool showTxHash = true)
             {
                 ["scripthash"] = $"{args?.ScriptHash}",
                 ["eventname"] = $"{args?.EventName}",
-                ["state"] = new JArray(args?.State?.Select(s => s.ToJson())),
+                ["state"] = args?.State?.Count > 0 ?
+                    new JArray(args!.State.Select(s => s.ToJson())) :
+                    Array.Empty<JToken?>(),
             };
 
             if (showTxHash)

src/WebSocketServer/WebSocketMethodAttribute.cs

@@ -5,6 +5,6 @@ namespace Neo.Plugins
     [AttributeUsage(AttributeTargets.Method, AllowMultiple = false)]
     internal class WebSocketMethodAttribute : Attribute
     {
-        public string Name { get; set; }
+        public string Name { get; set; } = string.Empty;
     }
 }

src/WebSocketServer/WebSocketRequestMessage.cs

@@ -5,18 +5,18 @@ namespace Neo.Plugins
 {
     internal class WebSocketRequestMessage
     {
-        public Version Version { get; set; }
+        public Version? Version { get; set; }
         public int RequestId { get; set; }
-        public string Method { get; set; }
-        public JArray Params { get; set; }
+        public string? Method { get; set; }
+        public JArray? Params { get; set; }
 
-        public static WebSocketRequestMessage FromJson(JToken message) =>
+        public static WebSocketRequestMessage FromJson(JToken? message) =>
             new()
             {
-                Version = new(message["version"].AsString()),
-                RequestId = checked((int)message["requestid"].AsNumber()),
-                Method = message["method"].AsString(),
-                Params = (JArray)message["params"],
+                Version = message?["version"] == null ? null : new(message["version"]!.AsString()),
+                RequestId = message?["requestid"] == null ? 0 : checked((int)message["requestid"]!.AsNumber()),
+                Method = message?["method"]?.AsString(),
+                Params = message?["params"] == null ? null : (JArray)message["params"]!,
             };
 
     }

src/WebSocketServer/WebSocketResponseMessage.cs

@@ -9,7 +9,7 @@ internal class WebSocketResponseMessage : IEquatable<WebSocketResponseMessage>
         public Version Version { get; private init; } = new("1.0");
         public int RequestId { get; private init; }
         public byte EventId { get; private init; }
-        public JToken Result { get; private init; }
+        public JToken? Result { get; private init; }
 
         internal static WebSocketResponseMessage Create(int requestId, JToken result, WebSocketResponseMessageEvent eventId) =>
             new()
@@ -39,9 +39,9 @@ public JToken ToJson() =>
         public static WebSocketResponseMessage FromJson(JToken message) =>
             new()
             {
-                Version = new(message["version"].AsString()),
-                RequestId = checked((int)message["requestid"].AsNumber()),
-                EventId = (byte)message["eventid"].AsNumber(),
+                Version = message["version"] == null ? new("1.0") : new(message["version"]!.AsString()),
+                RequestId = message["requestid"] == null ? 0 : checked((int)message["requestid"]!.AsNumber()),
+                EventId = message["eventid"] == null ? (byte)0 : unchecked((byte)message["eventid"]!.AsNumber()),
                 Result = message["result"],
             };
 
@@ -51,11 +51,11 @@ public override string ToString() =>
         public byte[] ToArray() =>
             Encoding.UTF8.GetBytes(ToString());
 
-        public bool Equals(WebSocketResponseMessage other) =>
+        public bool Equals(WebSocketResponseMessage? other) =>
             other != null && other.EventId == EventId && other.RequestId == RequestId &&
             other.Version == Version && other.Result == Result;
 
-        public override bool Equals(object obj)
+        public override bool Equals(object? obj)
         {
             if (ReferenceEquals(this, obj)) return true;
             return Equals(obj as WebSocketResponseMessage);

src/WebSocketServer/WebSocketServer.csproj

@@ -2,7 +2,8 @@
 
   <PropertyGroup>
     <PackageId>Neo.Plugins.WebSocketServer</PackageId>
-    <RootNamespace>Neo.Plugins</RootNamespace>
+    <RootNamespace>Neo.Plugins</RootNamespace>
+    <Nullable>enable</Nullable>
   </PropertyGroup>
 
 </Project>

src/WebSocketServer/WebSocketServerPlugin.cs

@@ -24,8 +24,8 @@ namespace Neo.Plugins
     public delegate void WebSocketDisconnect(Guid clientId);
     public delegate void WebSocketRequest(HttpContext httpContext);
     public delegate void WebSocketServerStarted();
-    public delegate void WebSocketMessageReceived(Guid clientId, JToken json);
-    public delegate void WebSocketMessageSent(Guid clientId, JToken json);
+    public delegate void WebSocketMessageReceived(Guid clientId, JToken? json);
+    public delegate void WebSocketMessageSent(Guid clientId, JToken? json);
 
     public class WebSocketServerPlugin : Plugin
     {
@@ -35,19 +35,19 @@ public class WebSocketServerPlugin : Plugin
 
         internal static readonly Dictionary<string, Func<JArray, object>> Methods;
         private static readonly WebSocketConnection<WebSocketClient> _connections;
-        public static event WebSocketRequest OnRequest;
-        public static event WebSocketServerStarted OnServerStarted;
+        public static event WebSocketRequest? OnRequest;
+        public static event WebSocketServerStarted? OnServerStarted;
 
         #endregion
 
         private readonly WebSocketOptions _webSocketOptions;
         private readonly List<NotifyEventArgs> _notifyEvents;
 
-        private BlockchainMethods blockchainMethods;
-        private NeoSystem _neoSystem;
+        private BlockchainMethods? blockchainMethods;
+        private NeoSystem? _neoSystem;
 
 
-        private IWebHost _host;
+        private IWebHost? _host;
 
         #endregion
 
@@ -86,7 +86,7 @@ public override void Dispose()
             _host?.Dispose();
             _connections?.Dispose();
             if (_neoSystem != null)
-                _neoSystem.MemPool.TransactionAdded -= OnMemPoolTransactionAdded;
+                _neoSystem.MemPool.TransactionAdded -= OnMemPoolTransactionAdded!;
             Blockchain.Committing -= OnBlockchainCommitting;
             Blockchain.Committed -= OnBlockchainCommitted;
             GC.SuppressFinalize(this);
@@ -106,11 +106,11 @@ protected override void OnSystemLoaded(NeoSystem system)
 
             if (WebSocketServerSettings.Current.DebugMode)
             {
-                ApplicationEngine.Log += OnApplicationEngineLog;
+                ApplicationEngine.Log += OnApplicationEngineLog!;
                 Utility.Logging += OnUtilityLogging;
             }
 
-            _neoSystem.MemPool.TransactionAdded += OnMemPoolTransactionAdded;
+            _neoSystem.MemPool.TransactionAdded += OnMemPoolTransactionAdded!;
             //_neoSystem.MemPool.TransactionRemoved += OnMemPoolTransactionRemoved;
 
             blockchainMethods = new BlockchainMethods(system);
@@ -130,7 +130,7 @@ private void OnMemPoolTransactionAdded(object sender, Network.P2P.Payloads.Trans
                 await _connections.SendAllJsonAsync(
                     WebSocketResponseMessage.Create(
                         RandomNumberGenerator.GetInt32(2, int.MaxValue),
-                        e.ToJson(_neoSystem.Settings),
+                        e.ToJson(_neoSystem?.Settings),
                         WebSocketResponseMessageEvent.MemoryPool)
                     .ToJson())
                 .ConfigureAwait(false));
@@ -303,9 +303,9 @@ private void StartWebSocketServer()
             .UseKestrel(options =>
             {
                 options.AddServerHeader = false;
-                options.Listen(WebSocketServerSettings.Current.BindAddress, WebSocketServerSettings.Current.Port, config =>
+                options.Listen(WebSocketServerSettings.Current?.BindAddress ?? WebSocketServerSettings.Default.BindAddress, WebSocketServerSettings.Current?.Port ?? WebSocketServerSettings.Default.Port, config =>
                 {
-                    if (string.IsNullOrEmpty(WebSocketServerSettings.Current.SslCertFile))
+                    if (string.IsNullOrEmpty(WebSocketServerSettings.Current?.SslCertFile))
                         return;
                     config.UseHttps(WebSocketServerSettings.Current.SslCertFile, WebSocketServerSettings.Current.SslCertPassword, httpsConnectionAdapterOptions =>
                     {
@@ -316,8 +316,8 @@ private void StartWebSocketServer()
                         {
                             if (err != SslPolicyErrors.None)
                                 return false;
-                            X509Certificate2 authority = chain.ChainElements[^1].Certificate;
-                            return WebSocketServerSettings.Current.TrustedAuthorities.Contains(authority.Thumbprint);
+                            X509Certificate2 authority = chain!.ChainElements[^1].Certificate;
+                            return WebSocketServerSettings.Current.TrustedAuthorities.Contains(authority!.Thumbprint);
                         };
                     });
                 });
@@ -328,9 +328,9 @@ private void StartWebSocketServer()
             //})
             .Configure(app =>
             {
-                _webSocketOptions.KeepAliveInterval = TimeSpan.FromSeconds(WebSocketServerSettings.Current.ConcurrentProxyTimeout);
+                _webSocketOptions.KeepAliveInterval = TimeSpan.FromSeconds(WebSocketServerSettings.Current?.ConcurrentProxyTimeout ?? WebSocketServerSettings.Default.ConcurrentProxyTimeout);
 
-                foreach (var origin in WebSocketServerSettings.Current.AllowOrigins)
+                foreach (var origin in WebSocketServerSettings.Current?.AllowOrigins ?? WebSocketServerSettings.Default.AllowOrigins)
                     _webSocketOptions.AllowedOrigins.Add(origin);
 
                 app.UseWebSockets(_webSocketOptions);
@@ -345,7 +345,7 @@ private void StartWebSocketServer()
 
         private async Task ProcessRequestsAsync(HttpContext context)
         {
-            if (WebSocketServerSettings.Current.EnableBasicAuthentication)
+            if (WebSocketServerSettings.Current?.EnableBasicAuthentication ?? WebSocketServerSettings.Default.EnableBasicAuthentication)
             {
                 if (IsAuthorized(context) == false)
                 {
@@ -383,7 +383,7 @@ private static bool IsAuthorized(HttpContext context)
                     {
                         var decodedParams = Encoding.UTF8.GetString(Convert.FromBase64String(authValue.Parameter));
                         var creds = decodedParams.Split(':', 2);
-                        if (creds[0] == WebSocketServerSettings.Current.User && creds[1] == WebSocketServerSettings.Current.Pass)
+                        if (creds[0] == WebSocketServerSettings.Current?.User && creds[1] == WebSocketServerSettings.Current?.Pass)
                             return true;
 
                     }

src/WebSocketServer/WebSocketServerSettings.cs

@@ -7,15 +7,15 @@ namespace Neo.Plugins
     public class WebSocketServerSettings
     {
         public uint Network { get; private init; }
-        public IPAddress BindAddress { get; private set; }
+        public IPAddress BindAddress { get; private set; } = IPAddress.Loopback;
         public int Port { get; private init; }
-        public string SslCertFile { get; private init; }
-        public string SslCertPassword { get; private init; }
-        public string[] TrustedAuthorities { get; private init; }
+        public string? SslCertFile { get; private init; }
+        public string? SslCertPassword { get; private init; }
+        public string[] TrustedAuthorities { get; private init; } = Array.Empty<string>();
         public bool EnableBasicAuthentication { get; private init; }
-        public string User { get; private init; }
-        public string Pass { get; private init; }
-        public string[] AllowOrigins { get; private init; }
+        public string? User { get; private init; }
+        public string? Pass { get; private init; }
+        public string[] AllowOrigins { get; private init; } = Array.Empty<string>();
         public uint ConcurrentProxyTimeout { get; private init; }
         public uint MessageSize { get; private init; }
         public long MaxGasInvoke { get; private init; }
@@ -41,7 +41,7 @@ public class WebSocketServerSettings
             DebugMode = false,
         };
 
-        public static WebSocketServerSettings Current { get; private set; }
+        public static WebSocketServerSettings? Current { get; private set; }
 
         internal static void Load(IConfigurationSection section)
         {

src/WebSocketServer/WebSocketUtilityLogResult.cs

@@ -4,9 +4,9 @@ namespace Neo.Plugins
 {
     internal class WebSocketUtilityLogResult
     {
-        public string SourceName { get; init; }
+        public string? SourceName { get; init; }
         public LogLevel LogLevel { get; init; }
-        public object Message { get; init; }
+        public object? Message { get; init; }
 
         public static WebSocketUtilityLogResult Create(string sourceName, LogLevel level, object message) =>
             new()