add logs to execution

src/ApplicationLogs/LogReader.cs

@@ -25,7 +25,7 @@ namespace Neo.Plugins
 {
     public class LogReader : Plugin
     {
-        private DB db;
+        private DB _db;
         private WriteBatch _writeBatch;
 
         public override string Name => "ApplicationLogs";
@@ -47,7 +47,7 @@ protected override void Configure()
         {
             Settings.Load(GetConfiguration());
             string path = string.Format(Settings.Default.Path, Settings.Default.Network.ToString("X8"));
-            db = DB.Open(GetFullPath(path), new Options { CreateIfMissing = true });
+            _db = DB.Open(GetFullPath(path), new Options { CreateIfMissing = true });
         }
 
         protected override void OnSystemLoaded(NeoSystem system)
@@ -60,7 +60,7 @@ protected override void OnSystemLoaded(NeoSystem system)
         public JObject GetApplicationLog(JArray _params)
         {
             UInt256 hash = UInt256.Parse(_params[0].AsString());
-            byte[] value = db.Get(ReadOptions.Default, hash.ToArray());
+            byte[] value = _db.Get(ReadOptions.Default, hash.ToArray());
             if (value is null)
                 throw new RpcException(-100, "Unknown transaction/blockhash");
 
@@ -176,8 +176,13 @@ private void OnCommitting(NeoSystem system, Block block, DataCache snapshot, IRe
             foreach (var appExec in applicationExecutedList.Where(p => p.Transaction != null))
             {
                 var txJson = TxLogToJson(appExec);
+                if (RpcServerPlugin.LogEvents.TryGetValue(appExec.Transaction.Hash, out var list))
+                {
+                    txJson["logs"] = new JArray(list.Select(q => new JString(q.Message)));
+                }
                 Put(appExec.Transaction.Hash.ToArray(), Neo.Utility.StrictUTF8.GetBytes(txJson.ToString()));
             }
+            RpcServerPlugin.LogEvents.Clear();
 
             //processing log for block
             var blockJson = BlockLogToJson(block, applicationExecutedList);
@@ -190,7 +195,7 @@ private void OnCommitting(NeoSystem system, Block block, DataCache snapshot, IRe
         private void OnCommitted(NeoSystem system, Block block)
         {
             if (system.Settings.Network != Settings.Default.Network) return;
-            db.Write(WriteOptions.Default, _writeBatch);
+            _db.Write(WriteOptions.Default, _writeBatch);
         }
 
         static string GetExceptionMessage(Exception exception)

src/RpcServer/RpcServer.SmartContract.cs

@@ -121,6 +121,8 @@ private JObject GetInvokeResult(byte[] script, Signer[] signers = null, Witness[
                 lock (sessions)
                     sessions.Add(id, session);
             }
+            if (session.Engine.ScriptContainer is Transaction tx && RpcServerPlugin.LogEvents.ContainsKey(tx.Hash))
+                json["logs"] = new JArray(RpcServerPlugin.LogEvents[tx.Hash].Select(p => new JString(p.Message)));
             return json;
         }
 
@@ -197,7 +199,7 @@ private static Witness[] WitnessesFromJson(JArray _params)
         [RpcMethod]
         protected virtual JObject InvokeFunction(JArray _params)
         {
-            UInt160 script_hash = UInt160.Parse(_params[0].AsString());
+            UInt160 scriptHash = UInt160.Parse(_params[0].AsString());
             string operation = _params[1].AsString();
             ContractParameter[] args = _params.Count >= 3 ? ((JArray)_params[2]).Select(p => ContractParameter.FromJson(p)).ToArray() : System.Array.Empty<ContractParameter>();
             Signer[] signers = _params.Count >= 4 ? SignersFromJson((JArray)_params[3], system.Settings) : null;
@@ -207,7 +209,7 @@ protected virtual JObject InvokeFunction(JArray _params)
             byte[] script;
             using (ScriptBuilder sb = new())
             {
-                script = sb.EmitDynamicCall(script_hash, operation, args).ToArray();
+                script = sb.EmitDynamicCall(scriptHash, operation, args).ToArray();
             }
             return GetInvokeResult(script, signers, witnesses, useDiagnostic);
         }
@@ -260,20 +262,20 @@ protected virtual JObject GetUnclaimedGas(JArray _params)
         {
             string address = _params[0].AsString();
             JObject json = new();
-            UInt160 script_hash;
+            UInt160 scriptHash;
             try
             {
-                script_hash = AddressToScriptHash(address, system.Settings.AddressVersion);
+                scriptHash = AddressToScriptHash(address, system.Settings.AddressVersion);
             }
             catch
             {
-                script_hash = null;
+                scriptHash = null;
             }
-            if (script_hash == null)
+            if (scriptHash == null)
                 throw new RpcException(-100, "Invalid address");
             var snapshot = system.StoreView;
-            json["unclaimed"] = NativeContract.NEO.UnclaimedGas(snapshot, script_hash, NativeContract.Ledger.CurrentIndex(snapshot) + 1).ToString();
-            json["address"] = script_hash.ToAddress(system.Settings.AddressVersion);
+            json["unclaimed"] = NativeContract.NEO.UnclaimedGas(snapshot, scriptHash, NativeContract.Ledger.CurrentIndex(snapshot) + 1).ToString();
+            json["address"] = scriptHash.ToAddress(system.Settings.AddressVersion);
             return json;
         }
 

src/RpcServer/RpcServer.cs

@@ -15,7 +15,6 @@
 using Microsoft.AspNetCore.ResponseCompression;
 using Microsoft.AspNetCore.Server.Kestrel.Https;
 using Microsoft.Extensions.DependencyInjection;
-using Neo.IO;
 using Neo.IO.Json;
 using Neo.Network.P2P;
 using System;
@@ -49,6 +48,7 @@ public RpcServer(NeoSystem system, RpcServerSettings settings)
             Initialize_SmartContract();
         }
 
+
         private bool CheckAuth(HttpContext context)
         {
             if (string.IsNullOrEmpty(settings.RpcUser)) return true;

src/RpcServer/RpcServer.csproj

@@ -4,5 +4,9 @@
     <PackageId>Neo.Plugins.RpcServer</PackageId>
     <RootNamespace>Neo.Plugins</RootNamespace>
   </PropertyGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\RpcClient\RpcClient.csproj" />
+  </ItemGroup>
 
 </Project>

src/RpcServer/RpcServerPlugin.cs

@@ -10,6 +10,9 @@
 
 using System.Collections.Generic;
 using System.Linq;
+using Neo.Ledger;
+using Neo.Network.P2P.Payloads;
+using Neo.SmartContract;
 
 namespace Neo.Plugins
 {
@@ -22,6 +25,16 @@ public class RpcServerPlugin : Plugin
         private static readonly Dictionary<uint, RpcServer> servers = new();
         private static readonly Dictionary<uint, List<object>> handlers = new();
 
+        /// <summary>
+        /// Public interface of _logEvents.
+        /// </summary>
+        public static Dictionary<UInt256, Queue<LogEventArgs>> LogEvents { get; } = new();
+
+        /// <summary>
+        /// Maximum number of events to be logged per contract
+        /// </summary>
+        private const int MaxLogEvents = 50;
+
         protected override void Configure()
         {
             settings = new Settings(GetConfiguration());
@@ -30,11 +43,9 @@ protected override void Configure()
                     server.UpdateSettings(s);
         }
 
-        public override void Dispose()
+        private void OnCommitted(NeoSystem system, Block block)
         {
-            foreach (var (_, server) in servers)
-                server.Dispose();
-            base.Dispose();
+            LogEvents.Clear();
         }
 
         protected override void OnSystemLoaded(NeoSystem system)
@@ -54,6 +65,34 @@ protected override void OnSystemLoaded(NeoSystem system)
 
             server.StartRpcServer();
             servers.TryAdd(s.Network, server);
+
+            // It is potentially possible to have dos attack by sending a lot of transactions and logs.
+            // To prevent this, we limit the number of logs to be logged per contract.
+            // If the number of logs is greater than MAX_LOG_EVENTS, we remove the oldest log.
+            void Ev(object _, LogEventArgs e)
+            {
+                if (e.ScriptContainer is not Transaction tx) return;
+                if (!LogEvents.TryGetValue(tx.Hash, out var _logs))
+                {
+                    _logs = new Queue<LogEventArgs>();
+                    LogEvents.Add(tx.Hash, _logs);
+                }
+                if (LogEvents[tx.Hash].Count >= MaxLogEvents)
+                {
+                    _logs.Dequeue();
+                }
+                _logs.Enqueue(e);
+            }
+            ApplicationEngine.Log += Ev;
+            Blockchain.Committed += OnCommitted;
+        }
+
+        public override void Dispose()
+        {
+            Blockchain.Committed -= OnCommitted;
+            foreach (var (_, server) in servers)
+                server.Dispose();
+            base.Dispose();
         }
 
         public static void RegisterMethods(object handler, uint network)