Process iterator in RPC result

src/RpcServer/RpcServer.SmartContract.cs

@@ -7,8 +7,10 @@
 using Neo.Network.P2P.Payloads;
 using Neo.Persistence;
 using Neo.SmartContract;
+using Neo.SmartContract.Iterators;
 using Neo.SmartContract.Native;
 using Neo.VM;
+using Neo.VM.Types;
 using Neo.Wallets;
 using System;
 using System.IO;
@@ -65,7 +67,7 @@ private JObject GetInvokeResult(byte[] script, Signers signers = null)
             Transaction tx = signers == null ? null : new Transaction
             {
                 Signers = signers.GetSigners(),
-                Attributes = Array.Empty<TransactionAttribute>(),
+                Attributes = System.Array.Empty<TransactionAttribute>(),
                 Witnesses = signers.Witnesses,
             };
             using ApplicationEngine engine = ApplicationEngine.Run(script, system.StoreView, container: tx, settings: system.Settings, gas: settings.MaxGasInvoke);
@@ -76,11 +78,12 @@ private JObject GetInvokeResult(byte[] script, Signers signers = null)
             json["exception"] = GetExceptionMessage(engine.FaultException);
             try
             {
-                json["stack"] = new JArray(engine.ResultStack.Select(p => p.ToJson()));
+                int max = settings.MaxResultItems;
+                json["stack"] = new JArray(engine.ResultStack.Select(p => ToJson(p, ref max)));
             }
             catch (InvalidOperationException)
             {
-                json["stack"] = "error: recursive reference";
+                json["stack"] = "error: invalid operation";
             }
             if (engine.State != VMState.FAULT)
             {
@@ -89,6 +92,34 @@ private JObject GetInvokeResult(byte[] script, Signers signers = null)
             return json;
         }
 
+        private JObject ToJson(StackItem p, ref int max)
+        {
+            if (max <= 0) throw new InvalidOperationException();
+            max--;
+
+            if (p is InteropInterface result)
+            {
+                var iterator = result.GetInterface<IIterator>();
+                if (iterator != null)
+                {
+                    VM.Types.Array resultList = new();
+                    while (iterator.Next())
+                    {
+                        resultList.Add(iterator.Value());
+                        max--;
+                        if (max <= 0) throw new InvalidOperationException();
+                    }
+
+                    JObject ret = new();
+                    ret["type"] = "InteropInterface";
+                    ret["value"] = ToJson(resultList, ref max);
+                    return ret;
+                }
+            }
+
+            return p.ToJson();
+        }
+
         private static Signers SignersFromJson(JArray _params, ProtocolSettings settings)
         {
             var ret = new Signers(_params.Select(u => new Signer()

src/RpcServer/RpcServer/config.json

@@ -13,6 +13,7 @@
         "MaxGasInvoke": 20,
         "MaxFee": 0.1,
         "MaxConcurrentConnections": 40,
+        "MaxResultItems": 100,
         "DisabledMethods": [ "openwallet" ]
       }
     ]

src/RpcServer/Settings.cs

@@ -31,6 +31,7 @@ public record RpcServerSettings
         public long MaxGasInvoke { get; init; }
         public long MaxFee { get; init; }
         public string[] DisabledMethods { get; init; }
+        public int MaxResultItems { get; init; }
 
         public static RpcServerSettings Default { get; } = new RpcServerSettings
         {
@@ -43,6 +44,7 @@ public record RpcServerSettings
             TrustedAuthorities = Array.Empty<string>(),
             DisabledMethods = Array.Empty<string>(),
             MaxConcurrentConnections = 40,
+            MaxResultItems = 100,
         };
 
         public static RpcServerSettings Load(IConfigurationSection section) => new RpcServerSettings
@@ -59,6 +61,7 @@ public record RpcServerSettings
             MaxFee = (long)new BigDecimal(section.GetValue<decimal>("MaxFee", Default.MaxFee), NativeContract.GAS.Decimals).Value,
             DisabledMethods = section.GetSection("DisabledMethods").GetChildren().Select(p => p.Get<string>()).ToArray(),
             MaxConcurrentConnections = section.GetValue("MaxConcurrentConnections", Default.MaxConcurrentConnections),
+            MaxResultItems = section.GetValue("MaxResultItems", Default.MaxResultItems),
         };
     }
 }