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fix verify api #564

Merged
merged 12 commits into from
Mar 17, 2021
17 changes: 8 additions & 9 deletions src/RpcServer/RpcServer.Wallet.cs
Original file line number Diff line number Diff line change
Expand Up @@ -333,7 +333,6 @@ protected virtual JObject SendToAddress(JArray _params)
[RpcMethod]
protected virtual JObject InvokeContractVerify(JArray _params)
{
CheckWallet();
UInt160 script_hash = UInt160.Parse(_params[0].AsString());
ContractParameter[] args = _params.Count >= 2 ? ((JArray)_params[1]).Select(p => ContractParameter.FromJson(p)).ToArray() : new ContractParameter[0];
Signers signers = _params.Count >= 3 ? SignersFromJson((JArray)_params[2], system.Settings) : null;
Expand All @@ -348,20 +347,20 @@ private JObject GetVerificationResult(UInt160 scriptHash, ContractParameter[] ar
{
throw new RpcException(-100, "Unknown contract");
}
var methodName = "verify";
var md = contract.Manifest.Abi.GetMethod("verify", 0);
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Can we set pcount to -1 here in order to be able to call verify with arguments? Just like in https://github.com/neo-project/neo/blob/master/src/neo/SmartContract/Helper.cs#L222.

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Updated it.

if (md is null)
throw new RpcException(-101, $"The smart contract {contract.Hash} haven't got verify method without arguments");
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Exception message should also be updated:

throw new RpcException(-101, $"The smart contract {contract.Hash} haven't got verify method");

if (md.ReturnType != ContractParameterType.Boolean)
throw new RpcException(-102, "The verify method doesn't return boolean value.");

Transaction tx = signers == null ? null : new Transaction
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Can we also fill the transaction when signers == null? We can do it because we know exactly at least one signer (it's the contract to be called). And we also know the witness for this signer: invocation script pushes args on the stack; verification script is empty because it's a contract witness.

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Ok.

{
Signers = signers.GetSigners(),
Attributes = Array.Empty<TransactionAttribute>()
Attributes = Array.Empty<TransactionAttribute>(),
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Can we also fill the transaction script? I think that []byte{OpCode.RET} is enough.

This is needed for those verify methods that use System.Runtime.GetScriptContainer interop, because transaction can't be serialized without a script.

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Updated.

Witnesses = signers.Witnesses,
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Witnesses it wil lbe null, isn't it?

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Yes, just like

Witnesses = signers.Witnesses,

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Removed it since no use here.

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Can we pass witnesses via RPC request parameters, just like signers are passed? And then fill Witnesses here.

};
ContractParametersContext context = new ContractParametersContext(snapshot, tx);
wallet.Sign(context);
tx.Witnesses = context.Completed ? context.GetWitnesses() : null;

using ApplicationEngine engine = ApplicationEngine.Create(TriggerType.Verification, tx, snapshot.CreateSnapshot(), settings: system.Settings);
engine.LoadScript(new ScriptBuilder().EmitDynamicCall(scriptHash, methodName, args).ToArray(), rvcount: 1);

engine.LoadContract(contract, md, CallFlags.ReadOnly);
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And create an invocation script from the given args (it will push all arguments on the stack). And load the script right after the contract script, just like in https://github.com/neo-project/neo/blob/master/src/neo/SmartContract/Helper.cs#L246.

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Updated it. Please test it like:

{
    "jsonrpc": "2.0",
    "method": "invokecontractverify",
    "params": [
        "0x31f714e04766139c8f3705f5ce94518e1411ec07",
        [
            {
                "type": "ByteArray",
                "value": "DED2HMp00JZ2zcJYjKgTp4Tl0GODm5r14PKN6ip8i2+8ox3JYqN2xNHxQzCgzENqSD52GhVF4eGx2i405zxM1KTH"
            }
        ],
        [
            {
                "account": "NMA2FKN8up2cEwaJgtmAiDrZWB69ApnDfp",
                "scopes": "CalledByEntry"
            }
        ]
    ],
    "id": 1
}

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It's not very convenient to construct an invocation script on the client. I would prefer to pass simple standard parameters to the server as we do in the InvokeFunction RPC method. Like the following:

{
    "jsonrpc": "2.0",
    "method": "invokecontractverify",
    "params": [
        "0x31f714e04766139c8f3705f5ce94518e1411ec07",
        [
            {
                "type": "Boolean",
                "value": "true"
            },
            {
                "type": "Integer",
                "value": 123
            }
        ],
        [
            {
                "account": "NMA2FKN8up2cEwaJgtmAiDrZWB69ApnDfp",
                "scopes": "CalledByEntry"
            }
        ]
    ],
    "id": 1
}

And then we can construct an invocation script on the server by performing the following:

using (ScriptBuilder sb = new ScriptBuilder())
{
        for (int i = args.Count - 1; i >= 0; i--)
                sb.EmitPush(args[i]);
}

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Agree with @AnnaShaleva

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Updated.

JObject json = new JObject();
json["script"] = Convert.ToBase64String(contract.Script);
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And let the resulting script be the InvocationScript (which is sb.ToArray()). Because 1) the user is aware of the contract being invoked and 2) the user should have the ability to check that all the parameters were converted as expected.

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What script mean if sb is empty?

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That no parameters were pushed on the stack before verify execution.

json["state"] = engine.Execute();
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