/// <summary>
/// Get any information required to construct a transaction for a specific network. Metadata returned here could be a recent hash to use, an account sequence number, or even arbitrary chain state.
/// The request used when calling this endpoint is often created by calling `/construction/preprocess` in an offline environment.
/// It is important to clarify that this endpoint should not pre-construct any transactions for the client (this should happen in `/construction/payloads`).
/// </summary>
/// <returns></returns>
public JObject ConstructionMetadata(ConstructionMetadataRequest request)
{
// check params
if (request.Options is null || request.Options.Pairs is null ||
!request.Options.ContainsKey("tx_type"))
{
return(Error.PARAMETER_INVALID.ToJson());
}
if (!request.Options.TryGetValue("tx_type", out JObject txType))
{
return(Error.PARAMETER_INVALID.ToJson());
}
Metadata metadata;
try
{
switch (txType.AsString())
{
case nameof(ClaimTransaction):
{
JObject json = new JObject();
json["type"] = "CoinReference[]";
json["required"] = "true";
json["reference"] = @"https://github.com/neo-project/neo/blob/master-2.x/neo/Network/P2P/Payloads/CoinReference.cs";
json["example"] = "[{\"txid\": \"0xe1e44f41a1f0854063ccdc9beb7537fc40565575e0ae2366b4a93a73c18b6166\", \"vout\": 2},{\"txid\": \"0x69fd452c92fb0e5861b27588549a8e55d3f9fee542884ae317600508bbacedbb\",\"vout\": 2}]";
metadata = new Metadata(new Dictionary <string, JObject>
{
{ "tx_type", nameof(ClaimTransaction) },
{ "claims", json }
});
break;
}
case nameof(ContractTransaction):
{
metadata = new Metadata(new Dictionary <string, JObject>
{
{ "tx_type", nameof(ContractTransaction) }
});
break;
}
case nameof(InvocationTransaction):
{
JObject script = new JObject();
script["type"] = "byte[] (represented in hex string)";
script["required"] = "true";
script["example"] = "00046e616d656724058e5e1b6008847cd662728549088a9ee82191";
JObject gas = new JObject();
gas["type"] = "Fixed8";
gas["required"] = "false";
gas["reference"] = @"https://github.com/neo-project/neo/blob/master-2.x/neo/Fixed8.cs";
gas["example"] = "1234567890";
metadata = new Metadata(new Dictionary <string, JObject>
{
{ "tx_type", nameof(InvocationTransaction) },
{ "script", script },
{ "gas", gas }
});
break;
}
case nameof(StateTransaction):
{
JObject json = new JObject();
json["type"] = "StateDescriptor[]";
json["required"] = "true";
json["reference"] = @"https://docs.neo.org/tutorial/zh-cn/3-transactions/3-NEO_transaction_types.html#statetransaction";
json["example"] = "[{\"type\":\"Account\",\"key\":\"ce47912d51b7ed8a24a77f97f2cb6ef9a0e0bf0d\",\"field\":\"Votes\",\"value\":\"04024c7b7fb6c310fccf1ba33b082519d82964ea93868d676662d4a59ad548df0e7d02aaec38470f6aad0042c6e877cfd8087d2676b0f516fddd362801b9bd3936399e02ca0e27697b9c248f6f16e085fd0061e26f44da85b58ee835c110caa5ec3ba55402df48f60e8f3e01c48ff40b9b7f1310d7a8b2a193188befe1c2e3df740e895093\"}]";
metadata = new Metadata(new Dictionary <string, JObject>
{
{ "tx_type", nameof(StateTransaction) },
{ "descriptors", json }
});
break;
}
default:
throw new NotSupportedException();
}
}
catch (Exception)
{
return(Error.PARAMETER_INVALID.ToJson());
}
ConstructionMetadataResponse response = new ConstructionMetadataResponse(metadata);
return(response.ToJson());
}
/// <summary>
/// Get any information required to construct a transaction for a specific network.
/// Metadata returned here could be a recent hash to use, an account sequence number, or even arbitrary chain state.
/// The request used when calling this endpoint is often created by calling `/construction/preprocess` in an offline environment.
/// You should NEVER assume that the request sent to this endpoint will be created by the caller or populated with any custom parameters. This must occur in /construction/preprocess.
/// It is important to clarify that this endpoint should not pre-construct any transactions for the client (this should happen in `/construction/payloads`).
/// This endpoint is left purposely unstructured because of the wide scope of metadata that could be required.
/// </summary>
/// <returns></returns>
public JObject ConstructionMetadata(ConstructionMetadataRequest request)
{
if (request.NetworkIdentifier?.Blockchain?.ToLower() != "neo n3")
{
return(Error.NETWORK_IDENTIFIER_INVALID.ToJson());
}
if (request.NetworkIdentifier?.Network?.ToLower() != network)
{
return(Error.NETWORK_IDENTIFIER_INVALID.ToJson());
}
// get signers
Signer[] signers = Array.Empty <Signer>();
try
{
signers = (request.Options["signers"] as JArray).Select(p => p.ToSigner(system.Settings.AddressVersion)).ToArray();
}
catch (Exception)
{
return(Error.PARAMETER_INVALID.ToJson());
}
// get public keys, need public keys to calculate network fee
if (!request.Options.ContainsKey("signer_metadata"))
{
return(Error.PARAMETER_INVALID.ToJson());
}
SignerMetadata[] signerMetadatas = (request.Options["signer_metadata"] as JArray).Select(p => SignerMetadata.FromJson(p, system.Settings.AddressVersion)).ToArray();
if (request.PublicKeys == null)
{
return(Error.PARAMETER_INVALID.ToJson());
}
// get script
byte[] script = Array.Empty <byte>();
if (request.Options.ContainsKey("has_existing_script") && request.Options["has_existing_script"].AsBoolean() == true)
{
if (request.Options.ContainsKey("script"))
{
script = Convert.FromBase64String(request.Options["script"].AsString());
}
else
{
return(Error.PARAMETER_INVALID.ToJson());
}
}
else if (request.Options.ContainsKey("has_existing_script") && request.Options["has_existing_script"].AsBoolean() == false)
{
if (request.Options.ContainsKey("operations_script"))
{
script = Convert.FromBase64String(request.Options["operations_script"].AsString());
}
else
{
return(Error.PARAMETER_INVALID.ToJson());
}
}
else
{
return(Error.PARAMETER_INVALID.ToJson());
}
// get max fee
long maxFee = 2000000000;
if (request.Options.ContainsKey("max_fee"))
{
maxFee = long.Parse(request.Options["max_fee"].AsString());
}
// invoke script
NeoTransaction tx = new NeoTransaction
{
Signers = signers,
Attributes = Array.Empty <TransactionAttribute>(),
};
using ApplicationEngine engine = ApplicationEngine.Run(script, system.StoreView, container: tx, settings: system.Settings, gas: maxFee);
if (engine.State == VMState.FAULT)
{
return(Error.VM_FAULT.ToJson());
}
// script
tx.Script = script;
// version
var version = (byte)0;
tx.Version = version;
// nonce
Random random = new();
var nonce = (uint)random.Next();
tx.Nonce = nonce;
// system fee
var sysFee = engine.GasConsumed;
tx.SystemFee = sysFee;
// network fee is not available here, will be calculated in
var netFee = CalculateNetworkFee(system.StoreView, tx, request.PublicKeys, signerMetadatas);
// valid until block
var validUntilBlock = NativeContract.Ledger.CurrentIndex(system.StoreView) + system.Settings.MaxValidUntilBlockIncrement;
Metadata metadata = new(new()
{
{ "version", version },
{ "nonce", nonce },