Add support for struct parameter for contract calls

[iron4548]

Problem

Let's assume I have a solidity contract with the following code

struct InputParams {
  uint256 value1;
  uint256 value2; 
}

function doCalc(InputParams calldata params) external returns (uint256 result);

The correct method signature for this is:
doCalc((uint256,uint256)) which has a hash of 0x07328a21

The other method signature (the incorrect one) is:
doCalc(uint256,uint256) which has a hash of 0x88e5e21d

The following code:

const params = new ContractFunctionParameters();
params.addUint256(5); //value1
params.addUint256(10); //value2

 const result = await new ContractExecuteTransaction()
      .setContractId(mathContractId)
      .setGas(gasGwei)
      .setFunction('doCalc', params)
      .execute(client);

Will fail because that gets reduced to: doCalc(uint256,uint256) (0x88e5e21d).

How can I reduce it to:

doCalc((uint256,uint256)) (0x07328a21)`

Does ContractFunctionParameters / ContractExecuteTransaction have support for Struct based parameters? If so, how can I achieve it? If not, can it be added? (the enhancement)

Solution

Alternatives

No response

[iron4548]

A possible solution (if one doesn't exist):

• Introduce a new ContractStructParameter class
• Add the the usual methods such as addBytes, addAddress, addUint256 etc.
• Then introduce a new method called addStruct(param:ContractStructParameter) to ContractFunctionParameters

//example what it could look like

const struct = ContractStructParameter();
struct.addUint256(5); //value 1
struct.addUint256(10); //value 2

const params = new ContractFunctionParameters();
params.addStruct(struct);

const result = await new ContractExecuteTransaction()
  .setContractId(mathContractId)
  .setGas(gasGwei)
  .setFunction('doCalc', params)
  .execute(client);

//the above will then get reduced to
`doCalc((uint256,uint256))`, method hash = 0x07328a21

[iron4548]

I found a suitable workaround using Ethers.js, so this 'feature request' is now a low priority.

But would be nice to have it built into the SDK one day to make it easier

Here's how I did it for anyone who's interested.

import * as ethers from 'ethers'; //V6

const abi = [
{
  'name': 'doCalc',
  'inputs': [
	{
	  'name': 'params',
	  'type': 'tuple',
	  'components': [
		{ 'name': 'value1', 'type': 'uint256' },
		{ 'name': 'value2', 'type': 'uint256' },
	  ]
	}
  ],
  'outputs': [{ 'name': 'result', 'type': 'uint256' }],
  'type': 'function'
}
];

const abiInterface = new ethers.Interface(abi);

const params = {
    value1: 5,
    value2: 10
};

const encodedData = abiInterface.encodeFunctionData('doCalc', [params]);

const encodedDataAsUint8Array = hexToUint8Array(encodedData.substring(2)); //remove leading 0x


const result = await new ContractExecuteTransaction()
.setContractId(ContractId.fromString(config.mathContract))
.setGas(gasGwei)
.setFunctionParameters(encodedDataAsUint8Array)
.execute(client);