How to use Paymaster with a Contract method call?

[richardcatlin]

Team or Project

No response

Select the SDK

Rust

ZK chain

Era Sepolia

Environment

Testnet

Issue Description

There is an example on how to use a paymaster with the Rust client when calling this method "send_transaction_eip712"
https://github.com/lambdaclass/zksync-web3-rs/blob/main/examples/paymaster/main.rs

How would I use a Paymaster for the "Perform a signed transaction calling the setGreeting method" in this example:
https://github.com/lambdaclass/zksync-web3-rs/blob/main/examples/contract-deployment/main.rs

Thanks for any help.
Richard Catlin

Expected Behavior

I think the issue description is sufficient. Let me know if more information is required.

Code Example

I reference the code examples in the Issue Description.

Repo Link (Optional)

No response

[dutterbutter]

@richardcatlin the library in reference (e.g. zksync-web3-rs) is very much unmaintained. I suggest making use of alloy-zksync instead: https://github.com/matter-labs/alloy-zksync/tree/main

[richardcatlin]

Thanks I did not realize you had upgraded zksync to alloy. I'll look there.

[dutterbutter]

You will want to do something along the lines of:

  let deploy_tx = TransactionRequest::default()
        .with_create_params(greeter_bytecode, Vec::new(), Vec::new())?
        .with_paymaster_params(PaymasterParams {
            paymaster,
            paymaster_input: paymaster_input.clone(),
        });

Where paymaster is your deployed funded paymaster and paymaster_input for general flow:

let paymaster_input: Bytes = IPaymasterFlow::generalCall {
    input: Bytes::default(),
}
.abi_encode()
.into();

[richardcatlin]

Thanks for the help.

• Where are you getting the IPaymasterFlow interace? I don't see it in either alloy or alloy-zksync.
• Where is Bytes coming from?
  Also, I am interested in how to use the Paymaster with a payable method call. I am looking to transcode the following code into Rust.

  const contributionAmount = ethers.parseEther("0.01");

  // Get paymaster params for the Gasless paymaster
  const paymasterParams = utils.getPaymasterParams(PAYMASTER_ADDRESS, {
    type: "General",
    innerInput: new Uint8Array(),
  });
  // Determine the gas limit for the contribution transaction
  const gasLimit = await contract.contribute.estimateGas({
    value: contributionAmount,
    customData: {
      gasPerPubdata: utils.DEFAULT_GAS_PER_PUBDATA_LIMIT,
      paymasterParams: paymasterParams,
    },
  });

  const fees = await ethers.provider.getFeeData();
  const gasPrice = fees.gasPrice;

  // Contribute to the crowdfund contract
  // and have the paymaster cover the funds
  const transaction = await contract.contribute({
    value: contributionAmount,
    maxPriorityFeePerGas: 0n,
    maxFeePerGas: gasPrice,
    gasLimit,
    // Pass the paymaster params as custom data
    customData: {
      gasPerPubdata: utils.DEFAULT_GAS_PER_PUBDATA_LIMIT,
      paymasterParams,
    },
  });
  await transaction.wait();

I am trying this, but don't know how to add the custom_data.

let tx = contract.contribute()
    .value(U256::from(10).pow(U256::from(14)))
    .max_priority_fee_per_gas(0)
    .max_fee_per_gas(gas_price)
    .gas(gas_limit)
    ...;

[richardcatlin]

Anyone have a suggestion on how to get this done? Thanks, Richard