Interacting with Smart Contracts Using call

The call method allows you to interact with deployed smart contracts without broadcasting a transaction. This method is useful for reading contract state or simulating transactions.

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Method

call(
  to: string | Address,
  data: Buffer | string,
  from?: Address,
  height?: BigNumberish
): Promise<CallResult | ICallRequestError>;

• Parameters:

  • to: string | Address: The address of the contract to call.
  • data: Buffer | string: The calldata to send to the contract.
  • from?: Address: (Optional) The address making the call.
  • height?: BigNumberish: (Optional) The blockchain height at which to perform the call.

• Returns:

  • Promise<CallResult>: Contains the execution result, including any returned data or events.
  • Promise<ICallRequestError>: Contains error details if the call fails.

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Object Definitions

CallResult Object

Property/Method	Type	Description
result	BinaryReader	The raw result of the call.
accessList	IAccessList	Accessed storage and contract addresses.
revert	string | undefined	The reason for revert, if the call fails.
calldata	Buffer | undefined	The calldata used for the call.
estimatedGas	bigint | undefined	Estimated gas for the call.
events	OPNetEvent[]	Events emitted during the call.
sendTransaction()	Function	Sends a transaction with the current parameters.

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Example Usage (Get Balance of a Public Key)

import { networks } from "@btc-vision/bitcoin";
import { getContract, IOP_20Contract, OP_20_ABI } from "opnet";

// Get the contract
const contractAddress = "bcrt1p..."; // Replace with actual contract address
const contract = getContract<IOP_20Contract>(
  contractAddress,
  OP_20_ABI,
  provider,
  networks.regtest
  // Optional: Add the sender's address
  // Address.fromString("your-public-key")
);

const pubKey = await provider.getPublicKeyInfo("bcrt1p..."); // Replace with the address

// Call the contract
const calldata = contract.encodeCalldata("balanceOf", [pubKey]);

try {
  const callResult = await provider.call(contractAddress, calldata);

  if ("error" in callResult) {
    throw new Error(callResult.error);
  }

  console.log("Call Result:", callResult.result.toString());
  console.log("Estimated Gas:", callResult.estimatedGas);
  console.log("Events:", callResult.events);
} catch (error) {
  console.error("Call Error:", error.error);
}

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Best Practices

• Ensure the contract address and calldata are correct before making a call.
• Use the height parameter to simulate the call at a specific block height, if needed.
• Handle errors gracefully using the ICallRequestError interface.

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What’s Next?

After interacting with contracts using call, you can explore:

• Fetching Transaction Data