Calling contracts with the Unity SDK

Smart contracts are backend programs that run on the Tezos blockchains. Smart contracts can do many tasks, but for gaming they have two main purposes:

• They handle tokens, which are digital assets stored on the blockchain
• They provide backend logic that users can trust because it cannot change

For more information about contracts, see Smart contracts.

The Unity SDK can call any deployed Tezos contract just like any other Tezos client can.

Calling contracts

To call a contract, create an OperationRequest object with the parameters for the transaction and pass it to the TezosAPI.RequestOperation() method. For example, this function calls a contract and passes the parameter 4 to its increment entrypoint:

public async void SendTransaction()
{
    try
    {
      var request = new OperationRequest
      {
          // Contract to call
          Destination = "KT1R2LTg3mQoLvHtUjo2xSi7RMBUJ1sJkDiD",
          // Entrypoint to call
          EntryPoint = "increment",
          // Parameter to pass, as a Michelson expression
          Arg = "4",
          // Amount of tez to send with the transaction
          Amount = "0",
        };

        var response = await TezosAPI.RequestOperation(request);
        Debug.Log($"Transaction hash: {response.TransactionHash}");
    }
    catch (Exception e) when (e is WalletOperationRejected or SocialOperationFailed)
    {
        Debug.LogError($"Operation failed: {e.Message}");
    }
    catch (Exception e)
    {
        Debug.LogError($"Unexpected error during operation: {e.Message}");
    }

}

The response includes the hash of the operation, which you can use to look up the status of the transaction.

Calling views

To call a view, pass the address of the contract, the name of the view, and the Michelson-encoded parameter to the TezosAPI.ReadView() method. You must set the return type on the TezosAPI.ReadView() method, as in this example for a view that returns a string:

var result = await TezosAPI.ReadView<string>("KT1K46vZTMEe8bnacFvFQfgHtNDKniEauRMJ", "simple", "\"String value\"");
Debug.Log("View response: " + result);