如何在web3swift中使用自定義json合約

Question

我如何在本地使用JSON合約，例如：

let jsonString = "[{\"constant\":true,\"inputs\":[],\"name\":\"name\",\"outputs\":[{\"name\":\"\",\"type\":\"string\"}],\"payable\":false,\"type\":\"function\"},{\"constant\":false,\"inputs\":[{\"name\":\"_spender\",\"type\":\"address\"},{\"name\":\"_value\",\"type\":\"uint256\"}],\"name\":\"approve\",\"outputs\":[{\"name\":\"success\",\"type\":\"bool\"}],\"payable\":false,\"type\":\"function\"},{\"constant\":true,\"inputs\":[],\"name\":\"totalSupply\",\"outputs\":[{\"name\":\"\",\"type\":\"uint256\"}],\"payable\":false,\"type\":\"function\"},{\"constant\":false,\"inputs\":[{\"name\":\"_from\",\"type\":\"address\"},{\"name\":\"_to\",\"type\":\"address\"},{\"name\":\"_value\",\"type\":\"uint256\"}],\"name\":\"transferFrom\",\"outputs\":[{\"name\":\"success\",\"type\":\"bool\"}],\"payable\":false,\"type\":\"function\"},{\"constant\":true,\"inputs\":[],\"name\":\"decimals\",\"outputs\":[{\"name\":\"\",\"type\":\"uint8\"}],\"payable\":false,\"type\":\"function\"},{\"constant\":true,\"inputs\":[],\"name\":\"version\",\"outputs\":[{\"name\":\"\",\"type\":\"string\"}],\"payable\":false,\"type\":\"function\"},{\"constant\":true,\"inputs\":[{\"name\":\"_owner\",\"type\":\"address\"}],\"name\":\"balanceOf\",\"outputs\":[{\"name\":\"balance\",\"type\":\"uint256\"}],\"payable\":false,\"type\":\"function\"},{\"constant\":true,\"inputs\":[],\"name\":\"symbol\",\"outputs\":[{\"name\":\"\",\"type\":\"string\"}],\"payable\":false,\"type\":\"function\"},{\"constant\":false,\"inputs\":[{\"name\":\"_to\",\"type\":\"address\"},{\"name\":\"_value\",\"type\":\"uint256\"}],\"name\":\"transfer\",\"outputs\":[{\"name\":\"success\",\"type\":\"bool\"}],\"payable\":false,\"type\":\"function\"},{\"constant\":false,\"inputs\":[{\"name\":\"_spender\",\"type\":\"address\"},{\"name\":\"_value\",\"type\":\"uint256\"},{\"name\":\"_extraData\",\"type\":\"bytes\"}],\"name\":\"approveAndCall\",\"outputs\":[{\"name\":\"success\",\"type\":\"bool\"}],\"payable\":false,\"type\":\"function\"},{\"constant\":true,\"inputs\":[{\"name\":\"_owner\",\"type\":\"address\"},{\"name\":\"_spender\",\"type\":\"address\"}],\"name\":\"allowance\",\"outputs\":[{\"name\":\"remaining\",\"type\":\"uint256\"}],\"payable\":false,\"type\":\"function\"},{\"inputs\":[{\"name\":\"_initialAmount\",\"type\":\"uint256\"},{\"name\":\"_tokenName\",\"type\":\"string\"},{\"name\":\"_decimalUnits\",\"type\":\"uint8\"},{\"name\":\"_tokenSymbol\",\"type\":\"string\"}],\"type\":\"constructor\"},{\"payable\":false,\"type\":\"fallback\"},{\"anonymous\":false,\"inputs\":[{\"indexed\":true,\"name\":\"_from\",\"type\":\"address\"},{\"indexed\":true,\"name\":\"_to\",\"type\":\"address\"},{\"indexed\":false,\"name\":\"_value\",\"type\":\"uint256\"}],\"name\":\"Transfer\",\"type\":\"event\"},{\"anonymous\":false,\"inputs\":[{\"indexed\":true,\"name\":\"_owner\",\"type\":\"address\"},{\"indexed\":true,\"name\":\"_spender\",\"type\":\"address\"},{\"indexed\":false,\"name\":\"_value\",\"type\":\"uint256\"}],\"name\":\"Approval\",\"type\":\"event\"},]"

Answer 1

您可以在let contract = Web3.InfuraMainnetWeb3().contract(<abiString: String>, at: <EthereumAddress?>, abiVersion: <Int>)

您還應該調用其所需的方法： let transaction = contract.method(<method: String>, parameters: <[AnyObject]>, extraData: <Data>, options: <Web3Options?>)

准備交易功能的示例：

let yourContractJsonABI = "[{\"constant\":true,\"inputs\":[],\"name\":\"name\",\"outputs\":[{\"name\":\"\",\"type\":\"string\"}],\"payable\":false,\"type\":\"function\"},{\"constant\":false,\"inputs\":[{\"name\":\"_spender\",\"type\":\"address\"},{\"name\":\"_value\",\"type\":\"uint256\"}],\"name\":\"approve\",\"outputs\":[{\"name\":\"success\",\"type\":\"bool\"}],\"payable\":false,\"type\":\"function\"},{\"constant\":true,\"inputs\":[],\"name\":\"totalSupply\",\"outputs\":[{\"name\":\"\",\"type\":\"uint256\"}],\"payable\":false,\"type\":\"function\"},{\"constant\":false,\"inputs\":[{\"name\":\"_from\",\"type\":\"address\"},{\"name\":\"_to\",\"type\":\"address\"},{\"name\":\"_value\",\"type\":\"uint256\"}],\"name\":\"transferFrom\",\"outputs\":[{\"name\":\"success\",\"type\":\"bool\"}],\"payable\":false,\"type\":\"function\"},{\"constant\":true,\"inputs\":[],\"name\":\"decimals\",\"outputs\":[{\"name\":\"\",\"type\":\"uint8\"}],\"payable\":false,\"type\":\"function\"},{\"constant\":true,\"inputs\":[],\"name\":\"version\",\"outputs\":[{\"name\":\"\",\"type\":\"string\"}],\"payable\":false,\"type\":\"function\"},{\"constant\":true,\"inputs\":[{\"name\":\"_owner\",\"type\":\"address\"}],\"name\":\"balanceOf\",\"outputs\":[{\"name\":\"balance\",\"type\":\"uint256\"}],\"payable\":false,\"type\":\"function\"},{\"constant\":true,\"inputs\":[],\"name\":\"symbol\",\"outputs\":[{\"name\":\"\",\"type\":\"string\"}],\"payable\":false,\"type\":\"function\"},{\"constant\":false,\"inputs\":[{\"name\":\"_to\",\"type\":\"address\"},{\"name\":\"_value\",\"type\":\"uint256\"}],\"name\":\"transfer\",\"outputs\":[{\"name\":\"success\",\"type\":\"bool\"}],\"payable\":false,\"type\":\"function\"},{\"constant\":false,\"inputs\":[{\"name\":\"_spender\",\"type\":\"address\"},{\"name\":\"_value\",\"type\":\"uint256\"},{\"name\":\"_extraData\",\"type\":\"bytes\"}],\"name\":\"approveAndCall\",\"outputs\":[{\"name\":\"success\",\"type\":\"bool\"}],\"payable\":false,\"type\":\"function\"},{\"constant\":true,\"inputs\":[{\"name\":\"_owner\",\"type\":\"address\"},{\"name\":\"_spender\",\"type\":\"address\"}],\"name\":\"allowance\",\"outputs\":[{\"name\":\"remaining\",\"type\":\"uint256\"}],\"payable\":false,\"type\":\"function\"},{\"inputs\":[{\"name\":\"_initialAmount\",\"type\":\"uint256\"},{\"name\":\"_tokenName\",\"type\":\"string\"},{\"name\":\"_decimalUnits\",\"type\":\"uint8\"},{\"name\":\"_tokenSymbol\",\"type\":\"string\"}],\"type\":\"constructor\"},{\"payable\":false,\"type\":\"fallback\"},{\"anonymous\":false,\"inputs\":[{\"indexed\":true,\"name\":\"_from\",\"type\":\"address\"},{\"indexed\":true,\"name\":\"_to\",\"type\":\"address\"},{\"indexed\":false,\"name\":\"_value\",\"type\":\"uint256\"}],\"name\":\"Transfer\",\"type\":\"event\"},{\"anonymous\":false,\"inputs\":[{\"indexed\":true,\"name\":\"_owner\",\"type\":\"address\"},{\"indexed\":true,\"name\":\"_spender\",\"type\":\"address\"},{\"indexed\":false,\"name\":\"_value\",\"type\":\"uint256\"}],\"name\":\"Approval\",\"type\":\"event\"},]"

func prepareTransaction(parameters: Data, gasLimit: BigUInt = 27500, completion: @escaping (Result<TransactionIntermediate>) -> Void) {
    DispatchQueue.global().async {
        guard let addressFrom: String = <YOURS WALLET ADDRESS> else {return}
        guard let ethAddressFrom = EthereumAddress(addressFrom) else {return}

        let yourContractAddress = "<YOUR CONTRACT ETH ADDRESS>"
        guard let ethContractAddress = EthereumAddress(contractAddress) else {return}

        let web3 = Web3.InfuraMainnetWeb3() //or any test network
        web3.addKeystoreManager(KeystoreManager.defaultManager)

        var options = Web3Options.defaultOptions()
        options.from = ethAddressFrom
        options.value = 0 // or any other value you want to send

        guard let contract = web3.contract(yourContractJsonABI, at: ethContractAddress, abiVersion: 2) else {return}

        guard let gasPrice = web3.eth.getGasPrice().value else {return}
        options.gasPrice = gasPrice
        options.gasLimit = gasLimit

        guard let transaction = contract.method("<METHOD OF CONTRACT YOU WANT TO CALL>", parameters: [parameters] as [AnyObject], options: options) else {return}
        guard case .success(let estimate) = transaction.estimateGas(options: options) else {return} //here is estimated gas - something like confirming that you made a transaction correctly
        print("estimated cost: \(estimate)")

        DispatchQueue.main.async {
            completion(Result.Success(transaction))
        }
    }
}