The use of the "addr" method of the web3swift library in the development of the Ethereum blockchain for iOS

Because the web3swift library is not perfect, the "addr" method is missing in the unit test, and I need to use it in the development process, that is: convert the ENS domain name into a hexadecimal address; so I wrote an article as a record, I hope the same The same shoes as required can be used.

First, we must introduce the web3swift library, address: https://github.com/BANKEX/web3swift

//MARK:将ENS域名转成16进制地址字符串
    func keccakHexStringFromENSString (inputName: String) -> String {
        
        var node = ""
        for _ in 0..<32 {
            node += "00"
        }

        let name = normalize(name: inputName)
    
        if name.count > 0 {
            //将字符串用“.”分割成数组并将数组倒序
            var labels = name.split(separator: ".")
            labels.reverse()
            

            //递归
            for subLabels in labels {

                let str = String(subLabels)
                var labbelSha = str.sha3(.keccak256)
                labbelSha = "0x" + node + labbelSha
                let data = convertToData(labbelSha as AnyObject)
                node = (data?.sha3(.keccak256).toHexString())!
                print("0x" + node)
            }
        }
        return infuratestResolver(encodeStr: "0x" + node)
    }

    //将某类型转成Data
    func convertToData(_ value: AnyObject) -> Data? {
        switch value {
        case let d as Data:
            return d
        case let d as String:
            if d.hasHexPrefix() {
                let hex = Data.fromHex(d)
                if hex != nil {
                    return hex
                }
            }
            let str = d.data(using: .utf8)
            if str != nil {
                return str
            }
        case let d as [UInt8]:
            return Data(d)
        case let d as EthereumAddress:
            return d.addressData
        case let d as [IntegerLiteralType]:
            var bytesArray = [UInt8]()
            for el in d {
                guard el >= 0, el <= 255 else {return nil}
                bytesArray.append(UInt8(el))
            }
            return Data(bytesArray)
        default:
            return nil
        }
        return nil
    }
    
    func normalize(name: String) -> String {
        var lastName = name.trimmingCharacters(in: .whitespaces)
        //判断表情的正则表达式，并把表情替换为空
        let pattern = "[\\ud83c\\udc00-\\ud83c\\udfff]|[\\ud83d\\udc00-\\ud83d\\udfff]|[\\u2600-\\u27ff]"
        lastName = lastName.pregReplace(pattern: pattern, with: "")
        return lastName
    }
    
    //执行"addr"方法
    func infuratestResolver(encodeStr: String) -> String {
        let jsonString = "[{\"constant\":true,\"inputs\":[{\"name\":\"interfaceID\",\"type\":\"bytes4\"}],\"name\":\"supportsInterface\",\"outputs\":[{\"name\":\"\",\"type\":\"bool\"}],\"payable\":false,\"type\":\"function\"},{\"constant\":true,\"inputs\":[{\"name\":\"node\",\"type\":\"bytes32\"},{\"name\":\"contentTypes\",\"type\":\"uint256\"}],\"name\":\"ABI\",\"outputs\":[{\"name\":\"contentType\",\"type\":\"uint256\"},{\"name\":\"data\",\"type\":\"bytes\"}],\"payable\":false,\"type\":\"function\"},{\"constant\":false,\"inputs\":[{\"name\":\"node\",\"type\":\"bytes32\"},{\"name\":\"x\",\"type\":\"bytes32\"},{\"name\":\"y\",\"type\":\"bytes32\"}],\"name\":\"setPubkey\",\"outputs\":[],\"payable\":false,\"type\":\"function\"},{\"constant\":true,\"inputs\":[{\"name\":\"node\",\"type\":\"bytes32\"}],\"name\":\"content\",\"outputs\":[{\"name\":\"ret\",\"type\":\"bytes32\"}],\"payable\":false,\"type\":\"function\"},{\"constant\":true,\"inputs\":[{\"name\":\"node\",\"type\":\"bytes32\"}],\"name\":\"addr\",\"outputs\":[{\"name\":\"ret\",\"type\":\"address\"}],\"payable\":false,\"type\":\"function\"},{\"constant\":false,\"inputs\":[{\"name\":\"node\",\"type\":\"bytes32\"},{\"name\":\"contentType\",\"type\":\"uint256\"},{\"name\":\"data\",\"type\":\"bytes\"}],\"name\":\"setABI\",\"outputs\":[],\"payable\":false,\"type\":\"function\"},{\"constant\":true,\"inputs\":[{\"name\":\"node\",\"type\":\"bytes32\"}],\"name\":\"name\",\"outputs\":[{\"name\":\"ret\",\"type\":\"string\"}],\"payable\":false,\"type\":\"function\"},{\"constant\":false,\"inputs\":[{\"name\":\"node\",\"type\":\"bytes32\"},{\"name\":\"name\",\"type\":\"string\"}],\"name\":\"setName\",\"outputs\":[],\"payable\":false,\"type\":\"function\"},{\"constant\":false,\"inputs\":[{\"name\":\"node\",\"type\":\"bytes32\"},{\"name\":\"hash\",\"type\":\"bytes32\"}],\"name\":\"setContent\",\"outputs\":[],\"payable\":false,\"type\":\"function\"},{\"constant\":true,\"inputs\":[{\"name\":\"node\",\"type\":\"bytes32\"}],\"name\":\"pubkey\",\"outputs\":[{\"name\":\"x\",\"type\":\"bytes32\"},{\"name\":\"y\",\"type\":\"bytes32\"}],\"payable\":false,\"type\":\"function\"},{\"constant\":false,\"inputs\":[{\"name\":\"node\",\"type\":\"bytes32\"},{\"name\":\"addr\",\"type\":\"address\"}],\"name\":\"setAddr\",\"outputs\":[],\"payable\":false,\"type\":\"function\"},{\"inputs\":[{\"name\":\"ensAddr\",\"type\":\"address\"}],\"payable\":false,\"type\":\"constructor\"},{\"anonymous\":false,\"inputs\":[{\"indexed\":true,\"name\":\"node\",\"type\":\"bytes32\"},{\"indexed\":false,\"name\":\"a\",\"type\":\"address\"}],\"name\":\"AddrChanged\",\"type\":\"event\"},{\"anonymous\":false,\"inputs\":[{\"indexed\":true,\"name\":\"node\",\"type\":\"bytes32\"},{\"indexed\":false,\"name\":\"hash\",\"type\":\"bytes32\"}],\"name\":\"ContentChanged\",\"type\":\"event\"},{\"anonymous\":false,\"inputs\":[{\"indexed\":true,\"name\":\"node\",\"type\":\"bytes32\"},{\"indexed\":false,\"name\":\"name\",\"type\":\"string\"}],\"name\":\"NameChanged\",\"type\":\"event\"},{\"anonymous\":false,\"inputs\":[{\"indexed\":true,\"name\":\"node\",\"type\":\"bytes32\"},{\"indexed\":true,\"name\":\"contentType\",\"type\":\"uint256\"}],\"name\":\"ABIChanged\",\"type\":\"event\"},{\"anonymous\":false,\"inputs\":[{\"indexed\":true,\"name\":\"node\",\"type\":\"bytes32\"},{\"indexed\":false,\"name\":\"x\",\"type\":\"bytes32\"},{\"indexed\":false,\"name\":\"y\",\"type\":\"bytes32\"}],\"name\":\"PubkeyChanged\",\"type\":\"event\"}]"
        do {
            
            let web3 = Web3.InfuraMainnetWeb3()
            let constractAddress = EthereumAddress("0x1da022710dF5002339274AaDEe8D58218e9D6AB5")
            var options = Web3Options.defaultOptions()
            options.to = constractAddress
            options.from = constractAddress
            let parametersCall = [encodeStr] as [AnyObject]
            let contract = web3.contract(jsonString, at: constractAddress, abiVersion: 2)!
            let transaction = contract.method("addr", parameters:parametersCall,  options: options)
            guard let tokenNameRes = transaction?.call(options: options) else {return ""}
            guard case .success(let result) = tokenNameRes else {return ""}
            if result.isEmpty {
                return ""
            }else {
                let dictValuesArray = [Any](result.values)
                if dictValuesArray.count > 0 {
                    let addr: EthereumAddress = dictValuesArray[0] as! EthereumAddress
                    return addr.address
                }else {
                    return ""
                }
            }
        } catch {
            XCTFail()
            print(error)
            return ""
        }
    }
    
    //测试
    func testABI() {
        let ENSString = keccakHexStringFromENSString(inputName: "linktime.eth")
        print(ENSString)
    }