I have a method which returns bytes type data from an external contract call. I need to convert that bytes type data into my desired output type data like address/uint/bool/string/int etc. I have tried finding conversion library but couldn't find any. Note if I convert the bytes as a string like this string(returnData) the address type data got converted into something I'm unable to decode it. the same thing happens for another data type as well.

function getData(string memory _key) public returns (string memory _stringData, address _addressData, uint _uintData, bytes memory _bytesData, bool _boolData) {

    Delegate _delegate = Delegate(MAN.getLatestDelegateContract()); // this is my own internal machanism, skip thi please 
    // Retrieve method name according to data type
    string memory _methodName = _delegate.getDataType(_key);
    // Prepare input call
    bytes memory _input = abi.encodePacked(bytes4(keccak256(abi.encodePacked("get",_methodName,"(bytes32)"))),keccak256(abi.encodePacked(_key)));
    // Make the call
    (bool success, bytes memory ret) = address(deployedEternalStorages).call(_input);
        // from the call data returned as bytes

        if (success) {
        // Return data as desired type
        if(keccak256(abi.encodePacked(_methodName)) == keccak256("address")){
            //convert bytes to address and assign into below variable
            //_addressData = 
        else if(keccak256(abi.encodePacked(_methodName)) == keccak256("uint")){
            //convert bytes to uint and assig into below variable
            //_uintData = 
        else if(keccak256(abi.encodePacked(_methodName)) == keccak256("bytes")){
            _bytesData = ret;
        else if(keccak256(abi.encodePacked(_methodName)) == keccak256("bool")){
            //convert bytes to bool and assig into below variable
            //_boolData = 
            _stringData = string(ret);
    } else {
        // Call failed revert

Can anybody help with any conversion library or any other way to convert the data types. Note: I'm using 0.5.0 version in my code.

2 Answers 2



Bytes is a not a value type according to the docs, and is actually a dynamically-sized array.

This library can convert uint to Bytes32 and vice-versa, if that helps any.

  • Thanks for the documentation link, but that library doesn't work. Anyway, an alternative solution for this. Feb 5, 2019 at 5:36

what you are looking is BytesLib.sol https://github.com/GNSPS/solidity-bytes-utils/blob/master/contracts/BytesLib.sol

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