Bytes32 – How to Pass Bytes32 to Constructor in Solidity Contract Deployment

apibytes32constructorcontract-deployment

I have s constructor that takes a bytes32 parameter and assign its value to the jobID variable

contract APIConsumer {

    bytes32 public jobId;

    constructor( bytes32 _jobId) {
        jobId = _jobId;
    }
}

But when I pass the value "ec013753fda740f8bc74a966daea0723" in the constructor it assign this value to the jobId variable "0x00000000000000000000000000000000ec013753fda740f8bc74a966daea0723"
I want to know why it adds those zeros and how to fix it (make it assign the same value passed in the parameters and do not add zeros).

Best Answer

This is intended behavior, the value is padded right ( = zeroes are added to the left of your number to fill the entire 32 bytes). I don't think you actually want to "fix" this, but if you do, you could use a byte array instead, like so:

bytes public jobId;

constructor( bytes  memory _jobId) {
    jobId = _jobId;
}

Related Solutions

Solidity Bytes32 – How to Convert/Decode Solidity Bytes32 to Python String Using Web3.py

The issue here is that your variable has a fixed length of 32 bytes, which explains the zeroes in the right. You can strip the zeros in python:

zbytes32 = contractInstance.functions.getzBytes32().call()
zbytes32 = zbytes32.hex().rstrip("0")
if len(zbytes32) % 2 != 0:
    zbytes32 = zbytes32 + '0'
zbytes32 = bytes.fromhex(zbytes32).decode('utf8')

Printing the variable zbytes32 gives: 'HelloBytes32' and: zbytes32=='HelloBytes32' is True

The conditional part if len(zbytes32) % 2 != 0 is there because it may be that the last character is indeed zero and we are removing it, the way to know this is that every byte is represented by two hexadecimal characters so if the length of the variable zbytes32 after removing the zeros is odd, one zero must be added to the right.

Hope this helps

Solidity Arrays – Invalid Conversion from address[2] memory to address[] memory

It is not possible to cast between fixed size arrays and dynamic size arrays.

You have to create a temporary dynamic array and copy the elements.

address[] memory t = new address[](2);

t[0] = 0xB4a925BAe55743AcF3Dc65a8de0b9507F0491617;
t[1] = 0x288071244112050c93389A950d02c9E626D611dD;

codeTested = new Buds(param1, param2, t);

Best Answer

Related Solutions

Solidity Bytes32 – How to Convert/Decode Solidity Bytes32 to Python String Using Web3.py

Solidity Arrays – Invalid Conversion from address[2] memory to address[] memory

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