How to convert a string to bytes32?

Question

How can I convert a string to a bytes32? Does anyone has a magic function or library which does it?

For example: This works since as input I gave 32-bits. But it won't work with "> 32-bit" chars.

set_txn_hash = a.transact().set("QmVoGzRDscx61k3RHHkLYaMFtxYZi3ps");#32-bit char

-

function get() returns (stringc value){  
    return list.get_head_data();   
}

But if I need to give more character for example contains 48-bit string this won't work. [Q] How could I make this work?

Answer 1

This has worked for me so far. Not sure if it's the best way.

function stringToBytes32(string memory source) public pure returns (bytes32 result) {
    bytes memory tempEmptyStringTest = bytes(source);
    if (tempEmptyStringTest.length == 0) {
        return 0x0;
    }

    assembly {
        result := mload(add(source, 32))
    }
}

Also, remember that strings in solidity are UTF8 so after converting them to bytes each byte is not necessarily a character.

EDIT: shorter version, should work the same.

Answer 2

string is not equal to bytes32 but it is equal to bytes, because its length is dynamic.

so you could use a casting bytes B=bytes(S); //S string

E.g

contract string_test {

    function string_tobytes( string s) constant returns (bytes){
        bytes memory b3 = bytes(s);
        return b3;
    }
}

The conversion of string to bytes32 is possible only using assembly

Answer 3

ethers.js has a built in utility function for this: https://docs.ethers.io/ethers.js/html/api-utils.html#bytes32-strings

const ethers = require('ethers')
const utils = ethers.utils

const inBytes = utils.formatBytes32String("test");

Answer 4

Assembly is not needed in version 0.8.7

string text = "whatever"; 
bytes32 stringInBytes32 = bytes32(bytes(text));

Answer 5

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.7;
contract stringtobytes{
    function set(string memory  _a)public pure returns(bytes memory){
        return (bytes(_a));
    } 
}

you can convert strings to bytes(in decimal format) with below code

1- bytes1=8bit=2decimal

2 bytes2=16bit=4decimal

3 bytes3=24bit=6decimal

4 bytes=dynamic array and reference value

Answer 6

Please reference this. You can convert string to bytes32 array.The length of string can be longer than 32 .

https://ethereum.stackexchange.com/a/13388/6353

Answer 7

function get(string memory key) 
    public 
    view 
    returns (bytes32) {
        return bytes32(abi.encodePacked(key));
}