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I am working in a ethereum project and i want to retrieve some data from an event. Let me show the details of what i am trying to do ;

    event fooev( address indexed sender, address indexed requesteeContractAddr, string indexed abc);

The fooev is an event that the contract emits

function foo(address requesteeContractAddr, string abc) public
{
    fooev(msg.sender, requesteeContractAddr, abc);
}

Foo is a function, when someone sends a transaction & calls foo, the fooev' event is emitted

assume abc = 'hey'

Now i am getting event data like this :

AttributeDict({'sender': '0xfc63c3aB84fc49bfDd7aB7FAcB6A80BE890eA062',
'requesteeContractAddr': '0x4cd53503e7Ab59D2aFB379195569424Df88f5BF6',
 'abc': b'&\xa2\x082:\x8c!\xa11#\xc1#\xa8\xdd|qDD\xc5a\x10;\x00b\xd1\xb8\xb6\xa9\xe9\x08\x9e*'})

notice that abc, which was input in the smart contract in a string form, is returned in a bytes form.

When i try to convert it from bytes to string by doing something like :

Web3.toText(AttributeDict.args.resourceType)

i get the error :

UnicodeDecodeError: 'utf-8' codec can't decode byte 0xa2 in position 1: invalid start byte

can someone please help me ? I just want to convert abc BACK to the string form i had originally input it in

1 Answer 1

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Did you figure this out? Strings are encoded as Bytes32 in events:

https://docs.ethers.io/v5/api/utils/strings/#Bytes32String

p.s. you will not want to index your strings in the event. They are not null terminated and you will get an error.

I decided to go with the interface pattern in ethers:

https://github.com/ethers-io/ethers.js/issues/422

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    It is not correct that an indexed string will cause an error. For dynamic parameters like string and bytes it will index its keccak256 value.
    – Ismael
    Sep 21, 2022 at 13:35

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