bytes32 as parameters

[GabCas]

Hi,

I have a method in my contract that expects a bytes32 parameter. I've seen how this is done in Issue #57 and Issue #63 but haven't been able to make it work.
I have a sha string that I turn to bytes32 like this:
let sha:Data = self.sha!.data(using: .utf8)![0..<32]

self.sha is a string like this: "4621c5cb24cca81ab0329089464ad54cd10e071bd21e86a237666228c6d2c04f"

I also have the bytes32 in a string representation from the server that looks like this: "b\'F!\\xc5\\xcb$\\xcc\\xa8\\x1a\\xb02\\x90\\x89FJ\\xd5L\\xd1\\x0e\\x07\\x1b\\xd2\\x1e\\x86\\xa27fb(\\xc6\\xd2\\xc0O\'"

However, the constructed Data (for bytes32) in swift comes out looking like this:
[52, 54, 50, 49, 99, 53, 99, 98, 50, 52, 99, 99, 97, 56, 49, 97, 98, 48, 51, 50, 57, 48, 56, 57, 52, 54, 52, 97, 100, 53, 52, 99]

As you can see the bytes32 created in swift is fairly different from the one my server provides in string representation.

Finally, I add it as the parameters for my function call like so:
let parameters = [sha] as [AnyObject]

Is there something I'm missing? The transactionIntermediate is getting created correctly so at least the parameter is good. I'm always getting 'revert' from my contract...

Any help is greatly appreciated.

Thanks,

[shamatar]

Hello @GabCas

A library takes care of parameter serialization for you. If you want to pass a hex string as "bytes32" parameter then you just need to prepend it with "0x" prefix, so passing

let hexData = "0x" + self.sha!
let parameters = [hexData] as [AnyObject]

should be enough for you. Just in case if you want to pass utf8 encoding of arbitrary string as bytes32 - just leave is without prefix, conversion will be handled automatically too.

Sincerely, Alex

[GabCas]

Thanks @shamatar ! That's exactly what I needed to do.