Add ethereum compatible signer to subxt_signer?

[jsdw]

Anybody can implement a custom signer for Subxt to sign things as they need.

An example which I put together just now which seems to work for creating ethereum-compatible signatures and using AccountId20s is here:

https://gist.github.com/jsdw/13240f9341e433ea639b89d0d4235c8b

I'd be interested to check with other eth-compatible chains whether this solution works for all of them, and if so, it might be a good idea to add this in a more complete form to subxt_signer.

For now though, if anybody needs eth style signing, please check out the Gist above and let me know whether it works for you!

(this has come up previously in #1037)

[ryanleecode]

On moonbeam this is working perfect. For other chains that claim they are "EVM compatible" i'm looking inside their metadata to see if there are any entries that are Account20. The issue with the implementation is trying to guess where the Account20 is located under eth_runtime::runtime_types. Because its not always the same path say eth_runtime_runtime_types::account:Account20.

[jsdw]

The issue with the implementation is trying to guess where the Account20 is located under eth_runtime::runtime_types. Because its not always the same path say eth_runtime_runtime_types::account:Account20.

It's totally ok if their AccountId20's live in different places (that part is configued separately per chain anyway) :)