Upgrade ethclient and abigen to support privateFor

[stevenroose]

Currently the privateFor parameters is supported by the JSON-RPC API. The Go bindings in ethclient and abigen (that uses ethclient under the hood) do not yet.

Depends on: #90

[stevenroose]

I'm looking into how hard it is to do.

[stevenroose]

Back then, I realised it would be possible once #90 was solved, since abigen primarily relies on sendRawTransaction. Anyone else trying to solve this?

[conor10]

I'm planning to take a look at #90, unless any of you guys are already @patrickmn? I saw the help wanted label was removed.

[patrickmn]

@conor10 Please feel free. I was going to, but haven't started.

[stevenroose]

There's two parts of the problem. One is the server, which allowing the sendRawTransaction JSON-RPC call to have a privateFor field somewhere. The other is incorporating that in the ethclient package. The latter should be more straightforward, but makes no sense if the former is not yet done.

It's not easy to find how and where there were modifications to geth regarding private transactions. F.e. I can only see private.P.Send being called with the data field being contract code, not when making normal non-deployment transactions.

Let me open a WIP PR with what I got.

[patrickmn]

Regarding modifications, see #146 (comment)

[prd-fox]

This has been implemented in #819