README use of FutureResult is out of date

[jbaublitz]

I tried using FutureResult as specified in the README when trying to prototype a derived interface, but the jsonrpc_core::Error type cannot be used in FutureResult as suggested by the README. I've dug into the code a little bit more and it appears that it is expecting the second type parameter to FutureResult to be a Future which jsonrpc_core::Error is not. Would you be able to update the README or provide a suggestion for how to work around this?

[niklasad1]

Which version/branch are you using?

#565 updated to futures v0.3 and the README might be outdated.

//cc @tomusdrw

[jbaublitz]

I'm using the latest released version which appears to be 15.1.0. I've checked both that branch and the master branch to see if there was a difference, but they both appear to be out of date. I tried playing around with this a little bit, but it appears that the derive macro only accepts the jsonrpc_core::Result or jsonrpc_core::FutureResult type as a return type for the trait methods.

[tomusdrw]

@jbaublitz master example indeed won't work with 15.1.0. Can you post a code sample which you have problem with and the compiler error?

This code uses 15.1.x:
https://github.com/paritytech/substrate/blob/53ab714d03babdcb5538232a7c36ca89266180e6/client/rpc-api/src/state/mod.rs#L43

FutureResult is defined like so:
https://github.com/paritytech/substrate/blob/53ab714d03babdcb5538232a7c36ca89266180e6/client/rpc-api/src/state/error.rs#L28

[jbaublitz]

This is no longer an issue for me. Closing.