subxt: How to derive serialize trait for runtime type?

Question

I want to define a struct serializeable to json

#[derive(Serialize)]
struct Struct {
    item: SomeRuntimeType,
}

but I get this error:

error[E0277]: the trait bound `pallet_pallet::types::SomeRuntimeType: conf::_::_serde::Serialize` is not satisfied
    --> src/main.rs:150:10
     |
150  | #[derive(Serialize)]
     |          ^^^^^^^^^ the trait `conf::_::_serde::Serialize` is not implemented for `pallet_pallet::types::SomeRuntimeType`

Is there a way to derive some kind of serialization in subxt?

#[subxt::subxt(
    runtime_metadata_path = "res/metadata.scale",
    derive_for_all_types = "Debug" // <--- like adding Serialize here
)]
pub mod runtime {}

Or do I have to manually implement serialization?

Answer 1

It probably won't work to derive serde::Serialize for all types in the subxt codegen because there are some types that doesn't implement Serialize.

For individual types you can try:

#[subxt::subxt(
    runtime_metadata_path = "artifacts/metadata.scale",
    derive_for_all_types = "Clone, Debug, Eq, PartialEq",
    derive_for_type(
        path = "pallet_election_provider_multi_phase::RoundSnapshot",
        derive = "Default, serde::Serialize"
    )
)]
pub mod runtime {}

If that won't work you need to provide your own Serialize impl/add wrapper struct, replace the type with your own or something similar.

I hope it helps