pezkuwi-subxt/subxt/examples/light_client_basic.rs

#![allow(missing_docs)]
use futures::StreamExt;
use pezkuwi_subxt::{PezkuwiConfig, client::OnlineClient, lightclient::LightClient};

// Generate an interface that we can use from the node's metadata.
#[pezkuwi_subxt::subxt(runtime_metadata_path = "../artifacts/pezkuwi_metadata_small.scale")]
pub mod pezkuwi {}

const POLKADOT_SPEC: &str = include_str!("../../artifacts/demo_chain_specs/pezkuwi.json");
const ASSET_HUB_SPEC: &str =
	include_str!("../../artifacts/demo_chain_specs/pezkuwi_asset_hub.json");

#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
	// The lightclient logs are informative:
	tracing_subscriber::fmt::init();

	// Instantiate a light client with the Pezkuwi relay chain,
	// and connect it to Asset Hub, too.
	let (lightclient, pezkuwi_rpc) = LightClient::relay_chain(POLKADOT_SPEC)?;
	let asset_hub_rpc = lightclient.parachain(ASSET_HUB_SPEC)?;

	// Create Subxt clients from these Smoldot backed RPC clients.
	let pezkuwi_api = OnlineClient::<PezkuwiConfig>::from_rpc_client(pezkuwi_rpc).await?;
	let asset_hub_api = OnlineClient::<PezkuwiConfig>::from_rpc_client(asset_hub_rpc).await?;

	// Use them!
	let pezkuwi_sub = pezkuwi_api
		.blocks()
		.subscribe_finalized()
		.await?
		.map(|block| ("Pezkuwi", block));
	let parachain_sub = asset_hub_api
		.blocks()
		.subscribe_finalized()
		.await?
		.map(|block| ("AssetHub", block));

	let mut stream_combinator = futures::stream::select(pezkuwi_sub, parachain_sub);

	while let Some((chain, block)) = stream_combinator.next().await {
		let block = block?;
		println!("     Chain {:?} hash={:?}", chain, block.hash());
	}

	Ok(())
}