Files
pezkuwi-subxt/examples/fetch_remote.rs
T
Andrew Jones dc2a73dc4a Wrap and export BlockNumber (#87)
* Add fetch example and wrap BlockNumber impl

* Fmt
2020-04-15 08:45:58 +01:00

46 lines
1.5 KiB
Rust

// Copyright 2020 Parity Technologies (UK) Ltd.
// This file is part of substrate-subxt.
//
// subxt is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// subxt is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with substrate-subxt. If not, see <http://www.gnu.org/licenses/>.
use substrate_subxt::{
system::System,
Error,
KusamaRuntime,
};
fn main() {
async_std::task::block_on(async move {
env_logger::init();
let block_hash = fetch_block_hash(1).await;
match block_hash {
Ok(Some(hash)) => println!("Block hash for block number 1: {}", hash),
Ok(None) => println!("Block number 1 not found."),
Err(_) => eprintln!("Failed to fetch block hash"),
}
});
}
async fn fetch_block_hash(
block_number: u32,
) -> Result<Option<<KusamaRuntime as System>::Hash>, Error> {
substrate_subxt::ClientBuilder::<KusamaRuntime>::new()
.set_url("wss://kusama-rpc.polkadot.io")
.build()
.await?
.block_hash(Some(block_number.into()))
.await
}