pezkuwi-subxt/subxt/examples/constants_dynamic.rs

#![allow(missing_docs)]
use pezkuwi_subxt::{OnlineClient, PolkadotConfig, dynamic::Value};

#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
	// Create a client to use:
	let api = OnlineClient::<PolkadotConfig>::new().await?;

	// We can query a constant by providing a tuple of the pallet and constant name. The return type
	// will be `Value` if we pass this query:
	let constant_query = ("System", "BlockLength");
	let _value = api.constants().at(&constant_query)?;

	// Or we can use the library function to query a constant, which allows us to pass a generic
	// type that Subxt will attempt to decode the constant into:
	let constant_query = pezkuwi_subxt::dynamic::constant::<Value>("System", "BlockLength");
	let value = api.constants().at(&constant_query)?;

	// Or we can obtain the bytes for the constant, using either form of query.
	let bytes = api.constants().bytes_at(&constant_query)?;

	println!("Constant bytes: {:?}", bytes);
	println!("Constant value: {}", value);
	Ok(())
}