Avail Rust

Avail Rust is a Rust library for communicating with Avail networks.

In Action

This example uses the Tokio runtime, but you can use any runtime you like. Your Cargo.toml file could look like this:

[dependencies]
avail-rust-client = { version = "0.2.1", default-features = false, features = ["native", "reqwest"] }
tokio = { version = "1.45.0", features = ["rt-multi-thread", "macros"] }

[!NOTE] For the WASM environment, replace "native" with "wasm".

And then the code:

use avail_rust_client::prelude::*;

#[tokio::main]
async fn main() -> Result<(), ClientError> {
    let client = Client::new(TURING_ENDPOINT).await?;

    // Transaction Creation
    let submittable_tx = client.tx().data_availability().submit_data(vec![0, 1, 2, 3, 4, 5]);

    // Transaction Submission
    let submitted_tx = submittable_tx.sign_and_submit(&alice(), Options::new(2)).await?;

    // Fetching Transaction Receipt
    let receipt = submitted_tx.receipt(false).await?;
    let Some(receipt) = receipt else {
        return Err("Transaction got dropped.".into());
    };

    // Fetching Block State
    let block_state = receipt.block_state().await?;
    match block_state {
        BlockState::Included => println!("Block is included but not finalized"),
        BlockState::Finalized => println!("Block is finalized"),
        BlockState::Discarded => println!("Block is discarded"),
        BlockState::DoesNotExist => println!("Block does not exist"),
    }

    // Fetching and displaying Transaction Events
    let events = receipt.tx_events().await?;
    for event in events {
        println!("Pallet Index: {}, Variant index: {}", event.emitted_index.0, event.emitted_index.1);
    }

    Ok(())
}

You can find this example and similar ones in the example directory.

Feature Flags

The library is designed to use only the necessary dependencies, so by using default-features = false, features = [], the library will not compile unless you choose either the native or wasm target.

After that, you are free to choose one or all of the following feature flags:

• reqwest: Sets up a basic RPC client for sending and receiving network data. If you’re unsure what this means, it’s best to add this feature flag to your list.
• tracing: Enables logging/tracing, which is useful when dealing with nonce and other transaction-related issues. The logging output can be set to JSON format if needed.

Examples

All existing and new examples can be found here. They cover most basic needs and interactions with the chain. If there is something you need that isn’t covered, let us know—we might add it. :)

Here is an incomplete list of current examples:

• Batching transactions
• Executing transactions in parallel
• Writing your own custom transaction, event or storage
• Dealing with blocks and events
• A full example on how to submit a transaction from start to finish
• Subscribing to block headers, blocks, and justifications

Logging/Tracing

To enable tracing, use the tracing feature flag and call Client::enable_tracing(boolean) in your code, where boolean is true or false depending on whether you want to enable JSON-format structured logging.

Example:

[dependencies]
avail-rust-client = { version = "0.2.1", default-features = false, features = ["native", "reqwest", "tracing"] }
tokio = { version = "1.45.0", features = ["rt-multi-thread", "macros"] }

use avail_rust_client::prelude::*;

#[tokio::main]
async fn main() -> Result<(), ClientError> {
    Client::enable_tracing(false);
    let client = Client::new(LOCAL_ENDPOINT).await?;
    ...
}

After everything is set up run the following command:

RUST_LOG=info cargo run

Custom Transactions and Events

Sometimes you need a specific transaction or event type not included in the default metadata. In such cases, you can define a custom transaction or event and use it just like any predefined type. Both are simple to implement and use.

Create a custom transaction:

use avail_rust_client::{
    avail::{TransactionCallLike, HasHeader},
    prelude::*,
};

#[derive(codec::Decode, codec::Encode, PartialEq, Eq)]
pub struct CustomTransaction {
    pub data: Vec<u8>,
}
impl HasHeader for CustomTransaction {
    const HEADER_INDEX: (u8, u8) = (29u8, 1u8);
}

#[tokio::main]
async fn main() -> Result<(), ClientError> {
    let client = Client::new(LOCAL_ENDPOINT).await?;

    let custom_tx = CustomTransaction { data: vec![0, 1, 2, 3] };
    let submittable = custom_tx.to_submittable(client.clone());
    let submitted = submittable.sign_and_submit(&alice(), Options::new(2)).await?;
    let receipt = submitted.receipt(true).await?.expect("Must be there");
}

Create a custom event:

use avail_rust_client::prelude::*;

#[derive(codec::Decode, codec::Encode, PartialEq, Eq)]
pub struct CustomEvent {
    pub who: AccountId,
    pub data_hash: H256,
}
impl HasHeader for CustomEvent {
    const HEADER_INDEX: (u8, u8) = (29, 1);
}

#[tokio::main]
async fn main() -> Result<(), ClientError> {
    // For brevity, the method of obtaining the encoded event is omitted.
    // In short, you can get it from the event client or from receipt.tx_events().
    let encoded_event = vec![0, 1, 2, 3];
    let event = CustomEvent::from_raw(&encoded_event).expect("Must be Ok");
    println!("Account: {}, Hash: {}", event.who, event.data_hash);

    Ok(())
}

Fetching Storage

The easiest way to fetch storage from the chain is by custom defining it and implementing either the StorageValue, StorageMap or StorageDoubleMap trait for it.

Create a custom storage:

use avail_rust_client::prelude::*;

pub struct DataAvailabilityAppKeys;
impl StorageMap for DataAvailabilityAppKeys {
	const PALLET_NAME: &str = "DataAvailability";
	const STORAGE_NAME: &str = "AppKeys";
	const KEY_HASHER: StorageHasher = StorageHasher::Blake2_128Concat;
	type KEY = Vec<u8>;
	type VALUE = AppKey;
}
#[derive(Debug, Clone, codec::Decode)]
pub struct AppKey {
	pub owner: AccountId,
	#[codec(compact)]
	pub id: u32,
}

#[tokio::main]
async fn main() -> Result<(), ClientError> {
	let client = Client::new(TURING_ENDPOINT).await?;
	let block_hash = client.finalized_block_hash().await.unwrap();

	// Fetching Storage Map
	let value = DataAvailabilityAppKeys::fetch(
		&client.rpc_client,
		"MyAwesomeKey".to_string().into_bytes(),
		Some(block_hash),
	)
	.await?
	.expect("Needs to be there");
	println!("Owner: {}, id: {}", value.owner, value.id);

	// Iterating Storage Map
	let mut iter = DataAvailabilityAppKeys::iter(client.rpc_client.clone(), block_hash);
	for _ in 0..5 {
		let value = iter.next().await?.expect("Needs to be there");
		println!("Owner: {}, id: {}", value.owner, value.id);

		let (key, value) = iter.next_key_value().await?.expect("Needs to be there");
		println!(
			"Key: {}, Owner: {}, id: {}",
			String::from_utf8(key).expect(""),
			value.owner,
			value.id
		);
	}

	Ok(())
}

Getting Help

In the avail-rust repository, we have many examples showing how to use this library. If something is missing or unclear, don't hesitate to open a discussion or reach out to us on Discord (the link is at the bottom of the page).

Contribution

Thank you for your interest in improving this project! As we are still adding new features and finalizing existing ones, it would be helpful to first post your idea in the discussions or issues.

Pull requests that only fix grammatical mistakes, resolve cargo clippy warnings, or do not add any substantial value will be closed immediately without feedback.