Light Client node with no RPC

note

Integrate with the Astar networks using a light client.

This documentation will guide you on how to connect to the Astar Network using a light client (ScProvider) with the Polkadot.js API and Substrate Connect.

Prerequisites:

• Node.js (https://nodejs.org/en/download/)
• npm (https://www.npmjs.com/get-npm)

Overview

Astar Network is a scalable smart contract platform on Polkadot that supports Ethereum compatibility. Connecting to the Astar Network using a light client (ScProvider) allows you to interact with the network without having to sync the entire blockchain.

1. Initialize a new Node.js project Create a new directory for your project and navigate to it in your terminal or command prompt. Initialize a new Node.js project by running:

mkdir astar-light-client
cd astar-light-client
npm init -y

2. Install required packages Install the required packages by running:

npm install @polkadot/api @substrate/connect

3. Create the chain specification file Create a new file named astar.json in the chain-specs directory of your project. You can download the latest Astar chain specification file from the Astar GitHub repository or use this link.

Create a new directory named chain-specs and save the astar.json file in it:

mkdir chain-specs
wget https://raw.githubusercontent.com/AstarNetwork/astar-apps/main/src/config/api/polkadot/chain-specs/astar.json -P chain-specs

4. Create a script to connect to the Astar Network Create a new file named connect-astar.js in your project directory and paste the following script into it:

const { ApiPromise, ScProvider } = require("@polkadot/api");
const Sc = require("@substrate/connect");

async function queryInfo(api) {
  const assetMetadata = await api.query.assets.metadata.entries();

  assetMetadata.map((asset) => {
    let h = asset[1].toHuman();
    console.log(JSON.stringify(h));
  });
}

async function setup() {
  const jsonParachainSpecAstar = require("./chain-specs/astar.json");
  const astarSpec = JSON.stringify(jsonParachainSpecAstar);

  const relayProvider = new ScProvider(Sc, Sc.WellKnownChain.polkadot);
  const provider = new ScProvider(Sc, astarSpec, relayProvider);

  await provider.connect();
  const api = await ApiPromise.create({ provider });

  console.log("Connected to Astar Network using ScProvider (light client)");
  await queryInfo(api);
  process.exit();
}

setup();

This script sets up a connection to the Astar Network using a light client (ScProvider) by leveraging Substrate Connect and the Polkadot.js API.

5. Run the script Now, you can run the script to connect to the Astar Network:

node connect-astar.js

If the connection is successful, the script will output the following message:

Connected to Astar Network using ScProvider (light client)
{"deposit":"86,000,000,000","name":"MochiMochiCoin","symbol":"MMC","decimals":"2","isFrozen":false}
...
{"deposit":"0","name":"Liquid DOT","symbol":"LDOT","decimals":"10","isFrozen":false}

Congratulations! You have successfully connected to the Astar Network using a light client (ScProvider) with the Polkadot.js API and Substrate Connect. You can now use the api instance to interact with the Astar Network and query data or submit transactions.

Run it in Replit