Guides

Read storage

Reading the storage also called the chain state is a common operation in blockchain development. The storage can hold anything from balance of an account to the configuration of the chain. It is also possible to read the storage from a specific block, which is useful for historical data analysis.

Here we are showing you how to retrieve the storage and decode it.

Reading storage from the current block


Future<void> main(List<String> arguments) async {
  final provider = Provider.fromUri(Uri.parse('wss://rpc.polkadot.io'));
  final polkadot = Polkadot(provider);

  polkadot.query.system.number().then((blockNumber) {
    print('Current block number: $blockNumber');
  });
}

// Output: Current block number: 23208989

Reading storage from a specific block


Future<void> main(List<String> arguments) async {
  final provider = Provider.fromUri(Uri.parse('wss://rpc.polkadot.io'));
  final polkadot = Polkadot(provider);
    final block = decodeHex('0x43c65760a5e36e9c95b2c493b78e7b01a2f8be5b0b48d543168d9f2c6fc4eb10');

  polkadot.query.system.number(at: block).then((blockNumber) {
    print('Current block number: $blockNumber');
  });
}

// Output: Current block number: 23208972

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Make a balance transfer

Perhaps the most common operation done in any blockchain is transferring funds from one account to another. Here we will show you how to make a simple balance transfer using Polkadart.

Using metadata hash

Transactions are encoded and readed using the runtime metadata, for offline wallets this implies that they need to have access to a trustable source to provide its metadata.