Create a Block

The simplest block you can create is an empty block. You will only need connect your client to a node and then call the Client.block(&self) function.

The following code example will:

1. Create a Client which will connect to the Shimmer Testnet.
2. Build and post an empty block.

Code Example

Rust

Dotenv

This example uses dotenv, which is not safe to use in production environments.

// Copyright 2021 IOTA Stiftung
// SPDX-License-Identifier: Apache-2.0

//! This example sends a block with no payload.
//! Run: `cargo run --example block_no_payload --release -- [NODE URL]`.

use iota_client::{Client, Result};

#[tokio::main]
async fn main() -> Result<()> {
    // Take the node URL from command line argument or use one from env as default.
    let node_url = std::env::args().nth(1).unwrap_or_else(|| {
        // This example uses dotenv, which is not safe for use in production.
        dotenv::dotenv().ok();
        std::env::var("NODE_URL").unwrap()
    });

    // Create a client with that node.
    let client = Client::builder().with_node(&node_url)?.finish()?;

    // Create and send the block.
    let block = client.block().finish().await?;

    println!("{block:#?}");

    println!(
        "Block with no payload sent: {}/block/{}",
        std::env::var("EXPLORER_URL").unwrap(),
        block.id()
    );

    Ok(())
}

Run the Example

Run the example by running the following command:

cargo run --example simple_block --release

Nodejs

Dotenv

This example uses dotenv, which is not safe to use in production environments.

// Copyright 2021-2022 IOTA Stiftung
// SPDX-License-Identifier: Apache-2.0

import { Client, initLogger } from '@iota/client';
require('dotenv').config({ path: '../.env' });

// Run with command:
// node ./dist/06_simple_block.js

// In this example we will send a block without a payload
async function run() {
    initLogger();
    if (!process.env.NODE_URL) {
        throw new Error('.env NODE_URL is undefined, see .env.example');
    }

    const client = new Client({
        // Insert your node URL in the .env.
        nodes: [process.env.NODE_URL],
        localPow: true,
    });

    try {
        // Create block with no payload
        const blockIdAndBlock = await client.buildAndPostBlock();
        console.log('Block:', blockIdAndBlock, '\n');

        console.log(
            `Empty block sent: ${process.env.EXPLORER_URL}/block/${blockIdAndBlock[0]}`,
        );
    } catch (error) {
        console.error('Error: ', error);
    }
}

run().then(() => process.exit());

You can run the example by running the following command from the bindings/node/examples/ folder:

node dist/06_simple_block.js

Python

from iota_client import IotaClient

# Create an IotaClient instance
client = IotaClient({'nodes': ['https://api.testnet.shimmer.network']})

# Create and post a block without payload
block = client.build_and_post_block()
print(f'{block}')

You can run the example by running the following command from the binding/python/examples folder:

python3 06_simple_block.py

Java

import org.iota.Client;
import org.iota.types.Block;
import org.iota.types.ClientConfig;
import org.iota.types.expections.ClientException;
import org.iota.types.expections.InitializeClientException;
import org.iota.types.ids.BlockId;

import java.util.Map;

public class CreateBlock {
    public static void main(String[] args) throws ClientException, InitializeClientException {
        // Build the client.
        Client client = new Client(new ClientConfig().withNodes(new String[]{"https://api.testnet.shimmer.network"}));

        // Create the most simple block.
        Map.Entry<BlockId, Block> b = client.buildAndPostBlock(null, null);

        // Print the block.
        System.out.println(b);
    }
}

Expected Output

Rust

Block {
    protocol_version: 2,
    parents: Parents(
        BoxedSlicePrefix([
            BlockId(0x2f68b25006f0e1b55ada3e9278e69796380971e97587c233d138c593139d255d),
            BlockId(0x76d25ac0073d14381d9a38c61ecb9665241d771bd89564e467c7fdf98e770ddd),
            BlockId(0xd072addb86a5a59a69b17d0e8fc3368771dc5ea7f7c2257045e508ae37f27a46),
            BlockId(0xfea2e90318a1b234569a3d698e97906d2c6a0084eb571971bf9ce9c4d31ee6c9),
        ]),
    ),
    payload: OptionalPayload(
        None,
    ),
    nonce: 4420,
}
Block with no payload sent: https://explorer.shimmer.network/testnet/block/0x9f794dde42c7be9cd209cc992f69e1f8b7b40578303825049079d8ac128aa20f

Nodejs

Block: [
  '0x7531a0983f941e50b1764165d8cf1e205605c269f43796d18e38264ddfce8d06',
  {
    protocolVersion: 2,
    parents: [
      '0x649914f510d1f9e8bb54f3ea0c810f7b591377a36edae8698df8a5be7e080e36',
      '0x76e0ce892ae9b3f0707ea6c068a3ee4faf98ac66e8089773a6ffe3951c6f111a',
      '0x8461d818b5fca64848f475aae434d994592bf0f5648b3ff7470e75437768295d',
      '0x994bcacab8bfc939a201e9ccf5a75eec2d047324a8a905cf1a4c1e09f3e1002a'
    ],
    nonce: '3074457345618276659'
  }
] 

Empty block sent: https://explorer.shimmer.network/testnet/block/0x7531a0983f941e50b1764165d8cf1e205605c269f43796d18e38264ddfce8d06

Python

[
  '0xa76b3551777d24fd20a045b2ebae11346c9f7ce76e2351eccb044b8842769250',
  {
    'protocolVersion': 2,
    'parents': [
      '0x485f44a5528b341a179db493fdd19138096f823fc034ba207a9ed85ebee5a109',
      '0x4a77573beb29edfa67ec00ee10577b31fe6a9e50b19ace0c833cfd1166069f7a',
      '0xa8edca4bda2db44e7bd29dd9282eff6011ff73fc1e318ba5950a67387be562da',
      '0xac283aa0ea563f81d7be39d2ae78bbadae838142e6d81280aeae02e96e35f013'
    ],
    'nonce': '12297829382473042444'
  }
]

Java

{
  "type": 3,
  "amount": "1000000",
  "unlockConditions": [
    {
      "type": 0,
      "address": {
        "type": 0,
        "pubKeyHash": "0x7ffec9e1233204d9c6dce6812b1539ee96af691ca2e4d9065daa85907d33e5d3"
      }
    }
  ]
}