How to post a transaction

This guide provides an overview of the different options for sending a transaction to a node.

Posting transaction with the node CLI

If you are managing a node, it is possible to send transaction directly via the node CLI with the transaction:send command.

lisk-core transaction:send 0802100018022080c2d72f2a20e03c09bdc8c023d94cf66a5d352e6258380210d97d545abbf75668ea3736e3123229088094ebdc031214ab0041a7d3f7b2c290b5b834d46bdc7b7eb858151a0b73656e6420746f6b656e733a40faa2626d7306506b1999f48aa2f4b1ffdee01e641fa76d37a9d1d6fd8c225a81065c856ea625c52d138a7e3ba86b62913dc8e5aef8b5e307641ab66e0277a60b

WS & IPC API example with API client

The Lisk API client is a JS package that allows connecting to a node API through WS and IPC protocols.

It can be used inside of a JS or a TS script to connect to a blockchain node API in order to post transactions to the node.

To use the Lisk API client, install the lisk-client package with NPM:

npm install @liskhq/lisk-client

  • WS API client example

  • IPC API client example

Create a file api-client.js which will export the function getClient().

Adjust the RPC_ENDPOINT to point to the node you want to post the transaction to.

api-client.js
const { apiClient } = require('@liskhq/lisk-client');

const RPC_ENDPOINT = 'ws://localhost:7887/rpc-ws';
let clientCache;

const getClient = async () => {
  if (!clientCache) {
    clientCache = await apiClient.createWSClient(RPC_ENDPOINT);
  }
  return clientCache;
};

module.exports = { getClient };

Create a file api-client.js which will export the function getClient().

Adjust the DATA_PATH to point to the blockchain client data path.

api-client.js
const { apiClient } = require('@liskhq/lisk-client');

const DATA_PATH = '~/.lisk/hello_client';
let clientCache;

const getClient = async () => {
    if (!clientCache) {
        clientCache = await apiClient.createIPCClient(DATA_PATH);
    }
    return clientCache;
};

module.exports = { getClient };

Create a new script post-transaction.js to post the transaction.

Import the getClient() function and execute it to use the API client to broadcast the transaction, as shown in the snippet below.

Use the client.transaction.send() function to post the transaction. It expects a signed transaction in the JSON-compatible object format as parameter.

post-transaction.js
const { getClient } = require('./api-client');

const signedTransaction = {
    module: 'token',
    command: 'transfer',
    fee: '1000000',
    params: {
        tokenID: '0400000000000000',
        amount: '800000000',
        recipientAddress: 'lskt8ovj2shbxrtno8xqqt7cnmzzygdkbt6brnvmj',
        data: 'Happy birthday!'
    },
    nonce: '0',
    senderPublicKey: '3972849f2ab66376a68671c10a00e8b8b67d880434cc65b04c6ed886dfa91c2c',
    signatures: [
        '960a67e3047dbc1bd2e2d1306d473674867eb81fdf90ec65f5759c1a1ec407f5baf9871ca76375557c7b23e225ae60cdda65fdce385bae076131ad5f7e39df0b'
    ]
}

// Use the API client to send the transaction to a node
getClient().then(async client => {
  try {
    const res = await client.transaction.send(signedTransaction);
    console.log(res);
  } catch (error) {
    console.log(error);
  }
});

HTTP API example with cURL

If a node has HTTP API enabled, it is possible to post HTTP requests to the node as shown in the example below.

The transaction is expected as parameter in the hex string format.

curl --location --request POST 'http://localhost:7887/rpc' \
--header 'Content-Type: application/json' \
--data-raw '{
    "jsonrpc": "2.0",
    "id": "1",
    "method": "txpool_postTransaction",
    "params": {
        "transaction": "08021000180d2080c2d72f2a200fe9a3f1a21b5530f27f87a414b549e79a940bf24fdf2b2f05e7f22aeeecc86a32270880c2d72f12144fd8cc4e27a3489b57ed986efe3d327d3de40d921a0a73656e6420746f6b656e3a4069242925e0e377906364fe6c2eed67f419dfc1a757f73e848ff2f1ff97477f90263487d20aedf538edffe2ce5b3e7601a8528e5cd63845272e9d79c294a6590a"
    }
}'