Introduction

@electrum-cash/network is a lightweight JavaScript library that lets you connect Electrum servers.

It offers encrypted connections by default, performs the expected protocol version negotiation and automatically keeps your connection alive until your close it.

Installation

Install the library with NPM:

# npm install @electrum-cash/network

Usage

Importing the library

To use the library, import the ElectrumClient into your project:

// Load the electrum library.
import { ElectrumClient } from '@electrum-cash/network';

Connecting to a server

Initialize and connect the client with your application identifier and protocol version, as well as a hostname to connect to.

// Initialize an electrum client.
const electrumClient = new ElectrumClient('Electrum client example', '1.4.1', 'bch.imaginary.cash');

// Wait for the client to connect.
await electrumClient.connect();

Alternatively, you can provide a pre-configured ElectrumSocket instead of the hostname:

// Set up your own socket, somehow.
const electrumSocket = new MyElectrumSocketClass();

// Initialize the electrum client.
const electrumClient = new ElectrumClient('Electrum client example', '1.4.1', electrumSocket);

// Wait for the client to connect.
await electrumClient.connect();

Request information

Once your ElectrumClient is connected and ready, you can call methods:

For a list of methods you can use, refer to the Electrum Cash documentation.

// Declare an example transaction ID.
const transactionID = '4db095f34d632a4daf942142c291f1f2abb5ba2e1ccac919d85bdc2f671fb251';

// Request the full transaction hex for the transaction ID.
const transactionHex = await electrumClient.request('blockchain.transaction.get', transactionID);

// Print out the transaction hex.
console.log(transactionHex);

Subscribe to notifications.

Once your ElectrumClient is connected and ready, you can set up subscriptions to get notifications on events:

For a list of methods you can subscribe to, refer to the Electrum Cash documentation.

// Set up a callback function to handle new blocks.
const handleNotifications = function(data)
{
	if(data.method === 'blockchain.headers.subscribe')
	{
		// Print out the block information.
		// {
		// 	jsonrpc: '2.0',
		// 	method: 'blockchain.headers.subscribe',
		// 	params:
		// 	[
		// 		{
		// 		height: 797111,
		// 		hex: '002001202a6b1367f68201ad957e95bec9bda3f132ca2fcb75c0c000000000000000000074befba60bd8615d87ddb636aa99bc032cec8db3adb0d915d45391bc811c1e9ceacf89647a60051819a79559'
		// 		}
		// 	]
		// }
		console.log(data);
	}
}

// Listen for notifications.
electrumClient.on('notification', handleNotifications);

// Set up a subscription for new block headers.
await electrumClient.subscribe('blockchain.headers.subscribe');

Shutting down

When you're done and don't want to be connected anymore you can disconnect the server:

// Close the connection.
await electrumClient.disconnect();

Documentation

For a complete list of methods and parameters, read the API documentation.

Support and communication

If you need help with how to use the library or just want to talk about electrum-cash, you can find us on Telegram and Discord.

Notes

The keep-alive functionality of this library only works when the protocol version is 1.2 or higher.