Electrum server cashaccount lookup

index.js

const ElectrumCli = require('electrum-client')
const CashAccounts = require('cashaccounts')
const BITBOX = require("bitbox-sdk").BITBOX
const assert = require("assert")
const crypto = require('crypto')

const bitbox = new BITBOX()

// Electrum API implementation is blockchain agnostic, so remember to add
// the modifier to the request.
const BCH_BLOCK_MODIFIER = 563620

const main = async () => {

    // Connect to our electrum server. If you're running it locally, you can
    // pass 50001, '127.0.0.1', 'tcp' and avoid dealing with SSL.
    const ecl = new ElectrumCli(50002, 'bitcoincash.network', 'tls') // tcp or tls
    await ecl.connect()

    // Lookup dagur#216, returns all transactions that register this identifier.
    // In this case, there is no conflict, so only 1 transaction is returned.
    const transactions = await ecl.request("cashaccount.query.name", ["dagur", 216 + BCH_BLOCK_MODIFIER]);
    console.log("Results:", transactions);

    // Lets use the BITBOX SDK to decode the first (and only in this case) result.
    const tx_hex = transactions.pop()["tx"]
    const tx = await bitbox.RawTransactions.decodeRawTransaction(tx_hex)

    // One of the outputs hash the OP_RETURN output containing the registration.
    const opreturn = tx.vout.find(o => o.scriptPubKey.type === 'nulldata').scriptPubKey.asm

    const cashaccounts = new CashAccounts()
    const payload = await cashaccounts.parsePaymentInfo(opreturn)
    console.log("Payload:", payload);

    // This address contains one regular payment address
    assert(payload[0].type === 'Key Hash')
    assert(payload[0].address === 'bitcoincash:qzxqjtkze0vy96y5xtru2w65mvaftryr55yzmhy8sl');

    // We already have an electrum connection open, so lets see what else
    // we can learn about this address.

    // Electrum uses scriphash for lookups, so we need to convert.
    const scriptHash = toScriptHash(payload[0].address)

    console.log("Transaction history: ",
        await ecl.request('blockchain.scripthash.get_history', [scriptHash]))

    console.log("Address balance: ",
        await ecl.request('blockchain.scripthash.get_balance', [scriptHash]))

    // disconnect from electrum server
    await ecl.close()
}

// Convert cashaddr to scripthash
// See https://electrumx.readthedocs.io/en/latest/protocol-basics.html#script-hashes
function toScriptHash(cashaddr) {

    const hash160 = bitbox.Address.cashToHash160(cashaddr);
    let scriptHash = bitbox.Script.fromASM(
        "OP_DUP OP_HASH160 " + hash160 + " OP_EQUALVERIFY OP_CHECKSIG")
    scriptHash = crypto.createHash('sha256').update(scriptHash).digest()
    scriptHash.reverse()
    return scriptHash.toString('hex')
}

main().catch((e) => { console.log("Error:", e) })