Ordinal w/ custom script

ordinals.ts

// @ts-ignore
import btc = require('bitcore-lib');
import axios from 'axios';
import { Address, Tap, Tx } from '@cmdcode/tapscript'  // Requires node >= 19

async function fetchP2WPKHUtxos(address: btc.Address): Promise<any[]> {
    const url = `https://blockstream.info/api/address/${address.toString()}/utxo`;

    let res = []
    try {
        // Make a GET request to the URL using axios
        const response = await axios.get(url);

        // The response data is available in `response.data`
        console.log(address.toString())

        if (response.data) {
            for (let i = 0; i < response.data.length; i++) {
                const e = response.data[i]
                const utxo = {
                    address: address.toString(),
                    txId: e.txid,
                    outputIndex: e.vout,
                    script: new btc.Script(address),
                    satoshis: e.value
                };
                res.push(utxo)
            }
        }

    } catch (error) {
        // Handle any errors that occurred during the request
        console.error('Failed to fetch data:', error);
    }
    return res
}

async function fetchFeeRate(): Promise<number> {
    const url = `https://blockstream.info/api/fee-estimates`;

    let res = 20.0
    try {
        // Make a GET request to the URL using axios
        const response = await axios.get(url);

        // The response data is available in `response.data`

        if (response.data) {
            return response.data['20'] // ~ blocks inclusion
        }

    } catch (error) {
        // Handle any errors that occurred during the request
        console.error('Failed to fetch data:', error);
    }
    return res
}


async function main() {
    // Sample secret / public key pair.
    const seckey = 'TODO'
    const pubkey = 'TODO'

    const marker = new Uint8Array(Buffer.from('ord', 'utf-8'))
    const mimetype = new Uint8Array(Buffer.from('text/plain', 'utf-8'))
    const textData = new Uint8Array(Buffer.from('Hello, sCrypt!', 'utf-8'))
    const scriptPrefix = new btc.Script('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')
    let script: any[] = []
    scriptPrefix.chunks.forEach((chunk: { opcodenum: number; buf: Buffer; }) => {
        if (chunk.buf) {
            script.push(new Uint8Array(chunk.buf))
        } else {
            script.push(btc.Opcode.reverseMap[chunk.opcodenum])
        }
    });
    script = [...script, 'OP_0', 'OP_IF', marker, '01', mimetype, 'OP_0', textData, 'OP_ENDIF']
    
    // For tapscript spends, we need to convert this script into a 'tapleaf'.
    const tapleaf = Tap.encodeScript(script)
    // Generate a tapkey that includes our leaf script. Also, create a merlke proof 
    // (cblock) that targets our leaf and proves its inclusion in the tapkey.
    const [tpubkey, cblock] = Tap.getPubKey(pubkey, { target: tapleaf })

    // Regular P2WPKH stuff used for funding...
    const alice = new btc.PrivateKey('TODO', btc.Networks.livenet)
    const aliceAddrP2WPKH = alice.toAddress(null, btc.Address.PayToWitnessPublicKeyHash)
    console.log(aliceAddrP2WPKH.toString())

    const scripP2TR = new btc.Script(`OP_1 32 0x${tpubkey}}`)
    console.log(scripP2TR.toString())

    // Fetch UTXO's for address
    const utxos = await fetchP2WPKHUtxos(aliceAddrP2WPKH)

    const tx0 = new btc.Transaction()
        .from(utxos)
        .addOutput(new btc.Transaction.Output({
            satoshis: 16000,
            script: scripP2TR
        }))
        .change(aliceAddrP2WPKH)
        .feePerByte(await fetchFeeRate())
        .sign(alice)

    console.log(tx0.serialize())

    ////// UNLOCKING TX //////
    const prevTxId = 'TODO'
    const utxoP2TR = {
        txId: prevTxId,
        outputIndex: 0,
        script: scripP2TR,
        satoshis: 16000
    };

    const p2trInput = new btc.Transaction.Input({
        prevTxId,
        output: utxoP2TR,
        outputIndex: 0,
        scriptBuffer: new btc.Script('')
    })

    const txdata = Tx.create({
        vin: [{
            txid: utxoP2TR.txId,
            vout: utxoP2TR.outputIndex,
            prevout: {
                value: utxoP2TR.satoshis,
                scriptPubKey: ['OP_1', tpubkey]
            },
        }],
        vout: [
            {
                value: 546,
                scriptPubKey: Address.toScriptPubKey(aliceAddrP2WPKH.toString())
            }
        ]
    })

    txdata.vin[0].witness = [
        '7f5b1bc34513931257bb7520d175079c29b18c54812c938cdc6c66a277111bf700', 
        '58b79cc3b0cfeb8e00561686416f09c355fed61fc13337b0d2fc914a3946759c01', 
        '55fe3e4a446371d0d522e63662cac69d9e77cd7e87038bcb0fe126a60f24e0f901', 
        script, 
        cblock
    ]

    const txHex = Buffer.from(Tx.encode(txdata)).toString('hex')
    console.log(txHex)
}

main().catch(error => console.error('Error in main function:', error));