transaction.js

var bitcoinjs = require('bitcoinjs-lib');
const fs = require('fs');
var mime = require('mime-types')



function Transaction(hash, transactionRaw) {
    this.isGenesis = false;
    this.hash = hash;
    this.decodedTransaction = bitcoinjs.Transaction.fromHex(Buffer.from(transactionRaw, 'hex'));
    let rawWitness = this.decodedTransaction.ins[0].witness[1]
    this.type = null;
    try {
        if (rawWitness[35] == 99 && rawWitness[37] == 111 && rawWitness[38] == 114 && rawWitness[39] == 100 && rawWitness[40] == 1 && rawWitness[41] == 1) {
            let length = rawWitness[42]
            this.contentType = ""
            for (let index = 0; index < length; index++) {
                this.contentType += String.fromCharCode(rawWitness[43 + index])
            }
            this.contentStart = 44 + length;
            this.isGenesis = true;
        }
    } catch (error) {

    }
}

Transaction.prototype._getAllContent = function (existing, start_index) {
    let rawWitness = this.decodedTransaction.ins[0].witness[1]
    let op_1 = rawWitness[start_index];
    if (op_1 > 0 && op_1 < 76) {  // The next opcode bytes is data to be pushed onto the stack
        existing = Buffer.concat([existing, rawWitness.slice(start_index + 1, rawWitness.length - 1)]);
    } else if (op_1 == 76) {
        existing = Buffer.concat([existing, rawWitness.slice(start_index + 2, rawWitness.length - 2)]);
    } else if (op_1 == 77) { // The next byte contains the number of bytes to be pushed onto the stack.
        let nb = rawWitness[start_index + 1] + (rawWitness[start_index + 2] * 255)
        let new_index = start_index + 5 + (nb);
        existing = Buffer.concat([existing, rawWitness.slice(start_index + 3, new_index)]);
        return (this._getAllContent(existing, new_index))
    }
    return existing;
}

Transaction.prototype.isOrdinalGenesis = function () {
    return this.isGenesis;
}

Transaction.prototype.getContentType = function () {
    return this.contentType;
}

Transaction.prototype.getContentLength = function () {
    return this.contentLength;
}

Transaction.prototype.getContentData = function () {
    return this._getAllContent(Buffer.alloc(0), this.contentStart);
}

Transaction.prototype.getHash = function () {
    return this.hash;
}

Transaction.prototype.contentToFile = function () {
    fs.writeFileSync('./tests/' + this.getHash() + "." + mime.extension(this.contentType), this.getContentData(), { flag: 'w' });
}

module.exports = Transaction;