quartzjer / raw-op-return

Post and read raw OP_RETURN messages on the Bitcoin blockchain.

Raw OP_RETURN

Post and read raw OP_RETURN messages on the Bitcoin blockchain.

npm install raw-op-return

Post

In our examples we're going to use the bitcoinjs-lib and the helloblock-js test faucet to get and process our private key, public address and unspent outputs.

var Bitcoin = require("bitcoinjs-lib");

var helloblock = require("helloblock-js")({
  network: 'testnet'
});

helloblock.faucet.get(1, function(err, res, body) {

  var privateKeyWIF = body.privateKeyWIF;
  var address = body.address;
  var unspentOutputs = body.unspents;
  
  // ...
  
});

We'll need to provide a few of your own functions.

Signing a transaction:

var signFromPrivateKeyWIF = function(privateKeyWIF) {
  return function(tx, callback) {
    var key = Bitcoin.ECKey.fromWIF(privateKeyWIF);
    tx.sign(0, key); 
    callback(false, tx);
  }
};
var signTransaction = signFromPrivateKeyWIF(privateKeyWIF);

Propagating a transaction:

var propagateTransaction = function(tx, callback) {
  helloblock.transactions.propagate(tx, function(err, res, body) {
    callback(err, res);
  });
};

Looking up and parsing a transaction:

var getTransaction = function(txHash, callback) {
  helloblock.transactions.get(txHash, function(err, res, tx) {
    callback(err, tx);
  });
};

And finally we're ready to post.

rawOpReturn.post({
  stringData: "a message",
  address: address,
  unspentOutputs: unspentOutputs,
  propagateTransaction: propagateTransaction,
  signTransaction: signTransaction
}, function(error, postedTx) {
  console.log("posted data:", postedTx.data);
});

Scan

var txHash = "b9a5a9bf941fb37abec789e6aa70964075d006aeff044e932491008a0a51577d";
getTransaction(txHash, function(err, tx) {
  rawOpReturn.scan(tx, function(err, scannedTx) {
    console.log("scanned data:", scannedTx.data);
  });
});