Adding a Memo to a Bitcoin Transaction

stuart · December 14, 2020, 3:05am

Hello

I was looking for an example of adding a memo to a Bitcoin transaction with Rosetta. Would it be simply be adding an additional Operation with the following values in the Metadata field?

import * as BitcoinJS from 'bitcoinjs-lib'

const senderAddress = 'xyz';
const memo = 'Hello World';

const ops = [... other operations to send transaction]

const memoOperation = {
      operation_identifier: {
        index: ops.length - 1,
      },
      type: 'OUTPUT',
      account: {
        address: senderAddress,
      },
      amount: {
        value: '0',
        currency: {
          symbol: 'tBTC',
          decimals: 8,
        },
      },
      metadata: {
        scriptPubKey: {
          asm: `OP_RETURN ${BitcoinJS.script.toASM(Buffer.from(memo))}`,
          hex: Buffer.from(memo).toString('hex'),
          type: 'nulldata',
        },
      },
    }

When I test out the above code, I get the error “Unable to parse intent” when passing to the payloads endpoint.

Thanks!

patrick.ogrady · December 14, 2020, 3:17pm

That’s a great question, @stuart! Unfortunately, the existing rosetta-bitcoin implementation only supports orchestrating simple sends. I’m all for you adding an extension to support more complex sends in rosetta-bitcoin (would just involve adding some logic to treat an output specially if it has some metadata).

All related logic can be found in this file:

github.com

coinbase/rosetta-bitcoin/blob/master/services/construction_service.go

// Copyright 2020 Coinbase, Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//      http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package services

import (
	"bytes"
	"context"
	"encoding/hex"

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stuart · December 19, 2020, 1:08pm

Hey @patrick.ogrady, thanks for the response. Sounds good, we can take a stab at it. To discuss how to implement, created an issue for this in github https://github.com/coinbase/rosetta-bitcoin/issues/58.