Module: MixinBot::API::Transfer

Included in:
MixinBot::API
Defined in:
lib/mixin_bot/api/transfer.rb

Overview

API methods for creating transfers using the Safe API.

The Safe API is the recommended way to transfer assets on Mixin Network. It provides better security, lower fees, and more flexibility than legacy transfers.

Transfer Process

A Safe transfer involves several steps:

  1. Select UTXOs (unspent transaction outputs) as inputs

  2. Build the transaction with outputs

  3. Sign the transaction with spend key

  4. Submit the signed transaction

This module handles all these steps automatically.

Usage

# Simple transfer to a single user
api.create_transfer(
  members: 'user-uuid',
  asset_id: 'asset-uuid',
  amount: '0.01',
  memo: 'Payment'
)

# Multisig transfer
api.create_transfer(
  members: ['user1-uuid', 'user2-uuid', 'user3-uuid'],
  threshold: 2,
  asset_id: 'asset-uuid',
  amount: '0.01'
)

Instance Method Summary collapse

Instance Method Details

#build_utxos(asset_id:, amount:) ⇒ Array<Hash>

Builds a UTXO set for a transfer.

Selects unspent outputs (UTXOs) from the bot’s wallet that sum up to at least the requested amount. This is used internally by create_safe_transfer but can be called directly if needed.

The method:

  • Fetches unspent outputs for the asset

  • Sorts them by amount (smallest first)

  • Selects outputs until the amount is reached

  • Limits to 256 UTXOs maximum

Examples:

utxos = api.build_utxos(
  asset_id: '965e5c6e-434c-3fa9-b780-c50f43cd955c',
  amount: '0.01'
)
puts "Selected #{utxos.length} UTXOs"
puts "Total: #{utxos.sum { |u| u['amount'].to_d }}"

Parameters:

  • asset_id (String) —

    the asset UUID

  • amount (String, Float, BigDecimal) —

    the amount needed

Returns:

  • (Array<Hash>) —

    array of selected UTXOs

Raises:



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# File 'lib/mixin_bot/api/transfer.rb', line 191

def build_utxos(asset_id:, amount:)
  amount = amount.to_d
  outputs = safe_outputs(state: 'unspent', asset: asset_id, limit: 500)['data'].sort_by { |o| o['amount'].to_d }

  utxos = []
  outputs.each do |output|
    break if utxos.size >= 256

    utxos << output
    break if utxos.sum { |o| o['amount'].to_d } >= amount
  end

  total_in = utxos.sum { |o| o['amount'].to_d }
  if total_in < amount
    raise MixinBot::UtxoInsufficientError.new(
      'insufficient utxo',
      total_input: total_in,
      total_output: amount,
      output_size: utxos.size
    )
  end

  utxos
end

#create_safe_transfer(**kwargs) ⇒ Object

Raises:



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# File 'lib/mixin_bot/api/transfer.rb', line 107

def create_safe_transfer(**kwargs)
  utxos = kwargs[:utxos]
  raise ArgumentError, 'utxos must be array' if utxos.present? && !utxos.is_a?(Array)

  asset_id =
    if utxos.present?
      utxos.first['asset_id']
    else
      kwargs[:asset_id]
    end

  raise ArgumentError, 'utxos or asset_id required' if utxos.blank? && asset_id.blank?

  amount = kwargs[:amount]&.to_d
  raise ArgumentError, 'amount required' if amount.blank?

  members = [kwargs[:members]].flatten.compact
  raise ArgumentError, 'members required' if members.blank?

  threshold = kwargs[:threshold] || members.length
  request_id = kwargs[:request_id] || kwargs[:trace_id] || SecureRandom.uuid
  memo = kwargs[:memo] || ''

  # step 1: select inputs
  utxos ||= build_utxos(asset_id:, amount:)

  # step 2: build transaction
  tx = build_safe_transaction(
    utxos:,
    receivers: [{
      members:,
      threshold:,
      amount:
    }],
    extra: memo
  )
  raw = MixinBot.utils.encode_raw_transaction tx

  # step 3: verify transaction
  request = create_safe_transaction_request(request_id, raw)['data']

  # step 4: sign transaction
  spend_key = MixinBot.utils.decode_key(kwargs[:spend_key]) || config.spend_key
  signed_raw = MixinBot.api.sign_safe_transaction(
    raw:,
    utxos:,
    request: request[0],
    spend_key:
  )

  # step 5: submit transaction
  send_safe_transaction(
    request_id,
    signed_raw
  )
end

#create_transfer(pin = nil, **kwargs) ⇒ Hash

Creates a Safe API transfer.

This is the main method for sending assets on Mixin Network. It handles the complete transfer process including UTXO selection, transaction building, signing, and submission.

Examples:

Simple transfer

result = api.create_transfer(
  members: '6ae1c7ae-1df1-498e-8f21-d48cb6d129b5',
  asset_id: '965e5c6e-434c-3fa9-b780-c50f43cd955c',
  amount: '0.01',
  memo: 'Test payment'
)
puts result['snapshot_id']

Multisig transfer (2-of-3)

result = api.create_transfer(
  members: [
    '6ae1c7ae-1df1-498e-8f21-d48cb6d129b5',
    '8017d200-7870-4b82-b53f-74bae1d2dad7',
    'e8e8cd79-cd40-4796-8c54-3a13cfe50115'
  ],
  threshold: 2,
  asset_id: '965e5c6e-434c-3fa9-b780-c50f43cd955c',
  amount: '0.01'
)

Parameters:

  • kwargs (Hash) —

    transfer options

Options Hash (**kwargs):

  • :members (String, Array<String>) —

    recipient user ID(s)

  • :threshold (Integer) —

    multisig threshold (defaults to members.length)

  • :asset_id (String) —

    the asset UUID to transfer

  • :amount (String, Float) —

    the amount to transfer

  • :trace_id (String) —

    unique trace ID (defaults to random UUID)

  • :request_id (String) —

    alias for trace_id

  • :memo (String) —

    transaction memo (max 140 characters)

  • :spend_key (String) —

    spend private key (defaults to config.spend_key)

  • :utxos (Array<Hash>) —

    specific UTXOs to use (optional, will auto-select if not provided)

Returns:

  • (Hash) —

    the transfer result including transaction hash and status

Raises:



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# File 'lib/mixin_bot/api/transfer.rb', line 84

def create_transfer(pin = nil, **kwargs)
  if pin.is_a?(String) && kwargs[:opponent_id].present?
    create_legacy_transfer(pin, **kwargs)
  else
    create_safe_transfer(**(pin.is_a?(Hash) ? pin : kwargs))
  end
end

#send_transaction ⇒ Object Also known as: send_transfer_transaction, send_transaction_with_outputs 



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# File 'lib/mixin_bot/api/transfer.rb', line 92

def send_transaction(**)
  create_safe_transfer(**)
end

#send_transaction_until_sufficient ⇒ Object 



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# File 'lib/mixin_bot/api/transfer.rb', line 98

def send_transaction_until_sufficient(**)
  create_safe_transfer(**)
end

#send_transaction_with_change_outputs ⇒ Object Also known as: send_transaction_with_utxos_and_change_outputs 



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# File 'lib/mixin_bot/api/transfer.rb', line 102

def send_transaction_with_change_outputs(**)
  create_safe_transfer(**)
end