BitcoinPayable

A rails gem that enables any model to have bitcoin payments. The polymorhpic table bitcoin_payments creates payments with unique addresses based on a BIP32 deterministic seed using https://github.com/wink/money-tree and uses the https://helloblock.io API to check for payments.

Payments have 3 states: pending, partial_payment, paid_in_full

No private keys needed, No bitcoind blockchain indexing on new servers, just address and payments.

Installation

Add this line to your application's Gemfile:

gem 'bitcoin_payable'

And then execute:

$ bundle

$ rails g bitcoin_payable:install

$ bundle exec rake db:migrate

Or install it yourself as:

$ gem install bitcoin_payable

Usage

Configuration

config/initializers/bitcoin_payable.rb

BitcoinPayable.config.currency = :cad
BitcoinPayable.config.master_seed = ENV["MASTER_SEED"]              # Use master_seed OR master_public_key
BitcoinPayable.config.master_public_key = ENV["MASTER_PUBLIC_KEY"]
BitcoinPayable.config.testnet = true

Master Seed

The 32 Hex master seed. Reference: https://github.com/wink/money-tree#create-a-master-node-seed

Master Public Key

A BIP32 MPK in "Extended Key" format.

Adding it to your model

class Product < ActiveRecord::Base
  has_bitcoin_payments
end

Creating a payment from your application

def create_payment(amount_in_cents)
  self.bitcoin_payments.create!(reason: 'sale', price: amount_in_cents)
end

Update payments with the current price of BTC based on your currency

BitcoinPayable also supports local currency conversions and BTC exchange rates.

The process_prices rake task connects to api.bitcoinaverage.com to get the 24 hour weighted average of BTC for your specified currency. It then updates all payments that havent received an update in the last 30 minutes with the new value owing in BTC. This honors the price of a payment for 30 minutes at a time.

rake bitcoin_payable:process_prices

Processing payments

All payments are calculated against the dollar amount of the payment. So a bitcoin_payment for $49.99 will have it's value calculated in BTC. It will stay at that price for 30 minutes. When a payment is made, a transaction is created that stores the BTC in satoshis paid, and the exchange rate is was paid at. This is very valuable for accounting later. (capital gains of all payments received)

If a partial payment is made, the BTC value is recalculated for the remaining dollar amount with the latest exchange rate. This means that if someone pays 0.01 for a 0.5 payment, that 0.01 is converted into dollars at the time of processing and the remaining amount is calculated in dollars and the remaining amount in BTC is issued. (If BTC bombs, that value could be greater than 0.5 now)

This prevents people from gaming the payments by paying very little BTC in hopes the price will rise. Payments are not recalculated based on the current value of BTC, but in dollars.

To run the payment processor:

rake bitcoin_payable:process_payments

Notify your application when a payment is made

Use the bitcoin_payment_paid method

def Product < ActiveRecord::Base
  has_bitcoin_payments

  def create_payment(amount_in_cents)
    self.bitcoin_payments.create!(reason: 'sale', price: amount_in_cents)
  end

  def bitcoin_payment_paid
    self.ship!
  end
end

View all the transactions in the payment

bitcoin_payment = @product.bitcoin_payments.first
bitcoin_payment.transactions.each do |transaction|
  puts transaction.block_hash
  puts transaction.block_time

  puts transaction.transaction_hash

  puts transaction.estimated_value
  puts transaction.estimated_time

  puts transaction.btc_conversion
end

Contributing

Fork it
Create your feature branch (git checkout -b my-new-feature)
Commit your changes (git commit -am 'Add some feature')
Push to the branch (git push origin my-new-feature)
Create new Pull Request