# Danconia A very simple money library for Ruby, backed by BigDecimal (no conversion to cents, i.e. "infinite precision") with support for external exchange rates services. [![Build Status](https://travis-ci.org/eeng/danconia.svg?branch=master)](https://travis-ci.org/eeng/danconia) ## Installation ```ruby gem 'danconia' ``` ## Basic Usage If you only need to work with a single currency: ```ruby # USD by default, but can be configured m1 = Money(10.25) # => 10.25 USD # Note that we keep all decimal places m2 = m1 / 2 # => 5.125 USD # Simple formatting by default puts m2 # => $5.13 ``` Please refer to `examples/single_currency.rb` for some configuration options. ## Multi-Currency Support To handle multiple currencies you need to configure an `Exchange` in order to fetch the rates. For example, with [CurrencyLayer](https://currencylayer.com/): ```ruby # This can be placed in a Rails initializer Danconia.configure do |config| config.default_exchange = Danconia::Exchanges::CurrencyLayer.new(access_key: '...') end ``` Then, download the exchange rates: ```ruby # You should do this periodically to keep rates up to date Danconia.config.default_exchange.update_rates! ``` And finally to convert between currencies: ```ruby Money(9, 'JPY').exchange_to('ARS') # => 2.272401 ARS ``` By default, rates are stored in memory, but you can supply a store in the exchange constructor to save them elsewhere. Please refer to `examples/currency_layer.rb` for an ActiveRecord example. ## Active Record Integration Given a `products` table with a decimal column `price` and a string column `price_currency` (optional), then you can use the `money` class method to automatically convert it to Money: ```ruby class Product < ActiveRecord::Base money :price end Product.new(price: 30, price_currency: 'ARS').price # => 30 ARS ``` Currently, there is no option to customize the names of the columns but should be fairly simple to implement if needed. ## Contributing 1. Fork it 2. Create your feature branch (`git checkout -b my-new-feature`) 3. Commit your changes (`git commit -am 'Add some feature'`) 4. Push to the branch (`git push origin my-new-feature`) 5. Create new Pull Request