Money Openexchangerates Bank

A gem that calculates the exchange rate using published rates from openexchangerates.org

Openexchangerates API

{
  "timestamp": 1441101909,
  "base": "USD",
  "rates": {
      /* 190 currencies */
      "AUD": 1.413637,
      "CAD": 1.316495,
      "CHF": 0.96355,
      "EUR": 0.888466,
      "BTC": 0.004322, /* Includes cryptocurrencies! */
      ...
      }
}

See more about Openexchangerates product plans on https://openexchangerates.org/signup.

Features

supports 190 currencies
includes cryptocurrencies
precision of rates up to 6 digits after point
uses fast and reliable json api
average response time < 20ms
supports caching currency rates
calculates every pair rate calculating inverse rate or using base currency rate
supports multiple server instances, thread safe

Installation

Add this line to your application's Gemfile:

gem 'money-openexchangerates-bank'

And then execute:

$ bundle

Or install it yourself as:

$ gem install money-openexchangerates-bank

Usage

# Minimal requirements
require 'money/bank/openexchangerates_bank'
moxb = Money::Bank::OpenexchangeratesBank.new
moxb.access_key = 'your access_key from https://openexchangerates.com/signup'

# Update rates (get new rates from remote if expired or access rates from cache)
moxb.update_rates

# Force update rates from remote and store in cache
# moxb.update_rates(true)

# (optional)
# Set the base currency for all rates. By default, USD is used.
# OpenexchangeratesBank only allows USD as base currency for the free plan users.
moxb.source = 'EUR'

# (optional)
# Set the seconds after than the current rates are automatically expired
# by default, they never expire, in this example 1 day.
moxb.ttl_in_seconds = 86400

# (optional)
# Use https to fetch rates from OpenexchangeratesBank
# OpenexchangeratesBank only allows http as connection for the free plan users.
moxb.secure_connection = true

# Define cache (string or pathname)
moxb.cache = 'path/to/file/cache'

# Set money default bank to Openexchangerates bank
Money.default_bank = moxb

More methods

moxb = Money::Bank::OpenexchangeratesBank.new

# Returns the base currency set for all rates.
moxb.source

# Include also alternative rates.
moxb.alternatives = :all

# Get only alternative rates.
moxb.alternatives = :only

# Default is nil to get only regular rates.
# moxb.alternatives = nil

# Expires rates if the expiration time is reached.
moxb.expire_rates!

# Returns true if the expiration time is reached.
moxb.expired?

# Get the API source url.
moxb.source_url

# Get the rates timestamp of the last API request.
moxb.rates_timestamp

# Get the rates timestamp of loaded rates in memory.
moxb.rates_mem_timestamp

How to exchange

# Exchange 1000 cents (10.0 USD) to EUR
Money.new(1000, 'USD').exchange_to('EUR')        # => #<Money fractional:89 currency:EUR>
Money.new(1000, 'USD').exchange_to('EUR').to_f   # => 8.9

# Format
Money.new(1000, 'USD').exchange_to('EUR').format # => €8.90

# Get the rate
Money.default_bank.get_rate('USD', 'CAD')        # => 0.9

See more on https://github.com/RubyMoney/money.

Using gem money-rails

You can also use it in Rails with the gem money-rails.

require 'money/bank/openexchangerates_bank'

MoneyRails.configure do |config|
  moxb = Money::Bank::OpenexchangeratesBank.new
  moxb.access_key = 'your access_key from https://openexchangerates.com/signup'
  moxb.update_rates

  config.default_bank = moxb
end

Cache

You can also provide a Proc as a cache to provide your own caching mechanism perhaps with Redis or just a thread safe Hash (global). For example:

moxb.cache = Proc.new do |v|
  key = 'money:openexchangerates_bank'
  if v
    Thread.current[key] = v
  else
    Thread.current[key]
  end
end

Process

The gem fetches all rates in a cache with USD as base currency. It's possible to compute the rate between any of the currencies by calculating a pair rate using base USD rate.

Tests

You can place your own key on a file or environment variable named TEST_ACCESS_KEY and then run:

bundle exec rake

Refs

Other Implementations

Contributors

See github.com/phlegx/money-openexchangerates-bank.
Inspired by github.com/phlegx/money-currencylayer-bank.

Contributing

Fork it ( https://github.com/[your-username]/money-openexchangerates-bank/fork )
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 a new Pull Request

License

The MIT License