A gem that calculates the exchange rate using published rates from currencylayer.com

Currencylayer API

<s>~ json { “timestamp”: 1441101909, “source”: “USD”, “quotes”: { /* 168 currencies / “USDAUD”: 1.413637, “USDCAD”: 1.316495, “USDCHF”: 0.96355, “USDEUR”: 0.888466, “USDBTC”: 0.004322, / Includes Bitcoin currency! */ … } } </s>~

See more about Currencylayer product plans on currencylayer.com/product.

Installation

Add this line to your application's Gemfile:

gem 'currencylayer-historical-bank'

And then execute:

$ bundle

Or install it yourself as:

$ gem install currencylayer-historical-bank

Usage

~~~ ruby

Minimal requirements

require 'money/bank/currencylayer_historical_bank' mclb = Money::Bank::CurrencylayerHistoricalBank.new mclb.access_key = 'your access_key from currencylayer.com/product'

Update rates (get new rates from remote if expired or access rates from cache)

mclb.update_rates

Force update rates from remote and store in cache

mclb.update_rates(true)

(optional)

Set the base currency for all rates. By default, USD is used.

CurrencylayerHistoricalBank only allows USD as base currency for the free plan users.

mclb.source = 'EUR'

(optional)

Set the seconds after than the current rates are automatically expired

by default, they never expire, in this example 1 day.

mclb.ttl_in_seconds = 86400

(optional)

Use https to fetch rates from CurrencylayerHistoricalBank

CurrencylayerHistoricalBank only allows http as connection for the free plan users.

mclb.secure_connection = true

Define cache (string or pathname)

mclb.cache = 'path/to/file/cache'

Set money default bank to currencylayer bank

Money.default_bank = mclb ~~~

More methods

~~~ ruby mclb = Money::Bank::CurrencylayerHistoricalBank.new

Returns the base currency set for all rates.

mclb.source

Expires rates if the expiration time is reached.

mclb.expire_rates!

Return true if the expiration time is reached.

mclb.expired?

Get the API source url.

mclb.source_url

Get the rates timestamp of the last API request.

mclb.rates_timestamp ~~~

How to exchange

~~~ ruby

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 github.com/RubyMoney/money.

Using gem money-rails

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

~~~ ruby require 'money/bank/currencylayer_bank'

MoneyRails.configure do |config| mclb = Money::Bank::CurrencylayerHistoricalBank.new mclb.access_key = 'your access_key from currencylayer.com/product' mclb.update_rates

config.default_bank = mclb 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:

<s>~ ruby mclb.cache = Proc.new do |v| key = 'money:currencylayer_bank' if v Thread.current = v else Thread.current end end </s>~

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:

<s>~ bundle exec rake </s>~

Refs

Other Implementations

Contributing

  1. Fork it ( github.com/[your-username]/currencylayer-historical-bank/fork )

  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 a new Pull Request

License

The MIT License

Copyright © 2017