FAFX

FAFX fetches data from the 90 day European Central Bank (ECB) feed and offers a simple CLI to interect with.

$ gem install fafx

$ fafx

Usage: fafx [options]
        --recent      Lists most recent rates
        --currencies  Lists available currencies
        --dates       Lists available dates
        --update      Fetches new data from the web

require 'fafx'

# Gets the most recent rates
Fafx::ExchangeRate.get('GBP', 'USD')
# => 1.2951645399597045

Fafx::ExchangeRate.at(Date.today, 'GBP', 'USD')
# => 1.2951645399597045

Fafx::ExchangeRate.currencies_available
# => ["EUR", "USD", "JPY", "BGN", "CZK", ...]

Fafx::ExchangeRate.dates_available
# => ["2018-09-10", "2018-09-07", "2018-09-06", "2018-09-05", ...]

Fafx::ExchangeRate.most_recent
# => {"USD"=>1.1571, "JPY"=>128.54, "BGN"=>1.9558, "CZK"=>25.648, ...}

The at function may raise a DateError or CurrencyError exception, should the date or currency be unavailable. Passing an object other than Date to at raises DateError as well.

Exchange rates are loaded once per process and cached in memory. Calling update_data refreshes the on-disk cache and clears the in-memory cache so subsequent lookups use the latest data.

You can update the exchange rates values either via the CLI, Rake task or programmatically:

$ fafx --update

$ rake update_data

require 'fafx'

Fafx::ExchangeRate.update_data