class Xrate::ExchangeRate
Public Class Methods
at(date, from_currency, target_currency)
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# File lib/xrate/exchange_rate.rb, line 7 def self.at(date, from_currency, target_currency) date_range = (date - fallback_days)..date get_latest(date_range, from_currency, target_currency) or raise Xrate::UnconvertableCurrencyException end
calculate_rate(date_range, from_currency, target_currency)
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# File lib/xrate/exchange_rate.rb, line 21 def self.calculate_rate(date_range, from_currency, target_currency) begin base_to_from = Xrate::Rate.where(date: date_range, currency: from_currency).first&.rate base_to_target = Xrate::Rate.where(date: date_range, currency: target_currency).first&.rate base_to_target / base_to_from rescue NoMethodError # handle divide by zero nil end end
fallback_days()
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# File lib/xrate/exchange_rate.rb, line 32 def self.fallback_days ENV.fetch("XRATE_FALLBACK_DAYS").to_i end
get_latest(date_range, from_currency, target_currency)
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# File lib/xrate/exchange_rate.rb, line 13 def self.get_latest(date_range, from_currency, target_currency) if from_currency == ENV.fetch("XRATE_BASE_CURRENCY") Xrate::Rate.where(date: date_range, currency: target_currency).first&.rate else calculate_rate(date_range, from_currency, target_currency) end end