Module: SimpleForex

Defined in:
lib/simple_forex.rb,
lib/simple_forex/railtie.rb,
lib/simple_forex/version.rb

Overview

Tip: open exchange rates’s free API gives 1000 calls monthly, and there are ~700 hours in month, so you safely run it hourly while staying within the free limit.

Defined Under Namespace

Classes: Currency, Error, Railtie

Constant Summary collapse

VERSION = 
"0.1.4"

Instance Method Summary collapse

Instance Method Details

#all_currencies ⇒ Object 



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# File 'lib/simple_forex.rb', line 165

def all_currencies
  # Acquired via Currency.last.blob['rates'].keys
  ["AED",   "AFN",   "ALL",   "AMD",   "ANG",   "AOA",   "ARS",   "AUD",   "AWG",   "AZN",   "BAM",   "BBD",   "BDT",   "BGN",   "BHD",   "BIF",   "BMD",   "BND",   "BOB",   "BRL",   "BSD",   "BTC",   "BTN",   "BWP",   "BYN",   "BZD",   "CAD",   "CDF",   "CHF",   "CLF",   "CLP",   "CNH",   "CNY",   "COP",   "CRC",   "CUC",   "CUP",   "CVE",   "CZK",   "DJF",   "DKK",   "DOP",   "DZD",   "EGP",   "ERN",   "ETB",   "EUR",   "FJD",   "FKP",   "GBP",   "GEL",   "GGP",   "GHS",   "GIP",   "GMD",   "GNF",   "GTQ",   "GYD",   "HKD",   "HNL",   "HRK",   "HTG",   "HUF",   "IDR",   "ILS",   "IMP",   "INR",   "IQD",   "IRR",   "ISK",   "JEP",   "JMD",   "JOD",   "JPY",   "KES",   "KGS",   "KHR",   "KMF",   "KPW",   "KRW",   "KWD",   "KYD",   "KZT",   "LAK",   "LBP",   "LKR",   "LRD",   "LSL",   "LYD",   "MAD",   "MDL",   "MGA",   "MKD",   "MMK",   "MNT",   "MOP",   "MRU",   "MUR",   "MVR",   "MWK",   "MXN",   "MYR",   "MZN",   "NAD",   "NGN",   "NIO",   "NOK",   "NPR",   "NZD",   "OMR",   "PAB",   "PEN",   "PGK",   "PHP",   "PKR",   "PLN",   "PYG",   "QAR",   "RON",   "RSD",   "RUB",   "RWF",   "SAR",   "SBD",   "SCR",   "SDG",   "SEK",   "SGD",   "SHP",   "SLL",   "SOS",   "SRD",   "SSP",   "STD",   "STN",   "SVC",   "SYP",   "SZL",   "THB",   "TJS",   "TMT",   "TND",   "TOP",   "TRY",   "TTD",   "TWD",   "TZS",   "UAH",   "UGX",   "USD",   "UYU",   "UZS",   "VES",   "VND",   "VUV",   "WST",   "XAF",   "XAG",   "XAU",   "XCD",   "XDR",   "XOF",   "XPD",   "XPF",   "XPT",   "YER",   "ZAR",   "ZMW",   "ZWL"] 
end

#convert(amount, from_currency, to_currency) ⇒ Object 



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# File 'lib/simple_forex.rb', line 145

def convert(amount, from_currency, to_currency)
  # Examples:
  # convert(100, "aud", "gbp") # 54.585
  # convert(100, "gbp", "aud") # 183.2
  # convert(100, "usd", "aud") # 129.0
  # convert(100, "aud", "usd") # 77.0
  begin
    rate = currency_exchange_rate(from_currency, to_currency)
  rescue => exception
     $stderr.puts "Error: #{exception} - \n\nYou could be seeing this error if you forgot to setup the database and fetch currency data. 
     \nDid you forget to run `rails g simple_forex:install`, `rake db:migrate` or `rake simple_forex:fetch_rates`?
     \nSee documentation for more information: https://github.com/stevecondylios/SimpleForex\n\n"
  end
    
  converted_amount = amount * rate
  return converted_amount 
end

#currency_exchange_rate(from, to) ⇒ Object 



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# File 'lib/simple_forex.rb', line 105

def currency_exchange_rate(from, to)

  currencies = Currency.last.blob

  # Tests: 
  # currency_exchange_rate("aud", "gbp") # 0.54
  # currency_exchange_rate("GBP", "AUD") # 1.832
  # currency_exchange_rate("USD", "AUD") # 1.29
  # currency_exchange_rate("AUD", "usd") # 0.77

  # The open exchange rate API uses UPPER case (unlike stripe and some other platforms)
  from = from.upcase
  to = to.upcase

  error_message = """
  The currency %{currency_code} is not a valid currency code. 
  Run `Currency.last.blob[\"rates\"].keys` to view 
  available currencies. 
  """
  # from = "AUDz"
  # error_message % {currency_code: from}

  raise error_message % {currency_code: from} unless currencies["rates"].keys.include? from
  raise error_message % {currency_code: to} unless currencies["rates"].keys.include? to


  usd_to_from = currencies['rates'][from].to_d
  usd_to_to = currencies['rates'][to].to_d
  rate = usd_to_to / usd_to_from
  # This converts 1 AUD to GPD (gives 0.54585)
  # R example: rates$rates$GBP / rates$rates$AUD 
  # Ruby: currency['rates']['GBP'].to_d / currency['rates']['AUD'].to_d

  return rate


end

#some_currencies ⇒ Object 



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# File 'lib/simple_forex.rb', line 173

def some_currencies
  ["AUD", "CAD", "EUR", "GBP", "HKD", "NZD", "SGD", "USD"]
end