Module: Lbank

Defined in:
lib/lbank.rb,
lib/lbank/errors.rb,
lib/lbank/version.rb

Defined Under Namespace

Classes: Error, MemoryCache, ResponseError

Constant Summary collapse

RATE_TYPE = 
'LT'
TIMEZONE = 
'Europe/Vilnius'
URL = 
'http://www.lb.lt/webservices/FxRates/FxRates.asmx/getFxRates'
LTL = 
'LTL'
LTL_RATE = 
BigDecimal('3.45280')
VERSION = 
'2.0.0'

Class Method Summary collapse

Class Method Details

.bank_date(time) ⇒ Object 



61
62
63
64
65
66
67
68
 
# File 'lib/lbank.rb', line 61

def bank_date(time)
  if time.is_a?(Date) && !time.is_a?(DateTime)
    time.strftime('%Y-%m-%d')
  else
    local_time = TZInfo::Timezone.get(TIMEZONE).utc_to_local(time.to_time.utc)
    local_time.strftime('%Y-%m-%d')
  end
end

.cache ⇒ Object 



20
21
22
 
# File 'lib/lbank.rb', line 20

def cache
  @cache ||= MemoryCache.new
end

.cache=(store) ⇒ Object 



24
25
26
 
# File 'lib/lbank.rb', line 24

def cache=(store)
  @cache = store
end

.cache_key(date) ⇒ Object 



57
58
59
 
# File 'lib/lbank.rb', line 57

def cache_key(date)
  "lbank-#{date}"
end

.connection ⇒ Object 



70
71
72
73
74
75
76
77
 
# File 'lib/lbank.rb', line 70

def connection
  @connection ||= Faraday.new do |builder|
    builder.request :url_encoded
    builder.response :raise_error
    builder.response :xml, content_type: /\bxml$/
    builder.adapter Faraday.default_adapter
  end
end

.convert_currency(amount, from_currency, to_currency, time = nil) ⇒ Object 



49
50
51
52
53
54
55
 
# File 'lib/lbank.rb', line 49

def convert_currency(amount, from_currency, to_currency, time = nil)
  rates = currency_rates(time)
  from_rate = rates[from_currency.to_s]
  to_rate = rates[to_currency.to_s]

  amount / from_rate * to_rate
end

.currency_rates(time = nil) ⇒ Object 



28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
 
# File 'lib/lbank.rb', line 28

def currency_rates(time = nil)
  date = bank_date(time || Time.now)

  cache.fetch(cache_key(date)) do
    response = connection.post(URL, tp: RATE_TYPE, dt: date)
    error = response.body['FxRates']['OprlErr']

    raise ResponseError.new(error['Desc']) if error

    fx_rates = response.body['FxRates']['FxRate']

    rates = { fx_rates[0]['CcyAmt'][0]['Ccy'] => 1 }
    rates[LTL] ||= LTL_RATE

    fx_rates.each_with_object(rates) do |rate, result|
      base, foreign = rate['CcyAmt']
      result[foreign['Ccy']] = BigDecimal(foreign['Amt']) / BigDecimal(base['Amt'])
    end
  end
end