54 lines
1.4 KiB
Ruby
54 lines
1.4 KiB
Ruby
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# frozen_string_literal: true
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require "net/http"
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require "oj"
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require "provider/adapters/adapter"
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class Provider
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module Adapters
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# Czech National Bank. Publishes daily exchange rates for 30 currencies
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# against the Czech koruna (CZK) via a REST JSON API.
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class CNB < Adapter
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URL = "https://api.cnb.cz/cnbapi/exrates/daily-year"
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def fetch(after: nil, upto: nil)
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end_date = upto || Date.today
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dataset = []
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(after.year..end_date.year).each do |year|
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dataset.concat(fetch_year(year))
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end
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dataset.select! { |r| r[:date].between?(after, end_date) }
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end
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def parse(json)
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data = json.is_a?(String) ? Oj.load(json, mode: :strict) : json
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rates = data.is_a?(Hash) ? data["rates"] : nil
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return [] unless rates.is_a?(Array) && !rates.empty?
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rates.filter_map do |r|
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code = r["currencyCode"]
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next unless code&.match?(/\A[A-Z]{3}\z/)
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amount = r["amount"].to_f
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rate = r["rate"].to_f
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next if rate.zero? || amount.zero?
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date = Date.parse(r["validFor"])
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{ date:, base: code, quote: "CZK", rate: rate / amount }
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end
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end
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private
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def fetch_year(year)
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url = URI(URL)
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url.query = URI.encode_www_form(year: year, lang: "EN")
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response = Net::HTTP.get(url)
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parse(response)
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end
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end
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end
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end
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