50 lines
1.3 KiB
Ruby
50 lines
1.3 KiB
Ruby
# frozen_string_literal: true
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require "json"
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require "net/http"
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require "provider/adapters/adapter"
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class Provider
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module Adapters
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# Bank of Canada daily indicative rates. Current series starts 2017-01-03.
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# Legacy noon rates (2007-2017) are available under the LEGACY_NOON_RATES group with ~65 currencies.
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class BOC < Adapter
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BASE_URL = "https://www.bankofcanada.ca/valet/observations/group/FX_RATES_DAILY/json"
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def fetch(after: nil, upto: nil)
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params = { start_date: after }
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params[:end_date] = upto if upto
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fetch_rates(**params)
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end
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def parse(json)
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data = json.is_a?(String) ? JSON.parse(json) : json
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data["observations"].flat_map do |obs|
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date = Date.parse(obs["d"])
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extract_rates(obs).map do |foreign, rate|
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{ date:, base: foreign, quote: "CAD", rate: }
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end
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end
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end
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private
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def fetch_rates(**params)
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url = URI(BASE_URL)
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url.query = URI.encode_www_form(params)
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parse(Net::HTTP.get(url))
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end
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def extract_rates(observation)
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observation.each_with_object({}) do |(series, data), rates|
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next unless series.start_with?("FX")
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iso = series.delete_prefix("FX").delete_suffix("CAD")
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rates[iso] = Float(data["v"])
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end
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end
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end
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end
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end
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