79 lines
2.3 KiB
Ruby
79 lines
2.3 KiB
Ruby
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# 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 Negara Malaysia daily exchange rates. Data available from 2006-01-03.
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# Historical rates are fetched per-currency per-month.
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class BNM < Adapter
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BASE_URL = "https://api.bnm.gov.my/public/exchange-rate"
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SESSION = "0900"
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HEADERS = { "Accept" => "application/vnd.BNM.API.v1+json" }.freeze
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class << self
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def backfill_range = 30
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end
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def fetch(after: nil, upto: nil)
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start_date = Date.parse(after.to_s)
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end_date = upto || Date.today
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currencies = fetch_currencies
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currencies.flat_map { |code| fetch_currency(code, start_date, end_date) }
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end
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private
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def fetch_currencies
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uri = URI("#{BASE_URL}?session=#{SESSION}")
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response = Net::HTTP.start(uri.host, uri.port, use_ssl: true) do |http|
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http.get("#{uri.path}?#{uri.query}", HEADERS)
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end
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data = JSON.parse(response.body)
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data["data"].map { |item| item["currency_code"] }
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end
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def fetch_currency(code, start_date, end_date)
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records = []
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each_month(start_date, end_date) do |year, month|
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uri = URI("#{BASE_URL}/#{code}/year/#{year}/month/#{month}?session=#{SESSION}")
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response = Net::HTTP.start(uri.host, uri.port, use_ssl: true) do |http|
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http.get("#{uri.path}?#{uri.query}", HEADERS)
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end
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data = JSON.parse(response.body)
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currency_data = data["data"]
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next if currency_data.nil? || currency_data.is_a?(Array)
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unit = currency_data["unit"] || 1
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rates = currency_data["rate"]
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rates = [rates] unless rates.is_a?(Array)
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rates.each do |rate|
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mid = rate["middle_rate"]
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next unless mid
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date = Date.parse(rate["date"])
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next if date > end_date
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records << { date:, base: code, quote: "MYR", rate: mid / unit }
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end
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sleep(1)
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end
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records
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end
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def each_month(start_date, end_date)
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date = Date.new(start_date.year, start_date.month, 1)
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while date <= end_date
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yield date.year, date.month
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date = date.next_month
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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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