78 lines
2 KiB
Ruby
78 lines
2 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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# Nepal Rastra Bank. Publishes daily buy/sell rates for 22 currencies
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# against NPR. Mid-market rate computed as average of buy and sell.
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# Rates with unit > 1 (e.g. JPY per 10) are normalized by dividing by unit.
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class NRB < Adapter
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BASE_URL = "https://www.nrb.org.np/api/forex/v1/rates"
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class << self
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def backfill_range = 90
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end
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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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page = 1
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loop do
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sleep(0.5) if page > 1
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url = URI(BASE_URL)
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url.query = URI.encode_www_form(
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from: after.to_s,
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to: end_date.to_s,
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page: page,
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per_page: 100,
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)
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response = Net::HTTP.get(url)
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data = JSON.parse(response)
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payload = data.dig("data", "payload") || []
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dataset.concat(parse(payload))
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pagination = data["pagination"] || {}
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break if page >= (pagination["pages"] || 1)
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page += 1
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end
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dataset
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end
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def parse(payload)
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payload = JSON.parse(payload) if payload.is_a?(String)
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return [] unless payload.is_a?(Array)
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payload.flat_map do |day|
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begin
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date = Date.parse(day["date"])
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rescue Date::Error
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next []
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end
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rates = day["rates"] || []
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rates.filter_map do |entry|
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iso = entry.dig("currency", "iso3")
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unit = Integer(entry.dig("currency", "unit") || 1)
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buy = entry["buy"]
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sell = entry["sell"]
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next unless buy && sell
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mid = (Float(buy) + Float(sell)) / 2.0
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rate = mid / unit
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next if rate.zero?
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{ date:, base: iso, quote: "NPR", rate: }
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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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end
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