btcpayserver/BTCPayServer/Services/Rates/BitpayRateProvider.cs

using NBitpayClient;
using System.Linq;
using System;
using System.Collections.Generic;
using System.Text;
using System.Threading.Tasks;
using NBitcoin;

namespace BTCPayServer.Services.Rates
{
    public class BitpayRateProviderDescription : RateProviderDescription
    {
        public IRateProvider CreateRateProvider(IServiceProvider serviceProvider)
        {
            return new BitpayRateProvider(new Bitpay(new Key(), new Uri("https://bitpay.com/")));
        }
    }
    public class BitpayRateProvider : IRateProvider
    {
        Bitpay _Bitpay;
        public BitpayRateProvider(Bitpay bitpay)
        {
            if (bitpay == null)
                throw new ArgumentNullException(nameof(bitpay));
            _Bitpay = bitpay;
        }
        public async Task<decimal> GetRateAsync(string currency)
        {
            var rates = await _Bitpay.GetRatesAsync().ConfigureAwait(false);
            var rate = rates.GetRate(currency);
            if (rate == 0m)
                throw new RateUnavailableException(currency);
            return (decimal)rate;
        }

        public async Task<ICollection<Rate>> GetRatesAsync()
        {
            return (await _Bitpay.GetRatesAsync().ConfigureAwait(false))
                .AllRates
                .Select(r => new Rate() { Currency = r.Code, Value = r.Value })
                .ToList();
        }
    }
}