btcpayserver/BTCPayServer/Services/Fees/NBxplorerFeeProvider.cs

using NBitcoin;
using NBXplorer;
using NBXplorer.Models;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;

namespace BTCPayServer.Services.Fees
{
    public class NBXplorerFeeProvider : IFeeProvider
    {
        public ExplorerClient ExplorerClient
        {
            get; set;
        }
        public FeeRate Fallback
        {
            get; set;
        }
        public int BlockTarget
        {
            get; set;
        }
        public async Task<FeeRate> GetFeeRateAsync()
        {
            try
            {
                return (await ExplorerClient.GetFeeRateAsync(BlockTarget).ConfigureAwait(false)).FeeRate;
            }
            catch (NBXplorerException ex) when (ex.Error.HttpCode == 400 && ex.Error.Code == "fee-estimation-unavailable")
            {
                return Fallback;
            }
        }
    }
}