btcpayserver/BTCPayServer/Configuration/ConfigurationExtensions.cs

using Microsoft.Extensions.Configuration;
using System;
using System.Collections.Generic;
using System.Globalization;
using System.Linq;
using System.Net;
using System.Threading.Tasks;
using Microsoft.Extensions.Primitives;
using NBitcoin;

namespace BTCPayServer.Configuration
{
    public static class ConfigurationExtensions
    {
        public static T GetOrDefault<T>(this IConfiguration configuration, string key, T defaultValue)
        {
            var str = configuration[key] ?? configuration[key.Replace(".", string.Empty, StringComparison.InvariantCulture)];
            if (str == null)
                return defaultValue;
            if (typeof(T) == typeof(bool))
            {
                var trueValues = new[] { "1", "true" };
                var falseValues = new[] { "0", "false" };
                if (trueValues.Contains(str, StringComparer.OrdinalIgnoreCase))
                    return (T)(object)true;
                if (falseValues.Contains(str, StringComparer.OrdinalIgnoreCase))
                    return (T)(object)false;
                throw new FormatException();
            }
            else if (typeof(T) == typeof(Uri))
                if (string.IsNullOrEmpty(str))
                {
                    return defaultValue;
                }
                else
                {
                    return (T)(object)new Uri(str, UriKind.Absolute);
                }
            else if (typeof(T) == typeof(string))
                return (T)(object)str;
            else if (typeof(T) == typeof(IPAddress))
                return (T)(object)IPAddress.Parse(str);
            else if (typeof(T) == typeof(IPEndPoint))
            {
                var separator = str.LastIndexOf(":", StringComparison.InvariantCulture);
                if (separator == -1)
                    throw new FormatException();
                var ip = str.Substring(0, separator);
                var port = str.Substring(separator + 1);
                return (T)(object)new IPEndPoint(IPAddress.Parse(ip), int.Parse(port, CultureInfo.InvariantCulture));
            }
            else if (typeof(T) == typeof(int))
            {
                return (T)(object)int.Parse(str, CultureInfo.InvariantCulture);
            }
            else
            {
                throw new NotSupportedException("Configuration value does not support time " + typeof(T).Name);
            }
        }
    }
}