BeWoPlaner/Service/Core/MergedConfig.cs

using System;
using System.Configuration;
using System.IO;
using System.Xml;

namespace BeWo.Service.Core
{
	public static class MergedConfig
	{
		public static string GetSetting(WebConfigSetting config)
		{
			return getSetting(config.ToString());
		}

		public static string GetSecretSetting(WebSecretConfigSetting webSecretConfigSetting)
		{
			if (webSecretConfigSetting == WebSecretConfigSetting.None)
				throw new ArgumentNullException("webSecretConfigSetting");

			return getSecretSetting(webSecretConfigSetting.ToString());
		}

		private static string getSetting(string key)
		{
			return ConfigurationManager.AppSettings[key];
		}

		private static string getSecretSetting(string key)
		{
			var localConfigPath = Path.Combine(AppDomain.CurrentDomain.BaseDirectory, "Web.Secrets.config");
			if (!File.Exists(localConfigPath))
				return null;

			var xml = new XmlDocument();
			xml.Load(localConfigPath);
			var node = xml.SelectSingleNode($"/appSettings/add[@key='{key}']");
			if (node is XmlElement element)
				return element.GetAttribute("value");

			return null;
		}
	}
}