A ConfigurationManager wrapper that allows the developer to store credentials and a like settings in a machine specific config file that takes precedence when loading over web.config

MachineConfigurationManager

    public class MachineConfigurationManager
    {
        private const string ConfigFileCacheKey = "ConfigFileCacheKey";
        private static readonly ILog Logger = LogManager.GetLogger(typeof(MachineConfigurationManager));

        public static void Init()
        {
            var _file = GetConfigFile();

            if (!_file.Exists)
            {
                if (Logger.IsInfoEnabled)
                {
                    Logger.InfoFormat("No machine specific configuration exists. {0} is created.", _file.FullName);
                }

                var _appSettings = new Dictionary<string, string>();
                foreach (var _key in ConfigurationManager.AppSettings.AllKeys)
                {
                    _appSettings.Add(_key, ConfigurationManager.AppSettings[_key]);
                }

                File.WriteAllText(_file.FullName, JsonConvert.SerializeObject(_appSettings, Formatting.Indented));
            }
        }

        public static MachineAppSetting AppSettings
        {
            get
            {
                return new MachineAppSetting();
            }
        }

        private static FileInfo GetConfigFile()
        {
            return new FileInfo(AppDomain.CurrentDomain.BaseDirectory + "\\machine." + Environment.MachineName.ToLower() + ".config");
        }

        public class MachineAppSetting
        {
            public string this[string key]
            {
                get
                {
                    Dictionary<string, string> _appSettings = (Dictionary<string, string>)HttpRuntime.Cache.Get(ConfigFileCacheKey);
                    if (_appSettings == null)
                    {
                        _appSettings = JsonConvert.DeserializeObject<Dictionary<string,string>>(File.ReadAllText(GetConfigFile().FullName));
                        HttpRuntime.Cache.Add(
                            ConfigFileCacheKey,
                            _appSettings,
                            new CacheDependency(GetConfigFile().FullName),
                            Cache.NoAbsoluteExpiration,
                            TimeSpan.FromDays(1),
                            CacheItemPriority.AboveNormal,
                            delegate(string s, object value, CacheItemRemovedReason reason)
                                {
                                    if (Logger.IsInfoEnabled)
                                    {
                                        Logger.InfoFormat("Machine configuration cache is cleared (Reason: " + reason + ")");
                                    }
                                });
                    }

                    if (_appSettings.ContainsKey(key))
                    {
                        return _appSettings[key];
                    }

                    return ConfigurationManager.AppSettings[key];
                }
            }
        }
    }