AutoPersist

AutoPersist.cs

    public class AutoPersist<T> : IEnumerable<T>
    {
        private readonly object _lock = new object();
        private readonly List<T> _list;
        private readonly string _path;

        public AutoPersist()
        {
            _path = FormatPath();

            if (File.Exists(_path))
            {
                var content = File.ReadAllText(_path);
                _list = JsonConvert.DeserializeObject<List<T>>(content);
            }
            else
            {
                _list = new List<T>();
            }
        }

        public int Count => _list.Count;

        public virtual void Add(T obj)
        {
            _list.Add(obj);
            Persist();
        }

        public virtual void Remove(T obj)
        {
            _list.Remove(obj);
            Persist();
        }

        protected virtual void Persist()
        {
            lock (_lock)
            {
                File.WriteAllText(_path, JsonConvert.SerializeObject(_list));
            }
        }

        protected virtual string FormatPath()
        {
            var path = HttpContext.Current == null
                ? "persist"
                : HttpContext.Current.Server.MapPath("~/persist");

            Directory.CreateDirectory(path);
            return Path.Combine(path, typeof(T).Name + ".json");
        }

        public virtual IEnumerator<T> GetEnumerator()
        {
            return _list.GetEnumerator();
        }

        IEnumerator IEnumerable.GetEnumerator()
        {
            return _list.GetEnumerator();
        }
    }