net-boot-server/DhcpServer/App/DhcpEntryManager.cs

using Newtonsoft.Json;
using System;
using System.Collections.Generic;
using System.IO;
using System.Text;
using Utils;

namespace DhcpServer
{
    internal static class DhcpEntryManager
    {
        private static readonly string EntriesDir = Path.Combine(AppDomain.CurrentDomain.BaseDirectory, "DhcpEntries");

        private static readonly HashSet<char> InvalidFileNameChars = new HashSet<char>(Path.GetInvalidFileNameChars());

        private static string FilterUserClass(string input)
        {
            if (input == null) return null;

            var sb = new StringBuilder(input);
            sb.FilterChars(InvalidFileNameChars);

            sb.Insert(0, '-');
            return sb.ToString();
        }

        

        private static string GetEntryPath(string mac, string userClass = null)
        {
            return Path.Combine(EntriesDir, "MAC-" + mac + FilterUserClass(userClass) + ".json");
        }

        private static string GetDefaultEntryPath(string userClass = null)
        {
            return Path.Combine(EntriesDir, "Default" + FilterUserClass(userClass) + ".json");
        }

        public static bool CreateDefaultEntryIfNoExist()
        {
            var path = GetDefaultEntryPath();
            if (File.Exists(path)) return false;
            if (false == Directory.Exists(EntriesDir)) Directory.CreateDirectory(EntriesDir);
            File.WriteAllText(path, JsonConvert.SerializeObject(new DhcpEntry(), Formatting.Indented));
            return true;
        }

        public static DhcpEntry GetDefaultEntry(string userClass = null)
        {
            var path = GetDefaultEntryPath(userClass);
            if (File.Exists(path)) return JsonConvert.DeserializeObject<DhcpEntry>(File.ReadAllText(path));

            var createNew = new DhcpEntry();
            File.WriteAllText(path, JsonConvert.SerializeObject(new DhcpEntry(), Formatting.Indented));
            return createNew;
        }

        public static DhcpEntry GetClientEntry(string mac, string userClass = null)
        {
            var path = GetEntryPath(mac, userClass);
            if (File.Exists(path)) return JsonConvert.DeserializeObject<DhcpEntry>(File.ReadAllText(path));

            var createNew = new DhcpEntry();
            File.WriteAllText(path, JsonConvert.SerializeObject(new DhcpEntry(), Formatting.Indented));
            return createNew;
        }
    }
}