一個CookieContainer的拓展類

　　最近項目中需要頻繁用到伺服器返回的Cookie，由於項目採用的是HttpClient，並且用CookieContainer自動托管Cookie，在獲取Cookie的時候不太方便。所以就寫了個拓展類。

　　首先的遍歷獲取所有的Cookie，然後存入字典當中，再把字典存入記憶體緩存中，在下次調用方法的時候，先判斷緩存中有沒有，沒有的話再次遍歷出來。當CookieContainer的數量改變後也會重新賦值

    public static class CookieParser
    {
        public static ObjectCache Cache = MemoryCache.Default;

        private static T Get<T>(this ObjectCache cache,string key)
        {
            return (T)cache.Get(key);
        }

        /// <summary>
        /// 增加緩存
        /// </summary>
        /// <param name="cache"></param>
        /// <param name="key"></param>
        /// <param name="obj"></param>
        /// <param name="timeout">緩存過期時間，單位分鐘，預設30分鐘</param>
        /// <returns></returns>
        private static bool Add(this ObjectCache cache,string key, object obj, int timeout=30)
        {
            return Cache.Add(key, obj, DateTime.Now+TimeSpan.FromMinutes(timeout));
        }

        private static readonly object Lock = new object();

        public static string GetCookieValue(this CookieContainer cc,string name)
        {
            return cc.GetCookie(name).Value;
        }

        public static Cookie GetCookie(this CookieContainer cc, string name)
        {
            var key = AddOrUpdateCache(cc);
            return Cache.Get<Dictionary<string, Cookie>>(key)["name"];
        }

        public static List<Cookie> GetAllCookie(this CookieContainer cc)
        {
            var key = AddOrUpdateCache(cc);
            return Cache.Get<Dictionary<string, Cookie>>(key).Values.ToList();
        }

        private static string AddOrUpdateCache(CookieContainer cc)
        {
            var key = cc.GetHashCode().ToString();
            lock (Lock)
            {
                if (!Cache.Contains(key))
                {
                    Cache.Add(key, cc.Parser());
                }
                else if(Cache.Get<Dictionary<string,Cookie>>(key).Count!=cc.Count)//數量改變，更新對象
                {
                    Cache[key] = cc.Parser();
                }
            }
            return key;
        }

        private static Dictionary<string, Cookie> Parser(this CookieContainer cc)
        {
            var table = (Hashtable)cc.GetType().InvokeMember("m_domainTable",
                System.Reflection.BindingFlags.NonPublic | System.Reflection.BindingFlags.GetField |
                System.Reflection.BindingFlags.Instance, null, cc, new object[] { });

            return (
                from object pathList
                    in table.Values
                select (SortedList)pathList.GetType().InvokeMember("m_list", System.Reflection.BindingFlags.NonPublic | System.Reflection.BindingFlags.GetField | System.Reflection.BindingFlags.Instance, null, pathList, new object[] { }) into lstCookieCol
                from CookieCollection colCookies in lstCookieCol.Values
                from Cookie c in colCookies
                select c)
                .ToDictionary(c => c.Name, c => c);
        }
    }