ASP.NET Cache 类

在查找资料的过程中。原来园子里面已经有过分析了。nopCommerce架构分析系列（二）数据Cache。 接下来是一些学习补充。

 

1.Nop中没有System.Web.Caching.Cache的实现。原因暂不明。先自己实现一个吧

using System;

using System.Collections.Generic;

using System.Web;

using System.Runtime.CompilerServices;

using System.Web.Caching;

using System.Collections;

using System.Text.RegularExpressions;



namespace SDF.Core.Caching

{



    public class CacheManager : ICacheManager

    {

        System.Web.Caching.Cache Cache = HttpRuntime.Cache;



        public void Set(string key, object data)

        {

            Cache.Insert(key, data);

        }

        public void Set(string key, object data, DateTime absoluteExpiration, TimeSpan slidingExpiration)

        {

            Cache.Insert(key, data, null,absoluteExpiration, slidingExpiration);

        }



        public object Get(string Key)

        {

            return Cache[Key];

        }



        public T Get<T>(string key)

        {

            return (T)Cache[key];

        }



        public bool IsSet(string key)

        {

            return Cache[key] != null;

        }



        public void Remove(string Key)

        {

            if (Cache[Key] != null) {

                Cache.Remove(Key);

            }

        }



        public void RemoveByPattern(string pattern)

        {

            IDictionaryEnumerator enumerator = Cache.GetEnumerator();

            Regex rgx = new Regex(pattern, (RegexOptions.Singleline | (RegexOptions.Compiled | RegexOptions.IgnoreCase)));

            while (enumerator.MoveNext()) {

                if (rgx.IsMatch(enumerator.Key.ToString())) {

                    Cache.Remove(enumerator.Key.ToString());

                }

            }

        }



        public void Clear()

        {

            IDictionaryEnumerator enumerator = Cache.GetEnumerator();

            while (enumerator.MoveNext())

            {

                Cache.Remove(enumerator.Key.ToString());

            }

        }



    }



}

 

 

2.MemoryCache 和 ASP.NET Cache 区别。

引用MSDN

MemoryCache 类类似于 ASP.NET Cache 类。 MemoryCache 类有许多用于访问缓存的属性和方法，如果您使用过 ASP.NET Cache 类，您将熟悉这些属性和方法。 Cache 和 MemoryCache 类之间的主要区别是：MemoryCache 类已被更改，以便 .NET Framework 应用程序（非 ASP.NET 应用程序）可以使用该类。 例如，MemoryCache 类对 System.Web 程序集没有依赖关系。 另一个差别在于您可以创建 MemoryCache 类的多个实例，以用于相同的应用程序和相同的 AppDomain 实例。

代码更清楚一点：

[Test]

        public void MemoryCacheTest()

        {

            var cache = new MemoryCache("cache1");

            var cache2 = new MemoryCache("cache2");

            var policy = new CacheItemPolicy();

            policy.AbsoluteExpiration = DateTime.Now + TimeSpan.FromMinutes(60);

            cache.Set(new CacheItem("key1", "data1"), policy);



            var obj = cache.Get("key1");

            Assert.IsNotNull(obj);



            var obj2 = cache2.Get("key1");

            Assert.IsNull(obj2);

        }

 

3.Nop中IOC和ICache

注册CacheManager

//cache manager

            builder.RegisterType<MemoryCacheManager>().As<ICacheManager>().Named<ICacheManager>("nop_cache_static").SingleInstance();

            builder.RegisterType<PerRequestCacheManager>().As<ICacheManager>().Named<ICacheManager>("nop_cache_per_request").InstancePerHttpRequest();

 

注册Service（可以根据实际需求为Service提供不同的缓存方式。）

//pass MemoryCacheManager to SettingService as cacheManager (cache settngs between requests)

            builder.RegisterType<SettingService>().As<ISettingService>()

                .WithParameter(ResolvedParameter.ForNamed<ICacheManager>("nop_cache_static"))

                .InstancePerHttpRequest();

            //pass MemoryCacheManager to LocalizationService as cacheManager (cache locales between requests)

            builder.RegisterType<LocalizationService>().As<ILocalizationService>()

                .WithParameter(ResolvedParameter.ForNamed<ICacheManager>("nop_cache_static"))

                .InstancePerHttpRequest();



            //pass MemoryCacheManager to LocalizedEntityService as cacheManager (cache locales between requests)

            builder.RegisterType<LocalizedEntityService>().As<ILocalizedEntityService>()

                .WithParameter(ResolvedParameter.ForNamed<ICacheManager>("nop_cache_static"))

                .InstancePerHttpRequest();

 

最后是构造器注入

/// <summary>

    /// Provides information about localizable entities

    /// </summary>

    public partial class LocalizedEntityService : ILocalizedEntityService

    {

     /// <summary>

        /// Ctor

        /// </summary>

        /// <param name="cacheManager">Cache manager</param>

        /// <param name="localizedPropertyRepository">Localized property repository</param>

        public LocalizedEntityService(ICacheManager cacheManager,

            IRepository<LocalizedProperty> localizedPropertyRepository)

        {

            this._cacheManager = cacheManager;

            this._localizedPropertyRepository = localizedPropertyRepository;

        }

    }

 

4.Cache的使用

 

一段Nop中的代码

 

private const string BLOGPOST_BY_ID_KEY = "Nop.blogpost.id-{0}";

       private const string BLOGPOST_PATTERN_KEY = "Nop.blogpost.";



/// <summary>

        /// Gets a blog post

        /// </summary>

        /// <param name="blogPostId">Blog post identifier</param>

        /// <returns>Blog post</returns>

        public virtual BlogPost GetBlogPostById(int blogPostId)

        {

            if (blogPostId == 0)

                return null;



            string key = string.Format(BLOGPOST_BY_ID_KEY, blogPostId);

            return _cacheManager.Get(key, () =>

            {

                var pv = _blogPostRepository.GetById(blogPostId);

                return pv;

            });

        }/// <summary>

       /// Updates the blog post

       /// </summary>

       /// <param name="blogPost">Blog post</param>

       public virtual void UpdateBlogPost(BlogPost blogPost)

       {

           if (blogPost == null)

               throw new ArgumentNullException("blogPost");



           _blogPostRepository.Update(blogPost);



           _cacheManager.RemoveByPattern(BLOGPOST_PATTERN_KEY);



           //event notification

           _eventPublisher.EntityUpdated(blogPost);

       }

 

在查找数据时，会先从缓存中读取，更新数据时再清空缓存。 但是在这里Update了一个blogPost对象。没有必要把所有的blogPost缓存全部清空掉。稍微改一下

 

/// <summary>

        /// Updates the blog post

        /// </summary>

        /// <param name="blogPost">Blog post</param>

        public virtual void UpdateBlogPostV2(BlogPost blogPost)

        {

            if (blogPost == null)

                throw new ArgumentNullException("blogPost");



            _blogPostRepository.Update(blogPost);



            string key = string.Format(BLOGPOST_BY_ID_KEY, blogPost.Id);

            _cacheManager.Remove(key);



            //event notification

            _eventPublisher.EntityUpdated(blogPost);

        }

 

总结：nop提供了易于扩展的Cache类，以及很好的使用实践。非常有借鉴和学习使用的意义。 只需稍微改造一下就可以用于自己的项目中。