Shulou(Shulou.com)06/02 Report--

The editor will share with you an example analysis of the .NET 4.0 Extensible caching Framework. I hope you will gain something after reading this article. Let's discuss it together.

The .NET Framework is called System.Runtime.Caching, which is not only a cache, but also a framework on which you can develop your own libraries. ObjectCache defines common operations to be implemented by all caches. It is accompanied by an in-memory cache implementation called MemoryCache. The structure of the cache system is as follows:

Can you see the corresponding products in the picture above?

Let me introduce you to a code example that implements such an architecture. The core of the code is ObjectCache:

Define an abstract Provider interface:

Public interface ICacheBuilder {ObjectCache GetInstance (); string DefaultRegionName {get;}}

The implementation of the In-memory provider uses MemoryCache:

Public class MemoryCacheBuilder: ICacheBuilder {public MemoryCacheBuilder () {} public ObjectCache GetInstance () {return MemoryCache.Default;} public string DefaultRegionName {get {return null;}

Distributed cache provider Memcached:

Public class MemcachedCache: ObjectCache, ICacheBuilder {private long _ lDefaultExpireTime = 3600; / / default ExpireTime private MemcachedClient _ client = null; # region ICache Members public MemcachedCache () {this._client = MemcachedClientService.Instance.Client;} public override void Set (string key, object value, System.DateTimeOffset absoluteExpiration, string regionName = null) {Enforce.NotNull (key, "key") CacheItem item = new CacheItem (key, value, regionName); CacheItemPolicy policy = new CacheItemPolicy (); policy.AbsoluteExpiration = absoluteExpiration; Set (item, policy);} public override void Set (CacheItem item, CacheItemPolicy policy) {if (item = = null | | item.Value = = null) return; item.Key = item.Key.ToLower () If (policy! = null & & policy.ChangeMonitors! = null & & policy.ChangeMonitors.Count > 0) throw new NotSupportedException ("Change monitors are not supported"); / / max timeout in scaleout = 65535 TimeSpan expire = (policy.AbsoluteExpiration.Equals (null))? Policy.SlidingExpiration: (policy.AbsoluteExpiration-DateTimeOffset.Now); double timeout = expire.TotalMinutes; if (timeout > 65535) timeout = 65535; else if (timeout > 0 & & timeout)

< 1) timeout = 1; this._client.Store(Enyim.Caching.Memcached.StoreMode.Set, item.Key.ToString(), item.Value); } public override object this[string key] { get { return Get(key); } set { Set(key, value, null); } } public override object AddOrGetExisting(string key, object value, CacheItemPolicy policy, string regionName = null) { CacheItem item = GetCacheItem(key, regionName); if (item == null) { Set(new CacheItem(key, value, regionName), policy); return value; } return item.Value; } public override CacheItem AddOrGetExisting(CacheItem value, CacheItemPolicy policy) { CacheItem item = GetCacheItem(value.Key, value.RegionName); if (item == null) { Set(value, policy); return value; } return item; } public override object AddOrGetExisting(string key, object value, System.DateTimeOffset absoluteExpiration, string regionName = null) { CacheItem item = new CacheItem(key, value, regionName); CacheItemPolicy policy = new CacheItemPolicy(); policy.AbsoluteExpiration = absoluteExpiration; return AddOrGetExisting(item, policy); } public override bool Contains(string key, string regionName = null) { return false; } public override CacheEntryChangeMonitor CreateCacheEntryChangeMonitor(System.Collections.Generic.IEnumerable keys, string regionName = null) { throw new System.NotImplementedException(); } public override DefaultCacheCapabilities DefaultCacheCapabilities { get { return DefaultCacheCapabilities.OutOfProcessProvider | DefaultCacheCapabilities.AbsoluteExpirations | DefaultCacheCapabilities.SlidingExpirations | DefaultCacheCapabilities.CacheRegions; } } public override object Get(string key, string regionName = null) { key = key.ToLower(); return this._client.Get(key); } public override CacheItem GetCacheItem(string key, string regionName = null) { object value = Get(key, regionName); if (value != null) return new CacheItem(key, value, regionName); return null; } public override long GetCount(string regionName = null) { return -1; } protected override System.Collections.Generic.IEnumerator GetEnumerator() { throw new System.NotImplementedException(); } public override System.Collections.Generic.IDictionary GetValues(System.Collections.Generic.IEnumerable keys, string regionName = null) { throw new System.NotImplementedException(); } public override string Name { get { return "MemcachedProvider"; } } public override object Remove(string key, string regionName = null) { key = key.ToLower(); return this._client.Remove(key); } public override void Set(string key, object value, CacheItemPolicy policy, string regionName = null) { Set(new CacheItem(key, value, regionName), policy); } #endregion #region ICacheBuilder Members public ObjectCache GetInstance() { return this; } public string DefaultRegionName { get { throw new NotImplementedException(); } } #endregion } 分布式缓存提供者Windows Server AppFabric Caching： public class AppFabricCacheProvider : ObjectCache, ICacheBuilder { public static DataCache factory = null; public static object syncObj = new object(); public override object AddOrGetExisting(string key, object value, CacheItemPolicy policy, string regionName = null) { CacheItem item = GetCacheItem(key, regionName); if (item == null) { Set(new CacheItem(key, value, regionName), policy); return value; } return item.Value; } public override CacheItem AddOrGetExisting(CacheItem value, CacheItemPolicy policy) { CacheItem item = GetCacheItem(value.Key, value.RegionName); if (item == null) { Set(value, policy); return value; } return item; } public override object AddOrGetExisting(string key, object value, System.DateTimeOffset absoluteExpiration, string regionName = null) { CacheItem item = new CacheItem(key, value, regionName); CacheItemPolicy policy = new CacheItemPolicy(); policy.AbsoluteExpiration = absoluteExpiration; return AddOrGetExisting(item, policy); } public override bool Contains(string key, string regionName = null) { return Get(key, regionName) != null; } public override CacheEntryChangeMonitor CreateCacheEntryChangeMonitor(System.Collections.Generic.IEnumerable keys, string regionName = null) { throw new NotImplementedException(); } public override DefaultCacheCapabilities DefaultCacheCapabilities { get { return DefaultCacheCapabilities.OutOfProcessProvider | DefaultCacheCapabilities.AbsoluteExpirations | DefaultCacheCapabilities.SlidingExpirations | DefaultCacheCapabilities.CacheRegions; } } public override object Get(string key, string regionName = null) { key = key.ToLower(); CreateRegionIfNeeded(); return (regionName == null) ? CacheFactory.Get(key) : CacheFactory.Get(key, regionName); } public override CacheItem GetCacheItem(string key, string regionName = null) { object value = Get(key, regionName); if (value != null) return new CacheItem(key, value, regionName); return null; } public override long GetCount(string regionName = null) { if (string.IsNullOrEmpty(regionName)) throw new NotSupportedException(); return CacheFactory.GetObjectsInRegion(regionName).LongCount(); } protected override System.Collections.Generic.IEnumerator GetEnumerator() { throw new NotSupportedException(); } public override System.Collections.Generic.IDictionary GetValues(System.Collections.Generic.IEnumerable keys, string regionName = null) { if (string.IsNullOrEmpty(regionName)) throw new NotSupportedException(); return CacheFactory.GetObjectsInRegion(regionName).ToDictionary(x =>

X.Key, x = > x.Value);} public override string Name {get {return "AppFabric";}} public override object Remove (string key, string regionName = null) {key = key.ToLower (); CreateRegionIfNeeded (); return (regionName = = null)? CacheFactory.Remove (key): CacheFactory.Remove (key, regionName);} public override void Set (string key, object value, CacheItemPolicy policy, string regionName = null) {Set (new CacheItem (key, value, regionName), policy);} public override void Set (CacheItem item, CacheItemPolicy policy) {if (item = null | | item.Value = null) return If (policy! = null & & policy.ChangeMonitors! = null & & policy.ChangeMonitors.Count > 0) throw new NotSupportedException ("Change monitors are not supported"); item.Key = item.Key.ToLower (); CreateRegionIfNeeded (); TimeSpan expire = (policy.AbsoluteExpiration.Equals (null))? Policy.SlidingExpiration: (policy.AbsoluteExpiration-DateTimeOffset.Now); if (string.IsNullOrEmpty (item.RegionName)) CacheFactory.Put (item.Key, item.Value, expire); else CacheFactory.Put (item.Key, item.Value, expire, item.RegionName) } private static DataCache CacheFactory {get {if (factory = = null) {lock (syncObj) {if (factory = = null) {DataCacheFactory cacheFactory = new DataCacheFactory () Factory = cacheFactory.GetDefaultCache ();} return factory;}} private void CreateRegionIfNeeded () 163: {try {CacheFactory.CreateRegion (DefaultRegionName) } catch (DataCacheException ex) {if (! ex.ErrorCode.Equals (DataCacheErrorCode.RegionAlreadyExists)) throw ex;}} public override void Set (string key, object value, System.DateTimeOffset absoluteExpiration, string regionName = null) {CacheItem item = new CacheItem (key, value, regionName); CacheItemPolicy policy = new CacheItemPolicy () Policy.AbsoluteExpiration = absoluteExpiration; Set (item, policy);} public override object this [string key] {get {return Get (key, DefaultRegionName);} set {Set (key, value, null, DefaultRegionName) } public ObjectCache GetInstance () {return this;} public string DefaultRegionName {get {string defaultRegion= FrameworkConfiguationManager.GetConfiguration (). GetAppVariable ("AppFabricCacheDefaultRegion"); if (string.IsNullOrEmpty (defaultRegion)) {defaultRegion= "Default";} return defaultRegion;}

Output caching has great benefits for improving performance. In ASP.NET 4.0, you can customize output caching policies, such as saving output to disk, external memcached services, and so on. You can even define some advanced rules, such as using the An output cache strategy to keep the data in memory for A pages and B output cache strategy for B pages to save the data on disk.

The code example can be found in the article http://www.buraksenyurt.com/post/AspNet-40-Custom-Cache-Provider.aspx, which is configured in web.config

In the default output caching policy of ASP.NET 4. All HTTP responses, rendered pages, and control caches use the default output cache provider shown in the previous example (where the defaultProvider attribute value is AspNetInternalProvider). By specifying a different provider for defaultProvider. You can change the default output cache provider for your web application.

In addition, you can select a different output cache provider for each user control and individual request. The easiest way to select different output cache providers for different Web user controls is to set the newly added providerName property in the page or control instruction, as shown in the following example:

To specify a different output cache provider for a HTTP request, you can override the newly added GetOutputCacheProviderName method in the Global.asax file to programmatically specify the provider to use for a particular request.

After reading this article, I believe you have some understanding of "sample Analysis of the .NET 4.0 Extensible caching Framework". If you want to know more about it, you are welcome to follow the industry information channel. Thank you for reading!

Welcome to subscribe "Shulou Technology Information " to get latest news, interesting things and hot topics in the IT industry, and controls the hottest and latest Internet news, technology news and IT industry trends.