[Asp.net mvc]OutputCacheAttribute

什么是Cache？

缓存在web应用中是一种以空间换去时间的技术，把频繁访问并且不经常变化的数据存储到内存中，以达到快速访问的目的。在web应用中是比较常见的优化方式。

OutputCacheAttribute

表示一个特性，该特性用于标记将缓存其输出的操作方法。

OutpuCacheAttribute定义

代码片段

[AttributeUsageAttribute(AttributeTargets.Class|AttributeTargets.Method, Inherited = true, AllowMultiple = false)]
public class OutputCacheAttribute : ActionFilterAttribute, IExceptionFilter

从上面的代码中可以看到该特性可以应用在类，方法上面。在mvc中，就可以直接在控制器上面或者控制器中的Action上面直接使用，做到细粒度的对缓存的控制。

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Mvc;namespace Wolfy.OutputCacheDemo.Controllers
{[OutputCache(Duration = 10)]public class HomeController : Controller{// GET: Homepublic string Index(){return DateTime.Now.ToString();}}
}

上面的代码是将OutputCache特性标记在了控制器类上，以达到该控制器上所有的Action都将应用该特性，过期时间设置为10s。10s后缓存过期，再访问就会更新时间。

OutputCache特性也可以设置在Action方法上面，以达到更细粒度的控制缓存。

代码片段

    public class HomeController : Controller{[OutputCache(Duration = 10)]// GET: Homepublic string Index(){return DateTime.Now.ToString();}}

此时，只有Index的页面进行了缓存。

WebConfig

如果多个控制器或者Action使用相同的缓存配置，可以在配置文件中进行统一配置。

  <system.web><caching><outputCacheSettings><outputCacheProfiles ><add name='myoutputcache' duration='10'/></outputCacheProfiles></outputCacheSettings></caching><compilation debug="true" targetFramework="4.5"/><httpRuntime targetFramework="4.5"/></system.web>

应用名称为myoutputcache的缓存

    public class HomeController : Controller{[OutputCache(CacheProfile = "myoutputcache")]// GET: Homepublic string Index(){return DateTime.Now.ToString();}}

Note：

当控制器和Action同时使用了OutputCache特性时，以Action为主。

OutputCache参数

#region Assembly System.Web.Mvc.dll, v5.2.2.0
#endregionusing System;
using System.Web.UI;namespace System.Web.Mvc
{// Summary://     Represents an attribute that is used to mark an action method whose output//     will be cached.[AttributeUsage(AttributeTargets.Class | AttributeTargets.Method, Inherited = true, AllowMultiple = false)]public class OutputCacheAttribute : ActionFilterAttribute, IExceptionFilter{// Summary://     Initializes a new instance of the System.Web.Mvc.OutputCacheAttribute class.public OutputCacheAttribute();// Summary://     Gets or sets the cache profile name.//// Returns://     The cache profile name.public string CacheProfile { get; set; }//// Summary://     Gets or sets the child action cache.//// Returns://     The child action cache.public static System.Runtime.Caching.ObjectCache ChildActionCache { get; set; }//// Summary://     Gets or sets the cache duration, in seconds.//// Returns://     The cache duration.public int Duration { get; set; }//// Summary://     Gets or sets the location.//// Returns://     The location.public OutputCacheLocation Location { get; set; }//// Summary://     Gets or sets a value that indicates whether to store the cache.//// Returns://     true if the cache should be stored; otherwise, false.public bool NoStore { get; set; }//// Summary://     Gets or sets the SQL dependency.//// Returns://     The SQL dependency.public string SqlDependency { get; set; }//// Summary://     Gets or sets the vary-by-content encoding.//// Returns://     The vary-by-content encoding.public string VaryByContentEncoding { get; set; }//// Summary://     Gets or sets the vary-by-custom value.//// Returns://     The vary-by-custom value.public string VaryByCustom { get; set; }//// Summary://     Gets or sets the vary-by-header value.//// Returns://     The vary-by-header value.public string VaryByHeader { get; set; }//// Summary://     Gets or sets the vary-by-param value.//// Returns://     The vary-by-param value.public string VaryByParam { get; set; }// Summary://     Returns a value that indicates whether a child action cache is active.//// Parameters://   controllerContext://     The controller context.//// Returns://     true if the child action cache is active; otherwise, false.public static bool IsChildActionCacheActive(ControllerContext controllerContext);//// Summary://     This method is an implementation of System.Web.Mvc.IActionFilter.OnActionExecuted(System.Web.Mvc.ActionExecutedContext)//     and supports the ASP.NET MVC infrastructure. It is not intended to be used//     directly from your code.//// Parameters://   filterContext://     The filter context.public override void OnActionExecuted(ActionExecutedContext filterContext);//// Summary://     This method is an implementation of System.Web.Mvc.IActionFilter.OnActionExecuting(System.Web.Mvc.ActionExecutingContext)//     and supports the ASP.NET MVC infrastructure. It is not intended to be used//     directly from your code.//// Parameters://   filterContext://     The filter context.public override void OnActionExecuting(ActionExecutingContext filterContext);//// Summary://     This method is an implementation of System.Web.Mvc.IExceptionFilter.OnException(System.Web.Mvc.ExceptionContext)//     and supports the ASP.NET MVC infrastructure. It is not intended to be used//     directly from your code.//// Parameters://   filterContext://     The filter context.public void OnException(ExceptionContext filterContext);//// Summary://     This method is an implementation of System.Web.Mvc.IResultFilter.OnResultExecuted(System.Web.Mvc.ResultExecutedContext)//     and supports the ASP.NET MVC infrastructure. It is not intended to be used//     directly from your code.//// Parameters://   filterContext://     The filter context.public override void OnResultExecuted(ResultExecutedContext filterContext);//// Summary://     Called before the action result executes.//// Parameters://   filterContext://     The filter context, which encapsulates information for using System.Web.Mvc.AuthorizeAttribute.//// Exceptions://   System.ArgumentNullException://     The filterContext parameter is null.public override void OnResultExecuting(ResultExecutingContext filterContext);}
}

常用的属性

CacheProfile：缓存使用的配置文件的缓存名称。

Duration：缓存时间，以秒为单位，这个除非你的Location=None，可以不添加此属性，其余时候都是必须的。

OutputCacheLocation：枚举类型，缓存的位置。当设置成None时，所有缓存将失效，默认为Any。

namespace System.Web.UI
{// Summary://     Specifies the valid values for controlling the location of the output-cached//     HTTP response for a resource.public enum OutputCacheLocation{// Summary://     The output cache can be located on the browser client (where the request//     originated), on a proxy server (or any other server) participating in the//     request, or on the server where the request was processed. This value corresponds//     to the System.Web.HttpCacheability.Public enumeration value.Any = 0,//// Summary://     The output cache is located on the browser client where the request originated.//     This value corresponds to the System.Web.HttpCacheability.Private enumeration//     value.Client = 1,//// Summary://     The output cache can be stored in any HTTP 1.1 cache-capable devices other//     than the origin server. This includes proxy servers and the client that made//     the request.Downstream = 2,//// Summary://     The output cache is located on the Web server where the request was processed.//     This value corresponds to the System.Web.HttpCacheability.Server enumeration//     value.Server = 3,//// Summary://     The output cache is disabled for the requested page. This value corresponds//     to the System.Web.HttpCacheability.NoCache enumeration value.None = 4,//// Summary://     The output cache can be stored only at the origin server or at the requesting//     client. Proxy servers are not allowed to cache the response. This value corresponds//     to the combination of the System.Web.HttpCacheability.Private and System.Web.HttpCacheability.Server//     enumeration values.ServerAndClient = 5,}
}

VaryByParam：用于多个输出缓存的字符串列表，并以分号进行分隔。默认时，该字符串与GET方法传递的参数或与POST方法传递的变量相对应。当被设置为多个参数时，输出缓存将会为每个参数都准备一个与之相对应的文档版本。可能值包括none，*，以及任何有效的查询串或POST参数名称。

结语

由于没找到缓存依赖mysql的办法，关于OutputCache的内容就先到这里。

关于缓存依赖的内容，可参考这篇文章

http://www.cnblogs.com/iamlilinfeng/p/4419362.html

转载于:https://www.cnblogs.com/wolf-sun/p/6219245.html