IResourceFilter 缓存应用

1、新建CustomResourceFilterAttribute类，继承Attribute和IResourceFilter

    using Microsoft.AspNetCore.Mvc;
using Microsoft.AspNetCore.Mvc.Filters;

namespace Project6.Utility.Filters
{
    public class CustomResourceFilterAttribute : Attribute, IResourceFilter
    {
        private static Dictionary<string, object> CacheDictionary = new Dictionary<string, object>();
        /// <summary>
        /// 资源访问后执行
        /// </summary>
        /// <param name="context"></param>
        public void OnResourceExecuted(ResourceExecutedContext context)
        {
            string key = context.HttpContext.Request.Path;
            CacheDictionary[key] = context.Result;
        }
        /// <summary>
        /// 资源访问前执行
        /// </summary>
        /// <param name="context"></param>
        public void OnResourceExecuting(ResourceExecutingContext context)
        {
            string key = context.HttpContext.Request.Path;
            if (CacheDictionary.ContainsKey(key))
            {
                //只要给Result赋值了，就会中断后面的执行，直接返回给视图
                context.Result = (IActionResult)CacheDictionary[key];
            }
        }
    }
}

2、新建CustomController控制器

using Microsoft.AspNetCore.Mvc;
using Project6.Utility.Filters;

namespace Project6.Controllers
{
    public class CustomController : Controller
    {
        private readonly ILogger _logger;

        public CustomController(ILogger<LogController> logger)
        {
            this._logger = logger;
        }

        [CustomResourceFilter]
        public IActionResult Index()
        {
            ViewBag.Date = DateTime.Now.ToString("yyyyMMdd HH:mm:ss");
            return View();
        }
    }
}

3、CustomController控制器Index视图对应的内容

<h1>控制器的时间：@ViewBag.Date</h1>
<h1>视图的时间：@DateTime.Now.ToString("yyyyMMdd HH:mm:ss")</h1>

4、在各个方法处设置断点，执行多次/Custom/Index

可以发现，当第二次执行时，执行到OnResourceExecuting方法时，直接跳到视图，不在执行CustomController里面方法。控制器里面的值也不在变化。说明缓存起到了作用。可以应用在一些没有变化的页面，如新闻页之类的，避免重复查询数据库，提高页面执行效率。