asp.net core 緩存和Session

原文: asp.net core 緩存和Session

緩存#

緩存在內存中 ASP.NET Core#

使用 IMemoryCache內存中緩存是使用依賴關係注入從應用中引用的服務。 請在ConfigureServices中調用AddMemoryCache():

 
 
 
 

  
  
  
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public class Startup
{
    public void ConfigureServices(IServiceCollection services) {
        services.AddMemoryCache();
        services.AddMvc().SetCompatibilityVersion(CompatibilityVersion.Version_2_1);
    }

    public void Configure(IApplicationBuilder app) {
        app.UseMvcWithDefaultRoute();
    }
}

在構造函數中請求 IMemoryCache實例：

 
 
 
 

  
  
  
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public class HomeController : Controller
    {
        private IMemoryCache cache;

        public HomeController(IMemoryCache cache) {
             this.cache = cache;
        }

        public IActionResult Index() {
            cache.Set("name", $"shijia{DateTime.Now}", TimeSpan.FromSeconds(10));
            return View();
        }

        public IActionResult About() {
            object result;
            string value = cache.TryGetValue("name", out result) ? $"獲取緩存name{result}" : "獲取緩存失敗";
            return Content(value);
        }

資料：https://docs.microsoft.com/zh-cn/aspnet/core/performance/caching/memory?view=aspnetcore-2.1#using-imemorycache

分佈式緩存#

https://docs.microsoft.com/zh-cn/aspnet/core/performance/caching/distributed?view=aspnetcore-2.1

Session#

要添加對Session支持，不然會報錯Session has not been configured for this
application or request。使用方法 http://www.cnblogs.com/sword-successful/p/6243841.html

（1）nuget安裝Microsoft.AspNetCore.Session
（2） ConfigureServices中services.AddSession();
（3）Configure中app.UseSession();
（4）TempData依賴於Session，因此也要配置Session。
（5）HttpContext.Session，可是原始只有void Set(string key, byte[] value)、bool TryGetValue(string key, out byte[] value)這兩個方法。若是using Microsoft.AspNetCore.Http;（須要安裝Microsoft.AspNetCore.Http.Extensions）還能夠使用SessionExtensions中的值是int、string類型的，其餘類型只能本身使用json進行序列化處理。
（6）推薦使用redis作進程外session：
http://www.hossambarakat.net/2016/02/03/configuring-redis-as-asp-net-core-1-0-session-store/

1.在MVC Controller裏使用HttpContext.Session

 
 
 
 

  
  
  
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using Microsoft.AspNetCore.Http;

public class HomeController:Controller
{
      public IActionResult Index() {
              HttpContext.Session.SetString("code","123456");
              return View();  
       }

       public IActionResult About() {
              ViewBag.Code=HttpContext.Session.GetString("code");
              return View();
        }
}

2.若是不是在Controller裏，你能夠注入IHttpContextAccessor

 
 
 
 

  
  
  
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public class SomeOtherClass
{
      private readonly IHttpContextAccessor _httpContextAccessor;
      private ISession _session=> _httpContextAccessor.HttpContext.Session;

      public SomeOtherClass(IHttpContextAccessor httpContextAccessor) {
           _httpContextAccessor=httpContextAccessor;              
     }

     public void Set() {
          _session.SetString("code","123456");
     }
    
     public void Get() {
         string code = _session.GetString("code");
     }
}

資料：ASP.NET Core 中的會話和應用狀態
https://docs.microsoft.com/zh-cn/aspnet/core/fundamentals/app-state?view=aspnetcore-2.1#session-state

問題：#

Session 保存以後取不到值的解決方案#

解決方案：
註釋掉下面這段：

 
 
 
 

  
  
  
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public void ConfigureServices(IServiceCollection services) {
// services.Configure<CookiePolicyOptions>(options =>
// {
// // This lambda determines whether user consent for non-essential cookies is needed for a given request.
// options.CheckConsentNeeded = context => true;
// options.MinimumSameSitePolicy = SameSiteMode.None;
// });
            
            services.AddMemoryCache();
            services.AddMvc().SetCompatibilityVersion(CompatibilityVersion.Version_2_1);
            services.AddSession();
        }