NET 5 Session、Cookie和Cache的使用

1.Cookie

public IConfiguration Configuration { get; }

    // This method gets called by the runtime. Use this method to add services to the container.
    public void ConfigureServices(IServiceCollection services)
    {  
        services.AddHttpContextAccessor();//配置Cookie HttpContext
        services.AddTransient<ICookie, Cookie>();//IOC配置 方便项目中使用
        services.AddTransient(typeof(Config));//基础配置
         
    }

    // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
    public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
    {
        if (env.IsDevelopment())
        {
            app.UseDeveloperExceptionPage();
        }
        else
        {
            app.UseExceptionHandler("/Home/Index");
            // The default HSTS value is 30 days. You may want to change this for production scenarios, see https://aka.ms/aspnetcore-hsts.
            app.UseHsts();
        }
        app.UseHttpsRedirection();
        app.UseStaticFiles();

        app.UseRouting();

        app.UseAuthorization();

        app.UseEndpoints(endpoints =>
        {
            endpoints.MapControllerRoute(
                name: "default",
                pattern: "{controller=Home}/{action=Index}/{id?}");
        });
    }
}

public interface ICookie
{
    void SetCookies(string key, string value, int minutes = 300);

    /// <summary>
    /// 删除指定的cookie
    /// </summary>
    /// <param name="key">键</param>
    void DeleteCookies(string key);

    /// <summary>
    /// 获取cookies
    /// </summary>
    /// <param name="key">键</param>
    /// <returns>返回对应的值</returns>
    string GetCookies(string key);
    
}

public class Cookie : ICookie
{
    private readonly IHttpContextAccessor _httpContextAccessor;

    public Cookie(IHttpContextAccessor httpContextAccessor)
    {
        _httpContextAccessor = httpContextAccessor;
    }
    /// <summary>
    /// 设置本地cookie
    /// </summary>
    /// <param name="key">键</param>
    /// <param name="value">值</param>  
    /// <param name="minutes">过期时长，单位：分钟</param>      
    public void SetCookies(string key, string value, int minutes = 300)
    {
        _httpContextAccessor.HttpContext.Response.Cookies.Append(key, value, new CookieOptions
        {
            Expires = DateTime.Now.AddMinutes(minutes)
        });
    }

    /// <summary>
    /// 删除指定的cookie
    /// </summary>
    /// <param name="key">键</param>
    public void DeleteCookies(string key)
    {
        _httpContextAccessor.HttpContext.Response.Cookies.Delete(key);
    }

    /// <summary>
    /// 获取cookies
    /// </summary>
    /// <param name="key">键</param>
    /// <returns>返回对应的值</returns>
    public string GetCookies(string key)
    {
        _httpContextAccessor.HttpContext.Request.Cookies.TryGetValue(key, out string value);
        if (string.IsNullOrEmpty(value))
            value = string.Empty;
        return value;
    } 
}

public class HomeController : Controller
{
    private readonly ILogger _logger;

    private readonly ICookie _cookie;

    private readonly Config _config;
    public HomeController(ILogger<HomeController> logger, ICookie cookie, Config config)
    {
        _logger = logger;
        this._cookie = cookie;
        this._config = config;
    }

    public IActionResult Index()
    {
        _cookie.SetCookies(_config.CookieName(), "CookieValue");

        string CookieValue = _cookie.GetCookies(_config.CookieName());

        _cookie.DeleteCookies(_config.CookieName());

        return View();
    }

    public IActionResult Privacy()
    {
        return View();
    }

    [ResponseCache(Duration = 0, Location = ResponseCacheLocation.None, NoStore = true)]
    public IActionResult Error()
    {
        return View(new ErrorViewModel { RequestId = Activity.Current?.Id ?? HttpContext.TraceIdentifier });
    }
}

2.Session

在你的项目上基于NuGet添加

Microsoft.AspNetCore.Session

在startup.cs找到方法ConfigureServices(IServiceCollection services) 注入Session

services.AddSession();

app.UseSession();

在控制器中设置和使用session

//写入session
HttpContext.Session.SetInt32("userId", 10);

//获取session

3.Cache

1    public void ConfigureServices(IServiceCollection services)
2    {
3        services.AddMemoryCache();
4    }

1 public class LoginController : Controller
2 {
3     private IMemoryCache _cache;
4 
5     public LoginController(IMemoryCache memoryCache)
6     {
7         _cache = memoryCache;
8     }

1 //检查用户名是否存在
 2 public JsonResult SelectUName(string uname)
 3 {
 4    //读取缓存
 5    var cache = _cache.Get("re_" + uname);
 6    if (cache == null)//如果没有该缓存
 7    {
 8       //查询用户名是否存在
 9       var re = _userdal.SelectUName(uname);
10       //将验证结果添加到缓存
11       _cache.Set("re_" + uname, re.Status, new MemoryCacheEntryOptions().SetSlidingExpiration(TimeSpan.FromMinutes(10)));
12       return Json(new { status = re.Status });
13    }
14    else//如果缓存不为空，则返回缓存内容
15    {
16       return Json(new { status = cache });
17    }
18 }

1         //删除
2         public int Delete(int uid)
3         {
4             var re = _maindal.Delete(uid);
5             //删除成功之后移除验证用户名缓存
6             _cache.Remove("re_" + HttpContext.Session.GetString("name"));
7             return re;
8         }

Session缓存和Cache缓存的区别如下：

（1）最大的区别是Cache提供缓存依赖来更新数据，而Session只能依靠定义的缓存时间来判断缓存数据是否有效。

（2）即使应用程序终止，只要Cache.Add方法中定义的缓存时间未过期，下次开启应用程序时，缓存的数据依然存在。而Session缓存只是存在于一次会话中，会话结束后，数据也就失效了。

（3）Session容易丢失，导致数据的不确定性，而Cache不会出现这种情况。

（4）由于Session是每次会话就被加载，所以不适宜存放大量信息，否则会导致服务器的性能降低。而Cache则主要用来保存大容量信息，如数据库中的多个表。

需要特别注意：为了提高Cache的有效利用率，建议对于不经常改动的数据使用Cache。

public void ConfigureServices(IServiceCollection services)
{　　
    //如何处理session
   services.AddSession();  
    //memoryCache   
   services.AddMemoryCache();
   
    //.......
}

 public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
{
    //启用session
    app.UseSession();
    app.UseRouting();
    //......
}