Asp.net Core认证和授权：Cookie认证

关于asp.net core 的文章，博客园已经有很多大牛写过了。

这里我只是记录下自己在学习中的点滴和一些不懂的地方

Cookie一般是用户网站授权，当用户访问需要授权（authorization）的页面，程序会判断是否已经授权，并认证

添加认证代码：
引入命名空间：Microsoft.AspNetCore.Authentication.Cookies;

添加服务

public void ConfigureServices(IServiceCollection services)
        {

            services.AddMvc().SetCompatibilityVersion(CompatibilityVersion.Version_2_2);

            services.AddAuthentication(CookieAuthenticationDefaults.AuthenticationScheme) .AddCookie();
        }

注册中间件，添加到管道

app.UseAuthentication();

注意：一定要在app.UseMvc之前添加

我们通过源码可以看到cookie的一些默认配置

// Copyright (c) .NET Foundation. All rights reserved.
// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.

using Microsoft.AspNetCore.Http;

namespace Microsoft.AspNetCore.Authentication.Cookies
{
    /// <summary>
    /// Default values related to cookie-based authentication handler
    /// </summary>
    public static class CookieAuthenticationDefaults
    {
        /// <summary>
        /// The default value used for CookieAuthenticationOptions.AuthenticationScheme
        /// </summary>
        public const string AuthenticationScheme = "Cookies";

        /// <summary>
        /// The prefix used to provide a default CookieAuthenticationOptions.CookieName
        /// </summary>
        public static readonly string CookiePrefix = ".AspNetCore.";

        /// <summary>
        /// The default value used by CookieAuthenticationMiddleware for the
        /// CookieAuthenticationOptions.LoginPath
        /// </summary>
        public static readonly PathString LoginPath = new PathString("/Account/Login");

        /// <summary>
        /// The default value used by CookieAuthenticationMiddleware for the
        /// CookieAuthenticationOptions.LogoutPath
        /// </summary>
        public static readonly PathString LogoutPath = new PathString("/Account/Logout");

        /// <summary>
        /// The default value used by CookieAuthenticationMiddleware for the
        /// CookieAuthenticationOptions.AccessDeniedPath
        /// </summary>
        public static readonly PathString AccessDeniedPath = new PathString("/Account/AccessDenied");

        /// <summary>
        /// The default value of the CookieAuthenticationOptions.ReturnUrlParameter
        /// </summary>
        public static readonly string ReturnUrlParameter = "ReturnUrl";
    }
}

我们可以自己修改：

  services.AddAuthentication(CookieAuthenticationDefaults.AuthenticationScheme)
                .AddCookie(option =>
                {
                    option.LoginPath = "/Login"; //没有授权，跳转的url
                    option.LogoutPath = "/Login"; //退出，的url
                });

因为cookie在有效期内都是有效的，如果用户资料修改了，客户端的Cookie是不知道的

网上有人提出了解决方案，如果用户修改了资料，在数据库用一个字段记录，cookie有个事件，在每次请求都会访问

option.Events.OnValidatePrincipal = ValidatePrincipal

想添加多个可以这样写：

option.Events = new CookieAuthenticationEvents
                    {
                        OnValidatePrincipal = ValidatePrincipal,
                        //OnRedirectToLogin =
                    };

 public async Task ValidatePrincipal(CookieValidatePrincipalContext context)
        {
            var _Context = context.HttpContext.RequestServices.GetRequiredService<EFContext>();
            var s = context.HttpContext.RequestServices.GetService<EFContext>();

            var principal = context.Principal;

            var u = principal.Claims.Select(c => c.Type == "isEdit").FirstOrDefault();

            if (u)
            {
                //更新数据库状态
                //

                // 1. 验证失败 等同于 Principal = principal;
                context.RejectPrincipal();

                //登出
               await AuthenticationHttpContextExtensions.SignOutAsync(context.HttpContext, CookieAuthenticationDefaults.AuthenticationScheme);
                // 2. 验证通过，并会重新生成Cookie。
                //context.ShouldRenew = true;

            }
        }

用户登陆，网上有人这里解释的

ClaimsIdentity（身份证），Claims（身份信息）
           ClaimsPrinciple （证件所有者）

这个也很恰当

https://www.cnblogs.com/dudu/p/6367303.html

  [HttpPost]
        public async Task<IActionResult> Login(string ReturnUrl, User model)
        {
            if (model.UserName=="cnblogs" && model.PassWord == "pwd")
            {
                /*
             ClaimsIdentity（身份证），Claims（身份信息）
           ClaimsPrinciple （证件所有者）
             */

                //身份信息
                var claims = new List<Claim> {
                    new Claim(ClaimTypes.Name,"sky"),
                    new Claim("Address","北京海淀"),
                };

                //身份证
                var claimsIdentity = new ClaimsIdentity(claims, CookieAuthenticationDefaults.AuthenticationScheme);

                //证件所有者
                var claimsPrinciple = new ClaimsPrincipal(claimsIdentity);

                /*
                 如果登陆选择了记住我，则将cookie持久化
                 这里默认持久化
                 */
                var properties = new AuthenticationProperties
                {
                    IsPersistent = true,
                    ExpiresUtc = DateTimeOffset.UtcNow.AddDays(),
                    //ExpiresUtc = DateTime.Now.AddDays(1)

                };
                await HttpContext.SignInAsync(CookieAuthenticationDefaults.AuthenticationScheme, claimsPrinciple, properties);

                return Redirect(ReturnUrl);
            }
            else
                return View("index");
        }

博客园的大神文章，很多。就放几个参考吧

https://www.cnblogs.com/RainingNight/p/7587194.html

https://www.cnblogs.com/tdfblog/p/7416589.html