asp.net core 2.0的认证和授权

在asp.net core中，微软提供了基于认证（Authentication）和授权（Authorization）的方式，来实现权限管理的，本篇博文，介绍基于固定角色的权限管理和自定义角色权限管理，本文内容，更适合传统行业的BS应用，而非互联网应用。

在asp.net core中，我们认证（Authentication）通常是在Login的Post Action中进行用户名或密码来验证用户是否正确，如果通过验证，即该用户就会获得一个或几个特定的角色，通过ClaimTypes.Role来存储角色，从而当一个请求到达时，用这个角色和Controller或Action上加的特性 [Authorize(Roles = "admin,system")]来授权是否有权访问该Action。本文中的自定义角色，会把验证放在中间件中进行处理。

 一、固定角色：

即把角色与具体的Controller或Action直接关联起来，整个系统中的角色是固定的，每种角色可以访问那些Controller或Action也是固定的，这做法比较适合小型项目，角色分工非常明确的项目。

项目代码：

https://github.com/axzxs2001/Asp.NetCoreExperiment/tree/master/Asp.NetCoreExperiment/%E6%9D%83%E9%99%90%E7%AE%A1%E7%90%86/RolePrivilegeManagement

始于startup.cs

需要在ConfigureServices中注入Cookie的相关信息，options是CookieAuthenticationOptions，关于这个类型提供如下属性，可参考：https://docs.microsoft.com/en-us/aspnet/core/security/authentication/cookie?tabs=aspnetcore2x

它提供了登录的一些信息，或登录生成Cookie的一些信息，用以后

        public void ConfigureServices(IServiceCollection services)
        {
            services.AddMvc();
            //添加认证Cookie信息
            services.AddAuthentication(CookieAuthenticationDefaults.AuthenticationScheme)
             .AddCookie(options =>
             {
                 options.LoginPath = new PathString("/login");
                 options.AccessDeniedPath = new PathString("/denied");
             });
        }

        public void Configure(IApplicationBuilder app, IHostingEnvironment env)
        {
            if (env.IsDevelopment())
            {
                app.UseDeveloperExceptionPage();
                app.UseBrowserLink();
            }
            else
            {
                app.UseExceptionHandler("/Home/Error");
            }
            app.UseStaticFiles();
            //验证中间件
            app.UseAuthentication();
            app.UseMvc(routes =>
            {
                routes.MapRoute(
                    name: "default",
                    template: "{controller=Home}/{action=Index}/{id?}");
            });
        }

HomeController.cs

对于Login Get的Action，把returnUrl用户想要访问的地址（有可能用户记录下想要访问的url了，但系统会转到登录页，登录成功后直接跳转到想要访问的returnUrl页）

对于Login Post的Action，验证用户密和密码，成功能，定义一个ClaimsIdentity，把用户名和角色，和用户姓名的声明都添回进来（这个角色，就是用来验证可访问action的角色 ）作来该用户标识，接下来调用HttpContext.SignInAsync进行登录，注意此方法的第一个参数，必需与StartUp.cs中services.AddAuthentication的参数相同，AddAuthentication是设置登录，SigninAsync是按设置参数进行登录

对于Logout Get的Action，是退出登录

HomeController上的[Authorize(Roles=”admin,system”)]角色和权限的关系时，所有Action只有admin和system两个角色能访问到，About上的[Authorize(Roles=”admin”)]声明这个action只能admin角色访问，Contact上的[Authorize(Roles=”system”)]声明这个action只能system角色访问，如果action上声明的是[AllowAnomymous]，说明不受授权管理，可以直接访问。

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Mvc;
using RolePrivilegeManagement.Models;
using System.Security.Claims;
using Microsoft.AspNetCore.Authentication;
using Microsoft.AspNetCore.Authentication.Cookies;
using Microsoft.AspNetCore.Authorization;

namespace RolePrivilegeManagement.Controllers
{
    [Authorize(Roles = "admin,system")]
    public class HomeController : Controller
    {
        public IActionResult Index()
        {
            return View();
        }
        [Authorize(Roles = "admin")]
        public IActionResult About()
        {
            ViewData["Message"] = "Your application description page.";
            return View();
        }
        [Authorize(Roles = "system")]
        public IActionResult Contact()
        {
            ViewData["Message"] = "Your contact page.";
            return View();
        }
        public IActionResult Error()
        {
            return View(new ErrorViewModel { RequestId = Activity.Current?.Id ?? HttpContext.TraceIdentifier });
        }
        [AllowAnonymous]
        [HttpGet("login")]
        public IActionResult Login(string returnUrl = null)
        {
            TempData["returnUrl"] = returnUrl;
            return View();
        }
        [AllowAnonymous]
        [HttpPost("login")]
        public async Task<IActionResult> Login(string userName, string password, string returnUrl = null)
        {
            var list = new List<dynamic> {
                new { UserName = "gsw", Password = "111111", Role = "admin" },
                new { UserName = "aaa", Password = "222222", Role = "system" }
            };
            var user = list.SingleOrDefault(s => s.UserName == userName && s.Password == password);
            if (user!=null)
            {
                //用户标识
                var identity = new ClaimsIdentity(CookieAuthenticationDefaults.AuthenticationScheme);
                identity.AddClaim(new Claim(ClaimTypes.Sid, userName));
                identity.AddClaim(new Claim(ClaimTypes.Name, user.Name));
                identity.AddClaim(new Claim(ClaimTypes.Role, user.Role));
                await HttpContext.SignInAsync(CookieAuthenticationDefaults.AuthenticationScheme, new ClaimsPrincipal(identity));
                if (returnUrl == null)
                {
                    returnUrl = TempData["returnUrl"]?.ToString();
                }
                if (returnUrl != null)
                {
                    return Redirect(returnUrl);
                }
                else
                {
                    return RedirectToAction(nameof(HomeController.Index), "Home");
                }
            }
            else
            {
                const string badUserNameOrPasswordMessage = "用户名或密码错误！";
                return BadRequest(badUserNameOrPasswordMessage);
            }
        }
        [HttpGet("logout")]
        public async Task<IActionResult> Logout()
        {
            await HttpContext.SignOutAsync(CookieAuthenticationDefaults.AuthenticationScheme);
            return RedirectToAction("Index", "Home");
        }
        [AllowAnonymous]
        [HttpGet("denied")]
        public IActionResult Denied()
        {
            return View();
        }
    }
}

前端_Layout.cshtml布局页，在登录成功后的任何页面都可以用@User.Identity.Name就可以获取用户姓名，同时用@User.Claims.SingleOrDefault(s=>s.Type== System.Security.Claims.ClaimTypes.Sid).Value可以获取用户名或角色。

   <nav class="navbar navbar-inverse navbar-fixed-top">
        <div class="container">
            <div class="navbar-header">
                <button type="button" class="navbar-toggle" data-toggle="collapse" data-target=".navbar-collapse">
                    <span class="sr-only">Toggle navigation</span>
                    <span class="icon-bar"></span>
                    <span class="icon-bar"></span>
                    <span class="icon-bar"></span>
                </button>
                <a asp-area="" asp-controller="Home" asp-action="Index" class="navbar-brand">RolePrivilegeManagement</a>
            </div>
            <div class="navbar-collapse collapse">
                <ul class="nav navbar-nav">
                    <li><a asp-area="" asp-controller="Home" asp-action="Index">Home</a></li>
                    <li><a asp-area="" asp-controller="Home" asp-action="About">About</a></li>
                    <li><a asp-area="" asp-controller="Home" asp-action="Contact">Contact</a></li>
                </ul>
                <ul class="" style="float:right; margin:0;">
                    <li style="overflow:hidden;">
                        <div style="float:left;line-height:50px;margin-right:10px;">
                            <span style="color:#ffffff">当前用户：@User.Identity.Name</span>
                        </div>
                        <div style="float:left;line-height:50px;">
                            <a asp-area="" asp-controller="Home" asp-action="Logout">注销</a>
                        </div>
                    </li>
                </ul>
            </div>
        </div>
    </nav>

现在可以用chrome运行了，进行登录页后F12，查看Network—Cookies，可以看到有一个Cookie，这个是记录returnUrl的Cookie，是否记得HomeController.cs中的Login Get的Action中代码：TempData["returnUrl"] = returnUrl;这个TempData最后转成了一个Cookie返回到客户端了，如下图：

输入用户名，密码登录，再次查看Cookies，发现多了一个.AspNetCore.Cookies，即把用户验证信息加密码保存在了这个Cookie中，当跳转到别的页面时，这两个Cookie会继续在客户端和服务传送，用以验证用户角色。

二、自定义角色

系统的角色可以自定义，用户是自写到义，权限是固定的，角色对应权限可以自定义，用户对应角色也是自定义的，如下图：

项目代码：

https://github.com/axzxs2001/Asp.NetCoreExperiment/tree/master/Asp.NetCoreExperiment/%E6%9D%83%E9%99%90%E7%AE%A1%E7%90%86/PrivilegeManagement

始于startup.cs

自定义角色与固定角色不同之处在于多了一个中间件（关于中间件学习参看：https://docs.microsoft.com/en-us/aspnet/core/fundamentals/middleware），即在Configure方法中，一定要在app.UseAuthentication下面添加验证权限的中间件，因为UseAuthentication要从Cookie中加载通过验证的用户信息到Context.User中，所以一定放在加载完后才能去验用户信息（当然自己读取Cookie也可以）

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.AspNetCore.Authentication.Cookies;
using Microsoft.AspNetCore.Http;
using PrivilegeManagement.Middleware;

namespace PrivilegeManagement
{
    public class Startup
    {
        public Startup(IConfiguration configuration)
        {
            Configuration = configuration;
        }
        public IConfiguration Configuration { get; }

        public void ConfigureServices(IServiceCollection services)
        {
            services.AddAuthentication(CookieAuthenticationDefaults.AuthenticationScheme)
           .AddCookie(options =>
           {
               options.LoginPath = new PathString("/login");
               options.AccessDeniedPath = new PathString("/denied");
           }
           );
            services.AddMvc();
        }

        public void Configure(IApplicationBuilder app, IHostingEnvironment env)
        {
            if (env.IsDevelopment())
            {
                app.UseDeveloperExceptionPage();
                app.UseBrowserLink();
            }
            else
            {
                app.UseExceptionHandler("/Home/Error");
            }

            app.UseStaticFiles();
            //验证中间件
            app.UseAuthentication();
            ////添加权限中间件, 一定要放在app.UseAuthentication后
            app.UsePermission(new PermissionMiddlewareOption()
            {
                LoginAction = @"/login",
                NoPermissionAction = @"/denied",
                //这个集合从数据库中查出所有用户的全部权限
                UserPerssions = new List<UserPermission>()
                 {
                     new UserPermission { Url="/", UserName="gsw"},
                     new UserPermission { Url="/home/contact", UserName="gsw"},
                     new UserPermission { Url="/home/about", UserName="aaa"},
                     new UserPermission { Url="/", UserName="aaa"}
                 }
            });
            app.UseMvc(routes =>
            {
                routes.MapRoute(
                    name: "default",
                    template: "{controller=Home}/{action=Index}/{id?}");
            });
        }
    }
}

下面看看中间件PermissionMiddleware.cs，在Invoke中用了context.User，如上面所述，首先要调用app.UseAuthentication加载用户信息后才能在这里使用，这个中间件逻辑较简单，如果没有验证的一律放过去，不作处理，如果验证过（登录成功了），就要查看本次请求的url和这个用户可以访问的权限是否匹配，如不匹配，就跳转到拒绝页面（这个是在Startup.cs中添加中间件时，用NoPermissionAction = @"/denied"设置的）

using Microsoft.AspNetCore.Http;
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Reflection;
using System.Security.Claims;
using System.Threading.Tasks;

namespace PrivilegeManagement.Middleware
{
    /// <summary>
    /// 权限中间件
    /// </summary>
    public class PermissionMiddleware
    {
        /// <summary>
        /// 管道代理对象
        /// </summary>
        private readonly RequestDelegate _next;
        /// <summary>
        /// 权限中间件的配置选项
        /// </summary>
        private readonly PermissionMiddlewareOption _option;

        /// <summary>
        /// 用户权限集合
        /// </summary>
        internal static List<UserPermission> _userPermissions;

        /// <summary>
        /// 权限中间件构造
        /// </summary>
        /// <param name="next">管道代理对象</param>
        /// <param name="permissionResitory">权限仓储对象</param>
        /// <param name="option">权限中间件配置选项</param>
        public PermissionMiddleware(RequestDelegate next, PermissionMiddlewareOption option)
        {
            _option = option;
            _next = next;
            _userPermissions = option.UserPerssions;
        }       
        /// <summary>
        /// 调用管道
        /// </summary>
        /// <param name="context">请求上下文</param>
        /// <returns></returns>
        public Task Invoke(HttpContext context)
        {
            //请求Url
            var questUrl = context.Request.Path.Value.ToLower();
       
            //是否经过验证
            var isAuthenticated = context.User.Identity.IsAuthenticated;
            if (isAuthenticated)
            {
                if (_userPermissions.GroupBy(g=>g.Url).Where(w => w.Key.ToLower() == questUrl).Count() > 0)
                {
                    //用户名
                    var userName = context.User.Claims.SingleOrDefault(s => s.Type == ClaimTypes.Sid).Value;
                    if (_userPermissions.Where(w => w.UserName == userName&&w.Url.ToLower()==questUrl).Count() > 0)
                    {
                        return this._next(context);
                    }
                    else
                    {
                        //无权限跳转到拒绝页面
                        context.Response.Redirect(_option.NoPermissionAction);
                    }
                }
            }
            return this._next(context);
        }
    }
}

扩展中间件类PermissionMiddlewareExtensions.cs

using Microsoft.AspNetCore.Builder;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;

namespace PrivilegeManagement.Middleware
{
    /// <summary>
    /// 扩展权限中间件
    /// </summary>
    public static class PermissionMiddlewareExtensions
    {
        /// <summary>
        /// 引入权限中间件
        /// </summary>
        /// <param name="builder">扩展类型</param>
        /// <param name="option">权限中间件配置选项</param>
        /// <returns></returns>
        public static IApplicationBuilder UsePermission(
              this IApplicationBuilder builder, PermissionMiddlewareOption option)
        {
            return builder.UseMiddleware<PermissionMiddleware>(option);
        }
    }
}

中间件属性PermissionMiddlewareOption.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;

namespace PrivilegeManagement.Middleware
{
    /// <summary>
    /// 权限中间件选项
    /// </summary>
    public class PermissionMiddlewareOption
    {
        /// <summary>
        /// 登录action
        /// </summary>
        public string LoginAction
        { get; set; }
        /// <summary>
        /// 无权限导航action
        /// </summary>
        public string NoPermissionAction
        { get; set; }

        /// <summary>
        /// 用户权限集合
        /// </summary>
        public List<UserPermission> UserPerssions
        { get; set; } = new List<UserPermission>();
    }
}

中间件实体类UserPermission.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;

namespace PrivilegeManagement.Middleware
{
    /// <summary>
    /// 用户权限
    /// </summary>
    public class UserPermission
    {
        /// <summary>
        /// 用户名
        /// </summary>
        public string UserName
        { get; set; }
        /// <summary>
        /// 请求Url
        /// </summary>
        public string Url
        { get; set; }
    }
}

关于自定义角色，因为不需要授权时带上角色，所以可以定义一个基Controller类BaseController.cs，其他的Controller都继承BaseController，这样所有的action都可以通过中间件来验证，当然像登录，无权限提示页面还是在Action上加[AllowAnomymous]

using Microsoft.AspNetCore.Authorization;
using Microsoft.AspNetCore.Mvc;
namespace PrivilegeManagement.Controllers
{
    [Authorize]
    public class BaseController:Controller
    {
    }
}

HomeController.cs如下，与固定角色的HomeController.cs差异只在Controller和Action上的Authorize特性。

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Mvc;
using PrivilegeManagement.Models;
using Microsoft.AspNetCore.Authorization;
using System.Security.Claims;
using Microsoft.AspNetCore.Authentication.Cookies;
using Microsoft.AspNetCore.Authentication;

namespace PrivilegeManagement.Controllers
{
 
    public class HomeController : BaseController
    {
        public IActionResult Index()
        {
            return View();
        }

        public IActionResult About()
        {
            ViewData["Message"] = "Your application description page.";
            
            return View();
        }

        public IActionResult Contact()
        {
            ViewData["Message"] = "Your contact page.";

            return View();
        }

        public IActionResult Error()
        {
            return View(new ErrorViewModel { RequestId = Activity.Current?.Id ?? HttpContext.TraceIdentifier });
        }
        [AllowAnonymous]
        [HttpGet("login")]
        public IActionResult Login(string returnUrl = null)
        {
            TempData["returnUrl"] = returnUrl;
            return View();
        }
        [AllowAnonymous]
        [HttpPost("login")]
        public async Task<IActionResult> Login(string userName,string password, string returnUrl = null)
        {
            var list = new List<dynamic> {
                new { UserName = "gsw", Password = "111111", Role = "admin",Name="桂素伟" },
                new { UserName = "aaa", Password = "222222", Role = "system",Name="测试A" }
            };
            var user = list.SingleOrDefault(s => s.UserName == userName && s.Password == password);
            if (user != null)
            {
                //用户标识
                var identity = new ClaimsIdentity(CookieAuthenticationDefaults.AuthenticationScheme);
                identity.AddClaim(new Claim(ClaimTypes.Sid, userName));
                identity.AddClaim(new Claim(ClaimTypes.Name, user.Name));
                identity.AddClaim(new Claim(ClaimTypes.Role, user.Role));

                await HttpContext.SignInAsync(CookieAuthenticationDefaults.AuthenticationScheme, new ClaimsPrincipal(identity));
                if (returnUrl == null)
                {
                    returnUrl = TempData["returnUrl"]?.ToString();
                }
                if (returnUrl != null)
                {
                    return Redirect(returnUrl);
                }
                else
                {
                    return RedirectToAction(nameof(HomeController.Index), "Home");
                }
            }
            else
            {
                const string badUserNameOrPasswordMessage = "用户名或密码错误！";
                return BadRequest(badUserNameOrPasswordMessage);
            }
        }
        [HttpGet("logout")]
        public async Task<IActionResult> Logout()
        {
            await HttpContext.SignOutAsync(CookieAuthenticationDefaults.AuthenticationScheme);
            return RedirectToAction("Index", "Home");
        }
        [HttpGet("denied")]
        public IActionResult Denied()
        {
            return View();
        }
    } 
}

 全部代码：https://github.com/axzxs2001/Asp.NetCoreExperiment/tree/master/Asp.NetCoreExperiment/%E6%9D%83%E9%99%90%E7%AE%A1%E7%90%86