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在《asp.net core认证与授权》中讲解了固定和自定义角色授权系统权限，其实我们还可以通过其他方式来授权，比如可以通过角色组，用户名，生日等，但这些主要取决于ClaimTypes，其实我们也可以自定义键值来授权，这些统一叫策略授权，其中更强大的是，我们可以自定义授权Handler来达到灵活授权，下面一一展开。
注意：下面的代码只是部分代码，完整代码参照：
首先看基于角色组，或用户名，或基于ClaimType或自定义键值等授权策略，这些都是通过Services.AddAuthorization添加，并且是AuthorizationOptions来AddPolicy，这里策略的名称统一用RequireClaim来命名，不同的请求的策略名称各不相同，如用户名时就用policy.RequireUserName()，同时，在登录时，验证成功后，要添加相应的Claim到ClaimsIdentity中：
Startup.cs
public void ConfigureServices(IServiceCollection services) { services.AddMvc(); services.AddAuthorization(options => { //基于角色的策略 options.AddPolicy("RequireClaim", policy => policy.RequireRole("admin", "system")); //基于用户名 //options.AddPolicy("RequireClaim", policy => policy.RequireUserName("桂素伟")); //基于Claim //options.AddPolicy("RequireClaim", policy => policy.RequireClaim(ClaimTypes.Country,"中国")); //自定义值 // options.AddPolicy("RequireClaim", policy => policy.RequireClaim("date","2017-09-02")); }).AddAuthentication(CookieAuthenticationDefaults.AuthenticationScheme).AddCookie(options =>{ options.LoginPath = new PathString("/login"); options.AccessDeniedPath = new PathString("/denied"); }); } HomeController.cs
using System.Collections.Generic;using System.Diagnostics;using System.Linq;using System.Threading.Tasks;using Microsoft.AspNetCore.Mvc;using PolicyPrivilegeManagement.Models;using Microsoft.AspNetCore.Authorization;using Microsoft.AspNetCore.Authentication;using Microsoft.AspNetCore.Authentication.Cookies;using System.Security.Claims;namespace PolicyPrivilegeManagement.Controllers{ [Authorize(Policy = "RequireClaim")] public class HomeController : Controller { PermissionHandler _permissionHandler; public HomeController(IAuthorizationHandler permissionHandler) { _permissionHandler = permissionHandler as PermissionHandler; } public IActionResult Index() { return View(); } public IActionResult PermissionAdd() { 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 Login(string userName, string password, string returnUrl = null) { var list = new List { new { UserName = "gsw", Password = "111111", Role = "admin",Name="桂素伟",Country="中国",Date="2017-09-02",BirthDay="1979-06-22"}, new { UserName = "aaa", Password = "222222", Role = "system",Name="测试A" ,Country="美国",Date="2017-09-03",BirthDay="1999-06-22"} }; 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)); identity.AddClaim(new Claim(ClaimTypes.Country, user.Country)); identity.AddClaim(new Claim("date", user.Date)); 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 Logout() { await HttpContext.SignOutAsync(CookieAuthenticationDefaults.AuthenticationScheme); return RedirectToAction("Index", "Home"); } [AllowAnonymous] [HttpGet("denied")] public IActionResult Denied() { return View(); } }} 上面的授权策略都相对简单，单一，使用场景也很有限，就和固定角色授权如出一辙，其实可以用更好的来例用授权，那就是自定义授权Handler，我们在《asp.net core认证与授权》一文中，是通过中间件来达到自定义解色的，现在我们换个思路，通过自定义授权Handler来实现。
首先定义一个UserPermission，即用户权限实体类
////// 用户权限 /// public class UserPermission { ////// 用户名 /// public string UserName { get; set; } ////// 请求Url /// public string Url { get; set; } }
接下来定义一个PermissionRequirement，为请求条件实体类