http://www.cnblogs.com/tdws/p/6536864.html

Token

　本篇分享主要关注在.NET Core的认证机制。无论我们是使用WebApi还是MvcWeb App，了解微软的认证机制总是有好处的。认证是应用API服务器识别用户身份的过程，token是更现代的认证方式，简化权限管理，降低服务器负载。在认证过程中，最重要的就是拿到token, token包含或者应该包含什么信息呢？

　　　　1.这个人是谁？

　　　　2.这个人可以用此token访问什么样的内容？（scope）

　　　　3.token的过期时间 (expire)

　　　　4.谁发行的token。

　　　　5.其他任何你希望加入的声明（Claims）

　那我们为什么要使用token呢？使用session或者用redis来实现stateServer不好吗？

　　　　1.token是低（无）状态的，Statelessness

　　　　2.token可以与移动端应用紧密结合

　　　　3.支持多平台服务器和分布式微服务

拿到token后如何带入HTTP请求传给后台？

　答案是两种方式，Cookies和Authorization Header。那么什么时候放到Cookies中，什么时候又放到Authentication中呢？

第一，如果是在Web应用，则放到Cookies当中，并且应该是HttpOnly的，js不能直接对其进行操作，安全性会比将其存在Web Stroage中好一些，因为在Web Storage当中的内容，可以很容的被潜在的XSS脚本攻击并获取。在HttpOnly的cookies当中会相对安全一些，不过也有潜在的CSRF跨站伪造请求的危险，不过这种hack的手段成功率是很低的，有兴趣的朋友可以自行看一下CSRF原理。

第二，如果是手机移动端应用的话，那一定是存储在App本地，并由Authorization Header带到后台并得到身份认证。

WebApp Cookies Authentication

上一段前两周写的最原始的小Demo吧，没有数据库访问等，可根据demo自行改变，现在的新代码已经加入了很多业务在其中

startup.cs代码

 1 using Microsoft.AspNetCore.Authentication.Cookies;
 2 using Microsoft.AspNetCore.Builder;
 3 using Microsoft.AspNetCore.Hosting;
 4 using Microsoft.AspNetCore.Http;
 5 using Microsoft.AspNetCore.Http.Authentication;
 6 using Microsoft.Extensions.Configuration;
 7 using Microsoft.Extensions.DependencyInjection;
 8 using Microsoft.Extensions.Logging;
 9 using System.Collections.Generic;
10 using System.Security.Claims;
11 using Wings.AuthenticationApp.Middleware;
12 
13 namespace Wings.AuthenticationApp
14 {
15     public class Startup
16     {
17         public Startup(IHostingEnvironment env)
18         {
19             var builder = new ConfigurationBuilder()
20                 .SetBasePath(env.ContentRootPath)
21                 .AddJsonFile("appsettings.json", optional: false, reloadOnChange: true)
22                 .AddJsonFile($"appsettings.{env.EnvironmentName}.json", optional: true)
23                 .AddEnvironmentVariables();
24             Configuration = builder.Build();
25 
26         }
27 
28         public IConfigurationRoot Configuration { get; }
29 
30         // This method gets called by the runtime. Use this method to add services to the container.
31         public void ConfigureServices(IServiceCollection services)
32         {
33             // Add framework services.
34             services.AddMvc();
35         }
36 
37         // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
38         public void Configure(IApplicationBuilder app, IHostingEnvironment env, ILoggerFactory loggerFactory)
39         {
40             loggerFactory.AddConsole(Configuration.GetSection("Logging"));
41             loggerFactory.AddDebug();
42 
43             app.UseCookieAuthentication(CookieAuthMiddleware.GetOptions());
44             app.UseOwin();
45             app.UseCors(a => { a.AllowAnyOrigin(); });
46             app.UseMvc();
47             // Listen for login and logout requests
48             app.Map("/login", builder =>
49             {
50                 builder.Run(async context =>
51                 {
52                     var name = context.Request.Form["name"];
53                     var pwd = context.Request.Form["pwd"];
54                     if (name == "wushuang" && pwd == "wushuang")
55                     {
56 
57                         var claims = new List<Claim>() { new Claim("name", name), new Claim("role", "admin") };
58                         var identity = new ClaimsIdentity(claims, "password");
59                         var principal = new ClaimsPrincipal(identity);
60                         await context.Authentication.SignInAsync(CookieAuthenticationDefaults.AuthenticationScheme, principal);
61                         context.Response.Redirect("http://www.baidu.com");
62                     }
63                     else
64                     {
65                         await context.Authentication.SignOutAsync(CookieAuthenticationDefaults.AuthenticationScheme);
66                         context.Response.Redirect("http://www.google.com");
67                     }
68                 });
69             });
70 
71             //app.Map("/logout", builder =>
72             //{
73             //    builder.Run(async context =>
74             //    {
75             //        // Sign the user out / clear the auth cookie
76             //        await context.Authentication.SignOutAsync(CookieAuthenticationDefaults.AuthenticationScheme);
77 
78             //        // Perform a simple redirect after logout
79             //        context.Response.Redirect("/");
80             //    });
81             //});
82             
83         }
84 
85     }
86 }

下面是Middleware---->CookieAuthMiddleware.cs的代码，

using Microsoft.AspNetCore.Authentication.Cookies;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Http;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Security.Claims;
using System.Security.Principal;
using System.Threading.Tasks;

namespace Wings.AuthenticationApp.Middleware
{
    public class CookieAuthMiddleware
    {
        public static CookieAuthenticationOptions GetOptions()
        {
            return new CookieAuthenticationOptions
            {
                AutomaticAuthenticate = true,
                AutomaticChallenge = true,
                LoginPath = new PathString("/login"),
                LogoutPath = new PathString("/logout"),
                AccessDeniedPath = new PathString("/test"),
                CookieHttpOnly = false,  //默认就是True了
                CookieName = "wings_access_token",
                SlidingExpiration = true,
                CookieManager = new ChunkingCookieManager()
            };
        }
    }
    public static class IdentityExtension
    {
        public static string FullName(this IIdentity identity)
        {
            var claim = ((ClaimsIdentity)identity).FindFirst("name");
            return (claim != null) ? claim.Value : string.Empty;
        }
        public static string Role(this IIdentity identity)
        {
            var claim = ((ClaimsIdentity)identity).FindFirst("role");
            return (claim != null) ? claim.Value : string.Empty;
        }
    }
}

对应如上demo,简单测试一下，结果如下：

首先使用错误的密码，来请求token endpoint，接下来我们看一下即使窗口，当有请求进入的时候，我用如下代码判断用户的认证情况，拿到的结果必然是false：

接下来，我使用正确的账号密码，来打入token,判断结果一定为true，所以我使用自定义的拓展方法，来获取下，该用户token的信息:

如上demo没有加入一些容错机制，请注意。在用户认证成功后，可以进入带有Authorize Attribute的Action,否则401.如下是几个重要参数的解释

自定义Authentication Middle生产Token

Startup.cs

 1 using System;
 2 using System.Collections.Generic;
 3 using System.Linq;
 4 using System.Threading.Tasks;
 5 using Microsoft.AspNetCore.Builder;
 6 using Microsoft.AspNetCore.Hosting;
 7 using Microsoft.Extensions.Configuration;
 8 using Microsoft.Extensions.DependencyInjection;
 9 using Microsoft.Extensions.Logging;
10 using Wings.TokenAuth.Middleware;
11 using System.Security.Claims;
12 using Microsoft.IdentityModel.Tokens;
13 using System.Text;
14 using Microsoft.Extensions.Options;
15 
16 namespace Wings.TokenAuth
17 {
18     public class Startup
19     {
20         public Startup(IHostingEnvironment env)
21         {
22             var builder = new ConfigurationBuilder()
23                 .SetBasePath(env.ContentRootPath)
24                 .AddJsonFile("appsettings.json", optional: false, reloadOnChange: true)
25                 .AddJsonFile($"appsettings.{env.EnvironmentName}.json", optional: true)
26                 .AddEnvironmentVariables();
27             Configuration = builder.Build();
28         }
29 
30         public IConfigurationRoot Configuration { get; }
31 
32         // This method gets called by the runtime. Use this method to add services to the container.
33         public void ConfigureServices(IServiceCollection services)
34         {
35             // Add framework services.
36             services.AddMvc();
37         }
38 
39         // The secret key every token will be signed with.
40         // In production, you should store this securely in environment variables
41         // or a key management tool. Don't hardcode this into your application!
42         private static readonly string secretKey = "mysupersecret_secretkey!123";
43 
44         public void Configure(IApplicationBuilder app, IHostingEnvironment env, ILoggerFactory loggerFactory)
45         {
46             loggerFactory.AddConsole(LogLevel.Debug);
47             loggerFactory.AddDebug();
48 
49             app.UseStaticFiles();
50 
51             // Add JWT generation endpoint:
52             var signingKey = new SymmetricSecurityKey(Encoding.ASCII.GetBytes(secretKey));
53             var options = new TokenProviderOptions
54             {
55                 Audience = "ExampleAudience",
56                 Issuer = "ExampleIssuer",
57                 SigningCredentials = new SigningCredentials(signingKey, SecurityAlgorithms.HmacSha256),
58             };
59 
60             app.UseMiddleware<TokenProviderMiddleware>(Options.Create(options));
61 
62             app.UseMvc();
63         }
64     }
65 }

TokenProviderOptions.cs

1 using Microsoft.AspNetCore.Http;
  2 using Microsoft.Extensions.Options;
  3 using Microsoft.IdentityModel.Tokens;
  4 using Newtonsoft.Json;
  5 using System;
  6 using System.Collections.Generic;
  7 using System.IdentityModel.Tokens.Jwt;
  8 using System.Linq;
  9 using System.Security.Claims;
 10 using System.Threading.Tasks;
 11 
 12 namespace Wings.TokenAuth.Middleware
 13 {
 14     public class TokenProviderOptions
 15     {
 16         public string Path { get; set; } = "/token";
 17 
 18         public string Issuer { get; set; }
 19 
 20         public string Audience { get; set; }
 21 
 22         public TimeSpan Expiration { get; set; } = TimeSpan.FromMinutes(5);
 23 
 24         public SigningCredentials SigningCredentials { get; set; }
 25     }
 26     public class TokenProviderMiddleware
 27     {
 28         private readonly RequestDelegate _next;
 29         private readonly TokenProviderOptions _options;
 30 
 31         public TokenProviderMiddleware(
 32           RequestDelegate next,
 33           IOptions<TokenProviderOptions> options)
 34         {
 35             _next = next;
 36             _options = options.Value;
 37         }
 38 
 39         public Task Invoke(HttpContext context)
 40         {
 41             // If the request path doesn't match, skip
 42             if (!context.Request.Path.Equals(_options.Path, StringComparison.Ordinal))
 43             {
　　　　　　　　　　　　 //use new JwtSecurityTokenHandler().ValidateToken() to valid token
 44                 return _next(context);
 45             }
 46 
 47             // Request must be POST with Content-Type: application/x-www-form-urlencoded
 48             if (!context.Request.Method.Equals("POST")
 49               || !context.Request.HasFormContentType)
 50             {
 51                 context.Response.StatusCode = 400;
 52                 return context.Response.WriteAsync("Bad request.");
 53             }
 54 
 55             return GenerateToken(context);
 56         }
 57         private async Task GenerateToken(HttpContext context)
 58         {
 59             var username = context.Request.Form["username"];
 60             var password = context.Request.Form["password"];
 61 
 62             var identity = await GetIdentity(username, password);
 63             if (identity == null)
 64             {
 65                 context.Response.StatusCode = 400;
 66                 await context.Response.WriteAsync("Invalid username or password.");
 67                 return;
 68             }
 69 
 70             var now = DateTime.UtcNow;
 71 
 72             // Specifically add the jti (random nonce), iat (issued timestamp), and sub (subject/user) claims.
 73             // You can add other claims here, if you want:
 74             var claims = new Claim[]
 75             {
 76     new Claim(JwtRegisteredClaimNames.Sub, username),
 77     new Claim(JwtRegisteredClaimNames.Jti, Guid.NewGuid().ToString()),
 78     new Claim(JwtRegisteredClaimNames.Iat, ToUnixEpochDate(now).ToString(), ClaimValueTypes.Integer64)
 79             };
 80 
 81             // Create the JWT and write it to a string
 82             var jwt = new JwtSecurityToken(
 83               issuer: _options.Issuer,
 84               audience: _options.Audience,
 85               claims: claims,
 86               notBefore: now,
 87               expires: now.Add(_options.Expiration),
 88               signingCredentials: _options.SigningCredentials);
 89             var encodedJwt = new JwtSecurityTokenHandler().WriteToken(jwt);
 90 
 91             var response = new
 92             {
 93                 access_token = encodedJwt,
 94                 expires_in = (int)_options.Expiration.TotalSeconds
 95             };
 96 
 97             // Serialize and return the response
 98             context.Response.ContentType = "application/json";
 99             await context.Response.WriteAsync(JsonConvert.SerializeObject(response, new JsonSerializerSettings { Formatting = Formatting.Indented }));
100         }
101 
102         private Task<ClaimsIdentity> GetIdentity(string username, string password)
103         {
104             // DON'T do this in production, obviously!
105             if (username == "wushuang" && password == "wushuang")
106             {
107                 return Task.FromResult(new ClaimsIdentity(new System.Security.Principal.GenericIdentity(username, "Token"), new Claim[] { }));
108             }
109 
110             // Credentials are invalid, or account doesn't exist
111             return Task.FromResult<ClaimsIdentity>(null);
112         }
113 
114         public static long ToUnixEpochDate(DateTime date)
115   => (long)Math.Round((date.ToUniversalTime() - new DateTimeOffset(1970, 1, 1, 0, 0, 0, TimeSpan.Zero)).TotalSeconds);
116 
117 
118     }
119 }

下面上测试结果：

使用错误的账户和密码请求token

使用正确的账户和密码来请求，返回结果如下：