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Asp.NetCoreAuthenticationMiddlewareAndGenerateToken

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本文版权归博客园和作者吴双本人共同所有转载和爬虫请注明原文地址 cnblogs.com/tdws

After using OWIN for months for basic OAuth authentication, it’s apparent that Microsoft is abandoning OWIN . This isn’t necessarily a bad thing. .NET Core is built on a similar structure as that which was implemented in OWIN. Essentially, we have a familiar middleware pipeline.

这句话出自老外的博客，在使用Owin的OAuth身份认证几个月后，发现微软在逐渐放弃OWIN,这未必是一件坏事情，.NET Core在一个和OWIN所实现的相似结构之上。我们有一个和OWIN极为相似的中间件管道。

　想必了解或者使用过OWIN的朋友们，在做.NET Core应用的时候都会有如上描述的这种感觉。就我个人的理解，微软在早几年推出OWIN的时候，就希望将管道留给用户，就以Startup.cs为管道配置和应用入口，OWIN脱离了Asp.Net管道事件，我们可以将任何中间件在管道中随意插拔。在OWIN中为我们提供了完备的认证流程，和一套完整的规范。比如 Microsoft.Owin.Security.OAuth等，在使用OWIN时，我们可以使用OWIN的默认实现，也可以实现其接口，自定义我们自己的实现方式。有关Microsoft OWIN的内容，不是本篇分享的主题，推荐腾飞的 MVC5 - ASP.NET Identity登录原理 - Claims-based认证和OWIN 和蟋蟀哥的 ASP.NET WebApi OWIN 实现 OAuth 2.0 。

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 }