时间:2021-07-01 10:21:17 帮助过:12人阅读
令牌认证(Token Authentication)已经成为单页应用(SPA)和移动应用事实上的标准。即使是传统的B/S应用也能利用其优点。优点很明白:极少的服务端数据管理、可扩展性、可以使用单独的认证服务器和应用服务器分离。
如果你对令牌(token)不是太了解,可以看这篇文章( overview of token authentication and JWTs)
令牌认证在asp.net core中集成。其中包括保护Bearer Jwt的路由功能,但是移除了生成token和验证token的部分,这些可以自定义或者使用第三方库来实现,得益于此,MVC和Web api项目可以使用令牌认证,而且很简单。下面将一步一步实现,代码可以在( 源码)下载。
ASP.NET Core令牌验证
首先,背景知识:认证令牌,例如JWTs,是通过http 认证头传递的,例如:
- GET /foo
- Authorization: Bearer [token]
令牌可以通过浏览器cookies。传递方式是header或者cookies取决于应用和实际情况,对于移动app,使用headers,对于web,推荐在html5 storage中使用cookies,来防止xss攻击。
asp.net core对jwts令牌的验证很简单,特别是你通过header传递。
1、生成 SecurityKey,这个例子,我生成对称密钥验证jwts通过HMAC-SHA256加密方式,在startup.cs中:
- // secretKey contains a secret passphrase only your server knows
- var secretKey = "mysupersecret_secretkey!123";
- var signingKey = new SymmetricSecurityKey(Encoding.ASCII.GetBytes(secretKey));
验证 header中传递的JWTs
在 Startup.cs中,使用Microsoft.AspNetCore.Authentication.JwtBearer中的UseJwtBearerAuthentication 方法获取受保护的api或者mvc路由有效的jwt。
- var tokenValidationParameters = new TokenValidationParameters
- {
- // The signing key must match!
- ValidateIssuerSigningKey = true,
- IssuerSigningKey = signingKey,
- // Validate the JWT Issuer (iss) claim
- ValidateIssuer = true,
- ValidIssuer = "ExampleIssuer",
- // Validate the JWT Audience (aud) claim
- ValidateAudience = true,
- ValidAudience = "ExampleAudience",
- // Validate the token expiry
- ValidateLifetime = true,
- // If you want to allow a certain amount of clock drift, set that here:
- ClockSkew = TimeSpan.Zero
- };
- app.UseJwtBearerAuthentication(new JwtBearerOptions
- {
- AutomaticAuthenticate = true,
- AutomaticChallenge = true,
- TokenValidationParameters = tokenValidationParameters
- });
通过这个中间件,任何[Authorize]的请求都需要有效的jwt:
签名有效;
过期时间;
有效时间;
Issuer 声明等于“ExampleIssuer”
订阅者声明等于 “ExampleAudience”
如果不是合法的JWT,请求终止,issuer声明和订阅者声明不是必须的,它们用来标识应用和客户端。
在cookies中验证JWTs
ASP.NET Core中的cookies 认证不支持传递jwt。需要自定义实现 ISecureDataFormat接口的类。现在,你只是验证token,不是生成它们,只需要实现Unprotect方法,其他的交给System.IdentityModel.Tokens.Jwt.JwtSecurityTokenHandler这个类处理。
- using System;
- using System.IdentityModel.Tokens.Jwt;
- using System.Security.Claims;
- using Microsoft.AspNetCore.Authentication;
- using Microsoft.AspNetCore.Http.Authentication;
- using Microsoft.IdentityModel.Tokens;
- namespace SimpleTokenProvider
- {
- public class CustomJwtDataFormat : ISecureDataFormat<AuthenticationTicket>
- {
- private readonly string algorithm;
- private readonly TokenValidationParameters validationParameters;
- public CustomJwtDataFormat(string algorithm, TokenValidationParameters validationParameters)
- {
- this.algorithm = algorithm;
- this.validationParameters = validationParameters;
- }
- public AuthenticationTicket Unprotect(string protectedText)
- => Unprotect(protectedText, null);
- public AuthenticationTicket Unprotect(string protectedText, string purpose)
- {
- var handler = new JwtSecurityTokenHandler();
- ClaimsPrincipal principal = null;
- SecurityToken validToken = null;
- try
- {
- principal = handler.ValidateToken(protectedText, this.validationParameters, out validToken);
- var validJwt = validToken as JwtSecurityToken;
- if (validJwt == null)
- {
- throw new ArgumentException("Invalid JWT");
- }
- if (!validJwt.Header.Alg.Equals(algorithm, StringComparison.Ordinal))
- {
- throw new ArgumentException($"Algorithm must be '{algorithm}'");
- }
- // Additional custom validation of JWT claims here (if any)
- }
- catch (SecurityTokenValidationException)
- {
- return null;
- }
- catch (ArgumentException)
- {
- return null;
- }
- // Validation passed. Return a valid AuthenticationTicket:
- return new AuthenticationTicket(principal, new AuthenticationProperties(), "Cookie");
- }
- // This ISecureDataFormat implementation is decode-only
- public string Protect(AuthenticationTicket data)
- {
- throw new NotImplementedException();
- }
- public string Protect(AuthenticationTicket data, string purpose)
- {
- throw new NotImplementedException();
- }
- }
- }
在startup.cs中调用
- var tokenValidationParameters = new TokenValidationParameters
- {
- // The signing key must match!
- ValidateIssuerSigningKey = true,
- IssuerSigningKey = signingKey,
- // Validate the JWT Issuer (iss) claim
- ValidateIssuer = true,
- ValidIssuer = "ExampleIssuer",
- // Validate the JWT Audience (aud) claim
- ValidateAudience = true,
- ValidAudience = "ExampleAudience",
- // Validate the token expiry
- ValidateLifetime = true,
- // If you want to allow a certain amount of clock drift, set that here:
- ClockSkew = TimeSpan.Zero
- };
- app.UseCookieAuthentication(new CookieAuthenticationOptions
- {
- AutomaticAuthenticate = true,
- AutomaticChallenge = true,
- AuthenticationScheme = "Cookie",
- CookieName = "access_token",
- TicketDataFormat = new CustomJwtDataFormat(
- SecurityAlgorithms.HmacSha256,
- tokenValidationParameters)
- });
如果请求中包含名为access_token的cookie验证为合法的JWT,这个请求就能返回正确的结果,如果需要,你可以加上额外的jwt chaims,或者复制jwt chaims到ClaimsPrincipal在CustomJwtDataFormat.Unprotect方法中,上面是验证token,下面将在asp.net core中生成token。
ASP.NET Core生成Tokens
在asp.net 4.5中,这个UseOAuthAuthorizationServer中间件可以轻松的生成tokens,但是在asp.net core取消了,下面写一个简单的token生成中间件,最后,有几个现成解决方案的链接,供你选择。
简单的token生成节点
首先,生成 POCO保存中间件的选项. 生成类:TokenProviderOptions.cs
- using System;
- using Microsoft.IdentityModel.Tokens;
- namespace SimpleTokenProvider
- {
- public class TokenProviderOptions
- {
- public string Path { get; set; } = "/token";
- public string Issuer { get; set; }
- public string Audience { get; set; }
- public TimeSpan Expiration { get; set; } = TimeSpan.FromMinutes(5);
- public SigningCredentials SigningCredentials { get; set; }
- }
- }
现在自己添加一个中间件,asp.net core 的中间件类一般是这样的:
- using System.IdentityModel.Tokens.Jwt;
- using System.Security.Claims;
- using System.Threading.Tasks;
- using Microsoft.AspNetCore.Http;
- using Microsoft.Extensions.Options;
- using Newtonsoft.Json;
- namespace SimpleTokenProvider
- {
- public class TokenProviderMiddleware
- {
- private readonly RequestDelegate _next;
- private readonly TokenProviderOptions _options;
- public TokenProviderMiddleware(
- RequestDelegate next,
- IOptions<TokenProviderOptions> options)
- {
- _next = next;
- _options = options.Value;
- }
- public Task Invoke(HttpContext context)
- {
- // If the request path doesn't match, skip
- if (!context.Request.Path.Equals(_options.Path, StringComparison.Ordinal))
- {
- return _next(context);
- }
- // Request must be POST with Content-Type: application/x-www-form-urlencoded
- if (!context.Request.Method.Equals("POST")
- || !context.Request.HasFormContentType)
- {
- context.Response.StatusCode = 400;
- return context.Response.WriteAsync("Bad request.");
- }
- return GenerateToken(context);
- }
- }
- }
这个中间件类接受TokenProviderOptions作为参数,当有请求且请求路径是设置的路径(token或者api/token),Invoke方法执行,token节点只对 POST请求而且包括form-urlencoded内容类型(Content-Type: application/x-www-form-urlencoded),因此调用之前需要检查下内容类型。
最重要的是GenerateToken,这个方法需要验证用户的身份,生成jwt,传回jwt:
- private async Task GenerateToken(HttpContext context)
- {
- var username = context.Request.Form["username"];
- var password = context.Request.Form["password"];
- var identity = await GetIdentity(username, password);
- if (identity == null)
- {
- context.Response.StatusCode = 400;
- await context.Response.WriteAsync("Invalid username or password.");
- return;
- }
- var now = DateTime.UtcNow;
- // Specifically add the jti (random nonce), iat (issued timestamp), and sub (subject/user) claims.
- // You can add other claims here, if you want:
- var claims = new Claim[]
- {
- new Claim(JwtRegisteredClaimNames.Sub, username),
- new Claim(JwtRegisteredClaimNames.Jti, Guid.NewGuid().ToString()),
- new Claim(JwtRegisteredClaimNames.Iat, ToUnixEpochDate(now).ToString(), ClaimValueTypes.Integer64)
- };
- // Create the JWT and write it to a string
- var jwt = new JwtSecurityToken(
- issuer: _options.Issuer,
- audience: _options.Audience,
- claims: claims,
- notBefore: now,
- expires: now.Add(_options.Expiration),
- signingCredentials: _options.SigningCredentials);
- var encodedJwt = new JwtSecurityTokenHandler().WriteToken(jwt);
- var response = new
- {
- access_token = encodedJwt,
- expires_in = (int)_options.Expiration.TotalSeconds
- };
- // Serialize and return the response
- context.Response.ContentType = "application/json";
- await context.Response.WriteAsync(JsonConvert.SerializeObject(response, new JsonSerializerSettings { Formatting = Formatting.Indented }));
- }
大部分代码都很官方,JwtSecurityToken 类生成jwt,JwtSecurityTokenHandler将jwt编码,你可以在claims中添加任何chaims。验证用户身份只是简单的验证,实际情况肯定不是这样的,你可以集成 identity framework或者其他的,对于这个实例只是简单的硬编码:
- private Task<ClaimsIdentity> GetIdentity(string username, string password)
- {
- // DON'T do this in production, obviously!
- if (username == "TEST" && password == "TEST123")
- {
- return Task.FromResult(new ClaimsIdentity(new System.Security.Principal.GenericIdentity(username, "Token"), new Claim[] { }));
- }
- // Credentials are invalid, or account doesn't exist
- return Task.FromResult<ClaimsIdentity>(null);
- }
添加一个将DateTime生成timestamp的方法:
- public static long ToUnixEpochDate(DateTime date)
- => (long)Math.Round((date.ToUniversalTime() - new DateTimeOffset(1970, 1, 1, 0, 0, 0, TimeSpan.Zero)).TotalSeconds);
现在,你可以将这个中间件添加到startup.cs中了:
- using System.Text;
- using Microsoft.AspNetCore.Builder;
- using Microsoft.AspNetCore.Hosting;
- using Microsoft.Extensions.Configuration;
- using Microsoft.Extensions.DependencyInjection;
- using Microsoft.Extensions.Logging;
- using Microsoft.Extensions.Options;
- using Microsoft.IdentityModel.Tokens;
- namespace SimpleTokenProvider
- {
- public partial class Startup
- {
- public Startup(IHostingEnvironment env)
- {
- var builder = new ConfigurationBuilder()
- .AddJsonFile("appsettings.json", optional: true);
- Configuration = builder.Build();
- }
- public IConfigurationRoot Configuration { get; set; }
- public void ConfigureServices(IServiceCollection services)
- {
- services.AddMvc();
- }
- // The secret key every token will be signed with.
- // In production, you should store this securely in environment variables
- // or a key management tool. Don't hardcode this into your application!
- private static readonly string secretKey = "mysupersecret_secretkey!123";
- public void Configure(IApplicationBuilder app, IHostingEnvironment env, ILoggerFactory loggerFactory)
- {
- loggerFactory.AddConsole(LogLevel.Debug);
- loggerFactory.AddDebug();
- app.UseStaticFiles();
- // Add JWT generation endpoint:
- var signingKey = new SymmetricSecurityKey(Encoding.ASCII.GetBytes(secretKey));
- var options = new TokenProviderOptions
- {
- Audience = "ExampleAudience",
- Issuer = "ExampleIssuer",
- SigningCredentials = new SigningCredentials(signingKey, SecurityAlgorithms.HmacSha256),
- };
- app.UseMiddleware<TokenProviderMiddleware>(Options.Create(options));
- app.UseMvc();
- }
- }
- }
测试一下,推荐使用chrome 的postman:
- POST /token
- Content-Type: application/x-www-form-urlencoded
- username=TEST&password=TEST123
结果:
OK
Content-Type: application/json
{
"access_token": "eyJhb...",
"expires_in": 300
}
你可以使用jwt工具查看生成的jwt内容。如果开发的是移动应用或者单页应用,你可以在后续请求的header中存储jwt,如果你需要在cookies中存储的话,你需要对代码修改一下,需要将返回的jwt字符串添加到cookie中。
测试下:
其他方案
下面是比较成熟的项目,可以在实际项目中使用:
下面的文章可以让你更加的了解认证:
以上就是本文的全部内容,希望对大家的学习有所帮助,也希望大家多多支持脚本之家。