发布：2023/12/7 15:25:46作者：大数据 来源：大数据 浏览次数：516

JWT(json web token)是一种基于json的身份验证机制，流程如下：

通过登录，来获取Token，再在之后每次请求的Header中追加Authorization为Token的凭据，服务端验证通过即可能获取想要访问的资源。关于JWT的技术，可参考网络上文章，这里不作详细说明，

这篇博文，主要说明在asp.net core 2.0中，基于jwt的web api的权限设置，即在asp.net core中怎么用JWT，再次就是不同用户或角色因为权限问题，即使援用Token，也不能访问不该访问的资源。

基本思路是我们自定义一个策略，来验证用户，和验证用户授权，PermissionRequirement是验证传输授权的参数。在Startup的ConfigureServices注入验证（Authentication），授权（Authorization），和JWT(JwtBearer)

自定义策略：

已封闭成AuthorizeRolicy.JWT nuget包，并发布到nuget上：

https://www.nuget.org/packages/AuthorizePolicy.JWT/

源码如下：

JwtToken.cs
/// <summary>
/// 获取基于JWT的Token
/// </summary>
/// <param name="username"></param>
/// <returns></returns>
public  static  dynamic BuildJwtToken(Claim[] claims, PermissionRequirement permissionRequirement)
{
var  now = DateTime.UtcNow;
var  jwt =  new  JwtSecurityToken(
issuer: permissionRequirement.Issuer,
audience: permissionRequirement.Audience,
claims: claims,
notBefore: now,
expires: now.Add(permissionRequirement.Expiration),
signingCredentials: permissionRequirement.SigningCredentials
);
var  encodedJwt =  new  JwtSecurityTokenHandler().WriteToken(jwt);
var  response =  new
{
Status =  true ,
access_token = encodedJwt,
expires_in = permissionRequirement.Expiration.TotalMilliseconds,
token_type =  "Bearer"
};
return  response;
}
Permission.cs
/// <summary>
/// 用户或角色或其他凭据实体
/// </summary>
public  class  Permission
{
/// <summary>
/// 用户或角色或其他凭据名称
/// </summary>
public  virtual  string  Name
{  get ;  set ; }
/// <summary>
/// 请求Url
/// </summary>
public  virtual  string  Url
{  get ;  set ; }
}
PermissionRequirement.cs
/// <summary>
/// 必要参数类
/// </summary>
public  class  PermissionRequirement : IAuthorizationRequirement
{
/// <summary>
/// 用户权限集合
/// </summary>
public  List<Permission> Permissions {  get ;  private  set ; }
/// <summary>
/// 无权限action
/// </summary>
public  string  DeniedAction {  get ;  set ; }

/// <summary>
/// 认证授权类型
/// </summary>
public  string  ClaimType {  internal  get ;  set ; }
/// <summary>
/// 请求路径
/// </summary>
public  string  LoginPath {  get ;  set ; } =  "/Api/Login" ;
/// <summary>
/// 发行人
/// </summary>
public  string  Issuer {  get ;  set ; }
/// <summary>
/// 订阅人
/// </summary>
public  string  Audience {  get ;  set ; }
/// <summary>
/// 过期时间
/// </summary>
public  TimeSpan Expiration {  get ;  set ; } = TimeSpan.FromMinutes(5000);
/// <summary>
/// 签名验证
/// </summary>
public  SigningCredentials SigningCredentials {  get ;  set ; }

/// <summary>
/// 构造
/// </summary>
/// <param name="deniedAction">无权限action</param>
/// <param name="userPermissions">用户权限集合</param>

/// <summary>
/// 构造
/// </summary>
/// <param name="deniedAction">拒约请求的url</param>
/// <param name="permissions">权限集合</param>
/// <param name="claimType">声明类型</param>
/// <param name="issuer">发行人</param>
/// <param name="audience">订阅人</param>
/// <param name="signingCredentials">签名验证实体</param>
public  PermissionRequirement( string  deniedAction, List<Permission> permissions,  string  claimType,  string  issuer,  string  audience, SigningCredentials signingCredentials)
{
ClaimType = claimType;
DeniedAction = deniedAction;
Permissions = permissions;
Issuer = issuer;
Audience = audience;
SigningCredentials = signingCredentials;
}
}
自定义策略类PermissionHandler.cs
/// <summary>
/// 权限授权Handler
/// </summary>
public  class  PermissionHandler : AuthorizationHandler<PermissionRequirement>
{
/// <summary>
/// 验证方案提供对象
/// </summary>
public  IAuthenticationSchemeProvider Schemes {  get ;  set ; }
/// <summary>
/// 自定义策略参数
/// </summary>
public  PermissionRequirement Requirement
{  get ;  set ; }
/// <summary>
/// 构造
/// </summary>
/// <param name="schemes"></param>
public  PermissionHandler(IAuthenticationSchemeProvider schemes)
{
Schemes = schemes;
}

protected  override  async Task HandleRequirementAsync(AuthorizationHandlerContext context, PermissionRequirement requirement)
{
////赋值用户权限
Requirement = requirement;
//从AuthorizationHandlerContext转成HttpContext，以便取出表求信息
var  httpContext = (context.Resource  as  Microsoft.AspNetCore.Mvc.Filters.AuthorizationFilterContext).HttpContext;
//请求Url
var  questUrl = httpContext.Request.Path.Value.ToLower();
//判断请求是否停止
var  handlers = httpContext.RequestServices.GetRequiredService<IAuthenticationHandlerProvider>();
foreach  ( var  scheme  in  await Schemes.GetRequestHandlerSchemesAsync())
{
var  handler = await handlers.GetHandlerAsync(httpContext, scheme.Name)  as  IAuthenticationRequestHandler;
if  (handler !=  null  && await handler.HandleRequestAsync())
{
context.Fail();
return ;
}
}
//判断请求是否拥有凭据，即有没有登录
var  defaultAuthenticate = await Schemes.GetDefaultAuthenticateSchemeAsync();
if  (defaultAuthenticate !=  null )
{
var  result = await httpContext.AuthenticateAsync(defaultAuthenticate.Name);
//result?.Principal不为空即登录成功
if  (result?.Principal !=  null )
{
httpContext.User = result.Principal;
//权限中是否存在请求的url
if  (Requirement.Permissions.GroupBy(g => g.Url).Where(w => w.Key.ToLower() == questUrl).Count() > 0)
{
var  name = httpContext.User.Claims.SingleOrDefault(s => s.Type == requirement.ClaimType).Value;
//验证权限
if  (Requirement.Permissions.Where(w => w.Name == name && w.Url.ToLower() == questUrl).Count() <= 0)
{
//无权限跳转到拒绝页面
httpContext.Response.Redirect(requirement.DeniedAction);
}
}
context.Succeed(requirement);
return ;
}
}
//判断没有登录时，是否访问登录的url,并且是Post请求，并助是form表单提交类型，否则为失败
if  (!questUrl.Equals(Requirement.LoginPath.ToLower(), StringComparison.Ordinal) && (!httpContext.Request.Method.Equals( "POST" )
|| !httpContext.Request.HasFormContentType))
{
context.Fail();
return ;
}
context.Succeed(requirement);
}
}
新建asp.net core 2.0的web api项目，并在项目添加AuthorizePolicy.JWT如图 .net core 2.2不用安装，直接用即可

先设置配置文件，用户可以定义密匙和发生人，订阅人

"Audience": {

"Secret": "ABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890",

"Issuer": "gsw",

"Audience": "everone"

}

在ConfigureServices中注入验证（Authentication），授权（Authorization），和JWT(JwtBearer)

Startup.cs
public  void  ConfigureServices(IServiceCollection services)
{
//读取配置文件
var  audienceConfig = Configuration.GetSection( "Audience" );
var  symmetricKeyAsBase64 = audienceConfig[ "Secret" ];
var  keyByteArray = Encoding.ASCII.GetBytes(symmetricKeyAsBase64);
var  signingKey =  new  SymmetricSecurityKey(keyByteArray);

var  tokenValidationParameters =  new  TokenValidationParameters
{
ValidateIssuerSigningKey =  true ,
IssuerSigningKey = signingKey,
ValidateIssuer =  true ,
ValidIssuer = audienceConfig[ "Issuer" ],
ValidateAudience =  true ,
ValidAudience = audienceConfig[ "Audience" ],
ValidateLifetime =  true ,
ClockSkew = TimeSpan.Zero
};
var  signingCredentials =  new  SigningCredentials(signingKey, SecurityAlgorithms.HmacSha256);
services.AddAuthorization(options =>
{
//这个集合模拟用户权限表,可从数据库中查询出来
var  permission =  new  List<Permission> {
new  Permission {  Url= "/" , Name= "admin" },
new  Permission {  Url= "/api/values" , Name= "admin" },
new  Permission {  Url= "/" , Name= "system" },
new  Permission {  Url= "/api/values1" , Name= "system" }
};
//如果第三个参数，是ClaimTypes.Role，上面集合的每个元素的Name为角色名称，如果ClaimTypes.Name，即上面集合的每个元素的Name为用户名
var  permissionRequirement =  new  PermissionRequirement( "/api/denied" , permission, ClaimTypes.Role, audienceConfig[ "Issuer" ], audienceConfig[ "Audience" ], signingCredentials);
options.AddPolicy( "Permission" ,
policy => policy.Requirements.Add(permissionRequirement));
}).AddAuthentication(options =>
{
options.DefaultAuthenticateScheme = JwtBearerDefaults.AuthenticationScheme;
options.DefaultChallengeScheme = JwtBearerDefaults.AuthenticationScheme;
})
.AddJwtBearer(o =>
{
//不使用https
o.RequireHttpsMetadata =  false ;
o.TokenValidationParameters = tokenValidationParameters;
});
//注入授权Handler
services.AddSingleton<IAuthorizationHandler, PermissionHandler>();
services.AddMvc();
}
在需要授的Controller上添加授权特性

[Authorize("Permission")]

PermissionController类有两个方法，一个是登录，验证用户名和密码是否正确，如果正确就发放Token，如果失败，验证失败，别一个成功登后的无权限导航action。
[Authorize( "Permission" )]
public  class  PermissionController : Controller
{
/// <summary>
/// 自定义策略参数
/// </summary>
PermissionRequirement _requirement;
public  PermissionController(IAuthorizationHandler authorizationHander)
{
_requirement = (authorizationHander  as  PermissionHandler).Requirement;
}
[AllowAnonymous]
[HttpPost( "/api/login" )]
public  IActionResult Login( string  username, string  password, string  role)
{
var  isValidated = username ==  "gsw"  && password ==  "111111" ;
if  (!isValidated)
{
return  new  JsonResult( new
{
Status =  false ,
Message =  "认证失败"
});
}
else
{
//如果是基于角色的授权策略，这里要添加用户;如果是基于角色的授权策略，这里要添加角色
var  claims = new  Claim[]{  new  Claim(ClaimTypes.Name, username), new  Claim(ClaimTypes.Role, role) };
//用户标识
var  identity =  new  ClaimsIdentity(JwtBearerDefaults.AuthenticationScheme);
identity.AddClaims(claims);
//登录
HttpContext.SignInAsync(JwtBearerDefaults.AuthenticationScheme,  new  ClaimsPrincipal(identity));
var  token = JwtToken.BuildJwtToken(claims, _requirement);
return  new  JsonResult(token);
}
}
[AllowAnonymous]
[HttpGet( "/api/denied" )]
public  IActionResult Denied()
{
return  new  JsonResult( new
{
Status =  false ,
Message =  "你无权限访问"
});
}
}
下面定义一个控制台（.NetFramewrok）程序，用RestSharp来访问我们定义的web api，其中1为admin角色登录，2为system角色登录，3为错误用户密码登录，4是一个查询功能，在startup.cs中，admin角色是具有查询/api/values的权限的，所以用admin登录是能正常访问的，用system登录，能成功登录，但没有权限访问/api/values，用户名密码错误，访问/aip/values，直接是没有授权的
class  Program
{
/// <summary>
/// 访问Url
/// </summary>
static  string  _url =  "http://localhost:39286" ;
static  void  Main( string [] args)
{
dynamic token =  null ;
while  ( true )
{
Console.WriteLine( "1、登录【admin】 2、登录【system】 3、登录【错误用户名密码】 4、查询数据 " );
var  mark = Console.ReadLine();
var  stopwatch =  new  Stopwatch();
stopwatch.Start();
switch  (mark)
{
case  "1" :
token = AdminLogin();
break ;
case  "2" :
token = SystemLogin();
break ;
case  "3" :
token = NullLogin();
break ;
case  "4" :
AdminInvock(token);
break ;
}
stopwatch.Stop();
TimeSpan timespan = stopwatch.Elapsed;
Console.WriteLine($ "间隔时间：{timespan.TotalSeconds}" );
}
}
static  dynamic NullLogin()
{
var  loginClient =  new  RestClient(_url);
var  loginRequest =  new  RestRequest( "/api/login" , Method.POST);
loginRequest.AddParameter( "username" ,  "gswaa" );
loginRequest.AddParameter( "password" ,  "111111" );
//或用用户名密码查询对应角色
loginRequest.AddParameter( "role" ,  "system" );
IRestResponse loginResponse = loginClient.Execute(loginRequest);
var  loginContent = loginResponse.Content;
Console.WriteLine(loginContent);
return  Newtonsoft.Json.JsonConvert.DeserializeObject(loginContent);
}
static  dynamic SystemLogin()
{
var  loginClient =  new  RestClient(_url);
var  loginRequest =  new  RestRequest( "/api/login" , Method.POST);
loginRequest.AddParameter( "username" ,  "gsw" );
loginRequest.AddParameter( "password" ,  "111111" );
//或用用户名密码查询对应角色
loginRequest.AddParameter( "role" ,  "system" );
IRestResponse loginResponse = loginClient.Execute(loginRequest);
var  loginContent = loginResponse.Content;
Console.WriteLine(loginContent);
return  Newtonsoft.Json.JsonConvert.DeserializeObject(loginContent);
}
static  dynamic AdminLogin()
{
var  loginClient =  new  RestClient(_url);
var  loginRequest =  new  RestRequest( "/api/login" , Method.POST);
loginRequest.AddParameter( "username" ,  "gsw" );
loginRequest.AddParameter( "password" ,  "111111" );
//或用用户名密码查询对应角色
loginRequest.AddParameter( "role" ,  "admin" );
IRestResponse loginResponse = loginClient.Execute(loginRequest);
var  loginContent = loginResponse.Content;
Console.WriteLine(loginContent);
return  Newtonsoft.Json.JsonConvert.DeserializeObject(loginContent);
}
static  void  AdminInvock(dynamic token)
{
var  client =  new  RestClient(_url);
//这里要在获取的令牌字符串前加Bearer
string  tk =  "Bearer "  + Convert.ToString(token?.access_token);
client.AddDefaultHeader( "Authorization" , tk);
var  request =  new  RestRequest( "/api/values" , Method.GET);
IRestResponse response = client.Execute(request);
var  content = response.Content;
Console.WriteLine($ "状态：{response.StatusCode}  返回结果：{content}" );
}
}
运行结果：

源码：https://github.com/axzxs2001/AuthorizePolicy.JWT
---------------------
作者：dotNET跨平台
来源：CSDN
原文：https://blog.csdn.net/sD7O95O/article/details/78096013
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