asp.net core 2.0 web api基于JWT自定义策略授权

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


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