.net core webapi jwt 更为清爽的认证

我的方式非主流，控制却可以更加灵活，喜欢的朋友，不妨花一点时间学习一下

jwt认证分为两部分，第一部分是加密解密，第二部分是灵活的应用于中间件，我的处理方式是将获取token放到api的一个具体的controller中，将发放token与验证分离，token的失效时间，发证者，使用者等信息存放到config中。

1.配置：

在appsettings.json中增加配置

"Jwt": {
"Issuer": "issuer",//随意定义
"Audience": "Audience",//随意定义
"SecretKey": "abc",//随意定义
"Lifetime": 20, //单位分钟
"ValidateLifetime": true,//验证过期时间
"HeadField": "useless", //头字段
"Prefix": "prefix", //前缀
"IgnoreUrls": [ "/Auth/GetToken" ]//忽略验证的url
}

2:定义配置类：

internal class JwtConfig
{
public string Issuer { get; set; }
public string Audience { get; set; }

/// <summary>
/// 加密key
/// </summary>
public string SecretKey { get; set; }
/// <summary>
/// 生命周期
/// </summary>
public int Lifetime { get; set; }
/// <summary>
/// 是否验证生命周期
/// </summary>
public bool ValidateLifetime { get; set; }
/// <summary>
/// 验证头字段
/// </summary>
public string HeadField { get; set; }
/// <summary>
/// jwt验证前缀
/// </summary>
public string Prefix { get; set; }
/// <summary>
/// 忽略验证的url
/// </summary>
public List<string> IgnoreUrls { get; set; }
}

3.加密解密接口：

public interface IJwt
{
string GetToken(Dictionary<string, string> Clims);
bool ValidateToken(string Token,out Dictionary<string ,string> Clims);
}

4.加密解密的实现类：

 install-package System.IdentityModel.Tokens.Jwt 

public class Jwt : IJwt
{
private IConfiguration _configuration;
private string _base64Secret;
private JwtConfig _jwtConfig = new JwtConfig();
public Jwt(IConfiguration configration)
{
this._configuration = configration;
configration.GetSection("Jwt").Bind(_jwtConfig);
GetSecret();
}
/// <summary>
/// 获取到加密串
/// </summary>
private void GetSecret()
{
var encoding = new System.Text.ASCIIEncoding();
byte[] keyByte = encoding.GetBytes("salt");
byte[] messageBytes = encoding.GetBytes(this._jwtConfig.SecretKey);
using (var hmacsha256 = new HMACSHA256(keyByte))
{
byte[] hashmessage = hmacsha256.ComputeHash(messageBytes);
this._base64Secret= Convert.ToBase64String(hashmessage);
}
}
/// <summary>
/// 生成Token
/// </summary>
/// <param name="Claims"></param>
/// <returns></returns>
public string GetToken(Dictionary<string, string> Claims)
{
List<Claim> claimsAll = new List<Claim>();
foreach (var item in Claims)
{
claimsAll.Add(new Claim(item.Key, item.Value));
}
var symmetricKey = Convert.FromBase64String(this._base64Secret);
var tokenHandler = new JwtSecurityTokenHandler();
var tokenDescriptor = new SecurityTokenDescriptor
{
Issuer = _jwtConfig.Issuer,
Audience = _jwtConfig.Audience,
Subject = new ClaimsIdentity(claimsAll),
NotBefore = DateTime.Now,
Expires = DateTime.Now.AddMinutes(this._jwtConfig.Lifetime),
SigningCredentials =new SigningCredentials(new SymmetricSecurityKey(symmetricKey),
SecurityAlgorithms.HmacSha256Signature)
};
var securityToken = tokenHandler.CreateToken(tokenDescriptor);
return tokenHandler.WriteToken(securityToken);
}
public bool ValidateToken(string Token, out Dictionary<string, string> Clims)
{
Clims = new Dictionary<string, string>();
ClaimsPrincipal principal = null;
if (string.IsNullOrWhiteSpace(Token))
{
return false;
}
var handler = new JwtSecurityTokenHandler();
try
{
var jwt = handler.ReadJwtToken(Token);

if (jwt == null)
{
return false;
}
var secretBytes = Convert.FromBase64String(this._base64Secret);
var validationParameters = new TokenValidationParameters
{
RequireExpirationTime = true,
IssuerSigningKey = new SymmetricSecurityKey(secretBytes),
ClockSkew = TimeSpan.Zero,
ValidateIssuer = true,//是否验证Issuer
ValidateAudience = true,//是否验证Audience
ValidateLifetime = this._jwtConfig.ValidateLifetime,//是否验证失效时间
ValidateIssuerSigningKey = true,//是否验证SecurityKey
ValidAudience = this._jwtConfig.Audience,
ValidIssuer = this._jwtConfig.Issuer
};
SecurityToken securityToken;
principal = handler.ValidateToken(Token, validationParameters, out securityToken);
foreach (var item in principal.Claims)
{
Clims.Add(item.Type, item.Value);
}
return true;
}
catch (Exception ex)
{
return false;
}
}
}

5.定义获取Token的Controller:

在Startup.ConfigureServices中注入 IJwt

 services.AddTransient<IJwt, Jwt>();//Jwt注入 

[Route("[controller]/[action]")]
[ApiController]
public class AuthController : ControllerBase
{
private IJwt _jwt;
public AuthController(IJwt jwt)
{
this._jwt = jwt;
}
/// <summary>
/// getToken
/// </summary>
/// <returns></returns>
[HttpPost]
public IActionResult GetToken()
{
if (true)
{
Dictionary<string, string> clims = new Dictionary<string, string>();
clims.Add("userName", userName);
return new JsonResult(this._jwt.GetToken(clims));
}
}
}

6.创建中间件：

public class UseJwtMiddleware
{
private readonly RequestDelegate _next;
private JwtConfig _jwtConfig =new JwtConfig();
private IJwt _jwt;
public UseJwtMiddleware(RequestDelegate next, IConfiguration configration,IJwt jwt)
{
_next = next;
this._jwt = jwt;
configration.GetSection("Jwt").Bind(_jwtConfig);
}
public Task InvokeAsync(HttpContext context)
{
if (_jwtConfig.IgnoreUrls.Contains(context.Request.Path))
{
return this._next(context);
}
else
{
if (context.Request.Headers.TryGetValue(this._jwtConfig.HeadField, out Microsoft.Extensions.Primitives.StringValues authValue))
{
var authstr = authValue.ToString();
if (this._jwtConfig.Prefix.Length > 0)
{
authstr = authValue.ToString().Substring(this._jwtConfig.Prefix.Length+1, authValue.ToString().Length -(this._jwtConfig.Prefix.Length+1));
}
if (this._jwt.ValidateToken(authstr, out Dictionary<string, string> Clims))
{
foreach (var item in Clims)
{
context.Items.Add(item.Key, item.Value);
}
return this._next(context);
}
else
{
context.Response.StatusCode = 401;
context.Response.ContentType = "application/json";
return context.Response.WriteAsync("{\"status\":401,\"statusMsg\":\"auth vaild fail\"}");
}
}
else
{
context.Response.StatusCode = 401;
context.Response.ContentType = "application/json";
return context.Response.WriteAsync("{\"status\":401,\"statusMsg\":\"auth vaild fail\"}");
}
}
}
}

7.中间件暴露出去

public static class UseUseJwtMiddlewareExtensions
{
/// <summary>
/// 权限检查
/// </summary>
/// <param name="builder"></param>
/// <returns></returns>
public static IApplicationBuilder UseJwt(this IApplicationBuilder builder)
{
return builder.UseMiddleware<UseJwtMiddleware>();
}
}

8.在Startup.Configure中使用中间件：

 app.UseJwt(); 

以1的配置为例：

除了请求 /auth/getToken 不需要加头信息外，其他的请求一律要求头信息中必须带着 

userless:prefix (从Auth/GetToken中获取到的token)