如何解码JWT令牌？

我不了解该库的工作方式。请问你能帮帮我吗 ？

这是我的简单代码：

public void TestJwtSecurityTokenHandler()
    {
        var stream =
            "eyJhbGciOiJSUzI1NiJ9.eyJpc3MiOiJJU1MiLCJzY29wZSI6Imh0dHBzOi8vbGFyaW0uZG5zY2UuZG91YW5lL2NpZWxzZXJ2aWNlL3dzIiwiYXVkIjoiaHR0cHM6Ly9kb3VhbmUuZmluYW5jZXMuZ291di5mci9vYXV0aDIvdjEiLCJpYXQiOiJcL0RhdGUoMTQ2ODM2MjU5Mzc4NClcLyJ9";
        var handler = new JwtSecurityTokenHandler();

        var jsonToken = handler.ReadToken(stream);
    }

这是错误：

该字符串必须采用紧凑的JSON格式，格式为：Base64UrlEncodedHeader.Base64UrlEndcodedPayload.OPTIONAL，Base64UrlEncodedSignature'。

如果您在jwt.io网站中复制流，则可以正常工作:)

我找到了解决方案，我只是忘了铸造结果：

var stream ="[encoded jwt]";  
var handler = new JwtSecurityTokenHandler();
var jsonToken = handler.ReadToken(stream);
var tokenS = handler.ReadToken(stream) as JwtSecurityToken;

我可以使用以下方法获得索赔：

var jti = tokenS.Claims.First(claim => claim.Type == "jti").Value;

new JwtSecurityTokenHandler().ReadToken("") 将返回一个 SecurityToken

new JwtSecurityTokenHandler().ReadJwtToken("") 将返回一个 JwtSecurityToken

如果您只是更改使用的方法，则可以避免在上述答案中进行强制转换

您需要用于生成加密令牌的秘密字符串。该代码对我有用：

protected string GetName(string token)
    {
        string secret = "this is a string used for encrypt and decrypt token"; 
        var key = Encoding.ASCII.GetBytes(secret);
        var handler = new JwtSecurityTokenHandler();
        var validations = new TokenValidationParameters
        {
            ValidateIssuerSigningKey = true,
            IssuerSigningKey = new SymmetricSecurityKey(key),
            ValidateIssuer = false,
            ValidateAudience = false
        };
        var claims = handler.ValidateToken(token, validations, out var tokenSecure);
        return claims.Identity.Name;
    }

使用.net core jwt软件包，可以使用Claims：

[Route("api/[controller]")]
[ApiController]
[Authorize(Policy = "Bearer")]
public class AbstractController: ControllerBase
{
    protected string UserId()
    {
        var principal = HttpContext.User;
        if (principal?.Claims != null)
        {
            foreach (var claim in principal.Claims)
            {
               log.Debug($"CLAIM TYPE: {claim.Type}; CLAIM VALUE: {claim.Value}");
            }

        }
        return principal?.Claims?.SingleOrDefault(p => p.Type == "username")?.Value;
    }
}

  var key = new SymmetricSecurityKey(Encoding.UTF8.GetBytes(_config["Jwt:Key"]));
        var creds = new SigningCredentials(key, SecurityAlgorithms.HmacSha256);
        var claims = new[]
                {
                    new Claim(JwtRegisteredClaimNames.Email, model.UserName),
                    new Claim(JwtRegisteredClaimNames.NameId, model.Id.ToString()),
                };
        var token = new JwtSecurityToken(_config["Jwt:Issuer"],
          _config["Jwt:Issuer"],
          claims,
          expires: DateTime.Now.AddMinutes(30),
          signingCredentials: creds);

然后提取内容

 var handler = new JwtSecurityTokenHandler();
        string authHeader = Request.Headers["Authorization"];
        authHeader = authHeader.Replace("Bearer ", "");
        var jsonToken = handler.ReadToken(authHeader);
        var tokenS = handler.ReadToken(authHeader) as JwtSecurityToken;

        var id = tokenS.Claims.First(claim => claim.Type == "nameid").Value;

扩展cooxkie答案和dpix答案，当您读取jwt令牌（例如从AD FS接收的access_token）时，可以将jwt令牌中的声明与“ context.AuthenticationTicket.Identity”中的声明合并具有与jwt令牌相同的声明集。

为了说明这一点，在使用OpenID Connect的身份验证代码流中，对用户进行身份验证后，您可以处理为您提供身份验证上下文的SecurityTokenValidated事件，然后您可以使用它来读取access_token作为jwt令牌，然后您可以“将access_token中的令牌与用户身份的一部分收到的标准声明列表合并：

    private Task OnSecurityTokenValidated(SecurityTokenValidatedNotification<OpenIdConnectMessage,OpenIdConnectAuthenticationOptions> context)
    {
        //get the current user identity
        ClaimsIdentity claimsIdentity = (ClaimsIdentity)context.AuthenticationTicket.Identity;

        /*read access token from the current context*/
        string access_token = context.ProtocolMessage.AccessToken;

        JwtSecurityTokenHandler hand = new JwtSecurityTokenHandler();
        //read the token as recommended by Coxkie and dpix
        var tokenS = hand.ReadJwtToken(access_token);
        //here, you read the claims from the access token which might have 
        //additional claims needed by your application
        foreach (var claim in tokenS.Claims)
        {
            if (!claimsIdentity.HasClaim(claim.Type, claim.Value))
                claimsIdentity.AddClaim(claim);
        }

        return Task.FromResult(0);
    }