how to get claims value from JWT token authentication

Question

I have set claims in JWT token in the token provider. now I want to get claim value through authentication when API is hit.

I have checked in Principal, details, credential, authorities but I am not getting claims in any of them.

Claims claims = Jwts.claims().setSubject(authentication.getName());
    claims.put(AUTHORITIES_KEY, authorities);
    claims.put("userId", userRepo.findUserIdByUsername(authentication.getName()));

   return Jwts.builder()
            .setSubject(authentication.getName())
            .setClaims(claims)
            //.claim(AUTHORITIES_KEY, authorities)
            .signWith(SignatureAlgorithm.HS512, SIGNING_KEY)
            .setIssuedAt(new Date(System.currentTimeMillis()))
            .setExpiration(new Date(System.currentTimeMillis() + ACCESS_TOKEN_VALIDITY_SECONDS*1000))
            .compact();

I want to get "userId" claim from the authentication or any other way to get claims value from token.

Answer 1

This is how I read Claim from Token

private Claims getAllClaimsFromToken(String token) {
        Claims claims;
        try {
            claims = Jwts.parser()
                    .setSigningKey(SECRET)
                    .parseClaimsJws(token)
                    .getBody();
        } catch (Exception e) {
            LOGGER.error("Could not get all claims Token from passed token");
            claims = null;
        }
        return claims;
    }

I am using this for JWT

<dependency>
    <groupId>io.jsonwebtoken</groupId>
    <artifactId>jjwt</artifactId>
    <version>0.9.0</version>
</dependency>

More detail here

Edit 1:

Adding Filter to get token from Request and Validate

import java.io.IOException;

import javax.servlet.FilterChain;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.security.core.context.SecurityContextHolder;
import org.springframework.security.core.userdetails.UserDetails;
import org.springframework.security.core.userdetails.UserDetailsService;
import org.springframework.web.filter.OncePerRequestFilter;

public class TokenAuthenticationFilter extends OncePerRequestFilter {

    protected final Log logger = LogFactory.getLog(getClass());

    private TokenHelper tokenHelper;

    private UserDetailsService userDetailsService;

    public TokenAuthenticationFilter(TokenHelper tokenHelper, UserDetailsService userDetailsService) {
        this.tokenHelper = tokenHelper;
        this.userDetailsService = userDetailsService;
    }


    @Override
    public void doFilterInternal(
            HttpServletRequest request,
            HttpServletResponse response,
            FilterChain chain
    ) throws IOException, ServletException {

        String username;
        String authToken = tokenHelper.getToken(request);

        logger.info("AuthToken: "+authToken);

        if (authToken != null) {
            // get username from token
            username = tokenHelper.getUsernameFromToken(authToken);
            logger.info("UserName: "+username);
            if (username != null) {
                // get user
                UserDetails userDetails = userDetailsService.loadUserByUsername(username);
                if (tokenHelper.validateToken(authToken, userDetails)) {
                    // create authentication
                    TokenBasedAuthentication authentication = new TokenBasedAuthentication(userDetails);
                    authentication.setToken(authToken);
                    SecurityContextHolder.getContext().setAuthentication(authentication);
                }
            }else{
                logger.error("Something is wrong with Token.");
            }
        }
        chain.doFilter(request, response);
    }



}

Answer 2

It should help.

You should be able to retrieve a claims like this within your controller

var identity = HttpContext.User.Identity as ClaimsIdentity;
if (identity != null)
{
    IEnumerable<Claim> claims = identity.Claims; 
    // or
    identity.FindFirst("ClaimName").Value;

}

If you wanted, you could write extension methods for the IPrincipal interface and retrieve claims using the code above, then retrieve them using (for example)

HttpContext.User.Identity.MethodName();

---

For completeness of the answer. To Decode the JWT token let's write a method to validate the token and extract the information.

public static ClaimsPrincipal ValidateToken(string jwtToken)
    {
        IdentityModelEventSource.ShowPII = true;

        SecurityToken validatedToken;
        TokenValidationParameters validationParameters = new TokenValidationParameters();

        validationParameters.ValidateLifetime = true;

        validationParameters.ValidAudience = _audience.ToLower();
        validationParameters.ValidIssuer = _issuer.ToLower();
        validationParameters.IssuerSigningKey = new Microsoft.IdentityModel.Tokens.SymmetricSecurityKey(Encoding.UTF8.GetBytes(_appSettings.Secret));

        ClaimsPrincipal principal = new JwtSecurityTokenHandler().ValidateToken(jwtToken, validationParameters, out validatedToken);


        return principal;
    }

Now we can validate and extract the Claims by using:

ValidateToken(tokenString)?.FindFirst("ClaimName")?.Value

You should note that the ValidateToken method will return null value if the validation fails.

Answer 3

Using Spring Security 5 you can use @AuthenticationPrincipal org.springframework.security.oauth2.jwt.Jwt token as parameter in your controller method. And then call token.getClaims()

Answer 4

It would be recommended to refer the blog given below. It explained how the JWT token works in spring boot

https://auth0.com/blog/implementing-jwt-authentication-on-spring-boot/

Answer 5

List out all the claims using JWT

private void listClaimUsingJWT(String accessToken) {
        try {
            SignedJWT signedJWT = SignedJWT.parse(accessToken);
            JWTClaimsSet claimsSet= signedJWT.getJWTClaimsSet();
            Map<String,Object> myClain =claimsSet.getClaims();

            String[] keySet = myClain.keySet().toArray(new String[0]);
            Log.d("JWT_Claims", "loadAllOptionalClaim JWT keySetSize "+keySet.length);

            for (String s : keySet) {
                Log.d("JWT_Claims", "loadAllOptionalClaim JWT key ==> " + s + " ====> " + myClain.get(s));
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }