In this post, you will see how to catch ExpiredJwtException in OncePerRequestFilter class and send a meaningful error message from a Spring Boot app .
Background
I came across this issue after I implemented JWT authentication in the file-sharing-app. As the JWT token functionality was being tested, I realised that there is an exception being thrown due to JWT expiry. The first thing I tried was to implement the GlobalExceptionHandler and define an ExceptionHandler for ExpiredJwtException. That however, did not work but after some time, I discovered another solution, that I will be sharing next.
Catch ExpiredJwtException in doFilterInternal
If you have added Jwt authentication to your app, then you would have added a class that extends the OncePerRequestFilter to filters requests by validating the token sent with it. Subsequently, you would also have a service class that implements functionalities such as createToken, method to extract claims etc. Now, you need to include the code in the doFilterInternal within a try block and catch the ExpiredJwtException and write the meaningful error in the response. Observe the code below taken from the file-sharing-app.
@Override
protected void doFilterInternal(HttpServletRequest request, HttpServletResponse response, FilterChain filterChain) throws ServletException, IOException, ExpiredJwtException {
String authHeader = request.getHeader("Authorization");
String token = null;
String username = null;
try {
if (authHeader != null && authHeader.startsWith("Bearer ")) {
token = authHeader.substring(7);
username = jwtService.extractUsername(token);
}
if (username != null && SecurityContextHolder.getContext().getAuthentication() == null) {
UserDetails userDetails = userDetailsService.loadUserByUsername(username);
if (jwtService.validateToken(token, userDetails)) {
log.info("JWT token validated for expiry and about to set session context");
UsernamePasswordAuthenticationToken authToken = new UsernamePasswordAuthenticationToken(userDetails, null, userDetails.getAuthorities());
authToken.setDetails(new WebAuthenticationDetailsSource().buildDetails(request));
log.info("The auth token looks like, {}", authToken.toString());
SecurityContextHolder.getContext().setAuthentication(authToken);
}
}
filterChain.doFilter(request, response);
} catch (ExpiredJwtException expiredJwtException) {
log.info("In the expired JWT Exception handler");
response.setContentType("application/json");
response.setStatus(HttpStatus.FORBIDDEN.value());
ObjectMapper mapper = new ObjectMapper();
String exMessage = mapper.writeValueAsString(expiredJwtException(expiredJwtException.getMessage()));
response.getWriter().write(exMessage);
}
}You can find the full source code for the file here.
Or for convenience I can include it all here,
import com.fasterxml.jackson.databind.ObjectMapper;
import com.mydaytodo.sfa.asset.model.ServiceResponse;
import com.mydaytodo.sfa.asset.service.JwtService;
import com.mydaytodo.sfa.asset.service.UserAuthServiceImpl;
import io.jsonwebtoken.ExpiredJwtException;
import jakarta.servlet.FilterChain;
import jakarta.servlet.ServletException;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.HttpStatus;
import org.springframework.security.authentication.UsernamePasswordAuthenticationToken;
import org.springframework.security.core.context.SecurityContextHolder;
import org.springframework.security.core.userdetails.UserDetails;
import org.springframework.security.web.authentication.WebAuthenticationDetailsSource;
import org.springframework.stereotype.Component;
import org.springframework.web.filter.OncePerRequestFilter;
import java.io.IOException;
// This class helps us to validate the generated jwt token
@Component
@Slf4j
public class JwtAuthFilter extends OncePerRequestFilter {
@Autowired
private JwtService jwtService;
@Autowired
private UserAuthServiceImpl userDetailsService;
@Override
protected void doFilterInternal(HttpServletRequest request, HttpServletResponse response, FilterChain filterChain) throws ServletException, IOException, ExpiredJwtException {
String authHeader = request.getHeader("Authorization");
String token = null;
String username = null;
try {
if (authHeader != null && authHeader.startsWith("Bearer ")) {
token = authHeader.substring(7);
username = jwtService.extractUsername(token);
}
if (username != null && SecurityContextHolder.getContext().getAuthentication() == null) {
UserDetails userDetails = userDetailsService.loadUserByUsername(username);
if (jwtService.validateToken(token, userDetails)) {
log.info("JWT token validated for expiry and about to set session context");
UsernamePasswordAuthenticationToken authToken = new UsernamePasswordAuthenticationToken(userDetails, null, userDetails.getAuthorities());
authToken.setDetails(new WebAuthenticationDetailsSource().buildDetails(request));
log.info("The auth token looks like, {}", authToken.toString());
SecurityContextHolder.getContext().setAuthentication(authToken);
}
}
filterChain.doFilter(request, response);
} catch (ExpiredJwtException expiredJwtException) {
log.info("In the expired JWT Exception handler");
response.setContentType("application/json");
response.setStatus(HttpStatus.FORBIDDEN.value());
ObjectMapper mapper = new ObjectMapper();
String exMessage = mapper.writeValueAsString(expiredJwtException(expiredJwtException.getMessage()));
response.getWriter().write(exMessage);
}
}
private ServiceResponse expiredJwtException(String message) {
return ServiceResponse.builder()
.data("Token expired, please logout and login again")
.message(message)
.status(HttpStatus.FORBIDDEN.value())
.build();
}
}Conclusion
If you have any questions on this, feel free to leave a comment on this post or send me an email directly.
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