aswi2022code-of-duty-gitlab/backend/src/main/java/cz/zcu/kiv/backendapi/security/jwt/JwtTokenVerifier.java @ ae654ef7

package cz.zcu.kiv.backendapi.security.jwt;

import com.auth0.jwt.JWT;
import com.auth0.jwt.JWTVerifier;
import com.auth0.jwt.algorithms.Algorithm;
import com.auth0.jwt.interfaces.DecodedJWT;
import com.google.common.base.Strings;
import lombok.RequiredArgsConstructor;
import lombok.extern.slf4j.Slf4j;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpMethod;
import org.springframework.security.authentication.UsernamePasswordAuthenticationToken;
import org.springframework.security.core.authority.SimpleGrantedAuthority;
import org.springframework.security.core.context.SecurityContextHolder;
import org.springframework.security.web.util.matcher.AntPathRequestMatcher;
import org.springframework.web.filter.OncePerRequestFilter;

import javax.servlet.FilterChain;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.util.Collection;
import java.util.List;
import java.util.Map;
import java.util.stream.Collectors;


/**
 * Class that verifies JWT per request
 */
@Slf4j
@RequiredArgsConstructor
public class JwtTokenVerifier extends OncePerRequestFilter {

    /**
     * JWT utils
     */
    private final JwtUtils jwtUtils;

    /**
     * Map of permitted endpoints with HTTP method (user does not need to be authenticated perform the request)
     */
    private final Map<String, HttpMethod> skipFilterEndpoints;

    /**
     * Filters request - checks for JWT token and validates it
     *
     * @param request     request
     * @param response    response
     * @param filterChain filter chain
     * @throws ServletException servlet exception
     * @throws IOException      I/O exception
     */
    @Override
    protected void doFilterInternal(HttpServletRequest request, HttpServletResponse response, FilterChain filterChain) throws ServletException, IOException {
        String authorizationHeader = request.getHeader(HttpHeaders.AUTHORIZATION);
        if (Strings.isNullOrEmpty(authorizationHeader) || !authorizationHeader.startsWith(jwtUtils.getTokenPrefix())) {
            filterChain.doFilter(request, response);
            return;
        }

        try {
            String token = authorizationHeader.substring(jwtUtils.getTokenPrefix().length());
            Algorithm algorithm = jwtUtils.getAlgorithm();
            JWTVerifier verifier = JWT.require(algorithm).build();
            DecodedJWT decodedJWT = verifier.verify(token);
            String username = decodedJWT.getSubject();
            List<String> authorities = decodedJWT.getClaim(jwtUtils.getClaimAuthoritiesName()).asList(String.class);
            Collection<SimpleGrantedAuthority> simpleGrantedAuthorities = authorities.stream().map(SimpleGrantedAuthority::new).collect(Collectors.toSet());

            UsernamePasswordAuthenticationToken authenticationToken =
                    new UsernamePasswordAuthenticationToken(username, null, simpleGrantedAuthorities);
            SecurityContextHolder.getContext().setAuthentication(authenticationToken);
        } catch (Exception e) {
            log.error("Error logging in: " + e.getMessage());
            jwtUtils.writeErrorToResponse(response, e);
        }
        filterChain.doFilter(request, response);
    }

    /**
     * Tells filter whether given request should not be scanned for JWT
     *
     * @param request request
     * @return true if given request should not be scanned for JWT, false otherwise
     */
    @Override
    protected boolean shouldNotFilter(HttpServletRequest request) {
        return skipFilterEndpoints.entrySet().stream().anyMatch(e -> new AntPathRequestMatcher(e.getKey(), e.getValue().toString()).matches(request));
    }
}