source: trip-planner/src/main/java/finki/diplomska/tripplanner/security/JwtAuthenticationFilter.java

package finki.diplomska.tripplanner.security;

import finki.diplomska.tripplanner.models.User;
import finki.diplomska.tripplanner.service.impl.CustomUserDetailsServiceImpl;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.security.authentication.UsernamePasswordAuthenticationToken;
import org.springframework.security.core.context.SecurityContextHolder;
import org.springframework.security.web.authentication.WebAuthenticationDetailsSource;
import org.springframework.util.StringUtils;
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.Collections;

public class JwtAuthenticationFilter extends OncePerRequestFilter {
    @Autowired
    private JwtTokenProvider tokenProvider;

    @Autowired
    private CustomUserDetailsServiceImpl customUserDetailsService;

    @Override
    protected void doFilterInternal(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse,
                                    FilterChain filterChain) throws ServletException, IOException {

        try {

            String jwt = getJWTFromRequest(httpServletRequest);

            if(StringUtils.hasText(jwt)&& tokenProvider.validateToken(jwt)){
                Long userId = tokenProvider.getUserIdFromJWT(jwt);
                User userDetails = customUserDetailsService.loadUserById(userId);

                UsernamePasswordAuthenticationToken authentication = new UsernamePasswordAuthenticationToken(
                        userDetails, null, Collections.emptyList());

                authentication.setDetails(new WebAuthenticationDetailsSource().buildDetails(httpServletRequest));
                SecurityContextHolder.getContext().setAuthentication(authentication);

            }

        }catch (Exception ex){
            logger.error("Could not set user authentication in security context", ex);
        }


        filterChain.doFilter(httpServletRequest, httpServletResponse);

    }



    private String getJWTFromRequest(HttpServletRequest request){
        String bearerToken = request.getHeader(SecurityConstants.HEADER_STRING);

        if(StringUtils.hasText(bearerToken)&&bearerToken.startsWith(SecurityConstants.TOKEN_PREFIX)){
            return bearerToken.substring(7, bearerToken.length());
        }

        return null;
    }
}