JavaAuthenticationPart5

import io.jsonwebtoken.Jwts;

import io.jsonwebtoken.SignatureAlgorithm;

import org.springframework.security.authentication.AuthenticationManager;

import org.springframework.security.authentication.UsernamePasswordAuthenticationToken;

import org.springframework.security.core.Authentication;

import org.springframework.security.core.AuthenticationException;

import org.springframework.security.web.authentication.UsernamePasswordAuthenticationFilter;

import javax.servlet.FilterChain;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import java.io.IOException;

import java.util.Date;

public class JwtAuthenticationFilter extends UsernamePasswordAuthenticationFilter {

    private AuthenticationManager authenticationManager;

    public JwtAuthenticationFilter(AuthenticationManager authenticationManager) {

        this.authenticationManager = authenticationManager;

    }

    @Override

    public Authentication attemptAuthentication(HttpServletRequest req, HttpServletResponse res) throws AuthenticationException {

        try {

            String username = req.getParameter("username");

            String password = req.getParameter("password");

            UsernamePasswordAuthenticationToken authenticationToken = new UsernamePasswordAuthenticationToken(username, password);

            return authenticationManager.authenticate(authenticationToken);

        } catch (Exception e) {

            throw new RuntimeException(e);

        }

    }

    @Override

    protected void successfulAuthentication(HttpServletRequest req, HttpServletResponse res, FilterChain chain, Authentication auth) throws IOException {

        String token = Jwts.builder()

                .setSubject(((org.springframework.security.core.userdetails.User) auth.getPrincipal()).getUsername())

                .setExpiration(new Date(System.currentTimeMillis() + 864_000_000)) // 10 days

                .signWith(SignatureAlgorithm.HS512, "SecretKeyToGenJWTs")

                .compact();

        res.addHeader("Authorization", "Bearer " + token);

    }

}