JWT Authentication Filter

package com.security.demo.security;

 

import com.auth0.jwt.JWT;

import com.fasterxml.jackson.databind.ObjectMapper;

import com.security.demo.models.LoginViewModel;

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.ServletException;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import java.io.IOException;

import java.util.ArrayList;

import java.util.Date;

 

import static com.auth0.jwt.algorithms.Algorithm.HMAC512;

 

public class JwtAuthenticationFilter extends UsernamePasswordAuthenticationFilter {

  private AuthenticationManager authenticationManager;

 

  public JwtAuthenticationFilter(AuthenticationManager authenticationManager) {

    this.authenticationManager = authenticationManager;

  }

 

  /* Trigger when we issue POST request to /login

  We also need to pass in {"username":"dan", "password":"dan123"} in the request body

   */

  @Override

  public Authentication attemptAuthentication(HttpServletRequest request, HttpServletResponse response) throws AuthenticationException {

 

    // Grab credentials and map them to login viewmodel

    LoginViewModel credentials = null;

    try {

      credentials = new ObjectMapper().readValue(request.getInputStream(), LoginViewModel.class);

    } catch (IOException e) {

      e.printStackTrace();

    }

 

    // Create login token

    UsernamePasswordAuthenticationToken authenticationToken = new UsernamePasswordAuthenticationToken(

            credentials.getUsername(),

            credentials.getPassword(),

            new ArrayList<>());

 

    // Authenticate user

    Authentication auth = authenticationManager.authenticate(authenticationToken);

 

    return auth;

  }

 

  @Override

  protected void successfulAuthentication(HttpServletRequest request, HttpServletResponse response, FilterChain chain, Authentication authResult) throws IOException, ServletException {

    // Grab principal

    UserPrincipal principal = (UserPrincipal) authResult.getPrincipal();

 

    // Create JWT Token

    String token = JWT.create()

            .withSubject(principal.getUsername())

            .withExpiresAt(new Date(System.currentTimeMillis() + JwtProperties.EXPIRATION_TIME))

            .sign(HMAC512(JwtProperties.SECRET.getBytes()));

 

    // Add token in response

    response.addHeader(JwtProperties.HEADER_STRING, JwtProperties.TOKEN_PREFIX +  token);

  }

}