JwtTokenProvider.java

package com.example.solidconnection.auth.token;

import static com.example.solidconnection.common.exception.ErrorCode.INVALID_TOKEN;

import com.example.solidconnection.auth.domain.Subject;
import com.example.solidconnection.auth.service.TokenProvider;
import com.example.solidconnection.auth.token.config.JwtProperties;
import com.example.solidconnection.common.exception.CustomException;
import io.jsonwebtoken.Claims;
import io.jsonwebtoken.JwtBuilder;
import io.jsonwebtoken.Jwts;
import io.jsonwebtoken.security.Keys;
import java.nio.charset.StandardCharsets;
import java.time.Duration;
import java.util.Date;
import java.util.Map;
import javax.crypto.SecretKey;
import lombok.RequiredArgsConstructor;
import org.springframework.stereotype.Component;

@Component
@RequiredArgsConstructor
public class JwtTokenProvider implements TokenProvider {

    private final JwtProperties jwtProperties;

    @Override
    public String generateToken(Subject subject, Duration expireTime) {
        return generateJwtTokenValue(subject.value(), Map.of(), expireTime);
    }

    @Override
    public String generateToken(Subject subject, Map<String, String> customClaims, Duration expireTime) {
        return generateJwtTokenValue(subject.value(), customClaims, expireTime);
    }

    private String generateJwtTokenValue(String subject, Map<String, String> claims, Duration expireTime) {
        Date now = new Date();
        Date expiredDate = new Date(now.getTime() + expireTime.toMillis());
        JwtBuilder builder = Jwts.builder()
                .subject(subject)
                .issuedAt(now)
                .expiration(expiredDate);
        claims.forEach(builder::claim);
        return builder.signWith(getSigningKey()).compact();
    }

    private SecretKey getSigningKey() {
        return Keys.hmacShaKeyFor(jwtProperties.secret().getBytes(StandardCharsets.UTF_8));
    }

    @Override
    public Subject parseSubject(String token) {
        String subject = parseJwtClaims(token).getSubject();
        if (subject == null || subject.isBlank()) {
            throw new CustomException(INVALID_TOKEN);
        }
        return new Subject(subject);
    }

    @Override
    public <T> T parseClaims(String token, String claimName, Class<T> claimType) {
        return parseJwtClaims(token).get(claimName, claimType);
    }

    private Claims parseJwtClaims(String token) {
        try {
            return Jwts.parser()
                    .verifyWith(getSigningKey())
                    .build()
                    .parseSignedClaims(token)
                    .getPayload();
        } catch (Exception e) {
            throw new CustomException(INVALID_TOKEN);
        }
    }
}