XuqmGroup-Server/common/src/main/java/com/xuqm/common/security/AppRequestSignatureUtil.java

package com.xuqm.common.security;

import javax.crypto.Mac;
import javax.crypto.spec.SecretKeySpec;
import java.nio.charset.StandardCharsets;
import java.security.MessageDigest;
import java.util.Base64;

public final class AppRequestSignatureUtil {

    private static final String HMAC_ALG = "HmacSHA256";

    private AppRequestSignatureUtil() {
    }

    public static String payload(String appId,
                                 String userId,
                                 String nickname,
                                 String avatar,
                                 long timestamp,
                                 String nonce) {
        return normalize(appId) + '\n'
                + normalize(userId) + '\n'
                + normalize(nickname) + '\n'
                + normalize(avatar) + '\n'
                + timestamp + '\n'
                + normalize(nonce);
    }

    public static String sign(String secret, String payload) {
        try {
            Mac mac = Mac.getInstance(HMAC_ALG);
            mac.init(new SecretKeySpec(secret.getBytes(StandardCharsets.UTF_8), HMAC_ALG));
            byte[] digest = mac.doFinal(payload.getBytes(StandardCharsets.UTF_8));
            return Base64.getUrlEncoder().withoutPadding().encodeToString(digest);
        } catch (Exception e) {
            throw new IllegalStateException("Failed to sign app request", e);
        }
    }

    public static boolean matches(String secret, String payload, String expectedSignature) {
        String actual = sign(secret, payload);
        return MessageDigest.isEqual(
                actual.getBytes(StandardCharsets.UTF_8),
                normalize(expectedSignature).getBytes(StandardCharsets.UTF_8)
        );
    }

    private static String normalize(String value) {
        return value == null ? "" : value;
    }
}