public interface RPCHook {
    void doBeforeRequest(final String remoteAddr, final RemotingCommand request);
    void doAfterResponse(final String remoteAddr, final RemotingCommand request,
        final RemotingCommand response);
}

public class AclClientRPCHook implements RPCHook {
    private final SessionCredentials sessionCredentials;
    protected ConcurrentHashMap<Class<? extends CommandCustomHeader>, Field[]> fieldCache =
        new ConcurrentHashMap<Class<? extends CommandCustomHeader>, Field[]>();
    public AclClientRPCHook(SessionCredentials sessionCredentials) {
        this.sessionCredentials = sessionCredentials;
    }
    @Override
    public void doBeforeRequest(String remoteAddr, RemotingCommand request) {
        byte[] total = AclUtils.combineRequestContent(request,
            parseRequestContent(request, sessionCredentials.getAccessKey(), sessionCredentials.getSecurityToken()));
        String signature = AclUtils.calSignature(total, sessionCredentials.getSecretKey());
        request.addExtField(SIGNATURE, signature);
        request.addExtField(ACCESS_KEY, sessionCredentials.getAccessKey());
        // The SecurityToken value is unneccessary,user can choose this one.
        if (sessionCredentials.getSecurityToken() != null) {
            request.addExtField(SECURITY_TOKEN, sessionCredentials.getSecurityToken());
        }
    }
    @Override
    public void doAfterResponse(String remoteAddr, RemotingCommand request, RemotingCommand response) {
    }
    protected SortedMap<String, String> parseRequestContent(RemotingCommand request, String ak, String securityToken) {
        CommandCustomHeader header = request.readCustomHeader();
        // Sort property
        SortedMap<String, String> map = new TreeMap<String, String>();
        map.put(ACCESS_KEY, ak);
        if (securityToken != null) {
            map.put(SECURITY_TOKEN, securityToken);
        }
        try {
            // Add header properties
            if (null != header) {
                Field[] fields = fieldCache.get(header.getClass());
                if (null == fields) {
                    fields = header.getClass().getDeclaredFields();
                    for (Field field : fields) {
                        field.setAccessible(true);
                    }
                    Field[] tmp = fieldCache.putIfAbsent(header.getClass(), fields);
                    if (null != tmp) {
                        fields = tmp;
                    }
                }
                for (Field field : fields) {
                    Object value = field.get(header);
                    if (null != value && !field.isSynthetic()) {
                        map.put(field.getName(), value.toString());
                    }
                }
            }
            return map;
        } catch (Exception e) {
            throw new RuntimeException("incompatible exception.", e);
        }
    }
    public SessionCredentials getSessionCredentials() {
        return sessionCredentials;
    }
}

public class SessionCredentials {
    public static final Charset CHARSET = Charset.forName("UTF-8");
    public static final String ACCESS_KEY = "AccessKey";
    public static final String SECRET_KEY = "SecretKey";
    public static final String SIGNATURE = "Signature";
    public static final String SECURITY_TOKEN = "SecurityToken";
    public static final String KEY_FILE = System.getProperty("rocketmq.client.keyFile",
        System.getProperty("user.home") + File.separator + "key");
    private String accessKey;
    private String secretKey;
    private String securityToken;
    private String signature;
    public SessionCredentials() {
        String keyContent = null;
        try {
            keyContent = MixAll.file2String(KEY_FILE);
        } catch (IOException ignore) {
        }
        if (keyContent != null) {
            Properties prop = MixAll.string2Properties(keyContent);
            if (prop != null) {
                this.updateContent(prop);
            }
        }
    }
    public SessionCredentials(String accessKey, String secretKey) {
        this.accessKey = accessKey;
        this.secretKey = secretKey;
    }
    public SessionCredentials(String accessKey, String secretKey, String securityToken) {
        this(accessKey, secretKey);
        this.securityToken = securityToken;
    }
    public void updateContent(Properties prop) {
        {
            String value = prop.getProperty(ACCESS_KEY);
            if (value != null) {
                this.accessKey = value.trim();
            }
        }
        {
            String value = prop.getProperty(SECRET_KEY);
            if (value != null) {
                this.secretKey = value.trim();
            }
        }
        {
            String value = prop.getProperty(SECURITY_TOKEN);
            if (value != null) {
                this.securityToken = value.trim();
            }
        }
    }
    //......
}

public class AclUtils {
    private static final InternalLogger log = InternalLoggerFactory.getLogger(LoggerName.COMMON_LOGGER_NAME);
    public static byte[] combineRequestContent(RemotingCommand request, SortedMap<String, String> fieldsMap) {
        try {
            StringBuilder sb = new StringBuilder("");
            for (Map.Entry<String, String> entry : fieldsMap.entrySet()) {
                if (!SessionCredentials.SIGNATURE.equals(entry.getKey())) {
                    sb.append(entry.getValue());
                }
            }
            return AclUtils.combineBytes(sb.toString().getBytes(CHARSET), request.getBody());
        } catch (Exception e) {
            throw new RuntimeException("Incompatible exception.", e);
        }
    }
    public static byte[] combineBytes(byte[] b1, byte[] b2) {
        int size = (null != b1 ? b1.length : 0) + (null != b2 ? b2.length : 0);
        byte[] total = new byte[size];
        if (null != b1)
            System.arraycopy(b1, 0, total, 0, b1.length);
        if (null != b2)
            System.arraycopy(b2, 0, total, b1.length, b2.length);
        return total;
    }
    public static String calSignature(byte[] data, String secretKey) {
        String signature = AclSigner.calSignature(data, secretKey);
        return signature;
    }
    //......
}

public class AclSigner {
    public static final Charset DEFAULT_CHARSET = Charset.forName("UTF-8");
    public static final SigningAlgorithm DEFAULT_ALGORITHM = SigningAlgorithm.HmacSHA1;
    private static final InternalLogger log = InternalLoggerFactory.getLogger(LoggerName.ROCKETMQ_AUTHORIZE_LOGGER_NAME);
    private static final int CAL_SIGNATURE_FAILED = 10015;
    private static final String CAL_SIGNATURE_FAILED_MSG = "[%s:signature-failed] unable to calculate a request signature. error=%s";
    public static String calSignature(String data, String key) throws AclException {
        return calSignature(data, key, DEFAULT_ALGORITHM, DEFAULT_CHARSET);
    }
    public static String calSignature(String data, String key, SigningAlgorithm algorithm,
        Charset charset) throws AclException {
        return signAndBase64Encode(data, key, algorithm, charset);
    }
    private static String signAndBase64Encode(String data, String key, SigningAlgorithm algorithm, Charset charset)
        throws AclException {
        try {
            byte[] signature = sign(data.getBytes(charset), key.getBytes(charset), algorithm);
            return new String(Base64.encodeBase64(signature), DEFAULT_CHARSET);
        } catch (Exception e) {
            String message = String.format(CAL_SIGNATURE_FAILED_MSG, CAL_SIGNATURE_FAILED, e.getMessage());
            log.error(message, e);
            throw new AclException("CAL_SIGNATURE_FAILED", CAL_SIGNATURE_FAILED, message, e);
        }
    }
    private static byte[] sign(byte[] data, byte[] key, SigningAlgorithm algorithm) throws AclException {
        try {
            Mac mac = Mac.getInstance(algorithm.toString());
            mac.init(new SecretKeySpec(key, algorithm.toString()));
            return mac.doFinal(data);
        } catch (Exception e) {
            String message = String.format(CAL_SIGNATURE_FAILED_MSG, CAL_SIGNATURE_FAILED, e.getMessage());
            log.error(message, e);
            throw new AclException("CAL_SIGNATURE_FAILED", CAL_SIGNATURE_FAILED, message, e);
        }
    }
    public static String calSignature(byte[] data, String key) throws AclException {
        return calSignature(data, key, DEFAULT_ALGORITHM, DEFAULT_CHARSET);
    }
    public static String calSignature(byte[] data, String key, SigningAlgorithm algorithm,
        Charset charset) throws AclException {
        return signAndBase64Encode(data, key, algorithm, charset);
    }
    private static String signAndBase64Encode(byte[] data, String key, SigningAlgorithm algorithm, Charset charset)
        throws AclException {
        try {
            byte[] signature = sign(data, key.getBytes(charset), algorithm);
            return new String(Base64.encodeBase64(signature), DEFAULT_CHARSET);
        } catch (Exception e) {
            String message = String.format(CAL_SIGNATURE_FAILED_MSG, CAL_SIGNATURE_FAILED, e.getMessage());
            log.error(message, e);
            throw new AclException("CAL_SIGNATURE_FAILED", CAL_SIGNATURE_FAILED, message, e);
        }
    }
}