@RateLimiter(
        rules = {
                // 60秒內(nèi)只能訪問(wèn)10次
                @RateRule(count = 10, time = 60, timeUnit = TimeUnit.SECONDS),
                // 120秒內(nèi)只能訪問(wèn)20次
                @RateRule(count = 20, time = 120, timeUnit = TimeUnit.SECONDS)

        },
        // 防重復(fù)提交 （5秒鐘只能訪問(wèn)1次）
        preventDuplicate = true
)

@Target(ElementType.METHOD)
@Retention(RetentionPolicy.RUNTIME)
@Inherited
public @interface RateLimiter {

    /**
     * 限流key
     */
    String key() default RedisKeyConstants.RATE_LIMIT_CACHE_PREFIX;

    /**
     * 限流類型 ( 默認(rèn) Ip 模式 )
     */
    LimitTypeEnum limitType() default LimitTypeEnum.IP;

    /**
     * 錯(cuò)誤提示
     */
    ResultCode message() default ResultCode.REQUEST_MORE_ERROR;

    /**
     * 限流規(guī)則 （規(guī)則不可變，可多規(guī)則）
     */
    RateRule[] rules() default {};

    /**
     * 防重復(fù)提交值
     */
    boolean preventDuplicate() default false;

    /**
     * 防重復(fù)提交默認(rèn)值
     */
    RateRule preventDuplicateRule() default @RateRule(count = 1, time = 5);
}

@Target(ElementType.ANNOTATION_TYPE)
@Retention(RetentionPolicy.RUNTIME)
@Inherited
public @interface RateRule {

    /**
     * 限流次數(shù)
     */
    long count() default 10;

    /**
     * 限流時(shí)間
     */
    long time() default 60;

    /**
     * 限流時(shí)間單位
     */
    TimeUnit timeUnit() default TimeUnit.SECONDS;

}

public String getCombineKey(RateLimiter rateLimiter, JoinPoint joinPoint) {
    StringBuffer key = new StringBuffer(rateLimiter.key());
    // 不同限流類型使用不同的前綴
    switch (rateLimiter.limitType()) {
        // XXX 可以新增通過(guò)參數(shù)指定參數(shù)進(jìn)行限流
        case IP:
            key.append(IpUtil.getIpAddr(((ServletRequestAttributes) Objects.requireNonNull(RequestContextHolder.getRequestAttributes())).getRequest())).append(":");
            break;
        case USER_ID:
            SysUserDetails user = SecurityUtil.getUser();
            if (!ObjectUtils.isEmpty(user)) key.append(user.getUserId()).append(":");
            break;
        case GLOBAL:
            break;
    }
    MethodSignature signature = (MethodSignature) joinPoint.getSignature();
    Method method = signature.getMethod();
    Class<?> targetClass = method.getDeclaringClass();
    key.append(targetClass.getSimpleName()).append("-").append(method.getName());
    return key.toString();
}

-- 1. 獲取參數(shù)
local key = KEYS[1]
local uuid = KEYS[2]
local currentTime = tonumber(KEYS[3])
-- 2. 以數(shù)組最大值為 ttl 最大值
local expireTime = -1;
-- 3. 遍歷數(shù)組查看是否超過(guò)限流規(guī)則
for i = 1, #ARGV, 2 do
    local rateRuleCount = tonumber(ARGV[i])
    local rateRuleTime = tonumber(ARGV[i + 1])
    -- 3.1 判斷在單位時(shí)間內(nèi)訪問(wèn)次數(shù)
    local count = redis.call('ZCOUNT', key, currentTime - rateRuleTime, currentTime)
    -- 3.2 判斷是否超過(guò)規(guī)定次數(shù)
    if tonumber(count) >= rateRuleCount then
        return true
    end
    -- 3.3 判斷元素最大值，設(shè)置為最終過(guò)期時(shí)間
    if rateRuleTime > expireTime then
        expireTime = rateRuleTime
    end
end
-- 4. redis 中添加當(dāng)前時(shí)間
redis.call('ZADD', key, currentTime, uuid)
-- 5. 更新緩存過(guò)期時(shí)間
redis.call('PEXPIRE', key, expireTime)
-- 6. 刪除最大時(shí)間限度之前的數(shù)據(jù)，防止數(shù)據(jù)過(guò)多
redis.call('ZREMRANGEBYSCORE', key, 0, currentTime - expireTime)
return false

-- 1. 獲取參數(shù)
local key = KEYS[1]
local currentTime = KEYS[2]
-- 2. 以數(shù)組最大值為 ttl 最大值
local expireTime = -1;
-- 3. 遍歷數(shù)組查看是否越界
for i = 1, #ARGV, 2 do
    local rateRuleCount = tonumber(ARGV[i])
    local rateRuleTime = tonumber(ARGV[i + 1])
    -- 3.1 判斷在單位時(shí)間內(nèi)訪問(wèn)次數(shù)
    local count = redis.call('ZCOUNT', key, currentTime - rateRuleTime, currentTime)
    -- 3.2 判斷是否超過(guò)規(guī)定次數(shù)
    if tonumber(count) >= rateRuleCount then
        return true
    end
    -- 3.3 判斷元素最大值，設(shè)置為最終過(guò)期時(shí)間
    if rateRuleTime > expireTime then
        expireTime = rateRuleTime
    end
end
-- 4. 更新緩存過(guò)期時(shí)間
redis.call('PEXPIRE', key, expireTime)
-- 5. 刪除最大時(shí)間限度之前的數(shù)據(jù)，防止數(shù)據(jù)過(guò)多
redis.call('ZREMRANGEBYSCORE', key, 0, currentTime - expireTime)
-- 6. redis 中添加當(dāng)前時(shí)間  ( 解決多個(gè)線程在同一毫秒添加相同 value 導(dǎo)致 Redis 漏記的問(wèn)題 )
-- 6.1 maxRetries 最大重試次數(shù) retries 重試次數(shù)
local maxRetries = 5
local retries = 0
while true do
    local result = redis.call('ZADD', key, currentTime, currentTime)
    if result == 1 then
        -- 6.2 添加成功則跳出循環(huán)
        break
    else
        -- 6.3 未添加成功則 value + 1 再次進(jìn)行嘗試
        retries = retries + 1
        if retries >= maxRetries then
            -- 6.4 超過(guò)最大嘗試次數(shù) 采用添加隨機(jī)數(shù)策略
            local random_value = math.random(1, 1000)
            currentTime = currentTime + random_value
        else
            currentTime = currentTime + 1
        end
    end
end

return false

@Autowired
private RedisTemplate<String, Object> redisTemplate;

@Autowired
private RedisScript<Boolean> limitScript;

/**
 * 限流
 * XXX 對(duì)限流要求比較高，可以使用在 Redis中對(duì)規(guī)則進(jìn)行存儲(chǔ)校驗(yàn) 或者使用中間件
 *
 * @param joinPoint   joinPoint
 * @param rateLimiter 限流注解
 */
@Before(value = "@annotation(rateLimiter)")
public void boBefore(JoinPoint joinPoint, RateLimiter rateLimiter) {
    // 1. 生成 key
    String key = getCombineKey(rateLimiter, joinPoint);
    try {
        // 2. 執(zhí)行腳本返回是否限流
        Boolean flag = redisTemplate.execute(limitScript,
                ListUtil.of(key, String.valueOf(System.currentTimeMillis())),
                (Object[]) getRules(rateLimiter));
        // 3. 判斷是否限流
        if (Boolean.TRUE.equals(flag)) {
            log.error("ip: '{}' 攔截到一個(gè)請(qǐng)求 RedisKey: '{}'",
                    IpUtil.getIpAddr(((ServletRequestAttributes) Objects.requireNonNull(RequestContextHolder.getRequestAttributes())).getRequest()),
                    key);
            throw new ServiceException(rateLimiter.message());
        }
    } catch (ServiceException e) {
        throw e;
    } catch (Exception e) {
        e.printStackTrace();
    }
}

/**
 * 獲取規(guī)則
 *
 * @param rateLimiter 獲取其中規(guī)則信息
 * @return
 */
private Long[] getRules(RateLimiter rateLimiter) {
    int capacity = rateLimiter.rules().length << 1;
    // 1. 構(gòu)建 args
    Long[] args = new Long[rateLimiter.preventDuplicate() ? capacity + 2 : capacity];
    // 3. 記錄數(shù)組元素
    int index = 0;
    // 2. 判斷是否需要添加防重復(fù)提交到redis進(jìn)行校驗(yàn)
    if (rateLimiter.preventDuplicate()) {
        RateRule preventRateRule = rateLimiter.preventDuplicateRule();
        args[index++] = preventRateRule.count();
        args[index++] = preventRateRule.timeUnit().toMillis(preventRateRule.time());
    }
    RateRule[] rules = rateLimiter.rules();
    for (RateRule rule : rules) {
        args[index++] = rule.count();
        args[index++] = rule.timeUnit().toMillis(rule.time());
    }
    return args;
}