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https://github.com/Wei-Shaw/sub2api.git
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TT
666a5c6f87
The redeem failure counter used INCR followed by Expire(24h) on every attempt, so each failed attempt refreshed the key TTL and the window never actually closed for a user who kept retrying within 24h. - Count attempts in a fixed 10-minute window via a small Lua script (INCR, then PEXPIRE only when the key is created or has no TTL), which is atomic and also repairs keys that lost their TTL. - Move the counter to the redeem:ratelimit:v2: key space so pre-existing 24h counters do not seed the new window. - Rename the service threshold to redeemMaxFailedAttempts (30) to reflect that it bounds attempts per window, not per hour. Public redeem behavior is unchanged apart from the window semantics: the check fails open when the counter read fails, and a failed increment never masks the underlying domain error.
75 lines
1.8 KiB
Go
75 lines
1.8 KiB
Go
package repository
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import (
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"context"
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"fmt"
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"time"
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"github.com/Wei-Shaw/sub2api/internal/service"
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"github.com/redis/go-redis/v9"
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)
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const (
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redeemRateLimitKeyPrefix = "redeem:ratelimit:v2:"
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redeemLockKeyPrefix = "redeem:lock:"
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redeemRateLimitWindow = 10 * time.Minute
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)
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var incrementRedeemAttemptScript = redis.NewScript(`
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local current = redis.call('INCR', KEYS[1])
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local ttl = redis.call('PTTL', KEYS[1])
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if current == 1 or ttl == -1 then
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redis.call('PEXPIRE', KEYS[1], ARGV[1])
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end
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return current
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`)
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// redeemRateLimitKey generates the Redis key for redeem attempt rate limiting.
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func redeemRateLimitKey(userID int64) string {
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return fmt.Sprintf("%s%d", redeemRateLimitKeyPrefix, userID)
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}
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// redeemLockKey generates the Redis key for redeem code locking.
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func redeemLockKey(code string) string {
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return redeemLockKeyPrefix + code
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}
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type redeemCache struct {
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rdb *redis.Client
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}
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func NewRedeemCache(rdb *redis.Client) service.RedeemCache {
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return &redeemCache{rdb: rdb}
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}
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func (c *redeemCache) GetRedeemAttemptCount(ctx context.Context, userID int64) (int, error) {
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key := redeemRateLimitKey(userID)
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count, err := c.rdb.Get(ctx, key).Int()
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if err == redis.Nil {
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return 0, nil
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}
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return count, err
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}
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func (c *redeemCache) IncrementRedeemAttemptCount(ctx context.Context, userID int64) error {
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key := redeemRateLimitKey(userID)
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return incrementRedeemAttemptScript.Run(
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ctx,
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c.rdb,
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[]string{key},
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redeemRateLimitWindow.Milliseconds(),
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).Err()
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}
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func (c *redeemCache) AcquireRedeemLock(ctx context.Context, code string, ttl time.Duration) (bool, error) {
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key := redeemLockKey(code)
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return c.rdb.SetNX(ctx, key, 1, ttl).Result()
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}
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func (c *redeemCache) ReleaseRedeemLock(ctx context.Context, code string) error {
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key := redeemLockKey(code)
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return c.rdb.Del(ctx, key).Err()
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}
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