func (c *Cache) exists(key string) error {
val, _ := c.client.Do("EXISTS", key)
if val.(int64) == 1 {
return nil
}
return errors.NewNonExistingKey(key)
}
// CompareAndReplace validates the token with the token in the store. If the
// tokens match, we will replace the value and return true. If it doesn't, we
// will not replace the value and return false.
func (c *Cache) CompareAndReplace(token, key string, value []byte, ttl int64) error {
if err := c.exists(key); err != nil {
return err
}
if c.items[key].token != token {
return errors.NewNonExistingKey(key)
}
return c.Set(key, value, ttl)
}
// exists checks if a key is stored in the cache.
//
// If the key is stored in the cache, but the expiry date has passed, we will
// remove the item from the cache and return false. If the expiry has not passed
// yet, it will return false.
func (c *Cache) exists(key string) error {
cachedItem, exists := c.items[key]
if exists {
if !cachedItem.expire || time.Now().Before(cachedItem.expiry) {
c.lru(key)
return nil
}
// Item is expired, delete it and act as it doesn't exist
c.Delete(key)
}
return errors.NewNonExistingKey(key)
}