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Doc(limiter): clarify variable name 'expire' #1742

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merged 1 commit into from Feb 3, 2022
Merged

Doc(limiter): clarify variable name 'expire' #1742

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6 changes: 3 additions & 3 deletions middleware/limiter/limited_fixed.go
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Expand Up @@ -64,7 +64,7 @@ func (FixedWindow) New(cfg Config) fiber.Handler {
e.currHits++

// Calculate when it resets in seconds
expire := e.exp - ts
resetInSec := e.exp - ts

// Set how many hits we have left
remaining := cfg.Max - e.currHits
Expand All @@ -79,7 +79,7 @@ func (FixedWindow) New(cfg Config) fiber.Handler {
if remaining < 0 {
// Return response with Retry-After header
// https://tools.ietf.org/html/rfc6584
c.Set(fiber.HeaderRetryAfter, strconv.FormatUint(expire, 10))
c.Set(fiber.HeaderRetryAfter, strconv.FormatUint(resetInSec, 10))

// Call LimitReached handler
return cfg.LimitReached(c)
Expand All @@ -101,7 +101,7 @@ func (FixedWindow) New(cfg Config) fiber.Handler {
// We can continue, update RateLimit headers
c.Set(xRateLimitLimit, max)
c.Set(xRateLimitRemaining, strconv.Itoa(remaining))
c.Set(xRateLimitReset, strconv.FormatUint(expire, 10))
c.Set(xRateLimitReset, strconv.FormatUint(resetInSec, 10))

return err
}
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22 changes: 11 additions & 11 deletions middleware/limiter/limited_sliding.go
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Expand Up @@ -77,10 +77,10 @@ func (SlidingWindow) New(cfg Config) fiber.Handler {
e.currHits++

// Calculate when it resets in seconds
expire := e.exp - ts
resetInSec := e.exp - ts

// weight = time until current window reset / total window length
weight := float64(expire) / float64(expiration)
weight := float64(resetInSec) / float64(expiration)

// rate = request count in previous window - weight + request count in current window
rate := int(float64(e.prevHits)*weight) + e.currHits
Expand All @@ -89,18 +89,18 @@ func (SlidingWindow) New(cfg Config) fiber.Handler {
remaining := cfg.Max - rate

// Update storage. Garbage collect when the next window ends.
// |-------------------------|-------------------------|
// ^ ^ ^ ^
// ts e.exp End sample window End next window
// <----------->
// expire
// expire = e.exp - ts - time until end of current window.
// |--------------------------|--------------------------|
// ^ ^ ^ ^
// ts e.exp End sample window End next window
// <------------>
// resetInSec
// resetInSec = e.exp - ts - time until end of current window.
// duration + expiration = end of next window.
// Because we don't want to garbage collect in the middle of a window
// we add the expiration to the duration.
// Otherwise after the end of "sample window", attackers could launch
// a new request with the full window length.
manager.set(key, e, time.Duration(expire+expiration)*time.Second)
manager.set(key, e, time.Duration(resetInSec+expiration)*time.Second)

// Unlock entry
mux.Unlock()
Expand All @@ -109,7 +109,7 @@ func (SlidingWindow) New(cfg Config) fiber.Handler {
if remaining < 0 {
// Return response with Retry-After header
// https://tools.ietf.org/html/rfc6584
c.Set(fiber.HeaderRetryAfter, strconv.FormatUint(expire, 10))
c.Set(fiber.HeaderRetryAfter, strconv.FormatUint(resetInSec, 10))

// Call LimitReached handler
return cfg.LimitReached(c)
Expand All @@ -131,7 +131,7 @@ func (SlidingWindow) New(cfg Config) fiber.Handler {
// We can continue, update RateLimit headers
c.Set(xRateLimitLimit, max)
c.Set(xRateLimitRemaining, strconv.Itoa(remaining))
c.Set(xRateLimitReset, strconv.FormatUint(expire, 10))
c.Set(xRateLimitReset, strconv.FormatUint(resetInSec, 10))

return err
}
Expand Down