68c6ab85c5
- MemoryStore mirrors Laravel tooManyAttempts-before-hit first-hit-wins - FixedWindowLimiter + throttle factory; success and 429 rate-limit headers - Trusted-proxy ClientIP; remove noOpLimit; keep Limiter interface seam
116 lines
2.6 KiB
Go
116 lines
2.6 KiB
Go
package surf
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import (
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"sync"
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"time"
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)
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// Store mirrors Illuminate\Cache\RateLimiter's hit/tooManyAttempts/
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// availableIn control flow: a fixed window, first-hit-wins (an existing
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// unexpired window is never extended), with resetAttempts as a side effect
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// of TooManyAttempts observing an expired window.
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type Store interface {
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Hit(key string, decay time.Duration) (attempts int)
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TooManyAttempts(key string, max int) bool
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AvailableIn(key string) time.Duration
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}
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type counterEntry struct {
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count int
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resetAt time.Time
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}
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// MemoryStore is an in-process, mutex-guarded Store.
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type MemoryStore struct {
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mu sync.Mutex
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entries map[string]*counterEntry
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sweep time.Duration
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stop chan struct{}
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}
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// NewMemoryStore returns an in-process, mutex-guarded Store. sweep controls
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// the background expired-entry cleanup interval (memory hygiene only --
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// correctness does not depend on it, since expiry is checked lazily).
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// A non-positive sweep disables the background goroutine.
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func NewMemoryStore(sweep time.Duration) *MemoryStore {
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s := &MemoryStore{
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entries: make(map[string]*counterEntry),
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sweep: sweep,
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stop: make(chan struct{}),
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}
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if sweep > 0 {
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go s.loop()
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}
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return s
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}
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func (s *MemoryStore) loop() {
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ticker := time.NewTicker(s.sweep)
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defer ticker.Stop()
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for {
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select {
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case <-ticker.C:
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s.purge()
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case <-s.stop:
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return
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}
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}
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}
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func (s *MemoryStore) purge() {
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s.mu.Lock()
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defer s.mu.Unlock()
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now := time.Now()
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for k, e := range s.entries {
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if now.After(e.resetAt) {
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delete(s.entries, k)
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}
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}
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}
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// Hit increments key's counter, opening a decay window on first hit
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// (first-hit-wins: an existing unexpired window is never extended).
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func (s *MemoryStore) Hit(key string, decay time.Duration) int {
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s.mu.Lock()
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defer s.mu.Unlock()
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now := time.Now()
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e, ok := s.entries[key]
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if !ok || now.After(e.resetAt) {
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e = &counterEntry{count: 0, resetAt: now.Add(decay)}
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s.entries[key] = e
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}
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e.count++
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return e.count
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}
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// TooManyAttempts is true only while count >= max and the window has not
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// expired. An expired window is deleted (PHP resetAttempts) and returns false.
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func (s *MemoryStore) TooManyAttempts(key string, max int) bool {
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s.mu.Lock()
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defer s.mu.Unlock()
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e, ok := s.entries[key]
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if !ok {
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return false
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}
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if time.Now().After(e.resetAt) {
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delete(s.entries, key)
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return false
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}
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return e.count >= max
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}
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// AvailableIn is the time until the window resets, or 0 if the key is absent.
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func (s *MemoryStore) AvailableIn(key string) time.Duration {
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s.mu.Lock()
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defer s.mu.Unlock()
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e, ok := s.entries[key]
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if !ok {
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return 0
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}
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d := e.resetAt.Sub(time.Now())
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if d < 0 {
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return 0
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}
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return d
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}
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