89 lines
1.3 KiB
Go
89 lines
1.3 KiB
Go
package mailserver
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import (
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"sync"
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"time"
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)
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type rateLimiter struct {
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sync.RWMutex
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lifespan time.Duration // duration of the limit
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db map[string]time.Time
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period time.Duration
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cancel chan struct{}
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}
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func newRateLimiter(duration time.Duration) *rateLimiter {
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return &rateLimiter{
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lifespan: duration,
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db: make(map[string]time.Time),
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period: time.Second,
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}
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}
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func (l *rateLimiter) Start() {
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cancel := make(chan struct{})
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l.Lock()
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l.cancel = cancel
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l.Unlock()
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go l.cleanUp(l.period, cancel)
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}
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func (l *rateLimiter) Stop() {
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l.Lock()
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defer l.Unlock()
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if l.cancel == nil {
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return
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}
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close(l.cancel)
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l.cancel = nil
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}
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func (l *rateLimiter) Add(id string) {
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l.Lock()
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l.db[id] = time.Now()
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l.Unlock()
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}
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func (l *rateLimiter) IsAllowed(id string) bool {
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l.RLock()
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defer l.RUnlock()
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if lastRequestTime, ok := l.db[id]; ok {
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return lastRequestTime.Add(l.lifespan).Before(time.Now())
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}
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return true
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}
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func (l *rateLimiter) cleanUp(period time.Duration, cancel <-chan struct{}) {
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t := time.NewTicker(period)
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defer t.Stop()
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for {
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select {
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case <-t.C:
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l.deleteExpired()
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case <-cancel:
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return
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}
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}
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}
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func (l *rateLimiter) deleteExpired() {
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l.Lock()
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defer l.Unlock()
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now := time.Now()
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for id, lastRequestTime := range l.db {
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if lastRequestTime.Add(l.lifespan).Before(now) {
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delete(l.db, id)
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}
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}
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}
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