84 lines
1.6 KiB
Go
84 lines
1.6 KiB
Go
package middleware
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import (
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"net/http"
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"strconv"
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"sync"
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"time"
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"github.com/gin-gonic/gin"
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)
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type rateLimitBucket struct {
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count int
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resetAt time.Time
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lastSeen time.Time
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}
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type rateLimiter struct {
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mu sync.Mutex
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limit int
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window time.Duration
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buckets map[string]rateLimitBucket
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}
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func RateLimitPerMinute(limit int) gin.HandlerFunc {
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if limit <= 0 {
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return func(c *gin.Context) {
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c.Next()
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}
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}
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limiter := &rateLimiter{
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limit: limit,
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window: time.Minute,
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buckets: make(map[string]rateLimitBucket),
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}
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return limiter.handle
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}
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func (l *rateLimiter) handle(c *gin.Context) {
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now := time.Now()
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key := c.ClientIP()
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allowed, resetAt := l.allow(key, now)
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if !allowed {
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c.Header("Retry-After", retryAfterSeconds(now, resetAt))
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c.AbortWithStatusJSON(http.StatusTooManyRequests, gin.H{
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"code": "rate_limited",
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"message": "请求过于频繁，请稍后再试",
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})
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return
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}
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c.Next()
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}
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func (l *rateLimiter) allow(key string, now time.Time) (bool, time.Time) {
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l.mu.Lock()
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defer l.mu.Unlock()
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l.cleanup(now)
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bucket := l.buckets[key]
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if bucket.resetAt.IsZero() || !now.Before(bucket.resetAt) {
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bucket = rateLimitBucket{resetAt: now.Add(l.window)}
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}
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bucket.count++
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bucket.lastSeen = now
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l.buckets[key] = bucket
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return bucket.count <= l.limit, bucket.resetAt
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}
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func (l *rateLimiter) cleanup(now time.Time) {
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for key, bucket := range l.buckets {
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if now.Sub(bucket.lastSeen) > 2*l.window {
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delete(l.buckets, key)
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}
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}
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}
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func retryAfterSeconds(now time.Time, resetAt time.Time) string {
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seconds := int(resetAt.Sub(now).Seconds())
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if seconds < 1 {
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seconds = 1
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}
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return strconv.Itoa(seconds)
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}
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