94 lines
2.0 KiB
Go
94 lines
2.0 KiB
Go
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// Package api — rate limit helpers for auth endpoints.
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package api
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import (
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"net"
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"net/http"
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"sync"
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"time"
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)
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// ipRateLimiter is a per-IP sliding window rate limiter.
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type ipRateLimiter struct {
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mu sync.Mutex
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windows map[string]*window
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limit int
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windowSz time.Duration
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}
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type window struct {
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hits []time.Time
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}
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func newIPRateLimiter(limit int, windowSz time.Duration) *ipRateLimiter {
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return &ipRateLimiter{
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windows: make(map[string]*window),
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limit: limit,
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windowSz: windowSz,
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}
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}
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// Allow returns true if the IP is within budget.
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func (rl *ipRateLimiter) Allow(ip string) bool {
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rl.mu.Lock()
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defer rl.mu.Unlock()
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now := time.Now()
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w, ok := rl.windows[ip]
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if !ok {
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w = &window{}
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rl.windows[ip] = w
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}
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// Trim entries outside the window.
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cutoff := now.Add(-rl.windowSz)
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n := 0
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for _, t := range w.hits {
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if t.After(cutoff) {
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w.hits[n] = t
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n++
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}
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}
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w.hits = w.hits[:n]
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if len(w.hits) >= rl.limit {
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return false
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}
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w.hits = append(w.hits, now)
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return true
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}
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// extractIP extracts the real client IP from X-Forwarded-For (Caddy sets this)
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// or falls back to RemoteAddr.
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func extractIP(r *http.Request) string {
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if xff := r.Header.Get("X-Forwarded-For"); xff != "" {
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// First IP in the chain is the original client.
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if ip := net.ParseIP(xff[:len(xff)]); ip != nil {
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return xff
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}
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// Handle comma-separated: take first.
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for i := 0; i < len(xff); i++ {
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if xff[i] == ',' {
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return xff[:i]
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}
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}
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return xff
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}
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host, _, err := net.SplitHostPort(r.RemoteAddr)
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if err != nil {
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return r.RemoteAddr
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}
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return host
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}
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// rateLimitAuth is middleware that limits auth-related endpoints per IP:
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// max requests per sliding window.
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func (s *Server) rateLimitAuth(rl *ipRateLimiter, next http.Handler) http.Handler {
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return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
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ip := extractIP(r)
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if !rl.Allow(ip) {
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writeErr(w, http.StatusTooManyRequests, "terlalu banyak percobaan, coba lagi nanti")
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return
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}
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next.ServeHTTP(w, r)
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})
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}
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