implement rate limiting

helpers/ratelimit.go

@@ -0,0 +1,35 @@
+package helpers
+
+import (
+	"net"
+	"net/http"
+	"sync"
+
+	"golang.org/x/time/rate"
+)
+
+var visitors = make(map[string]*rate.Limiter)
+var mu sync.Mutex
+
+func GetVisitorLimiter(ip string) *rate.Limiter {
+	mu.Lock()
+	defer mu.Unlock()
+
+	limiter, exists := visitors[ip]
+	if !exists {
+		limiter = rate.NewLimiter(1, 5)
+		visitors[ip] = limiter
+	}
+	return limiter
+}
+
+func RateLimit(next http.Handler) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		ip, _, _ := net.SplitHostPort(r.RemoteAddr)
+		if !GetVisitorLimiter(ip).Allow() {
+			http.Error(w, "Too many requests", http.StatusTooManyRequests)
+			return
+		}
+		next.ServeHTTP(w, r)
+	})
+}