Implement comment length and IP rate limiting in comment creation

server/utils/request_limit.go

@@ -0,0 +1,54 @@
+package utils
+
+import (
+	"sync"
+	"time"
+)
+
+type RequestLimiter struct {
+	limit        int
+	requestsByIP map[string]int
+	mu           sync.Mutex
+}
+
+func NewRequestLimiter(limit int, duration time.Duration) *RequestLimiter {
+	l := &RequestLimiter{
+		limit:        limit,
+		requestsByIP: make(map[string]int),
+	}
+
+	if duration > 0 {
+		go func() {
+			for {
+				time.Sleep(duration)
+				l.resetCounts()
+			}
+		}()
+	}
+
+	return l
+}
+
+func (rl *RequestLimiter) AllowRequest(ip string) bool {
+	rl.mu.Lock()
+	defer rl.mu.Unlock()
+
+	count, exists := rl.requestsByIP[ip]
+	if !exists {
+		count = 0
+	}
+
+	if count >= rl.limit {
+		return false // Exceeded request limit for this IP
+	}
+
+	rl.requestsByIP[ip] = count + 1
+	return true // Request allowed
+}
+
+func (rl *RequestLimiter) resetCounts() {
+	rl.mu.Lock()
+	defer rl.mu.Unlock()
+
+	rl.requestsByIP = make(map[string]int) // Reset all counts
+}