Merge pull request #6 from augustus281/DEV

[algo]: sliding window log

Author: augustus281

README.md

@@ -6,4 +6,4 @@ The package can be installed as a Go module.
 
 ```
 go get github.com/augustus281/ratelimiter
-```
+```

sliding_window_log.go

@@ -0,0 +1,40 @@
+package ratelimiter
+
+import (
+	"sync"
+	"time"
+)
+
+type SlidingWindowLog struct {
+	window_size time.Duration
+	maxRequests int
+	requestLog  []time.Time
+	mu          sync.Mutex
+}
+
+func NewSlidingWindowLog(window_size time.Duration, max_requests int) *SlidingWindowLog {
+	return &SlidingWindowLog{
+		window_size: window_size,
+		maxRequests: max_requests,
+		requestLog:  make([]time.Time, 0),
+	}
+}
+
+func (swl *SlidingWindowLog) AllowRequest() bool {
+	swl.mu.Lock()
+	defer swl.mu.Unlock()
+
+	now := time.Now()
+	// Remove timestamps that are outside the current window
+	for len(swl.requestLog) > 0 && now.Sub(swl.requestLog[0]) >= swl.window_size {
+		swl.requestLog = swl.requestLog[1:]
+	}
+
+	// Check if we're still within the limit
+	if len(swl.requestLog) < swl.maxRequests {
+		swl.requestLog = append(swl.requestLog, now)
+		return true
+	}
+
+	return false
+}

sliding_window_log_test.go

@@ -0,0 +1,26 @@
+package ratelimiter
+
+import (
+	"testing"
+	"time"
+)
+
+func TestSlidingWindowLog(t *testing.T) {
+	limiter := NewSlidingWindowLog(1*time.Second, 3)
+
+	for i := 0; i < 3; i++ {
+		if !limiter.AllowRequest() {
+			t.Errorf("Expected request %d to be allowed, but it was denied", i+1)
+		}
+	}
+
+	if limiter.AllowRequest() {
+		t.Errorf("Expected the 4th request to be denied, but it was allowed")
+	}
+
+	time.Sleep(1 * time.Second)
+
+	if !limiter.AllowRequest() {
+		t.Errorf("Expected the request after the window slide to be allowed, but it was denied")
+	}
+}