From 1883d62cc66a8f5fb4b02279c165d8f2e1bead0d Mon Sep 17 00:00:00 2001
From: Anton Vakhrushev <anwinged@ya.ru>
Date: Fri, 13 Jun 2025 17:51:31 +0300
Subject: [PATCH] Add rate limiting

---
 go.mod  |  2 ++
 go.sum  |  2 ++
 main.go | 19 +++++++++++++++++++
 3 files changed, 23 insertions(+)
 create mode 100644 go.sum

diff --git a/go.mod b/go.mod
index 9b7d059..dfe65d1 100644
--- a/go.mod
+++ b/go.mod
@@ -1,3 +1,5 @@
 module imgdownloader
 
 go 1.24.3
+
+require golang.org/x/time v0.12.0
diff --git a/go.sum b/go.sum
new file mode 100644
index 0000000..457536c
--- /dev/null
+++ b/go.sum
@@ -0,0 +1,2 @@
+golang.org/x/time v0.12.0 h1:ScB/8o8olJvc+CQPWrK3fPZNfh7qgwCrY0zJmoEQLSE=
+golang.org/x/time v0.12.0/go.mod h1:CDIdPxbZBQxdj6cxyCIdrNogrJKMJ7pr37NYpMcMDSg=
diff --git a/main.go b/main.go
index 70bc99a..d8ed9de 100644
--- a/main.go
+++ b/main.go
@@ -1,6 +1,7 @@
 package main
 
 import (
+	"context"
 	"encoding/json"
 	"flag"
 	"fmt"
@@ -10,15 +11,21 @@ import (
 	"path/filepath"
 	"sync"
 	"time"
+
+	"golang.org/x/time/rate"
 )
 
 // HTTP клиент с таймаутом
 var httpClient *http.Client
 
+// Глобальный rate limiter
+var limiter *rate.Limiter
+
 func main() {
 	timeout := flag.Duration("t", 60*time.Second, "request timeout")
 	retries := flag.Int("r", 5, "number of download attempts")
 	jobs := flag.Int("j", 5, "concurrent downloads")
+	rateLimit := flag.Float64("rate", 0, "maximum downloads per second (0 = no limit)")
 
 	flag.Parse()
 
@@ -36,6 +43,11 @@ func main() {
 		Timeout: *timeout,
 	}
 
+	// Инициализируем rate limiter
+	if *rateLimit > 0 {
+		limiter = rate.NewLimiter(rate.Limit(*rateLimit), 1)
+	}
+
 	// Создаем директорию для загрузок
 	if err := os.MkdirAll(outputDir, 0755); err != nil {
 		fmt.Printf("Error creating directory: %v\n", err)
@@ -128,6 +140,13 @@ func downloadImage(url, filename string, maxRetries int) error {
 
 // Одна попытка скачивания
 func attemptDownload(url, filename string) error {
+	// Применяем rate limiting если он включен
+	if limiter != nil {
+		if err := limiter.Wait(context.Background()); err != nil {
+			return fmt.Errorf("rate limiter error: %v", err)
+		}
+	}
+
 	resp, err := httpClient.Get(url)
 	if err != nil {
 		return err