optimize itv

Golang/liveurls/itv.go

@@ -299,6 +299,11 @@ func getHTTPResponse(requestURL string) (string, string, error) {
 	}
 	defer resp.Body.Close()
 
+	if resp.StatusCode != http.StatusOK {
+		clearCache(requestURL) // 请求失败清除缓存
+		return "", "", err
+	}
+
 	redirectURL := resp.Header.Get("Location")
 	if redirectURL == "" {
 		redirectURL = requestURL
@@ -306,14 +311,11 @@ func getHTTPResponse(requestURL string) (string, string, error) {
 
 	body, err := readResponseBody(resp)
 	if err != nil {
-		clearCache(requestURL) // 清除缓存失败的IP
+		clearCache(requestURL) // 读取响应体失败时清除缓存
 		return "", "", err
 	}
 
-	// 调整缓存时间：仅在成功获取内容时缓存24小时
-	if resp.StatusCode == http.StatusOK {
-		updateCacheTime(requestURL, successCacheTime)
-	}
+	updateCacheTime(requestURL, successCacheTime) // 成功获取响应后缓存IP
 
 	return body, redirectURL, nil
 }
@@ -323,33 +325,31 @@ func resolveIP(host string) string {
 	if entry, found := dnsCache.Load(host); found {
 		cachedEntry := entry.(cacheEntry)
 		if now.Before(cachedEntry.expiry) {
-			return cachedEntry.ip
+			return cachedEntry.ip // 使用缓存中的IP
 		}
-		dnsCache.Delete(host)
+		dnsCache.Delete(host) // 缓存过期，删除
 	}
 
-	ips, err := net.LookupIP(host)
+	ips, err := net.LookupIP(host) // DNS解析
 	if err != nil || len(ips) == 0 {
-		return ""
+		return "" // 解析失败，返回空字符串
 	}
 
-	ip := ips[0].String()
-	dnsCache.Store(host, cacheEntry{ip: ip, expiry: now})
-	return ip
+	return ips[0].String() // 返回解析到的IP
 }
 
 func updateCacheTime(requestURL string, duration time.Duration) {
 	host := extractHost(requestURL)
 	if entry, found := dnsCache.Load(host); found {
 		cachedEntry := entry.(cacheEntry)
-		cachedEntry.expiry = time.Now().Add(duration)
+		cachedEntry.expiry = time.Now().Add(duration) // 更新缓存过期时间
 		dnsCache.Store(host, cachedEntry)
 	}
 }
 
 func clearCache(requestURL string) {
 	host := extractHost(requestURL)
-	dnsCache.Delete(host)
+	dnsCache.Delete(host) // 删除缓存
 }
 
 func extractHost(requestURL string) string {