記錄一次 HttpWebRequest 嘗試自動重定向太多 錯誤

 當使用HttpWebRequest進行訪問時，結果提示為302重定向錯誤。

使用代碼，

            HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
            request.Method = "GET";
            request.ContentType = "text/html";
            request.AllowAutoRedirect = true;//設置自動重定向

            request.ServicePoint.Expect100Continue = true;//設置自動重定向
            request.MaximumAutomaticRedirections = 50;//允許最大重定向次數
            request.CookieContainer = new CookieContainer();
            //request.Timeout = 30000;
            //request.ReadWriteTimeout = 30000;

            ServicePointManager.ServerCertificateValidationCallback += (se, cert, chain, sslerror) =>
            {
                return true;
            };

            request.UserAgent = "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/56.0.2924.87 Safari/537.36";
            HttpWebResponse response = (HttpWebResponse)request.GetResponse();
            var heards = request.GetResponse().Headers;
            Stream myResponseStream = response.GetResponseStream();
            using (StreamReader myStreamReader = new StreamReader(myResponseStream, encoding))
            {
                string retString = myStreamReader.ReadToEnd();
                myStreamReader.Close();
                myResponseStream.Close();
                return retString;
            }

　

最終發現。是少加了CookieContainer...猜測是由於重定向時候第一個網頁往頭部添加了一個Cookie這個Cookie發送給重定向地址，所以必須帶上CookieContainer。