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偶爾會遇到「嘗試嘗試重定向太多」的例外情況。嘗試使用WebRequest嘗試抓取網頁的HTML時,嘗試使用WebRequest嘗試使用太多重定向
這樣的網站的一個例子是http://www.magicshineuk.co.uk/
通常我會設置超時時間爲像6秒......但即使有30秒,最大重定向允許一些瘋狂喜歡200,它仍然會拋出「太多重定向」異常,或者會發生超時。
我該如何解決這個問題?
我的代碼如下...
try
{
System.Net.WebRequest request = System.Net.WebRequest.Create("http://www.magicshineuk.co.uk/");
var hwr = ((HttpWebRequest)request);
hwr.UserAgent ="Mozilla/5.0 (Windows NT 10.0; WOW64; rv:42.0) Gecko/20100101 Firefox/42.0";
hwr.Headers.Add("Accept-Language", "en-US,en;q=0.5");
hwr.Headers.Add("Accept-Encoding", "gzip, deflate");
hwr.ContentType = "text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8"; ;
hwr.KeepAlive = true;
hwr.Timeout = 30000; // 30 seconds... normally set to 6000
hwr.Method = "GET";
hwr.AllowAutoRedirect = true;
hwr.CookieContainer = new System.Net.CookieContainer();
// Setting this Makes no difference... normally I would like to keep to a sensible maximum but I will leave as the default of 50 if needs be...
// Either way, the Too Many Redirections exception occurs
hwr.MaximumAutomaticRedirections = 200;
using (var response = (HttpWebResponse)hwr.GetResponse())
{
Console.WriteLine(String.Format("{0} {1}", (int)response.StatusCode, response.StatusCode));
Console.WriteLine(response.ResponseUri);
Console.WriteLine("Last modified: {0}", response.LastModified);
Console.WriteLine("Server: {0}", response.Server);
Console.WriteLine("Supports Headers: {0}", response.SupportsHeaders);
Console.WriteLine("Headers: ");
// do something... e.g:
int keyCount = response.Headers.Keys.Count;
int i = 0;
Dictionary<string, string> hc = new Dictionary<string, string>();
foreach (var hname in response.Headers)
{
var hv = response.Headers[i].ToString();
hc.Add(hname.ToString(), hv);
i++;
}
foreach (var di in hc)
{
Console.WriteLine(" {0} = {1}", di.Key, di.Value);
}
}
}
catch (Exception ex)
{
Console.WriteLine("Exception: ");
Console.WriteLine(ex.Message);
}
我的錯。你刪除的線是罪魁禍首!我的函數「GetSimpleUrl(url)」返回「magicshineuk.co.uk」,因此重定向是因爲主機在請求發生前被設置。代碼現在實際運行良好。 – collumbo
爲了記錄,我刪除了行hwr.Host = Utils.GetSimpleUrl(url);以避免混淆。這些代碼現在適合其他人使用。 – collumbo
FTW!很高興現在排序。 –