如何使用ASP.Net/C#读取客户端URL的HTTP标头状态代码

Question

在ASP.Net中使用C＃读取URL时，需要读取HTTP标头的状态（403或404）。 例如：URL1： https : //www.instagram.com/khaniki.ah URL2： https : //www.instagram.com/khaniki.ah123456当我尝试读取URL1时，状态为200（HttpStatusCode.Found）用于读取不存在的URL2； 在照片中查看更多。

另外，我使用以下代码：

    var Url = UrlTbx.Text;
    Uri urlCheck = new Uri(Url);

    HttpWebRequest HttpRequest = (HttpWebRequest)WebRequest.Create(Url);
    HttpRequest.Timeout = 15000;
    HttpRequest.AllowAutoRedirect = false;
    HttpRequest.ServicePoint.Expect100Continue = false;
    HttpRequest.ContentType = "application/x-www-form-urlencoded";
    //HttpRequest.Method = "GET";
    HttpRequest.Method = "HEAD";//both methods was tested
    HttpWebResponse HttpResponse;

    try
    {
        HttpResponse = (HttpWebResponse)HttpRequest.GetResponse();

        if (HttpResponse.StatusCode == HttpStatusCode.Found)
            Lit.Text = "YES" + " / " + HttpResponse.StatusCode;
        else if (HttpResponse.StatusCode == HttpStatusCode.NotFound)
            Lit.Text = "NO" + " / " + HttpResponse.StatusCode;
    }
    catch (Exception)
    {
       return false;
    }

Answer 1

您请求的服务器似乎不接受HEAD请求。 尝试保留GET标头方法，然后尝试删除

HttpRequest.ContentType = "application/x-www-form-urlencoded";

还发现不是200。您在谈论HttpStatusCode.OK为200。简单地做时，我得到的是您要查找的404

   var Url = "https://www.instagram.com/khaniki.ah123456/";
   Uri urlCheck = new Uri(Url);

   HttpWebRequest HttpRequest = (HttpWebRequest)WebRequest.Create(Url);

   HttpRequest.Method = "Get";

   var dHttpWebResponse = await HttpRequest.GetResponseAsync();

或尝试使用httpclient api（以避免异常）

var Url = "https://www.instagram.com/khaniki.ah123456/";
        Uri urlCheck = new Uri(Url);
        var client = new HttpClient();
        var res = client.GetAsync(urlCheck).Result;
        var statusCode = res.StatusCode; //should be 404