How to get status code from webclient

Question

I am using the WebClient class to post some data to a web form  I would like to get the response status code of the form submission  So far I ve found out how to get the status code if there is a exception  Catch wex As WebException         If TypeOf wex Response Is HttpWebResponse Then           msgbox DirectCast wex Response  HttpWebResponse  StatusCode              End If   However if the form is submitted successfully and no exception is thrown then I won t know the status code 200 301 302       Is there some way to get the status code when there is no exceptions thrown   PS  I prefer not to use httpwebrequest httpwebresponse

User · Answer

There is a way to do it using reflection. It works with .NET 4.0. It accesses a private field and may not work in other versions of .NET without modifications.

I have no idea why Microsoft did not expose this field with a property.

private static int GetStatusCode(WebClient client, out string statusDescription)
{
    FieldInfo responseField = client.GetType().GetField("m_WebResponse", BindingFlags.Instance | BindingFlags.NonPublic);

    if (responseField != null)
    {
        HttpWebResponse response = responseField.GetValue(client) as HttpWebResponse;

        if (response != null)
        {
            statusDescription = response.StatusDescription;
            return (int)response.StatusCode;
        }
    }

    statusDescription = null;
    return 0;
}

User · Answer

Just in case someone else needs an F  version of the above described hack   open System open System IO open System Net  type WebClientEx          inherit WebClient           lt DefaultValue gt   val mutable m Resp   WebResponse       override x GetWebResponse  req  WebRequest             x m Resp  lt - base GetWebResponse req           req    gt  HttpWebRequest  AllowAutoRedirect  lt - false          x m Resp       override x GetWebResponse  req  WebRequest   ar  IAsyncResult              x m Resp  lt - base GetWebResponse req  ar           req    gt  HttpWebRequest  AllowAutoRedirect  lt - false          x m Resp       member x StatusCode with get     HttpStatusCode                if not  obj ReferenceEquals  x m Resp  null    amp  amp  x m Resp GetType     typeof lt HttpWebResponse gt  then                  x m Resp    gt  HttpWebResponse  StatusCode             else                 HttpStatusCode OK  let wc   new WebClientEx   let st   wc OpenRead  http   www stackoverflow com   let sr   new StreamReader st  let res   sr ReadToEnd   wc StatusCode sr Close   st Close

User · Answer

You should be able to use the  client ResponseHeaders      call  see this link for examples of getting stuff back from the response

User · Answer

If you are using  Net 4 0  or less    class BetterWebClient   WebClient           private WebRequest  Request   null           protected override WebRequest GetWebRequest Uri address                        this  Request   base GetWebRequest address                if  this  Request is HttpWebRequest                                  HttpWebRequest this  Request  AllowAutoRedirect   false                             return this  Request                      public HttpStatusCode StatusCode                         HttpStatusCode result               if  this  Request    null                                throw  new InvalidOperationException  Unable to retrieve the status                         code  maybe you haven t made a request yet                                 HttpWebResponse response   base GetWebResponse this  Request                                          as HttpWebResponse               if  response    null                                result   response StatusCode                            else                               throw  new InvalidOperationException  Unable to retrieve the status                         code  maybe you haven t made a request yet                                 return result                    If you are using  Net 4 5 X or newer  switch to HttpClient   var response   await client GetAsync  http   www contoso com     var statusCode   response StatusCode

User · Answer

You should use   if  e Status    WebExceptionStatus ProtocolError       HttpWebResponse response    HttpWebResponse ex Response                  if  response StatusCode    HttpStatusCode NotFound        System Diagnostics Debug WriteLine  Not found

User · Answer

You can try this code to get HTTP status code from WebException or from OpenReadCompletedEventArgs Error  It works in Silverlight too because SL does not have WebExceptionStatus ProtocolError defined   HttpStatusCode GetHttpStatusCode System Exception err        if  err is WebException                WebException we    WebException err          if  we Response is HttpWebResponse                        HttpWebResponse response    HttpWebResponse we Response              return response StatusCode                      return 0

User · Answer

You can check if the error is of type WebException and then inspect the response code   if  e Error GetType   Name     WebException        WebException we    WebException e Error     HttpWebResponse response    System Net HttpWebResponse we Response     if  response StatusCode  HttpStatusCode NotFound        System Diagnostics Debug WriteLine  Not found         or  try          send request   catch  WebException e           check e Status as above etc

User · Answer

Erik s answer doesn t work on Windows Phone as is  The following does   class WebClientEx   WebClient       private WebResponse m Resp   null       protected override WebResponse GetWebResponse WebRequest Req  IAsyncResult ar                try                       this m Resp   base GetWebResponse request                     catch  WebException ex                        if  this m Resp    null                  this m Resp   ex Response                    return this m Resp             public HttpStatusCode StatusCode               get                       if  m Resp    null  amp  amp  m Resp is HttpWebResponse                  return  m Resp as HttpWebResponse  StatusCode              else                 return HttpStatusCode OK                      At least it does when using OpenReadAsync  for other xxxAsync methods  careful testing would be highly recommended  The framework calls GetWebResponse somewhere along the code path  all one needs to do is capture and cache the response object   The fallback code is 200 in this snippet because genuine HTTP errors - 500  404  etc - are reported as exceptions anyway  The purpose of this trick is to capture non-error codes  in my specific case 304  Not modified   So the fallback assumes that if the status code is somehow unavailable  at least it s a non-erroneous one

User · Answer

Tried it out  ResponseHeaders do not include status code   If I m not mistaken  WebClient is capable of abstracting away multiple distinct requests in a single method call  e g  correctly handling 100 Continue responses  redirects  and the like   I suspect that without using HttpWebRequest and HttpWebResponse  a distinct status code may not be available   It occurs to me that  if you are not interested in intermediate status codes  you can safely assume the final status code is in the 2xx  successful  range  otherwise  the call would not be successful   The status code unfortunately isn t present in the ResponseHeaders dictionary

User · Answer

This is what I use for expanding WebClient functionality  StatusCode and StatusDescription will always contain the most recent response code description                        lt summary gt                      An expanded web client that allows certificate auth and                      the retrieval of status  for successful requests                      lt  summary gt                  public class WebClientCert   WebClient                                       private X509Certificate2  cert                      public WebClientCert X509Certificate2 cert    base      cert   cert                        protected override WebRequest GetWebRequest Uri address                                                HttpWebRequest request    HttpWebRequest base GetWebRequest address                           if   cert    null    request ClientCertificates Add  cert                             return request                                            protected override WebResponse GetWebResponse WebRequest request                                                WebResponse response   null                          response   base GetWebResponse request                           HttpWebResponse baseResponse   response as HttpWebResponse                          StatusCode   baseResponse StatusCode                          StatusDescription   baseResponse StatusDescription                          return response                                                 lt summary gt                          The most recent response statusCode                          lt  summary gt                      public HttpStatusCode StatusCode   get  set                             lt summary gt                          The most recent response statusDescription                          lt  summary gt                      public string StatusDescription   get  set                        Thus you can do a post and get result via               byte   response   null              using  WebClientCert client   new WebClientCert                                  response   client UploadValues postUri  PostFields                   HttpStatusCode code   client StatusCode                  string description   client StatusDescription                    Use this information

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