Question

I previously had a small VBScript that would test if a specific website was accessible by sending a GET request. The script itself was extremely simple and did everything I needed:

Function GETRequest(URL) 'Sends a GET http request to a specific URL
   Dim objHttpRequest

   Set objHttpRequest = CreateObject("MSXML2.XMLHTTP.3.0")
   objHttpRequest.Open "GET", URL, False

   On Error Resume Next 'Error checking in case access is denied
   objHttpRequest.Send

   GETRequest = objHttpRequest.Status
End Function

I now want to include this sort of functionality in an expanded C# application. However I’ve been unable to get the same results my previous script provided.

Using code similar to what I’ve posted below sort of gets me a proper result, but fails to run if my network connection has failed.

public static void GETRequest()
{
    HttpWebRequest request = (HttpWebRequest)WebRequest.Create("http://url");
    request.Method = "GET";
    HttpStatusCode status;
    HttpWebResponse response;
    try
    {
       response = (HttpWebResponse)request.GetResponse();
       status = response.StatusCode;
       Console.WriteLine((int)response.StatusCode);
       Console.WriteLine(status);
    }
    catch (WebException e)
    {
       status = ((HttpWebResponse)e.Response).StatusCode;
       Console.WriteLine(status);
    }
}

But as I said, I need to know if the site is accessible, not matter the reason: the portal could be down, or the problem might reside on the side of the PC that’s trying to access it. Either way: I don’t care.

When I used MSXML2.XMLHTTP.3.0 in the script I was able to get values ranging from 12000 to 12156 if I was having network problems. I would like to have the same functionality in my C# app, that way I could at least write a minimum of information to a log and let the computer act accordingly. Any ideas?

Answer 1

A direct translation of your code would be something like this:

static void GetStatusCode(string url)
{
    dynamic httpRequest = Activator.CreateInstance(Type.GetTypeFromProgID("MSXML2.XMLHTTP.3.0"));
    httpRequest.Open("GET", url, false);

    try     { httpRequest.Send(); }
    catch   { }
    finally { Console.WriteLine(httpRequest.Status); }
}

It’s as small and simple as your VBScript script, and uses the same COM object to send the request.

This code happily gives me error code like 12029 ERROR_WINHTTP_CANNOT_CONNECT or 12007 ERROR_WINHTTP_NAME_NOT_RESOLVED etc.