.NET: Check URL's response status code?

Question

What\'s the easiest way in .NET to check what status code a web server replies with to a GET request?

Note that I do not need the body of the response. In fact, if possi

Answer 1

If you use HttpWebRequest, it's pretty easy:

HttpWebRequest request = (HttpWebRequest)WebRequest.Create("http://url");
request.Method = "GET";
HttpWebResponse response = (HttpWebResponse)request.GetResponse();
HttpStatusCode status = response.StatusCode;

You can surround that with a blanket catch clause, or look at the docs for WebRequest.Create and .GetResponse to see what exceptions will get thrown.

Answer 2

Use the HTTP method HEAD, which is the same as GET except doesn't return the body:

var request = (HttpWebRequest)WebRequest.Create("http://www.example.com");
request.Method = "HEAD";
var response = (HttpWebResponse)request.GetResponse();

// status code...
response.StatusCode;

From Section 9.4 of RFC2616:

The HEAD method is identical to GET except that the server MUST NOT return a message-body in the response. The metainformation contained in the HTTP headers in response to a HEAD request SHOULD be identical to the information sent in response to a GET request. This method can be used for obtaining metainformation about the entity implied by the request without transferring the entity-body itself. This method is often used for testing hypertext links for validity, accessibility, and recent modification.

Answer 3

Here is what I came up with that handles 404 exceptions. There is also a test below.

public static HttpStatusCode GetUrlStatus(string url, string userAgent)
{
    HttpStatusCode result = default(HttpStatusCode);

    HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
    request.UserAgent = userAgent;
    request.Method = "HEAD";

    try
    {
        using (var response = request.GetResponse() as HttpWebResponse)
        {
            if (response != null)
            {
                result = response.StatusCode;
                response.Close();
            }
        }
    }
    catch (WebException we)
    {
        result = ((HttpWebResponse)we.Response).StatusCode;
    }

    return result;
}


[Test]
public void PageNotFoundShouldReturn404()
{
    //Arrange
    HttpStatusCode expected = HttpStatusCode.NotFound;
    string userAgent = "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/68.0.3440.106 Safari/537.36";

    //Act
    HttpStatusCode result = WebHelper.GetUrlStatus("http://www.kellermansoftware.com/SomePageThatDoesNotExist", userAgent);

    //Assert
    Assert.AreEqual(expected, result);
}   

Answer 4

public HttpStatusCode GetHeaders(string url)
    {
        HttpStatusCode result = default(HttpStatusCode);

        var request = HttpWebRequest.Create(url);
        request.Method = "HEAD";
        using (var response = request.GetResponse() as HttpWebResponse)
        {
            if (response != null)
            {
                result = response.StatusCode;
                response.Close();
            }
        }

        return result;
    }

Answer 5

I've ended up with this method which combines Ivan Ferić's answer and with proper exceptional cases support:

public async Task<bool> IsAccessibleAsync (string url)
{
    if (url == null)
        throw new ArgumentNullException ("url");

    if (url.IndexOf (':') < 0)
        url = "http://" + url.TrimStart ('/');

    if (!Uri.IsWellFormedUriString (url, UriKind.Absolute))
        return false;

    var request = (HttpWebRequest) WebRequest.Create (url);
    request.Method = "HEAD";

    try
    {
        using (var response = await request.GetResponseAsync () as HttpWebResponse)
        {
            if (response != null && response.StatusCode == HttpStatusCode.OK)
                return true;

            return false;
        }
    }
    catch (WebException)
    {
        return false;
    }
}