Question

I am validating a regular URL as follows:

private static bool IsUrlAvailable(string url)
    {

        if ((string.IsNullOrEmpty(url.Trim()) == true) ||
            (url.Trim().ToLower().Equals("http://")) ||
            (url.Trim().ToLower().Equals("https://")))
        {
            return false;
        }
        if (!url.ToLower().StartsWith("http://") && !url.ToLower().StartsWith("https://"))
        {
            url = "http://" + url;
        }
        try
        {
            var req = (HttpWebRequest)WebRequest.Create(url);
            req.Timeout = 15000;
            req.Method = "HEAD";
            using (var rsp = (HttpWebResponse)req.GetResponse())
            {
                if (rsp.StatusCode == HttpStatusCode.OK)
                {
                    return true;
                }
            }
        }
        catch (Exception ex)
        {
            // Eat it because all we want to do is return false 
        }

        // Otherwise 
        return false;
    }

But since I am using a WebRequest.Create, authenticated SharePoint urls on the intranet are failing validation because of permission denied (404) error. Now I know we can validate it using SPSite.Exists or OpenWeb but these are only available in microsoft.sharepoint.dll and I was wondering if there is a way of doing this without using this DLL?

Answer 1

404 is not permission denied… but file-not-found. So you may indeed hit non-existing Url.

You need to pass credentials with your request

WebRequest request = WebRequest.Create ("http://www.contoso.com/default.html");
// If required by the server, set the credentials.
request.Credentials = CredentialCache.DefaultCredentials;
// Get the response.
HttpWebResponse response = (HttpWebResponse)request.GetResponse ();

Side note: please do not “eat all exceptions” – there is very small set of exceptions that are interesting in case of making WebRequests which you can find in article about HttpWebRequest.GetResponse (you likley should only handle WebException).