I need to extract the first folder from url

Question

I need to improve the method below.

The thing is to extract the first folder of an URL if it exists. The urls that can be pass are with domain or without domain, that is to say: http://www.xxx.com/es/test/test.aspx or http://xxx.com/es/test/ or /us/xxx/xxx.aspx.

public string ExtractURL(string url)
{
    string result = "";
    try
    {
        string[] urlSplitted = url.Split("//".ToCharArray());
        //si encontramos /
        if (urlSplitted.Length > 0)
        {
            string strFin = urlSplitted[urlSplitted.GetUpperBound(0) - 1];
            //comprobamos que exista algo
            if (String.IsNullOrEmpty(strFin))
            {
                result = url;
            }
            else
            {
                //devuelvo la url hasta /ES o /EN
                result = url.Substring(0,url.ToLower().IndexOf("/" +strFin.ToLower()));
            }
        }
        else
        {
            result = url;
        }
    }
    catch
    {
        result = "";
    }
    return result;
}

Answer 1

Consider using System.Uri class to pre-parse the Uri and extract the relative path with LocalPath property. Then use String.split().

Answer 2

public string ExtractURL(string URL)
    {
        string result = "";
        try
        {
            httpindex = URL.ToLower().IndexOf("http://");
            if (httpindex > 0)
            {
                URL = URL.Substring(0, 6);
            }
            URL = URL.ToLower().TrimStart("http://".ToCharArray());
            string[] urlArray = URL.Split('/');
            if (urlArray.Length > 1)
            {
                    result = urlArray[1];
            }
        }
        catch
        {
            result = "";
        }
        return result;
    }

That should do what you want I think

Answer 3

I agree with Sergii Volchkov and I think using System.Uri is the right way to go but instead of using string.split you may want to use Path.GetParentDirectory() on the local path.

Answer 4

Cast to a Uri and then use the Segments property. You'll actually want the second segment because the first is just the leading slash.

public string ExtractURL(string url)
{
    Uri webAddress = null;
    string firstFolder = null;
    if (Uri.TryCreate(url, UriKind.RelativeOrAbsolute, out webAddress))
    {
        if (!webAddress.IsAbsoluteUri)
        {
            webAddress = new Uri(Request.Url, url);
        }
        if (webAddress.Segments.Length >= 2)
        {
            firstFolder = webAddress.Segments[1];
        }
    }
    return firstFolder;
}

Answer 5

If you want to solve this with a regular expression (as you tagged your question "regex"), try this:

public string ExtractURL(string url)
{
  return Regex.Match(url, "(?<!/)/[^/?#]+").Value;
}

This regex works on absolute URLs, and on relative URLs that begin with a slash. If it also needs to work on relative URLs without a slash, try this:

public string ExtractURL(string url)
{
  Regex.Match(url, @"(\w*:(//[^/?#]+)?/)?(?<folder>[^/?#]+)").Groups["folder"].Value;
}