Question

I have a bit of code that is supposed to check whether a directory exists on a remote server. It executes the ListDirectory command on the path and expects a response if it exists and an exception if it doesn’t.

The problem is that the command returns the code 125 DataAlreadyOpen, so my code interprets that as success, when it should have failed.

I might be completely misunderstanding how FTP works. I’m creating a new request every time, so I don’t understand how a connection can already be open.

Oh, and the code works with root directories like ftp://myIP/Folder1, but doesn’t work with ftp://myIP/Folder1/Folder2. I’m using the IIS FTP server, by the way.

public static bool DirectoryExists(string path)
{
    try
    {
        var request = (FtpWebRequest)WebRequest.Create(path);
        request.Credentials = new NetworkCredential("foo", "bar");
        request.Method = WebRequestMethods.Ftp.ListDirectory;
        request.KeepAlive = false;

        using (var response = (FtpWebResponse)request.GetResponse())
            return true;
    }
    catch (Exception ex)
    {
        return false;
    }
}

How can I reliably check whether a directory exists? All the code examples I’ve found use this technique.

Answer 1

I worked around this issue by using the WebRequestMethods.Ftp.MakeDirectory command whenever I want to check if a directory exists. If it doesn’t exist, it’s created, if it exists, I catch the exception and carry on.