Check if file exists on FTP - Don't know the n

问题:

I receive a file on the FTP server, the name of the file is generated dynamically. I am trying to write a program to check if any file exists on the server.

        string userName = Dts.Variables["User::SFTPUsername"].Value.ToString();
        string password = Dts.Variables["User::SFTPPassword"].Value.ToString();
        **string fileName = Dts.Variables["User::FilePattern"].Value.ToString();**
        string ftpURL = String.Format("ftp://11.11.11/upload/{0}", fileName);

            WebClient request = new WebClient();
            request.Credentials = new NetworkCredential(userName, password);


            FtpWebRequest ftpRequest = (FtpWebRequest)WebRequest.Create(ftpURL);
            ftpRequest.Method = WebRequestMethods.Ftp.GetFileSize;
            ftpRequest.Credentials = new NetworkCredential(userName, password);

            using (FtpWebResponse ftpResponse = (FtpWebResponse)ftpRequest.GetResponse())
            {
                byte[] newFileData = request.DownloadData(ftpURL.ToString());
                string fileString = System.Text.Encoding.UTF8.GetString(newFileData);

                string strexist = String.Format("exist");
                MessageBox.Show(strexist);
                Dts.Variables["User::FileExists"].Value = true;
            }

This works well only when I specify the "fileName". Is there anyway I can do a wildcard search ("*.txt") or search if anyfile is in the upload folder?

Any help appreciated!!

回答1:

You can list out the file names from the FTP. Like Below...

            FtpWebRequest request = (FtpWebRequest)WebRequest.Create(ftpURL);
            request.Method = WebRequestMethods.Ftp.ListDirectory; 

            FtpWebResponse response = (FtpWebResponse) request.GetResponse();
            using (Stream respStream = response.GetResponseStream())
            {
                StreamReader reader = new StreamReader(respStream);
                //Read each file name from the response
                for (string fname = reader.ReadLine(); fname != null; fname = reader.ReadLine())
                {
                    // Add the file name into a list
                }
            }

If the list count is 0 then there is no file available. Also you will get the each file name in a list from the single request.

Iterate the list values using foreach loop. And make the above code as a method. Pass the File name to the method.

You can also do make sure particular file name is exists or not in the list.

Note: In the above code no need to provide the file name to the Url.

回答2:

There sure is!

Try setting ftpURL to the directory name in question and request.Method to WebRequestMethods.Ftp.ListDirectory;.

        var request = (FtpWebRequest)WebRequest.Create("ftp://www.example.com/uploads");
        request.Method = WebRequestMethods.Ftp.ListDirectory;
        request.Credentials = new NetworkCredential(userName, password);

        using (FtpWebResponse ftpResponse = (FtpWebResponse)ftpRequest.GetResponse())
        {
                    ...
        }    

For examples, check out http://timtrott.co.uk/ultimate-guide-ftp/ and http://msdn.microsoft.com/en-us/library/ms229716%28v=vs.110%29.aspx (note: the latter uses WebRequestMethods.Ftp.ListDirectoryDetails instead of ListDirectory, so you may need to slightly modify it).