Parsing FtpWebRequest ListDirectoryDetails line

Not sure if you still need this, but this is the solution i came up with:

Regex regex = new Regex ( @"^([d-])([rwxt-]{3}){3}\s+\d{1,}\s+.*?(\d{1,})\s+(\w+\s+\d{1,2}\s+(?:\d{4})?)(\d{1,2}:\d{2})?\s+(.+?)\s?$",
    RegexOptions.Compiled | RegexOptions.Multiline | RegexOptions.IgnoreCase | RegexOptions.IgnorePatternWhitespace );

Match Groups:

1. object type:
   • d : directory
   • - : file
2. Array[3] of permissions (rwx-)
3. File Size
4. Last Modified Date
5. Last Modified Time
6. File/Directory Name

For this specific listing, the following code will do:

var request = (FtpWebRequest)WebRequest.Create("ftp://ftp.example.com/");
request.Credentials = new NetworkCredential("user", "password");
request.Method = WebRequestMethods.Ftp.ListDirectoryDetails;
var reader = new StreamReader(request.GetResponse().GetResponseStream());

string pattern =
    @"^([\w-]+)\s+(\d+)\s+(\w+)\s+(\w+)\s+(\d+)\s+" +
    @"(\w+\s+\d+\s+\d+|\w+\s+\d+\s+\d+:\d+)\s+(.+)$";
Regex regex = new Regex(pattern);
IFormatProvider culture = CultureInfo.GetCultureInfo("en-us");
string[] hourMinFormats =
    new[] { "MMM dd HH:mm", "MMM dd H:mm", "MMM d HH:mm", "MMM d H:mm" };
string[] yearFormats =
    new[] { "MMM dd yyyy", "MMM d yyyy" };

while (!reader.EndOfStream)
{
    string line = reader.ReadLine();
    Match match = regex.Match(line);
    string permissions = match.Groups[1].Value;
    int inode = int.Parse(match.Groups[2].Value, culture);
    string owner = match.Groups[3].Value;
    string group = match.Groups[4].Value;
    long size = long.Parse(match.Groups[5].Value, culture);
    string s = Regex.Replace(match.Groups[6].Value, @"\s+", " ");
    
    string[] formats = (s.IndexOf(':') >= 0) ? hourMinFormats : yearFormats;
    var modified = DateTime.ParseExact(s, formats, culture, DateTimeStyles.None);
    string name = match.Groups[7].Value;

    Console.WriteLine(
        "{0,-16} permissions = {1}  size = {2, 9}  modified = {3}",
        name, permissions, size, modified.ToString("yyyy-MM-dd HH:mm"));
}

You will get (as of year 2016):

bin              permissions = d--x--x--x  size =      4096  modified = 2002-03-07 00:00
TEST.TXT         permissions = -rw-r--r--  size =    659450  modified = 2016-06-15 05:07
TEST03-05.TXT    permissions = -rw-r--r--  size = 101786380  modified = 2008-09-08 00:00
dropoff          permissions = drwxrwxr-x  size =      4096  modified = 2016-05-06 12:24

But, actually trying to parse the listing returned by the ListDirectoryDetails is not the right way to go.

You want to use an FTP client that supports the modern MLSD command that returns a directory listing in a machine-readable format specified in the RFC 3659. Parsing the human-readable format returned by the ancient LIST command (used internally by the FtpWebRequest for its ListDirectoryDetails method) should be used as the last resort option, when talking to obsolete FTP servers, that do not support the MLSD command (like the Microsoft IIS FTP server).

Many servers use a different format for the LIST command response. Particularly IIS can use DOS format. See C# class to parse WebRequestMethods.Ftp.ListDirectoryDetails FTP response.

For example with WinSCP .NET assembly, you can use its Session.ListDirectory or Session.EnumerateRemoteFiles methods.

They internally use the MLSD command, but can fall back to the LIST command and support dozens of different human-readable listing formats.

The returned listing is presented as collection of RemoteFileInfo instances with properties like:

• Name
• LastWriteTime (with correct timezone)
• Length
• FilePermissions (parsed into individual rights)
• Group
• Owner
• IsDirectory
• IsParentDirectory
• IsThisDirectory

(I'm the author of WinSCP)

Most other 3rd party libraries will do the same. Using the FtpWebRequest class is not reliable for this purpose. Unfortunately, there's no other built-in FTP client in the .NET framework.