adarsh's blog

Sample code for parsing FtpwebRequest response for ListDirectoryDetails

ResponseStream of FtpWebResponse provides the raw data bytes to the user, some of you had asked that it would be more useful to provide methods which return list of directory and files on ListDirectory request to the server. Current .Net frameworks doesn't support this, so here is some sample code I had written for parsing, in general I found it works very well against most of the server. But just to make sure it is not extensively tested, so treat only as sample, its not guaranteed to work against every server.

using System;
using System.IO;
using System.Net;
using System.Collections;
using System.Collections.Generic;
using System.Text.RegularExpressions;

   public struct FileStruct
   {
        public string Flags;
        public string Owner;
        public string Group;
        public bool IsDirectory;
        public DateTime CreateTime;
        public string Name;
    }
   public enum FileListStyle{
        UnixStyle,
        WindowsStyle,
        Unknown  
    }

public class ParseListDirectory
{
       public static void Main(string[] args)
       {
              if(args.Length < 1)
              {
                  Console.WriteLine("\n Usage FTPListDirParser <uriString>");
                  return;
              }
              try
              {
                     FtpWebRequest ftpclientRequest = WebRequest.Create(args[0]) as FtpWebRequest;
                     ftpclientRequest.Method = FtpMethods.ListDirectoryDetails;
                     ftpclientRequest.Proxy = null;  
                     FtpWebResponse response = ftpclientRequest.GetResponse() as FtpWebResponse;
                     StreamReader sr = new StreamReader(response.GetResponseStream(), System.Text.Encoding.ASCII);
                     string Datastring = sr.ReadToEnd(); 
                     response.Close();
   
                     FileStruct[]  list = (new ParseListDirectory()).GetList(Datastring);
                     Console.WriteLine ("------------After Parsing-----------");
                     foreach(FileStruct thisstruct in list)
                     { 
                            if(thisstruct.IsDirectory)
                                Console.WriteLine("<DIR> "+thisstruct.Name+","+thisstruct.Owner+","+thisstruct.Flags+","+thisstruct.CreateTime);
                            else
                                  Console.WriteLine(thisstruct.Name+","+thisstruct.Owner+","+thisstruct.Flags+","+thisstruct.CreateTime);
                     }  
           }
           catch(Exception e)
           {
                  Console.WriteLine(e);
           }
    }
 
 private FileStruct[] GetList(string datastring)
 {
  List<FileStruct> myListArray = new List<FileStruct>(); 
  string[] dataRecords = datastring.Split('\n');
  FileListStyle _directoryListStyle = GuessFileListStyle(dataRecords);
  foreach (string s in dataRecords)
  {    
   if (_directoryListStyle != FileListStyle.Unknown && s != "")
   {
    FileStruct f = new FileStruct();
    f.Name = "..";
    switch (_directoryListStyle)
    {
     case FileListStyle.UnixStyle:
      f = ParseFileStructFromUnixStyleRecord(s);
      break;
     case FileListStyle.WindowsStyle:
      f = ParseFileStructFromWindowsStyleRecord(s);
      break;
    }
    if (!(f.Name == "." || f.Name == ".."))
    {
     myListArray.Add(f);     
    }    
   }
  }
  return myListArray.ToArray(); ;
 }

 private FileStruct ParseFileStructFromWindowsStyleRecord(string Record)
 {
  ///Assuming the record style as
  /// 02-03-04  07:46PM       <DIR>          Append
  FileStruct f = new FileStruct();
  string processstr = Record.Trim();
  string dateStr = processstr.Substring(0,8);      
  processstr = (processstr.Substring(8, processstr.Length - 8)).Trim();
  string timeStr = processstr.Substring(0, 7);
  processstr = (processstr.Substring(7, processstr.Length - 7)).Trim();
  f.CreateTime = DateTime.Parse(dateStr + " " + timeStr);
  if (processstr.Substring(0,5) == "<DIR>")
  {
   f.IsDirectory = true;    
   processstr = (processstr.Substring(5, processstr.Length - 5)).Trim();
  }
  else
  {
   string[] strs = processstr.Split(new char[] { ' ' }, true);
   processstr = strs[1].Trim();
   f.IsDirectory = false;
  }   
  f.Name = processstr;  //Rest is name   
  return f;
 }

 public FileListStyle GuessFileListStyle(string[] recordList)
 {
  foreach (string s in recordList)
  {
   if(s.Length > 10
    && Regex.IsMatch(s.Substring(0,10),"(-|d)(-|r)(-|w)(-|x)(-|r)(-|w)(-|x)(-|r)(-|w)(-|x)"))
   {
    return FileListStyle.UnixStyle;
   }      
   else if (s.Length > 8
    && Regex.IsMatch(s.Substring(0, 8),  "[0-9][0-9]-[0-9][0-9]-[0-9][0-9]"))
   {
    return FileListStyle.WindowsStyle;
   }   
  }
  return FileListStyle.Unknown;
 }

 private FileStruct ParseFileStructFromUnixStyleRecord(string Record)
 {
  ///Assuming record style as
  /// dr-xr-xr-x   1 owner    group               0 Nov 25  2002 bussys
  FileStruct f= new FileStruct();   
  string processstr = Record.Trim();        
  f.Flags = processstr.Substring(0,9);
  f.IsDirectory = (f.Flags[0] == 'd');  
  processstr =  (processstr.Substring(11)).Trim();
  _cutSubstringFromStringWithTrim(ref processstr,' ',0);   //skip one part
  f.Owner = _cutSubstringFromStringWithTrim(ref processstr,' ',0);
  f.Group = _cutSubstringFromStringWithTrim(ref processstr,' ',0);
  _cutSubstringFromStringWithTrim(ref processstr,' ',0);   //skip one part
  f.CreateTime = DateTime.Parse(_cutSubstringFromStringWithTrim(ref processstr,' ',8));    
  f.Name =  processstr;   //Rest of the part is name
  return f;
 }

     private string _cutSubstringFromStringWithTrim(ref string s, char c, int startIndex)
     {
            int pos1 = s.IndexOf(c, startIndex);
           string retString = s.Substring(0,pos1);
           s = (s.Substring(pos1)).Trim();
           return retString;
       }
}
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