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FTP component written with fully managed code

, 7 May 2002
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A .NET FTP component

Recently, I needed to write a program which could automatically download files from an FTP server. Unfortunately the .NET Framework lacks good support for FTP services. Although a few companies have already written libraries which can be used directly, the price is really too high for poor men like me. As a result, I decided to write my own FTP library and here it is.

Disclaimer

This FTP component is an incomplete implementation of my design nor has it been fully tested. Please keep in mind it may contain bugs or even design flaws.

Connect to FTP server

FtpSession session = new FtpSession();
session.Server = "localhost";
session.Port   = 21; //not required if using the default ftp port 21
session.Connect("anonymous", "someone@somewhere.com");

Enum subdirectories and files

/*
* It is possible an incorrect list will be returned.
* In this case, you need to add your own regular expression to 
* interpret the list result (try to find it within ftpdirectory.cs)
*/
FtpDirectory root = session.RootDirectory;
foreach(FtpDirectory d in root.SubDirectories)
    //do something

    foreach(FtpFile f in root.Files)
        //do something

        /*
         * Only CurrentDirectory's item can be legally used.
         * Do not save down FtpDirectory and FtpFile for later use
         * unless you are sure they belongs to CurrentDirectory.
         * Here is some sample may cause problems
         */
        FtpDirectory d1 = session.CurrentDirectory.FindSubdirectory("somesubdir");
        FtpDirectory d2 = session.CurrentDirectory.FindSubdirectory("othersubdir");
        session.CurrentDirectory = d2;
        
        /*
         * Following 2 line will cause problem since CurrentDirectory 
         * is not d1's parent anymore
         */
        foreach(FtpDirectory d in d1) 
            //dosomthing

Change current directory

session.CurrentDirectory = somesubdirectory

Upload file

//Blocking call
session.CurrentDirectory.PutFile("somelocalfile");
    
//Async call using callback
session.CurrentDirectory.BeginPutFile("somelocalfile", +
    new FtpAsyncDelegate(yourcallback);
    
//Async call using event
session.EndPutFile += new FtpFileEventHandler(yourhandler);
session.CurrectDirectory.BeginPutFile("somelocalfile");
        
    //Manually upload the file
    FileInfo fi = new FileInfo(localfilefullpath);
    Stream r = File.OpenRead(fi.FullName);

    // actually will return a FtpOutputDataStream object
    Stream w = session.CurrentDirectory.CreateDataStream(fi.Name); 
    int readed;
    byte[] buff = new byte[4096];
    while((readed=r.Read(buff, 0, 4096) != 0)
	    w.Write(buff, 0, readed);
    /*
    * Must call FtpDataStream.Close().
    * This is because it will try to read the file transfer 
    * result from FTP server.
    */
    w.Close();
    s.Close();

Download file

//Blocking call
session.CurrentDirectory.GetFile("someremotefile");
    
//Async call using callback
session.CurrentDirectory.BeginGetFile("someremotefile", + 
    new FtpAsyncDelegate(yourcallback);
    
//Async call using event
session.EngGetFile += new FtpFileEventHandler(yourhandler);
session.CurrectDirectory.BeginGetFile("someremotefile");

//Manually download a file
Stream r = File.OpenWrite(localfilepath);

    FtpFile remoteFile = session.CurrentDirectory.FindFile(remotefilename);
    Stream w = remoteFile.GetOutputDataStream();
    int readed;
    byte[] buff = new byte[4096];
    while((readed=r.Read(buff, 0, 4096) != 0)
        w.Write(buff, 0, readed);
    /*
    * Must call FtpDataStream.Close().
    * This is because it will try to read the file transfer 
    * result from FTP server.
    */
    w.Close();
    s.Close();

Create a new file in ftp server

//method 1
session.CurrentDirectory.CreateFile(newfilename);
        
//method 2
Stream s = session.CurrentDirectory.CreateFileStream(newfilename);
// do something with s
s.Close();

Delete a file from ftp server

//method 1
session.CurrentDirectory.RemoveFile(remotefilename);
        
//method 2
IFtpItem item = session.CurrentDirectory.FindItem(remotefilename)
if(item != null)
    session.CurrentDirectory.RemoveItem(item);

Delete a subdirectory

//method 1
session.CurrentDirectory.RemoveSubdir(subdirectoryname);

//method 2
IFtpItem item = session.CurrentDirectory.FindItem(sub directoryname)
if(item != null)
    session.CurrentDirectory.RemoveItem(item);

Refresh the content of ftp directory

/*
* If you have saved down some some directory item(subdir or ftpfile).
* They will become invalid after you refresh the directory
*/
FtpFile f = session.CurrentDirectory.FindFile(somefile);
         
// you can not leagally use f anymore after the following line
session.CurrentDirectory.Refresh();

Rename a file or directory

IFtpItem item = session.FindItem(directoryorfile);
if(item != null)
    session.RenameSubitem(item, newname);

Known Limitations

  • No support for active mode
  • No support for proxy server

Updates

  • Removed FileCollection and DirectoryCollection
  • Added support for VB's for each statement
  • VB client can directly access FtpDirectory.Files and FtpDirectory.SubDirectories with for each statement now.

Please send me a email if you find any bugs. Please include at least a description of the bug you have found. It will be nice if a testing program or even a solution is included.

Have fun.

License

This article has no explicit license attached to it but may contain usage terms in the article text or the download files themselves. If in doubt please contact the author via the discussion board below.

A list of licenses authors might use can be found here

About the Author

Alex Kwok
Web Developer
Hong Kong Hong Kong
No Biography provided

Comments and Discussions

 
GeneralCannot connect .. Help !! PinmemberStar999919-Apr-06 17:18 
GeneralSubdirectory Pinmembernmbvc2-Mar-06 5:01 
GeneralRe: Subdirectory Pinmembertherearefartoomanybens13-Dec-09 14:51 
Questioncan't download demo file? PinsussAnonymous6-Oct-05 13:39 
GeneralHi Alex Pinmembersantosh poojari14-Sep-05 20:40 
GeneralHelp!! Problem Kcommon GetFile PinmemberJugkrit_Emp@hotmail.com22-Aug-05 21:07 
GeneralRe: Help!! Problem Kcommon GetFile PinsussAnonymous29-Aug-05 0:58 
Generalavoid blocking while reading response stream! Pinmember[pascal]17-Aug-05 4:59 
ReadAppendChar will block in s.read (::response.cs) if there isn't anything incomming from remote server, so your thread hangs and isn't interruptible (thread.abort() has no effect - no idea, why). so i wrote this fix to have a timeout (set the time as needed! by yourself).
 
<code>
private char ReadAppendChar(Stream s, ref System.Text.StringBuilder Text)
{
   try
   {
         byte[] Buffer = new byte[1];
         IAsyncResult Result = s.BeginRead(Buffer, 0, Buffer.Length, null, null);
         Result.AsyncWaitHandle.WaitOne(500, false);
 
         if (s.EndRead(Result) > 0)
         {
            char Sign = (char)Buffer[0];
            Text.Append(Sign);
            return Sign;
         }
         else
         {
            throw new Exception("timeout");
         }
   }
   catch (Exception ex)
   {
         throw ex;
   }
}
</code>
 
greetings!
pascal
 
/* no comment */
GeneralRe: avoid blocking while reading response stream! Pinmembercphexad13-Feb-07 3:44 
GeneralHi Help needed PinmemberNR_gopal3-Aug-05 1:40 
Generalunhandled exceptions Pinmember[pascal]27-Jul-05 6:24 
Generalpatch for linux ftp list parsing Pinmember[pascal]25-Jul-05 5:57 
GeneralRe: patch for linux ftp list parsing Pinmembercwetzelberger8-May-07 4:41 
Generaluploading images to ftp using files Pinmemberv.venkannababu4-Jun-05 23:44 
Generaldoesnt compile PinsussDavid Every3-Jun-05 12:20 
QuestionHow to use this coding in ASP.NET ?? Pinsusspathakmakrand@yahoo.com16-May-05 18:54 
GeneralUnix Regular Expression PinmemberSasquatP29-Mar-05 9:34 
GeneralVPN performance problem-design flaw Pinmemberfmoldoveanu21-Mar-05 13:28 
QuestionMultipel-files? Pinsussanonymous24-Feb-05 3:13 
GeneralIncomplete download PinsussAnonymous2-Feb-05 12:18 
GeneralTypo in kcommon FTP class PinmemberWyatt Wong31-Jan-05 14:44 
Generalproxy server support PinmemberJohn Makin6-Jan-05 2:12 
GeneralAnother free, open-source .NET FTP component PinsussHans Andersen11-Nov-04 11:45 
GeneralRe: Another free, open-source .NET FTP component Pinmember[pascal]27-Jul-05 6:17 
GeneralcAse-sEnSItiVe regular expressions Match Pinmemberttocek8-Nov-04 9:50 

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