FTP component written with fully managed code

• Download the ftp assembly project - 20 Kb
• Download the demo project - 10 Kb

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.