FTP Client library in C#
Author: Jaimon Mathew
This is the C# version of an FTP client library which is originally written in Java. The library will be compiled to a DLL file. A test program is also included to show the usage of this library. You will get more details about FTP from its rfc. Most of the commands are supported here. File upload & download methods are capable enough of doing resuming also.
The given test program is a console based application. I抦 inviting somebody on the net to develop a front end application with this library.
/*
FTPFactory.cs
Better view with tab space=4
Written by Jaimon Mathew (jaimonmathew@rediffmail.com)
Rolander,Dan (Dan.Rolander@marriott.com) has modified the
download
method to cope with file name with path information. He also
provided
the XML comments so that the library provides Intellisense
descriptions.
use the following line to compile
csc /target:library /out:FTPLib.dll /r:System.DLL FTPFactory.cs
*/
using System;
using System.Net;
using System.IO;
using System.Text;
using System.Net.Sockets;
namespace FtpLib
{
public class FTPFactory
{
private string
remoteHost,remotePath,remoteUser,remotePass,mes;
private int remotePort,bytes;
private Socket clientSocket;
private int retValue;
private Boolean debug;
private Boolean logined;
private string reply;
private static int BLOCK_SIZE = 512;
Byte[] buffer = new Byte[BLOCK_SIZE];
Encoding ASCII = Encoding.ASCII;
public FTPFactory()
{
remoteHost = "localhost";
remotePath = ".";
remoteUser = "anonymous";
remotePass = "jaimon@school2000.co.uk";
remotePort = 21;
debug = false;
logined = false;
}
///
/// Set the name of the FTP server to connect to.
///
/// Server name
public void setRemoteHost(string remoteHost)
{
this.remoteHost = remoteHost;
}
///
/// Return the name of the current FTP server.
///
/// Server name
public string getRemoteHost()
{
return remoteHost;
}
///
/// Set the port number to use for FTP.
///
/// Port number
public void setRemotePort(int remotePort)
{
this.remotePort = remotePort;
}
///
/// Return the current port number.
///
/// Current port number
public int getRemotePort()
{
return remotePort;
}
///
/// Set the remote directory path.
///
/// The remote directory path
public void setRemotePath(string remotePath)
{
this.remotePath = remotePath;
}
///
/// Return the current remote directory path.
///
/// The current remote directory path.
public string getRemotePath()
{
return remotePath;
}
///
/// Set the user name to use for logging into the remote
server.
///
/// Username
public void setRemoteUser(string remoteUser)
{
this.remoteUser = remoteUser;
}
///
/// Set the password to user for logging into the remote
server.
///
/// Password
public void setRemotePass(string remotePass)
{
this.remotePass = remotePass;
}
///
/// Return a string array containing the remote directory's
file list.
///
///
///
public string[] getFileList(string mask)
{
if(!logined)
{
login();
}
Socket cSocket = createDataSocket();
sendCommand("NLST " + mask);
if(!(retValue == 150 || retValue == 125))
{
throw new IOException(reply.Substring(4));
}
mes = "";
while(true)
{
int bytes = cSocket.Receive(buffer, buffer.Length, 0);
mes += ASCII.GetString(buffer, 0, bytes);
if(bytes < buffer.Length)
{
break;
}
}
char[] seperator = {'\n'};
string[] mess = mes.Split(seperator);
cSocket.Close();
readReply();
if(retValue != 226)
{
throw new IOException(reply.Substring(4));
}
return mess;
}
///
/// Return the size of a file.
///
///
///
public long getFileSize(string fileName)
{
if(!logined)
{
login();
}
sendCommand("SIZE " + fileName);
long size=0;
if(retValue == 213)
{
size = Int64.Parse(reply.Substring(4));
}
else
{
throw new IOException(reply.Substring(4));
}
return size;
}
///
/// Login to the remote server.
///
public void login()
{
clientSocket = new
Socket(AddressFamily.InterNetwork,SocketType.Stream,ProtocolType.Tcp);
IPEndPoint ep = new
IPEndPoint(Dns.Resolve(remoteHost).AddressList[0], remotePort);
try
{
clientSocket.Connect(ep);
}
catch(Exception)
{
throw new IOException("Couldn't connect to remote
server");
}
readReply();
if(retValue != 220)
{
close();
throw new IOException(reply.Substring(4));
}
if(debug)
Console.WriteLine("USER "+remoteUser);
sendCommand("USER "+remoteUser);
if( !(retValue == 331 || retValue == 230) )
{
cleanup();
throw new IOException(reply.Substring(4));
}
if( retValue != 230 )
{
if(debug)
Console.WriteLine("PASS xxx");
sendCommand("PASS "+remotePass);
if( !(retValue == 230 || retValue == 202) )
{
cleanup();
throw new IOException(reply.Substring(4));
}
}
logined = true;
Console.WriteLine("Connected to "+remoteHost);
chdir(remotePath);
}
///
/// If the value of mode is true, set binary mode for
downloads.
/// Else, set Ascii mode.
///
///
public void setBinaryMode(Boolean mode)
{
if(mode)
{
sendCommand("TYPE I");
}
else
{
sendCommand("TYPE A");
}
if (retValue != 200)
{
throw new IOException(reply.Substring(4));
}
}
///
/// Download a file to the Assembly's local directory,
/// keeping the same file name.
///
///
public void download(string remFileName)
{
download(remFileName,"",false);
}
///
/// Download a remote file to the Assembly's local
directory,
/// keeping the same file name, and set the resume flag.
///
///
///
public void download(string remFileName,Boolean resume)
{
download(remFileName,"",resume);
}
///
/// Download a remote file to a local file name which can
include
/// a path. The local file name will be created or
overwritten,
/// but the path must exist.
///
///
///
public void download(string remFileName,string locFileName)
{
download(remFileName,locFileName,false);
}
///
/// Download a remote file to a local file name which can
include
/// a path, and set the resume flag. The local file name will
be
/// created or overwritten, but the path must exist.
///
///
///
///
public void download(string remFileName,string
locFileName,Boolean resume)
{
if(!logined)
{
login();
}
setBinaryMode(true);
Console.WriteLine("Downloading file "+remFileName+" from
"+remoteHost + "/"+remotePath);
if (locFileName.Equals(""))
{
locFileName = remFileName;
}
if(!File.Exists(locFileName))
{
Stream st = File.Create(locFileName);
st.Close();
}
FileStream output = new
FileStream(locFileName,FileMode.Open);
Socket cSocket = createDataSocket();
long offset = 0;
if(resume)
{
offset = output.Length;
if(offset > 0 )
{
sendCommand("REST "+offset);
if(retValue != 350)
{
//throw new IOException(reply.Substring(4));
//Some servers may not support resuming.
offset = 0;
}
}
if(offset > 0)
{
if(debug)
{
Console.WriteLine("seeking to " + offset);
}
long npos = output.Seek(offset,SeekOrigin.Begin);
Console.WriteLine("new pos="+npos);
}
}
sendCommand("RETR " + remFileName);
if(!(retValue == 150 || retValue == 125))
{
throw new IOException(reply.Substring(4));
}
while(true)
{
bytes = cSocket.Receive(buffer, buffer.Length, 0);
output.Write(buffer,0,bytes);
if(bytes <= 0)
{
break;
}
}
output.Close();
if (cSocket.Connected)
{
cSocket.Close();
}
Console.WriteLine("");
readReply();
if( !(retValue == 226 || retValue == 250) )
{
throw new IOException(reply.Substring(4));
}
}
///
/// Upload a file.
///
///
public void upload(string fileName)
{
upload(fileName,false);
}
///
/// Upload a file and set the resume flag.
///
///
///
public void upload(string fileName,Boolean resume)
{
if(!logined)
{
login();
}
Socket cSocket = createDataSocket();
long offset=0;
if(resume)
{
try
{
setBinaryMode(true);
offset = getFileSize(fileName);
}
catch(Exception)
{
offset = 0;
}
}
if(offset > 0 )
{
sendCommand("REST " + offset);
if(retValue != 350)
{
//throw new IOException(reply.Substring(4));
//Remote server may not support resuming.
offset = 0;
}
}
sendCommand("STOR "+Path.GetFileName(fileName));
if( !(retValue == 125 || retValue == 150) )
{
throw new IOException(reply.Substring(4));
}
// open input stream to read source file
FileStream input = new
FileStream(fileName,FileMode.Open);
if(offset != 0)
{
if(debug)
{
Console.WriteLine("seeking to " + offset);
}
input.Seek(offset,SeekOrigin.Begin);
}
Console.WriteLine("Uploading file "+fileName+" to
"+remotePath);
while ((bytes = input.Read(buffer,0,buffer.Length)) > 0)
{
cSocket.Send(buffer, bytes, 0);
}
input.Close();
Console.WriteLine("");
if (cSocket.Connected)
{
cSocket.Close();
}
readReply();
if( !(retValue == 226 || retValue == 250) )
{
throw new IOException(reply.Substring(4));
}
}
///
/// Delete a file from the remote FTP server.
///
///
public void deleteRemoteFile(string fileName)
{
if(!logined)
{
login();
}
sendCommand("DELE "+fileName);
if(retValue != 250)
{
throw new IOException(reply.Substring(4));
}
}
///
/// Rename a file on the remote FTP server.
///
///
///
public void renameRemoteFile(string oldFileName,string
newFileName)
{
if(!logined)
{
login();
}
sendCommand("RNFR "+oldFileName);
if(retValue != 350)
{
throw new IOException(reply.Substring(4));
}
// known problem
// rnto will not take care of existing file.
// i.e. It will overwrite if newFileName exist
sendCommand("RNTO "+newFileName);
if(retValue != 250)
{
throw new IOException(reply.Substring(4));
}
}
///
/// Create a directory on the remote FTP server.
///
///
public void mkdir(string dirName)
{
if(!logined)
{
login();
}
sendCommand("MKD "+dirName);
if(retValue != 250)
{
throw new IOException(reply.Substring(4));
}
}
///
/// Delete a directory on the remote FTP server.
///
///
public void rmdir(string dirName)
{
if(!logined)
{
login();
}
sendCommand("RMD "+dirName);
if(retValue != 250)
{
throw new IOException(reply.Substring(4));
}
}
///
/// Change the current working directory on the remote FTP
server.
///
///
public void chdir(string dirName)
{
if(dirName.Equals("."))
{
return;
}
if(!logined)
{
login();
}
sendCommand("CWD "+dirName);
if(retValue != 250)
{
throw new IOException(reply.Substring(4));
}
this.remotePath = dirName;
Console.WriteLine("Current directory is "+remotePath);
}
///
/// Close the FTP connection.
///
public void close()
{
if( clientSocket != null )
{
sendCommand("QUIT");
}
cleanup();
Console.WriteLine("Closing...");
}
///
/// Set debug mode.
///
///
public void setDebug(Boolean debug)
{
this.debug = debug;
}
private void readReply()
{
mes = "";
reply = readLine();
retValue = Int32.Parse(reply.Substring(0,3));
}
private void cleanup()
{
if(clientSocket!=null)
{
clientSocket.Close();
clientSocket = null;
}
logined = false;
}
private string readLine()
{
while(true)
{
bytes = clientSocket.Receive(buffer, buffer.Length, 0);
mes += ASCII.GetString(buffer, 0, bytes);
if(bytes < buffer.Length)
{
break;
}
}
char[] seperator = {'\n'};
string[] mess = mes.Split(seperator);
if(mes.Length > 2)
{
mes = mess[mess.Length-2];
}
else
{
mes = mess[0];
}
if(!mes.Substring(3,1).Equals(" "))
{
return readLine();
}
if(debug)
{
for(int k=0;k < mess.Length-1;k++)
{
Console.WriteLine(mess[k]);
}
}
return mes;
}
private void sendCommand(String command)
{
Byte[] cmdBytes =
Encoding.ASCII.GetBytes((command+"\r\n").ToCharArray());
clientSocket.Send(cmdBytes, cmdBytes.Length, 0);
readReply();
}
private Socket createDataSocket()
{
sendCommand("PASV");
if(retValue != 227)
{
throw new IOException(reply.Substring(4));
}
int index1 = reply.IndexOf('(');
int index2 = reply.IndexOf(')');
string ipData =
reply.Substring(index1+1,index2-index1-1);
int[] parts = new int[6];
int len = ipData.Length;
int partCount = 0;
string buf="";
for (int i = 0; i < len && partCount <= 6; i++)
{
char ch = Char.Parse(ipData.Substring(i,1));
if (Char.IsDigit(ch))
buf+=ch;
else if (ch != ',')
{
throw new IOException("Malformed PASV reply: " +
reply);
}
if (ch == ',' || i+1 == len)
{
try
{
parts[partCount++] = Int32.Parse(buf);
buf="";
}
catch (Exception)
{
throw new IOException("Malformed PASV reply: " +
reply);
}
}
}
string ipAddress = parts[0] + "."+ parts[1]+ "." +
parts[2] + "." + parts[3];
int port = (parts[4] << 8) + parts[5];
Socket s = new
Socket(AddressFamily.InterNetwork,SocketType.Stream,ProtocolType.Tcp);
IPEndPoint ep = new
IPEndPoint(Dns.Resolve(ipAddress).AddressList[0], port);
try
{
s.Connect(ep);
}
catch(Exception)
{
throw new IOException("Can't connect to remote
server");
}
return s;
}
}
}
Following is the listing of a test program which uses this
library
/*
File : Test.cs
Better view with tab space=4
use the following line to compile
csc.exe /t:exe /r:System.DLL /r:FTPLib.dll /out:"Test.exe"
"Test.cs"
*/
using System;
using FtpLib;
public class Test {
public static void Main() {
try {
Console.WriteLine("Starting...");
FTPFactory ff = new FTPFactory();
ff.setDebug(true);
ff.setRemoteHost("192.168.0.30");
ff.setRemoteUser("jaimon");
ff.setRemotePass("mathew");
ff.login();
ff.chdir("incoming");
string[] fileNames = ff.getFileList("*.*");
for(int i=0;i < fileNames.Length;i++) {
Console.WriteLine(fileNames[i]);
}
ff.setBinaryMode(true);
ff.upload("c:\jaimon\tmp\Webdunia.ttf");
ff.close();
}catch(Exception e) {
Console.WriteLine("Caught Error :"+e.Message);
}
}
}
