FTP Factory class in C#

/*
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.
*/

using System;
using System.Net;
using System.IO;
using System.Text;
using System.Net.Sockets;

namespace Common
{
///

/// This class provides the functionality for FTP Server connection
/// and related functions.
///

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;

///

/// Default constuctor for FTP Factory class
///

public FTPFactory()
{
remoteHost = "localhost";
remotePath = ".";
remoteUser = null;
remotePass = null;
remotePort = 21;
debug = false;
logined = false;
}

///

/// Sets the name of the FTP server to connect to
///

/// Remote host Name
public void setRemoteHost(string remoteHost)
{
this.remoteHost = remoteHost;
}

///

/// Returns the name of the current FTP server
///

/// Host Name
public string getRemoteHost()
{
return remoteHost;
}

///

/// Sets the port number to use for FTP.
///

/// Port number
public void setRemotePort(int remotePort)
{
this.remotePort = remotePort;
}

///

/// Returns the current port number.
///

/// Current port number
public int getRemotePort()
{
return remotePort;
}

///

/// Sets 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;
}

///

/// Sets the user name to use for logging into the remote server.
///

/// Username
public void setRemoteUser(string remoteUser)
{
this.remoteUser = remoteUser;
}

///

/// Sets the password to user for logging into the remote server.
///

/// Password
public void setRemotePass(string remotePass)
{
this.remotePass = remotePass;
}

///

/// Returns a string array containing the remote directory's file list.
///

/// Mask to be used for filteration
/// List of files in string array format
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;
}

///

/// Returns the size of a file.
///

/// Name of the file for which the size is required
/// size in long format
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);
}

///

/// Sets the mode for file transfer
///

/// Value of the Mode, 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.
///

/// File to be downlaoded
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.
///

/// File to be downlaoded
/// Flag to set if the resume is managed or not
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.
///

/// File to be downlaoded
/// Local file name
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.
///

/// File to be downlaoded
/// Local file name
/// Flag stating if it is required to set the resume
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));
}
}

///

/// Uploads a file
///

/// File name to be uplaoded
public void upload(string fileName)
{
upload(fileName,false);
}

///

/// Upload a file and set the resume flag.
///

/// File name to be uplaoded
/// Flag to set if the operation needs the resume functionality
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));
}
}

///

/// Deletes a file from the remote FTP server.
///

/// File name to be deleted
public void deleteRemoteFile(string fileName)
{

if(!logined)
{
login();
}

sendCommand("DELE "+fileName);

if(retValue != 250)
{
throw new IOException(reply.Substring(4));
}
}

///

/// Renames a file on the remote FTP server.
///

/// Old File Name
/// New File Name
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));
}
}

///

/// Creates a directory on the remote FTP server.
///

/// Name of the directory
public void mkdir(string dirName)
{
if(!logined)
{
login();
}

sendCommand("MKD "+dirName);

if(retValue != 250)
{
throw new IOException(reply.Substring(4));
}
}

///

/// Deletes a directory on the remote FTP server.
///

/// Removes the directory
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.
///

/// New directory Name
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;
}

// Reads a reply from the server
private void readReply()
{
mes = "";
reply = readLine();
retValue = Int32.Parse(reply.Substring(0,3));
}

// Clean up the socket connections
private void cleanup()
{
if(clientSocket!=null)
{
clientSocket.Close();
clientSocket = null;
}
logined = false;
}

// Read line
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;
}
}
}