.NET下的FTP上傳、下載文件操作類

基本原理就是先建立Socket連接，然后發請求命令和取回應答碼。編碼方式采用Encoding ASCII = Encoding.Default;來支持中文文件名。

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

namespace PMTSS.Common
{
 /// <summary>
 /// FTP 操作類
 /// </summary>
 public class FTP
 {
  private string strRemoteHost;
  private int strRemotePort;
  private string strRemotePath;
  private string strRemoteUser;
  private string strRemotePass;
  private Boolean bConnected;

  #region 內部變量
  /// <summary>
  /// 服務器返回的應答信息(包含應答碼)
  /// </summary>
  private string strMsg;
  /// <summary>
  /// 服務器返回的應答信息(包含應答碼)
  /// </summary>
  private string strReply;
  /// <summary>
  /// 服務器返回的應答碼
  /// </summary>
  private int iReplyCode;
  /// <summary>
  /// 進行控制連接的socket
  /// </summary>
  private Socket socketControl;
  /// <summary>
  /// 傳輸模式
  /// </summary>
  private TransferType trType;
  /// <summary>
  /// 傳輸模式:二進制類型、ASCII類型
  /// </summary>
  public enum TransferType
  {
   /// <summary>
   /// Binary
   /// </summary>
   Binary,
   /// <summary>
   /// ASCII
   /// </summary>
   ASCII
  };

  /// <summary>
  /// 接收和發送數據的緩沖區
  /// </summary>
  private static int BLOCK_SIZE = 512;
  Byte[] buffer = new Byte[ BLOCK_SIZE];
  /// <summary>
  /// 編碼方式
  /// </summary>
  Encoding ASCII = Encoding.Default;
  #endregion

  #region 內部函數

  #region 構造函數
  /// <summary>
  /// 缺省構造函數
  /// </summary>
  public FTP()
  {
   strRemoteHost  = "";
   strRemotePath  = "";
   strRemoteUser  = "";
   strRemotePass  = "";
   strRemotePort  = 21;
   bConnected     = false;
  }

  /// <summary>
  /// 構造函數
  /// </summary>
  /// <param name="remoteHost"></param>
  /// <param name="remotePath"></param>
  /// <param name="remoteUser"></param>
  /// <param name="remotePass"></param>
  /// <param name="remotePort"></param>
  public FTP( string remoteHost, string remotePath, string remoteUser, string remotePass, int remotePort )
  {
   strRemoteHost  = remoteHost;
   strRemotePath  = remotePath;
   strRemoteUser  = remoteUser;
   strRemotePass  = remotePass;
   strRemotePort  = remotePort;
   Connect();
  }
  public FTP( string remoteHost, string remotePath, string remoteUser, string remotePass)
  {
   strRemoteHost  = remoteHost;
   strRemotePath  = remotePath;
   strRemoteUser  = remoteUser;
   strRemotePass  = remotePass;
   strRemotePort  = 21;
   Connect();
  }
  #endregion

  #region 登陸
  /// <summary>
  /// FTP服務器IP地址
  /// </summary>
 
  public string RemoteHost
  {
   get
   {
    return strRemoteHost;
   }
   set
   {
    strRemoteHost = value;
   }
  }
  /// <summary>
  /// FTP服務器端口
  /// </summary>
  public int RemotePort
  {
   get
   {
    return strRemotePort;
   }
   set
   {
    strRemotePort = value;
   }
  }
  /// <summary>
  /// 當前服務器目錄
  /// </summary>
  public string RemotePath
  {
   get
   {
    return strRemotePath;
   }
   set
   {
    strRemotePath = value;
   }
  }
  /// <summary>
  /// 登錄用戶賬號
  /// </summary>
  public string RemoteUser
  {
   set
   {
    strRemoteUser = value;
   }
  }
  /// <summary>
  /// 用戶登錄密碼
  /// </summary>
  public string RemotePass
  {
   set
   {
    strRemotePass = value;
   }
  }

  /// <summary>
  /// 是否登錄
  /// </summary>
  public bool Connected
  {
   get
   {
    return bConnected;
   }
  }
  #endregion

  #region 鏈接
  /// <summary>
  /// 建立連接
  /// </summary>
  public void Connect()
  {
   socketControl = new Socket(AddressFamily.InterNetwork,SocketType.Stream,ProtocolType.Tcp);
   IPEndPoint ep = new IPEndPoint(IPAddress.Parse(RemoteHost), strRemotePort);
   // 鏈接
   try
   {
    socketControl.Connect(ep);
   }
   catch(Exception)
   {
    throw new IOException("Couldn't connect to remote server");
   }

   // 獲取應答碼
   ReadReply();
   if(iReplyCode != 220)
   {
    DisConnect();
    throw new IOException(strReply.Substring(4));
   }

   // 登陸
   SendCommand("USER "+strRemoteUser);
   if( !(iReplyCode == 331 || iReplyCode == 230) )
   {
    CloseSocketConnect();//關閉連接
    throw new IOException(strReply.Substring(4));
   }
   if( iReplyCode != 230 )
   {
    SendCommand("PASS "+strRemotePass);
    if( !(iReplyCode == 230 || iReplyCode == 202) )
    {
     CloseSocketConnect();//關閉連接
     throw new IOException(strReply.Substring(4));
    }
   }
   bConnected = true;

   // 切換到目錄
   ChDir(strRemotePath);
  }

  /// <summary>
  /// 關閉連接
  /// </summary>
  public void DisConnect()
  {
   if( socketControl != null )
   {
    SendCommand("QUIT");
   }
   CloseSocketConnect();
  }

  #endregion

  #region 傳輸模式

  /// <summary>
  /// 設置傳輸模式
  /// </summary>
  /// <param name="ttType">傳輸模式</param>
  public void SetTransferType(TransferType ttType)
  {
   if(ttType == TransferType.Binary)
   {
    SendCommand("TYPE I");//binary類型傳輸
   }
   else
   {
    SendCommand("TYPE A");//ASCII類型傳輸
   }
   if (iReplyCode != 200)
   {
    throw new IOException(strReply.Substring(4));
   }
   else
   {
    trType = ttType;
   }
  }

  /// <summary>
  /// 獲得傳輸模式
  /// </summary>
  /// <returns>傳輸模式</returns>
  public TransferType GetTransferType()
  {
   return trType;
  }

  #endregion

  #region 文件操作
  /// <summary>
  /// 獲得文件列表
  /// </summary>
  /// <param name="strMask">文件名的匹配字符串</param>
  /// <returns></returns>
  public string[] Dir(string strMask)
  {
   // 建立鏈接
   if(!bConnected)
   {
    Connect();
   }

   //建立進行數據連接的socket
   Socket socketData = CreateDataSocket();

   //傳送命令
   SendCommand("NLST " + strMask);

   //分析應答代碼
   if(!(iReplyCode == 150 || iReplyCode == 125 || iReplyCode == 226))
   {
    throw new IOException(strReply.Substring(4));
   }

   //獲得結果
   strMsg = "";
   while(true)
   {
    int iBytes = socketData.Receive(buffer, buffer.Length, 0);
    strMsg += ASCII.GetString(buffer, 0, iBytes);
    if(iBytes < buffer.Length)
    {
     break;
    }
   }
   char[] seperator = {'\n'};
   string[] strsFileList = strMsg.Split(seperator);
   socketData.Close();//數據socket關閉時也會有返回碼
   if(iReplyCode != 226)
   {
    ReadReply();
    if(iReplyCode != 226)
    {
     throw new IOException(strReply.Substring(4));
    }
   }
   return strsFileList;
  }

  /// <summary>
  /// 獲取文件大小
  /// </summary>
  /// <param name="strFileName">文件名</param>
  /// <returns>文件大小</returns>
  private long GetFileSize(string strFileName)
  {
   if(!bConnected)
   {
    Connect();
   }
   SendCommand("SIZE " + Path.GetFileName(strFileName));
   long lSize=0;
   if(iReplyCode == 213)
   {
    lSize = Int64.Parse(strReply.Substring(4));
   }
   else
   {
    throw new IOException(strReply.Substring(4));
   }
   return lSize;
  }

  /// <summary>
  /// 刪除
  /// </summary>
  /// <param name="strFileName">待刪除文件名</param>
  public void Delete(string strFileName)
  {
   if(!bConnected)
   {
    Connect();
   }
   SendCommand("DELE "+strFileName);
   if(iReplyCode != 250)
   {
    throw new IOException(strReply.Substring(4));
   }
  }

  /// <summary>
  /// 重命名(如果新文件名與已有文件重名,將覆蓋已有文件)
  /// </summary>
  /// <param name="strOldFileName">舊文件名</param>
  /// <param name="strNewFileName">新文件名</param>
  public void Rename(string strOldFileName,string strNewFileName)
  {
   if(!bConnected)
   {
    Connect();
   }
   SendCommand("RNFR "+strOldFileName);
   if(iReplyCode != 350)
   {
    throw new IOException(strReply.Substring(4));
   }
   //  如果新文件名與原有文件重名,將覆蓋原有文件
   SendCommand("RNTO "+strNewFileName);
   if(iReplyCode != 250)
   {
    throw new IOException(strReply.Substring(4));
   }
  }
  #endregion

  #region 上傳和下載
  /// <summary>
  /// 下載一批文件
  /// </summary>
  /// <param name="strFileNameMask">文件名的匹配字符串</param>
  /// <param name="strFolder">本地目錄(不得以\結束)</param>
  public void Get(string strFileNameMask,string strFolder)
  {
   if(!bConnected)
   {
    Connect();
   }
   string[] strFiles = Dir(strFileNameMask);
   foreach(string strFile in strFiles)
   {
    if(!strFile.Equals(""))//一般來說strFiles的最后一個元素可能是空字符串
    {
     Get(strFile,strFolder,strFile);
    }
   }
  }

  /// <summary>
  /// 下載一個文件
  /// </summary>
  /// <param name="strRemoteFileName">要下載的文件名</param>
  /// <param name="strFolder">本地目錄(不得以\結束)</param>
  /// <param name="strLocalFileName">保存在本地時的文件名</param>
  public void Get(string strRemoteFileName,string strFolder,string strLocalFileName)
  {
   if(!bConnected)
   {
    Connect();
   }
   SetTransferType(TransferType.Binary);
   if (strLocalFileName.Equals(""))
   {
    strLocalFileName = strRemoteFileName;
   }
   if(!File.Exists(strLocalFileName))
   {
    Stream st = File.Create(strLocalFileName);
    st.Close();
   }
   FileStream output = new
    FileStream(strFolder + "\\" + strLocalFileName,FileMode.Create);
   Socket socketData = CreateDataSocket();
   SendCommand("RETR " + strRemoteFileName);
   if(!(iReplyCode == 150 || iReplyCode == 125
    || iReplyCode == 226 || iReplyCode == 250))
   {
    throw new IOException(strReply.Substring(4));
   }
   while(true)
   {
    int iBytes = socketData.Receive(buffer, buffer.Length, 0);
    output.Write(buffer,0,iBytes);
    if(iBytes <= 0)
    {
     break;
    }
   }
   output.Close();
   if (socketData.Connected)
   {
    socketData.Close();
   }
   if(!(iReplyCode == 226 || iReplyCode == 250))
   {
    ReadReply();
    if(!(iReplyCode == 226 || iReplyCode == 250))
    {
     throw new IOException(strReply.Substring(4));
    }
   }
  }

  /// <summary>
  /// 上傳一批文件
  /// </summary>
  /// <param name="strFolder">本地目錄(不得以\結束)</param>
  /// <param name="strFileNameMask">文件名匹配字符(可以包含*和?)</param>
  public void Put(string strFolder,string strFileNameMask)
  {
   string[] strFiles = Directory.GetFiles(strFolder,strFileNameMask);
   foreach(string strFile in strFiles)
   {
    //strFile是完整的文件名(包含路徑)
    Put(strFile);
   }
  }

  /// <summary>
  /// 上傳一個文件
  /// </summary>
  /// <param name="strFileName">本地文件名</param>
  public void Put(string strFileName)
  {
   if(!bConnected)
   {
    Connect();
   }
   Socket socketData = CreateDataSocket();
   SendCommand("STOR "+Path.GetFileName(strFileName));
   if( !(iReplyCode == 125 || iReplyCode == 150) )
   {
    throw new IOException(strReply.Substring(4));
   }
   FileStream input = new
    FileStream(strFileName,FileMode.Open);
   int iBytes = 0;
   while ((iBytes = input.Read(buffer,0,buffer.Length)) > 0)
   {
    socketData.Send(buffer, iBytes, 0);
   }
   input.Close();
   if (socketData.Connected)
   {
    socketData.Close();
   }
   if(!(iReplyCode == 226 || iReplyCode == 250))
   {
    ReadReply();
    if(!(iReplyCode == 226 || iReplyCode == 250))
    {
     throw new IOException(strReply.Substring(4));
    }
   }
  }

  #endregion

  #region 目錄操作
  /// <summary>
  /// 創建目錄
  /// </summary>
  /// <param name="strDirName">目錄名</param>
  public void MkDir(string strDirName)
  {
   if(!bConnected)
   {
    Connect();
   }
   SendCommand("MKD "+strDirName);
   if(iReplyCode != 257)
   {
    throw new IOException(strReply.Substring(4));
   }
  }

  /// <summary>
  /// 刪除目錄
  /// </summary>
  /// <param name="strDirName">目錄名</param>
  public void RmDir(string strDirName)
  {
   if(!bConnected)
   {
    Connect();
   }
   SendCommand("RMD "+strDirName);
   if(iReplyCode != 250)
   {
    throw new IOException(strReply.Substring(4));
   }
  }

  /// <summary>
  /// 改變目錄
  /// </summary>
  /// <param name="strDirName">新的工作目錄名</param>
  public void ChDir(string strDirName)
  {
   if(strDirName.Equals(".") || strDirName.Equals(""))
   {
    return;
   }
   if(!bConnected)
   {
    Connect();
   }
   SendCommand("CWD "+strDirName);
   if(iReplyCode != 250)
   {
    throw new IOException(strReply.Substring(4));
   }
   this.strRemotePath = strDirName;
  }

  #endregion

  /// <summary>
  /// 將一行應答字符串記錄在strReply和strMsg
  /// 應答碼記錄在iReplyCode
  /// </summary>
  private void ReadReply()
  {
   strMsg = "";
   strReply = ReadLine();
   iReplyCode = Int32.Parse(strReply.Substring(0,3));
  }

  /// <summary>
  /// 建立進行數據連接的socket
  /// </summary>
  /// <returns>數據連接socket</returns>
  private Socket CreateDataSocket()
  {
   SendCommand("PASV");
   if(iReplyCode != 227)
   {
    throw new IOException(strReply.Substring(4));
   }
   int index1 = strReply.IndexOf('(');
   int index2 = strReply.IndexOf(')');
   string ipData =
    strReply.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 strReply: " +
      strReply);
    }
    if (ch == ',' || i+1 == len)
    {
     try
     {
      parts[partCount++] = Int32.Parse(buf);
      buf="";
     }
     catch (Exception)
     {
      throw new IOException("Malformed PASV strReply: " +
       strReply);
     }
    }
   }
   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(IPAddress.Parse(ipAddress), port);
   try
   {
    s.Connect(ep);
   }
   catch(Exception)
   {
    throw new IOException("Can't connect to remote server");
   }
   return s;
  }

  /// <summary>
  /// 關閉socket連接(用于登錄以前)
  /// </summary>
  private void CloseSocketConnect()
  {
   if(socketControl!=null)
   {
    socketControl.Close();
    socketControl = null;
   }
   bConnected = false;
  }

  /// <summary>
  /// 讀取Socket返回的所有字符串
  /// </summary>
  /// <returns>包含應答碼的字符串行</returns>
  private string ReadLine()
  {
   while(true)
   {
    int iBytes = socketControl.Receive(buffer, buffer.Length, 0);
    strMsg += ASCII.GetString(buffer, 0, iBytes);
    if(iBytes < buffer.Length)
    {
     break;
    }
   }
   char[] seperator = {'\n'};
   string[] mess = strMsg.Split(seperator);
   if(strMsg.Length > 2)
   {
    strMsg = mess[mess.Length-2];
    //seperator[0]是10,換行符是由13和0組成的,分隔后10后面雖沒有字符串,
    //但也會分配為空字符串給后面(也是最后一個)字符串數組,
    //所以最后一個mess是沒用的空字符串
    //但為什么不直接取mess[0],因為只有最后一行字符串應答碼與信息之間有空格
   }
   else
   {
    strMsg = mess[0];
   }
   if(!strMsg.Substring(3,1).Equals(" "))//返回字符串正確的是以應答碼(如220開頭,后面接一空格,再接問候字符串)
   {
    return ReadLine();
   }
   return strMsg;
  }

  /// <summary>
  /// 發送命令并獲取應答碼和最后一行應答字符串
  /// </summary>
  /// <param name="strCommand">命令</param>
  private void SendCommand(string strCommand)
  {
   Byte[] cmdBytes = ASCII.GetBytes((strCommand + "\r\n").ToCharArray());
   socketControl.Send(cmdBytes, cmdBytes.Length, 0);
   ReadReply();
  }

  #endregion
 }
}