ftp.cs

*****************************************************************
// Copyright (C) 2006-2007 Newegg Corporation
// All rights reserved.
// 
// Author:       Charles Ge (Charles.Y.Ge@Newegg.com)
// Create Date:  04/12/2007 15:33:42
// Usage: DFIS Ftp Client Service,add ftp site,upload files,download files
//
// RevisionHistory
// Date         Author               Description
// Asp.net2.0中FTP支持断点续传源码
*****************************************************************/
using System;
using System.IO;
using System.Net;
using System.Net.Security;
using System.Collections;
using System.Collections.Generic;
using System.Security.Cryptography.X509Certificates;
using System.Web;
using System.Web.Configuration;
public sealed class FtpClientService
{
    #region Internal Members

    private NetworkCredential certificate;

    #endregion

    /// <summary>
    /// 构造函数，提供初始化数据的功能，打开Ftp站点
    /// </summary>
    public FtpClientService()
    {
        certificate = new NetworkCredential(WebConfigurationManager.AppSettings["UserName"], WebConfigurationManager.AppSettings["PassWord"]);
    }

    /// <summary>
    /// 创建FTP请求
    /// </summary>
    /// <param name="uri">ftp://myserver/upload.txt</param>
    /// <param name="method">Upload/Download</param>
    /// <returns></returns>
    private FtpWebRequest CreateFtpWebRequest(Uri uri, string method)
    {
        FtpWebRequest ftpClientRequest = (FtpWebRequest) WebRequest.Create(uri);

        ftpClientRequest.Proxy = null;
        ftpClientRequest.Credentials = certificate;
        ftpClientRequest.KeepAlive = true;
        ftpClientRequest.UseBinary = true;
        ftpClientRequest.UsePassive = true;
        ftpClientRequest.Method = method;

        //ftpClientRequest.Timeout = -1;

        return ftpClientRequest;
    }
    #region 支持断点续传

    public bool UploadFile(string sourceFile, Uri destinationPath, int offSet, string ftpMethod)
    {
        try
        {
            FileInfo file = new FileInfo(sourceFile);
            Uri uri = new Uri(destinationPath.AbsoluteUri + "/" + file.Name);
            FtpWebRequest request = CreateFtpWebRequest(uri, ftpMethod);
            request.ContentOffset = offSet;
            Stream requestStream = request.GetRequestStream();//需要获取文件的流
            FileStream fileStream = new FileStream(sourceFile, FileMode.Open, FileAccess.Read);//创建存储文件的流
            int sourceLength = (int) fileStream.Length;
            offSet = CopyDataToDestination(fileStream, requestStream, offSet);
            WebResponse response = request.GetResponse();
            response.Close();
            if (offSet != 0)
            {
                UploadFile(sourceFile, destinationPath, offSet, WebRequestMethods.Ftp.AppendFile);
            }
        }
        catch (Exception ex)
        {
            ex.ToString();
            return false;
        }

        return true;
    }

    private int CopyDataToDestination(Stream sourceStream, Stream destinationStream, int offSet)
    {
        try
        {
            int sourceLength = (int) sourceStream.Length;
            int length = sourceLength - offSet;
            byte[] buffer = new byte[length + offSet];
            int bytesRead = sourceStream.Read(buffer, offSet, length);
            while (bytesRead != 0)
            {
                destinationStream.Write(buffer, 0, bytesRead);
                bytesRead = sourceStream.Read(buffer, 0, length);
                length = length - bytesRead;
                offSet = (bytesRead == 0) ? 0 : (sourceLength - length);//(length - bytesRead);                  
            }
        }
        catch (Exception ex)
        {
            string error = ex.ToString();
            return offSet;
        }
        finally
        {
            destinationStream.Close();
            sourceStream.Close();
        }
        return offSet;
    }
    #endregion
}