.Net/C#: 实现支持断点续传多线程下载的 Http Web 客户端工具类 (C# DIY HttpWebClient)

/* .Net/C#: 实现支持断点续传多线程下载的 Http Web 客户端工具类 (C# DIY HttpWebClient)
 * Reflector 了一下 System.Net.WebClient ,重载或增加了若干:
 * DownLoad、Upload 相关方法!
 * DownLoad 相关改动较大!
 * 增加了 DataReceive、ExceptionOccurrs 事件!
 * 了解服务器端与客户端交互的 HTTP 协议参阅:
 * 使文件下载的自定义连接支持 FlashGet 的断点续传多线程链接下载! JSP/Servlet 实现!
 * http://blog.csdn.net/playyuer/archive/2004/08/02/58430.aspx
 * 使文件下载的自定义连接支持 FlashGet 的断点续传多线程链接下载! C#/ASP.Net 实现! 
 * http://blog.csdn.net/playyuer/archive/2004/08/02/58281.aspx
 */

namespace Microshaoft.Utils
{
 using System;
 using System.IO;
 using System.Net;
 using System.Text;
 using System.Security;
 using System.Threading;
 using System.Collections.Specialized;
 
 /// <summary>
 /// 记录下载的字节位置
 /// </summary>
 public class DownLoadState
 {
  private string _FileName;

  private string _AttachmentName;
  private int _Position;
  private string _RequestURL;
  private string _ResponseURL;
  private int _Length;

  private byte[] _Data;

  public string FileName
  {
   get
   {
    return _FileName;
   }
  }

  public int Position
  {
   get
   {
    return _Position;
   }
  }

  public int Length
  {
   get
   {
    return _Length;
   }
  }

  public string AttachmentName
  {
   get
   {
    return _AttachmentName;
   }
  }

  public string RequestURL
  {
   get
   {
    return _RequestURL;
   }
  }

  public string ResponseURL
  {
   get
   {
    return _ResponseURL;
   }
  }

  public byte[] Data
  {
   get
   {
    return _Data;
   }
  }

  internal DownLoadState(string RequestURL, string ResponseURL, string FileName, string AttachmentName, int Position, int Length, byte[] Data)
  {
   this._FileName = FileName;
   this._RequestURL = RequestURL;
   this._ResponseURL = ResponseURL;
   this._AttachmentName = AttachmentName;
   this._Position = Position;
   this._Data = Data;
   this._Length = Length;
  }

  internal DownLoadState(string RequestURL, string ResponseURL, string FileName, string AttachmentName, int Position, int Length, ThreadCallbackHandler tch)
  {
   this._RequestURL = RequestURL;
   this._ResponseURL = ResponseURL;
   this._FileName = FileName;
   this._AttachmentName = AttachmentName;
   this._Position = Position;
   this._Length = Length;
   this._ThreadCallback = tch;
  }

  internal DownLoadState(string RequestURL, string ResponseURL, string FileName, string AttachmentName, int Position, int Length)
  {
   this._RequestURL = RequestURL;
   this._ResponseURL = ResponseURL;
   this._FileName = FileName;
   this._AttachmentName = AttachmentName;
   this._Position = Position;
   this._Length = Length;
  }

  private ThreadCallbackHandler _ThreadCallback;

  //
  internal void StartDownloadFileChunk()
  {
   if (this._ThreadCallback != null)
   {
    this._ThreadCallback(this._RequestURL, this._FileName, this._Position, this._Length);
   }
  }

 }

 //委托代理线程的所执行的方法签名一致
 public delegate void ThreadCallbackHandler(string S, string s, int I, int i);

 //异常处理动作
 public enum ExceptionActions
 {
  Throw,
  CancelAll,
  Ignore,
  Retry
 }

 /// <summary>
 /// 包含 Exception 事件数据的类
 /// </summary>
 public class ExceptionEventArgs : System.EventArgs
 {
  private System.Exception _Exception;
  private ExceptionActions _ExceptionAction;

  private DownLoadState _DownloadState;

  public DownLoadState DownloadState
  {
   get
   {
    return _DownloadState;
   }
  }

  public Exception Exception
  {
   get
   {
    return _Exception;
   }
  }

  public ExceptionActions ExceptionAction
  {
   get
   {
    return _ExceptionAction;
   }
   set
   {
    _ExceptionAction = value;
   }
  }

  internal ExceptionEventArgs(System.Exception e, DownLoadState DownloadState)
  {
   this._Exception = e;
   this._DownloadState = DownloadState;
  }
 }

 /// <summary>
 /// 包含 DownLoad 事件数据的类
 /// </summary>
 public class DownLoadEventArgs : System.EventArgs
 {
  private DownLoadState _DownloadState;

  public DownLoadState DownloadState
  {
   get
   {
    return _DownloadState;
   }
  }

  public DownLoadEventArgs(DownLoadState DownloadState)
  {
   this._DownloadState = DownloadState;
  }

 }

 /// <summary>
 /// 支持断点续传多线程下载的类
 /// </summary>
 public class HttpWebClient
 {
  private static object _SyncLockObject = new object();

  public delegate void DataReceiveEventHandler(HttpWebClient Sender, DownLoadEventArgs e);

  public event DataReceiveEventHandler DataReceive; //接收字节数据事件

  public delegate void ExceptionEventHandler(HttpWebClient Sender, ExceptionEventArgs e);

  public event ExceptionEventHandler ExceptionOccurrs; //发生异常事件

  private int _FileLength; //下载文件的总大小

  public int FileLength
  {
   get
   {
    return _FileLength;
   }
  }

  /// <summary>
  /// 分块下载文件
  /// </summary>
  /// <param name="Address">URL 地址</param>
  /// <param name="FileName">保存到本地的路径文件名</param>
  /// <param name="ChunksCount">块数,线程数</param>
  public void DownloadFile(string Address, string FileName, int ChunksCount)
  {
   int p = 0; // position
   int s = 0; // chunk size
   string a = null;
   HttpWebRequest hwrq;
   HttpWebResponse hwrp = null;
   try
   {
    hwrq = (HttpWebRequest) WebRequest.Create(this.GetUri(Address));
    hwrp = (HttpWebResponse) hwrq.GetResponse();
    long L = hwrp.ContentLength;

    hwrq.Credentials = this.m_credentials;

    L = ((L == -1) || (L > 0x7fffffff)) ? ((long) 0x7fffffff) : L; //Int32.MaxValue 该常数的值为 2,147,483,647; 即十六进制的 0x7FFFFFFF

    int l = (int) L;

    this._FileLength = l;

    //    在本地预定空间(竟然在多线程下不用先预定空间)
    //    FileStream sw = new FileStream(FileName, FileMode.OpenOrCreate, FileAccess.ReadWrite, FileShare.ReadWrite);
    //    sw.Write(new byte[l], 0, l);
    //    sw.Close();
    //    sw = null;

    bool b = (hwrp.Headers["Accept-Ranges"] != null & hwrp.Headers["Accept-Ranges"] == "bytes");
    a = hwrp.Headers["Content-Disposition"]; //attachment
    if (a != null)
    {
     a = a.Substring(a.LastIndexOf("filename=") + 9);
    }
    else
    {
     a = FileName;
    }

    int ss = s;
    if (b)
    {
     s = l / ChunksCount;
     if (s < 2 * 64 * 1024) //块大小至少为 128 K 字节
     {
      s = 2 * 64 * 1024;
     }
     ss = s;
     int i = 0;
     while (l > s)
     {
      l -= s;
      if (l < s)
      {
       s += l;
      }
      if (i++ > 0)
      {
       DownLoadState x = new DownLoadState(Address, hwrp.ResponseUri.AbsolutePath, FileName, a, p, s, new ThreadCallbackHandler(this.DownloadFileChunk));
       //       单线程下载
       //       x.StartDownloadFileChunk();

       //多线程下载
       //Thread t =
       new Thread(new ThreadStart(x.StartDownloadFileChunk)).Start();
       //t.Start();
      }
      p += s;
     }
     s = ss;
     byte[] buffer = this.ResponseAsBytes(Address, hwrp, s, FileName);

     //    lock (_SyncLockObject)
     //    {
     //     this._Bytes += buffer.Length;
     //    }
    }
   }
   catch (Exception e)
   {
    ExceptionActions ea = ExceptionActions.Throw;
    if (this.ExceptionOccurrs != null)
    {
     DownLoadState x = new DownLoadState(Address, hwrp.ResponseUri.AbsolutePath, FileName, a, p, s);
     ExceptionEventArgs eea = new ExceptionEventArgs(e, x);
     ExceptionOccurrs(this, eea);
     ea = eea.ExceptionAction;
    }

    if (ea == ExceptionActions.Throw)
    {
     if (!(e is WebException) && !(e is SecurityException))
     {
      throw new WebException("net_webclient", e);
     }
     throw;
    }
   }

  }

  /// <summary>
  /// 下载一个文件块,利用该方法可自行实现多线程断点续传
  /// </summary>
  /// <param name="Address">URL 地址</param>
  /// <param name="FileName">保存到本地的路径文件名</param>
  /// <param name="Length">块大小</param>
  public void DownloadFileChunk(string Address, string FileName, int FromPosition, int Length)
  {
   HttpWebResponse hwrp = null;
   string a = null;
   try
   {
    //this._FileName = FileName;
    HttpWebRequest hwrq = (HttpWebRequest) WebRequest.Create(this.GetUri(Address));
    //hwrq.Credentials = this.m_credentials;
    hwrq.AddRange(FromPosition);
    hwrp = (HttpWebResponse) hwrq.GetResponse();
    a = hwrp.Headers["Content-Disposition"]; //attachment
    if (a != null)
    {
     a = a.Substring(a.LastIndexOf("filename=") + 9);
    }
    else
    {
     a = FileName;
    }

    byte[] buffer = this.ResponseAsBytes(Address, hwrp, Length, FileName);
    //   lock (_SyncLockObject)
    //   {
    //    this._Bytes += buffer.Length;
    //   }
   }
   catch (Exception e)
   {
    ExceptionActions ea = ExceptionActions.Throw;
    if (this.ExceptionOccurrs != null)
    {
     DownLoadState x = new DownLoadState(Address, hwrp.ResponseUri.AbsolutePath, FileName, a, FromPosition, Length);
     ExceptionEventArgs eea = new ExceptionEventArgs(e, x);
     ExceptionOccurrs(this, eea);
     ea = eea.ExceptionAction;
    }

    if (ea == ExceptionActions.Throw)
    {
     if (!(e is WebException) && !(e is SecurityException))
     {
      throw new WebException("net_webclient", e);
     }
     throw;
    }
   }
  }

  internal byte[] ResponseAsBytes(string RequestURL, WebResponse Response, long Length, string FileName)
  {
   string a = null; //AttachmentName
   int P = 0; //整个文件的位置指针
   int num2 = 0;
   try
   {
    a = Response.Headers["Content-Disposition"]; //attachment
    if (a != null)
    {
     a = a.Substring(a.LastIndexOf("filename=") + 9);
    }

    long num1 = Length; //Response.ContentLength;
    bool flag1 = false;
    if (num1 == -1)
    {
     flag1 = true;
     num1 = 0x10000; //64k
    }
    byte[] buffer1 = new byte[(int) num1];

    int p = 0; //本块的位置指针

    string s = Response.Headers["Content-Range"];
    if (s != null)
    {
     s = s.Replace("bytes ", "");
     s = s.Substring(0, s.IndexOf("-"));
     P = Convert.ToInt32(s);
    }
    int num3 = 0;

    Stream S = Response.GetResponseStream();
    do
    {
     num2 = S.Read(buffer1, num3, ((int) num1) - num3);

     num3 += num2;
     if (flag1 && (num3 == num1))
     {
      num1 += 0x10000;
      byte[] buffer2 = new byte[(int) num1];
      Buffer.BlockCopy(buffer1, 0, buffer2, 0, num3);
      buffer1 = buffer2;
     }

     //    lock (_SyncLockObject)
     //    {
     //     this._bytes += num2;
     //    }
     if (num2 > 0)
     {
      if (this.DataReceive != null)
      {
       byte[] buffer = new byte[num2];
       Buffer.BlockCopy(buffer1, p, buffer, 0, buffer.Length);
       DownLoadState dls = new DownLoadState(RequestURL, Response.ResponseUri.AbsolutePath, FileName, a, P, num2, buffer);
       DownLoadEventArgs dlea = new DownLoadEventArgs(dls);
       //触发事件
       this.OnDataReceive(dlea);
       //System.Threading.Thread.Sleep(100);

      }
      p += num2; //本块的位置指针
      P += num2; //整个文件的位置指针
     }
     else
     {
      break;
     }

    }
    while (num2 != 0);

    S.Close();
    S = null;
    if (flag1)
    {
     byte[] buffer3 = new byte[num3];
     Buffer.BlockCopy(buffer1, 0, buffer3, 0, num3);
     buffer1 = buffer3;
    }
    return buffer1;
   }
   catch (Exception e)
   {
    ExceptionActions ea = ExceptionActions.Throw;
    if (this.ExceptionOccurrs != null)
    {
     DownLoadState x = new DownLoadState(RequestURL, Response.ResponseUri.AbsolutePath, FileName, a, P, num2);
     ExceptionEventArgs eea = new ExceptionEventArgs(e, x);
     ExceptionOccurrs(this, eea);
     ea = eea.ExceptionAction;
    }

    if (ea == ExceptionActions.Throw)
    {
     if (!(e is WebException) && !(e is SecurityException))
     {
      throw new WebException("net_webclient", e);
     }
     throw;
    }
    return null;
   }
  }

  private void OnDataReceive(DownLoadEventArgs e)
  {
   //触发数据到达事件
   DataReceive(this, e);
  }

  public byte[] UploadFile(string address, string fileName)
  {
   return this.UploadFile(address, "POST", fileName, "file");
  }

  public string UploadFileEx(string address, string method, string fileName, string fieldName)
  {
   return Encoding.ASCII.GetString(UploadFile(address, method, fileName, fieldName));
  }

  public byte[] UploadFile(string address, string method, string fileName, string fieldName)
  {
   byte[] buffer4;
   FileStream stream1 = null;
   try
   {
    fileName = Path.GetFullPath(fileName);
    string text1 = "---------------------" + DateTime.Now.Ticks.ToString("x");

    string text2 = "application/octet-stream";

    stream1 = new FileStream(fileName, FileMode.Open, FileAccess.Read);
    WebRequest request1 = WebRequest.Create(this.GetUri(address));
    request1.Credentials = this.m_credentials;
    request1.ContentType = "multipart/form-data; boundary=" + text1;

    request1.Method = method;
    string[] textArray1 = new string[7] {"--", text1, "/r/nContent-Disposition: form-data; name=/"" + fieldName + "/"; filename=/"", Path.GetFileName(fileName), "/"/r/nContent-Type: ", text2, "/r/n/r/n"};
    string text3 = string.Concat(textArray1);
    byte[] buffer1 = Encoding.UTF8.GetBytes(text3);
    byte[] buffer2 = Encoding.ASCII.GetBytes("/r/n--" + text1 + "/r/n");
    long num1 = 0x7fffffffffffffff;
    try
    {
     num1 = stream1.Length;
     request1.ContentLength = (num1 + buffer1.Length) + buffer2.Length;
    }
    catch
    {
    }
    byte[] buffer3 = new byte[Math.Min(0x2000, (int) num1)];
    using (Stream stream2 = request1.GetRequestStream())
    {
     int num2;
     stream2.Write(buffer1, 0, buffer1.Length);
     do
     {
      num2 = stream1.Read(buffer3, 0, buffer3.Length);
      if (num2 != 0)
      {
       stream2.Write(buffer3, 0, num2);
      }
     }
     while (num2 != 0);
     stream2.Write(buffer2, 0, buffer2.Length);
    }
    stream1.Close();
    stream1 = null;
    WebResponse response1 = request1.GetResponse();

    buffer4 = this.ResponseAsBytes(response1);
   }
   catch (Exception exception1)
   {
    if (stream1 != null)
    {
     stream1.Close();
     stream1 = null;
    }
    if (!(exception1 is WebException) && !(exception1 is SecurityException))
    {
     //throw new WebException(SR.GetString("net_webclient"), exception1);
     throw new WebException("net_webclient", exception1);
    }
    throw;
   }
   return buffer4;
  }

  private byte[] ResponseAsBytes(WebResponse response)
  {
   int num2;
   long num1 = response.ContentLength;
   bool flag1 = false;
   if (num1 == -1)
   {
    flag1 = true;
    num1 = 0x10000;
   }
   byte[] buffer1 = new byte[(int) num1];
   Stream stream1 = response.GetResponseStream();
   int num3 = 0;
   do
   {
    num2 = stream1.Read(buffer1, num3, ((int) num1) - num3);
    num3 += num2;
    if (flag1 && (num3 == num1))
    {
     num1 += 0x10000;
     byte[] buffer2 = new byte[(int) num1];
     Buffer.BlockCopy(buffer1, 0, buffer2, 0, num3);
     buffer1 = buffer2;
    }
   }
   while (num2 != 0);
   stream1.Close();
   if (flag1)
   {
    byte[] buffer3 = new byte[num3];
    Buffer.BlockCopy(buffer1, 0, buffer3, 0, num3);
    buffer1 = buffer3;
   }
   return buffer1;
  }

  private NameValueCollection m_requestParameters;
  private Uri m_baseAddress;
  private ICredentials m_credentials = CredentialCache.DefaultCredentials;

  public ICredentials Credentials
  {
   get
   {
    return this.m_credentials;
   }
   set
   {
    this.m_credentials = value;
   }
  }

  public NameValueCollection QueryString
  {
   get
   {
    if (this.m_requestParameters == null)
    {
     this.m_requestParameters = new NameValueCollection();
    }
    return this.m_requestParameters;
   }
   set
   {
    this.m_requestParameters = value;
   }
  }

  public string BaseAddress
  {
   get
   {
    if (this.m_baseAddress != null)
    {
     return this.m_baseAddress.ToString();
    }
    return string.Empty;
   }
   set
   {
    if ((value == null) || (value.Length == 0))
    {
     this.m_baseAddress = null;
    }
    else
    {
     try
     {
      this.m_baseAddress = new Uri(value);
     }
     catch (Exception exception1)
     {
      throw new ArgumentException("value", exception1);
     }
    }
   }
  }

  private Uri GetUri(string path)
  {
   Uri uri1;
   try
   {
    if (this.m_baseAddress != null)
    {
     uri1 = new Uri(this.m_baseAddress, path);
    }
    else
    {
     uri1 = new Uri(path);
    }
    if (this.m_requestParameters == null)
    {
     return uri1;
    }
    StringBuilder builder1 = new StringBuilder();
    string text1 = string.Empty;
    for (int num1 = 0; num1 < this.m_requestParameters.Count; num1++)
    {
     builder1.Append(text1 + this.m_requestParameters.AllKeys[num1] + "=" + this.m_requestParameters[num1]);
     text1 = "&";
    }
    UriBuilder builder2 = new UriBuilder(uri1);
    builder2.Query = builder1.ToString();
    uri1 = builder2.Uri;
   }
   catch (UriFormatException)
   {
    uri1 = new Uri(Path.GetFullPath(path));
   }
   return uri1;
  }

 }

}

/// <summary>
/// 测试类
/// </summary>
class AppTest
{
 static void Main()
 {
  AppTest a = new AppTest();
  Microshaoft.Utils.HttpWebClient x = new Microshaoft.Utils.HttpWebClient();

  //订阅 DataReceive　事件
  x.DataReceive += new Microshaoft.Utils.HttpWebClient.DataReceiveEventHandler(a.x_DataReceive);
  //订阅 ExceptionOccurrs　事件
  x.ExceptionOccurrs += new Microshaoft.Utils.HttpWebClient.ExceptionEventHandler(a.x_ExceptionOccurrs);

  string F = "http://localhost/download/phpMyAdmin-2.6.1-pl2.zip";
  a._F = F;
  F = "http://localhost/download/jdk-1_5_0_01-windows-i586-p.aa.exe";
  //F = "http://localhost/download/ReSharper1.5.exe";

  //F = "http://localhost/mywebapplications/WebApplication7/WebForm1.aspx";
  //F = "http://localhost:1080/test/download.jsp";

  //F = "http://localhost/download/Webcast20050125_PPT.zip";
  //F = "http://www.morequick.com/greenbrowsergb.zip";
  //F = "http://localhost/download/test_local.rar";
  string f = F.Substring(F.LastIndexOf("/") + 1);

  //(new System.Threading.Thread(new System.Threading.ThreadStart(new ThreadProcessState(F, @"E:/temp/" + f, 10, x).StartThreadProcess))).Start();

  x.DownloadFile(F, @"E:/temp/temp/" + f, 10);
  //  x.DownloadFileChunk(F, @"E:/temp/" + f,15,34556);

  System.Console.ReadLine();
  // Upload 测试
  //  string uploadfile = "e://test_local.rar";
  //  string str = x.UploadFileEx("http://localhost/phpmyadmin/uploadaction.php", "POST", uploadfile, "file1");
  //  System.Console.WriteLine(str);
  //  System.Console.ReadLine();
 }

 string bs = ""; //用于记录上次的位数
 bool b = false;
 private int i = 0;
 private static object _SyncLockObject = new object();
 string _F;
 string _f;

 private void x_DataReceive(Microshaoft.Utils.HttpWebClient Sender, Microshaoft.Utils.DownLoadEventArgs e)
 {
  if (!this.b)
  {
   lock (_SyncLockObject)
   {
    if (!this.b)
    {
     System.Console.Write(System.DateTime.Now.ToString() + " 已接收数据:           ");
     //System.Console.Write( System.DateTime.Now.ToString() + " 已接收数据:           ");
     this.b = true;
    }
   }
  }
  string f = e.DownloadState.FileName;
  if (e.DownloadState.AttachmentName != null)
   f = System.IO.Path.GetDirectoryName(f) + @"/" + e.DownloadState.AttachmentName;

  this._f = f;

  using (System.IO.FileStream sw = new System.IO.FileStream(f, System.IO.FileMode.OpenOrCreate, System.IO.FileAccess.ReadWrite, System.IO.FileShare.ReadWrite))
  {
   sw.Position = e.DownloadState.Position;
   sw.Write(e.DownloadState.Data, 0, e.DownloadState.Data.Length);
   sw.Close();
  }
  string s = System.DateTime.Now.ToString();
  lock (_SyncLockObject)
  {
   this.i += e.DownloadState.Data.Length;
   System.Console.Write(bs + "/b/b/b/b/b/b/b/b/b/b" + i + " / " + Sender.FileLength + " 字节数据 " + s);
   //System.Console.Write(bs + i + " 字节数据 " + s);
   this.bs = new string('/b', Digits(i) + 3 + Digits(Sender.FileLength) + s.Length);
  }
 }

 int Digits(int n) //数字所占位数
 {
  n = System.Math.Abs(n);
  n = n / 10;
  int i = 1;
  while (n > 0)
  {
   n = n / 10;
   i++;
  }
  return i;
 }

 private void x_ExceptionOccurrs(Microshaoft.Utils.HttpWebClient Sender, Microshaoft.Utils.ExceptionEventArgs e)
 {
  System.Console.WriteLine(e.Exception.Message);
  //发生异常重新下载相当于断点续传,你可以自己自行选择处理方式或自行处理
  Microshaoft.Utils.HttpWebClient x = new Microshaoft.Utils.HttpWebClient();
  x.DownloadFileChunk(this._F, this._f, e.DownloadState.Position, e.DownloadState.Length);
  e.ExceptionAction = Microshaoft.Utils.ExceptionActions.Ignore;
 }
}

/*
 * 用于 upload 测试的 Action php:
http://localhost/phpmyadmin/uploadaction.php:
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML>
<HEAD>
<TITLE> New Document </TITLE>
</HEAD>
<BODY>
<?php
 print_r($_REQUEST);
 $uploadDir = '';
 $uploadFile = $uploadDir . $_FILES['file1']['name'];
 print "<pre>";
 if (move_uploaded_file($_FILES['file1']['tmp_name'], $uploadFile))
 {
  print "File is valid, and was successfully uploaded. ";
 }
 else
 {
  print "Possible file upload attack!  Here's some debugging info:/n";
  print_r($_FILES);
 }
 print "</pre>";
?>
</BODY>
</HTML>
*/