用asp获取文件md5值

  网上asp加密字符的MD5很多,也很普遍,但是对文件进行md5的确很少,因为受到asp语言本身的限制。我们知道字符串的md5可以对明文进行不可逆的加密,从而保证数据储存或者传送的安全性。同样的,对文件进行md5加密也是为了保证在网络传送时不被修改和校验,另外还有一个用途就是在个人站点里面的应用:可以保证上传的图片或文件具有唯一性。原理是,上传到服务器之后,同时在数据库中记录该上传文件的md5值,这样在下次传同样文件的时候,可以通过查询数据库是否是相同的文件,md5值相同,我们就认为它是相同的文件,md5值就是文件的“身份证”,其实百度也有这方面的应用,在百度搜索图片,点开图片后,有时候会出现“您还可以点击以下链接查看到这张图片:XXX网址”,原理也是一样,对文件进行md5。
  废话少说,开始正文。
  一、asp通过xml交互方式调用.Net程序实现文件md5
  asp由于本身语言的限制,无法实现文件的md5,但是.net确可以,那是不是可以通过.net对文件进行md5,然后发送信息给asp接收,这样就可以做到asp的md5了呢,答案是肯定的。这里涉及到asp与.net程序间的交互,我以前写过一个asp的类:《asp处理xml数据的发送、接收类》,可以上我的百度空间看:http://hi.baidu.com/manbutianmi/blog/item/dec182fc6db36587b801a0f6.html,讲的是asp处理xml数据的发送与接收,可用于各种异构系统之间API接口间通讯。本文正好是这个类的一个应用。代码如下:
  asp端代码
  xmlcls.asp
  <%
  Rem 处理xml数据的发送、接收类
  '--------------------------------------------------
  '转载的时候必须保留此版权信息
  '作者:walkman
  '网址:手机主题网:http://www.shouji138.com
  '版本:ver1.0
  '--------------------------------------------------
  Class XmlClass
  Rem 变量定义
  Private XmlDoc,XmlHttp
  Private MessageCode,SysKey,XmlPath
  Private m_GetXmlDoc,m_url
  Private m_XmlDocAccept
  Rem 初始化
  Private Sub Class_Initialize()
   On Error Resume Next
   MessageCode = ""
   XmlPath = ""
   Set XmlDoc = Server.CreateObject("msxml2.FreeThreadedDOMDocument.3.0")
   XmlDoc.ASYNC = False
  End Sub
  Rem 销毁对象
  Private Sub Class_Terminate()
   If IsObject(XmlDoc) Then Set XmlDoc = Nothing
   If IsObject(m_XmlDocAccept) Then Set m_XmlDocAccept = Nothing
   If IsObject(m_GetXmlDoc) Then Set m_GetXmlDoc = Nothing
  End Sub
  '公共属性定义开始--------------------------
  Rem 错误信息
  Public Property Get Message()
   Message = MessageCode
  End Property
  Rem 发送xml的地址
  Public Property Let URL(str)
   m_url = str
  End Property
  '公共属性定义结束--------------------------
  '私有过程、方法开始--------------------------
  Rem 加载xml
  Private Sub LoadXmlData()
   If XmlPath <> "" Then
   If Not XmlDoc.Load(XmlPath) Then
   XmlDoc.LoadXml "<?xml version=""1.0"" encoding=""gb2312""?><root/>"
   End If
   Else
   XmlDoc.LoadXml "<?xml version=""1.0"" encoding=""gb2312""?><root/>"
   End If
  End Sub
  Rem 字符转化
  Private Function AnsiToUnicode(ByVal str)
   Dim i, j, c, i1, i2, u, fs, f, p
   AnsiToUnicode = ""
   p = ""
   For i = 1 To Len(str)
   c = Mid(str, i, 1)
   j = AscW(c)
   If j < 0 Then
   j = j + 65536
   End If
   If j >= 0 And j <= 128 Then
   If p = "c" Then
   AnsiToUnicode = " " & AnsiToUnicode
   p = "e"
   End If
   AnsiToUnicode = AnsiToUnicode & c
   Else
   If p = "e" Then
   AnsiToUnicode = AnsiToUnicode & " "
   p = "c"
   End If
   AnsiToUnicode = AnsiToUnicode & ("&#" & j & ";")
   End If
   Next
  End Function
  Rem 字符转化
  Private Function strAnsi2Unicode(asContents)
   Dim len1,i,varchar,varasc
   strAnsi2Unicode = ""
   len1=LenB(asContents)
   If len1=0 Then Exit Function
   For i=1 to len1
   varchar=MidB(asContents,i,1)
   varasc=AscB(varchar)
   If varasc > 127 Then
   If MidB(asContents,i+1,1)<>"" Then
   strAnsi2Unicode = strAnsi2Unicode & chr(ascw(midb(asContents,i+1,1) & varchar))
   End If
   i=i+1
   Else
   strAnsi2Unicode = strAnsi2Unicode & Chr(varasc)
   End If
   Next
  End Function
  Rem 往文件中追加字符
  Private Sub WriteStringToFile(filename,str)
   On Error Resume Next
   Dim fs,ts
   Set fs= createobject("script_ing.filesystemobject")
   If Not IsObject(fs) Then Exit Sub
   Set ts=fs.OpenTextFile(Server.MapPath(filename),8,True)
   ts.writeline(str)
   ts.close
   Set ts=Nothing
   Set fs=Nothing
  End Sub
  '私有过程、方法结束--------------------------
  '公共方法开始--www.devdao.com------------------------
  '''''''''''发送xml部分开始
  Rem 从外部xml文件填充XmlDoc对象
  Public Sub LoadXmlFromFile(path)
   XmlPath = Server.MapPath(path)
   LoadXmlData()
  End Sub
  Rem 用字符串填充XmlDoc对象
  Public Sub LoadXmlFromString(str)
   XmlDoc.LoadXml str
  End Sub
  Rem 设置node的参数 如 NodeValue "appID",AppID,1,False
  '--------------------------------------------------
  '参数 :
  'NodeName 节点名
  'NodeText 值
  'NodeType 保存类型 [text=0,cdata=1]
  'blnEncode 是否编码 [true,false]
  '--------------------------------------------------
  Public Sub NodeValue(Byval NodeName,Byval NodeText,Byval NodeType ,Byval blnEncode)
   Dim ChildNode,CreateCDATASection
   NodeName = Lcase(NodeName)
   If XmlDoc.documentElement.selectSingleNode(NodeName) is nothing Then
   Set ChildNode = XmlDoc.documentElement.appendChild(XmlDoc.createNode(1,NodeName,""))
   Else
   Set ChildNode = XmlDoc.documentElement.selectSingleNode(NodeName)
   End If
   If blnEncode = True Then
   NodeText = AnsiToUnicode(NodeText)
   End If
   If NodeType = 1 Then
   ChildNode.Text = ""
   Set CreateCDATASection = XmlDoc.createCDATASection(Replace(NodeText,"]]>","]]&gt;"))
   ChildNode.appendChild(createCDATASection)
   Else
   ChildNode.Text = NodeText
   End If
  End Sub
  '--------------------------------------------------
  '获取发送包XML中节点的值
  '参数 :
  'Str 节点名
  '--------------------------------------------------
  Public Property Get XmlNode(Byval Str)
   If XmlDoc.documentElement.selectSingleNode(Str) is Nothing Then
   XmlNode = "Null"
   Else
   XmlNode = XmlDoc.documentElement.selectSingleNode(Str).text
   End If
  End Property
  '--------------------------------------------------
  '获取返回XML数据对象
  '例:
  '当GetXmlData不为NULL时,GetXmlData为XML对象
  '--------------------------------------------------
  Public Property Get GetXmlData()
   Set GetXmlData = m_GetXmlDoc
  End Property
  '--------------------------------------------------
  '发送xml包
  '--------------------------------------------------
  Public Sub SendHttpData()
   Dim i,GetXmlDoc,LoadAppid
   Set Xmlhttp = Server.CreateObject("MSXML2.ServerXMLHTTP.3.0")
   Set GetXmlDoc = Server.CreateObject("msxml2.FreeThreadedDOMDocument.3.0") ' 返回xml包
   XmlHttp.Open "POST", m_url, false
   XmlHttp.SetRequestHeader "content-type", "text/xml"
   XmlHttp.Send XmlDoc
   'Response.Write strAnsi2Unicode(xmlhttp.responseBody)
   If GetXmlDoc.load(XmlHttp.responseXML) Then
   Set m_GetXmlDoc = GetXmlDoc
   Else
   MessageCode = "请求数据错误!"
   Exit Sub
   End If
   Set GetXmlDoc = Nothing
   Set XmlHttp = Nothing
  End Sub
  
  
  '--------------------------------------------------
  '打印发送请求XML数据
  '--------------------------------------------------
  Public Sub PrintSendXmlData()
   Response.Clear
   Response.ContentType = "text/xml"
   Response.CharSet = "gb2312"
   Response.Expires = 0
   Response.Write "<?xml version=""1.0"" encoding=""gb2312""?>"&vbNewLine
   Response.Write XmlDoc.documentElement.XML
  End Sub
  '--------------------------------------------------
  '打印返回XML数据
  '--------------------------------------------------
  Public Sub PrintGetXmlData()
  
   Response.Clear
   Response.ContentType = "text/xml"
   Response.CharSet = "gb2312"
   Response.Expires = 0
   If IsObject(m_GetXmlDoc) Then
   Response.Write "<?xml version=""1.0"" encoding=""gb2312""?>"&vbNewLine
   Response.Write m_GetXmlDoc.documentElement.XML
   Else
   Response.Write "<?xml version=""1.0"" encoding=""gb2312""?><root></root>"
   End If
  End Sub
  Rem 保存发送请求xml数据到文件,文件名为sendxml_日期.txt
  Public Sub SaveSendXmlDataToFile()
   Dim filename,str
   filename = "sendxml_" & DateValue(now) & ".txt"
   str = ""
   str = str & ""& Now() & vbNewLine
   str = str & "---------------------------------------------"& vbNewLine
   str = str & "<?xml version=""1.0"" encoding=""gb2312""?>" & vbNewLine
   str = str & XmlDoc.documentElement.XML & vbNewLine
   str = str & "---------------------------------------------"& vbNewLine
   str = str & vbNewLine & vbNewLine & vbNewLine
   WriteStringToFile filename,str
  End Sub
  Rem 保存返回XML数据到文件,文件名为getxml_日期.txt
  Public Sub SaveGetXmlDataToFile()
   Dim filename,str
   filename = "getxml_" & DateValue(now) & ".txt"
   str = ""
   str = str & ""& Now() & vbNewLine
   str = str & "---------------------------------------------"& vbNewLine
   If IsObject(m_GetXmlDoc) Then
   str = str & "<?xml version=""1.0"" encoding=""gb2312""?>" & vbNewLine
   str = str & m_GetXmlDoc.documentElement.XML
   Else
   str = str & "<?xml version=""1.0"" encoding=""gb2312""?>" & vbNewLine & "<root>" & vbNewLine & "</root>"
   End If
   str = str & vbNewLine
   str = str & "---------------------------------------------"& vbNewLine
   str = str & vbNewLine & vbNewLine & vbNewLine
   WriteStringToFile filename,str
  End Sub
  
  '--------------------------------------------------
  '获取返回xml的节点信息
  'XmlClassObj.GetSingleNode("//msg")
  '--------------------------------------------------
  Public Function GetSingleNode(nodestring)
   If IsObject(m_GetXmlDoc) Then
   GetSingleNode = m_GetXmlDoc.documentElement.selectSingleNode(nodestring).text
   Else
   GetSingleNode = ""
   End If
  End Function
  ''''''''''''''''''发送xml部分结束
  
  ''''''''''''''''''接收xml部分开始
  '--------------------------------------------------
  '接收XML包,错误信息通过Message对象获取
  '--------------------------------------------------
  Public Function AcceptHttpData()
   Dim XMLdom
   Set XMLdom = Server.CreateObject("Microsoft.XMLDOM")
   XMLdom.Async = False
   XMLdom.Load(Request)
   If XMLdom.parseError.errorCode <> 0 Then
   MessageCode = "不能正确接收数据" & "Descript_ion: " & XMLdom.parseError.reason & "<br>Line: " & XMLdom.parseError.Line
   Set m_XmlDocAccept = Null
   Else
   Set m_XmlDocAccept = XMLdom
   End If
  End Function
  '--------------------------------------------------
  '返回接收XML包节点信息
  'XmlClassObj.GetSingleNode("//msg")
  '--------------------------------------------------
  Public Function AcceptSingleNode(nodestring)
   If IsObject(m_XmlDocAccept) Then
   AcceptSingleNode = m_XmlDocAccept.documentElement.selectSingleNode(nodestring).text
   Else
   AcceptSingleNode = ""
   End If
  End Function
  '--------------------------------------------------
  '打印接收端接收到的XML数据
  '--------------------------------------------------
  Public Sub PrintAcceptXmlData()
   Response.Clear
   Response.ContentType = "text/xml"
   Response.CharSet = "gb2312"
   Response.Expires = 0
   If IsObject(m_XmlDocAccept) Then
   Response.Write "<?xml version=""1.0"" encoding=""gb2312""?>"&vbNewLine
   Response.Write m_XmlDocAccept.documentElement.XML
   Else
   Response.Write "<?xml version=""1.0"" encoding=""gb2312""?><root></root>"
   End If
  End Sub
  Rem 保存接收的XML包数据到文件,文件名为acceptxml_日期.txt
  Public Sub SaveAcceptXmlDataToFile()
   Dim filename,str
   filename = "acceptxml_" & DateValue(now) & ".txt"
   str = ""
   str = str & ""& Now() & vbNewLine
   str = str & "---------------------------------------------"& vbNewLine
   If IsObject(m_XmlDocAccept) Then
   str = str & "<?xml version=""1.0"" encoding=""gb2312""?>" & vbNewLine
   str = str & m_XmlDocAccept.documentElement.XML
   Else
   str = str & "<?xml version=""1.0"" encoding=""gb2312""?>" & vbNewLine & "<root>" & vbNewLine & "</root>"
   End If
   str = str & vbNewLine
   str = str & "---------------------------------------------"& vbNewLine
   str = str & vbNewLine & vbNewLine & vbNewLine
   WriteStringToFile filename,str
  End Sub
  ''''''''''''''''''接收xml部分结束
  Rem 保存调试数据到文件,文件名为debugnote_日期.txt
  Public Sub SaveDebugStringToFile(debugstr)
   Dim filename,str
   filename = "debugnote_" & DateValue(now) & ".txt"
   str = ""
   str = str & ""& Now() & vbNewLine
   str = str & "---------------------------------------------"& vbNewLine
   str = str & debugstr & vbNewLine
   str = str & "---------------------------------------------"
   str = str & vbNewLine & vbNewLine & vbNewLine
   WriteStringToFile filename,str
  End Sub
  '公共方法结束--------------------------
  End Class
  %>
  filemd5fun.asp
  <!--#Include File="xmlcls.asp"-->
  <%
  Rem 取得文件的md5,参数为文件名
  Function GetFileMD5(filename)
  Const Apisysno = "k8n6g2b0m1a6b0f6e8" '接口的Key值,防止被非法适用 接口应该保持一致
  Dim XmlClassObj
  Set XmlClassObj = new XmlClass '创建对象
  XmlClassObj.LoadXmlFromString("<?xml version=""1.0"" encoding=""gb2312""?><root/>") '用xml字符填充XMLDOC对象,用来发送xml
  XmlClassObj.URL = "http://www.shouji138.com/aspnet2/FileMD5.aspx" '设置响应的url,这里应该改成你的网址
  Rem xml格式
  Rem "<?xml version="1.0" encoding="gb2312"?>
  Rem <root>
  Rem <sysno></sysno>
  Rem <apiaction></apiaction>
  Rem <filename></filename>
  Rem </root>
  XmlClassObj.NodeValue "sysno",Apisysno,0,False '接口的Key值,防止被非法适用
  XmlClassObj.NodeValue "apiaction","createfilemd5",0,False '接口的响应动作,用于定义一个接口用于多种用途
  XmlClassObj.NodeValue "filename",filename,0,False '文件路径和文件名,用相对路径
  'XmlClassObj.SaveSendXmlDataToFile() '将发送的xml数据库包存入txt文件,用于调试之用
  XmlClassObj.SendHttpData() '发送xml数据
  'XmlClassObj.SaveGetXmlDataToFile() '保存接收到的xml数据
  Rem 处理结果
  Dim message,status
  status = XmlClassObj.GetSingleNode("//status") '显示状态,如果为OK则表示成功,否则有错误发生
  message = XmlClassObj.GetSingleNode("//message") '显示取到的MD5值,如果status不为OK,则message为错误信息
  Set XmlClassObj = Nothing
  If status = "OK" Then
   GetFileMD5 = message
  Else
   GetFileMD5 = ""
  End If
  End Function
  %>
  test.asp
  <!--#Include File="filemd5fun.asp"-->
  <%
  Response.Write "web.config的md5值是:" & GetFileMD5("web.config") & "<br />"
  Response.Write "files/logo-yy.gif的md5值是:" & GetFileMD5("files/logo-yy.gif") & "<br />"
  Response.Write "xmlcls.asp的md5值是:" & GetFileMD5("xmlcls.asp") & "<br />"
  %>
  .net端代码:
  MD5.cs
  using System;
  using System.Collections.Generic;
  using System.Text;
  using System.IO;
  namespace Winsteps.FileMD5
  {
   public class MD5
   {
   public static string md5_hash(string path)
   {
   try
   {
   FileStream get_file = new FileStream(path, FileMode.Open, FileAccess.Read, FileShare.Read);
   System.Security.Cryptography.MD5CryptoServiceProvider get_md5 = new System.Security.Cryptography.MD5CryptoServiceProvider();
   byte[] hash_byte = get_md5.ComputeHash(get_file);
   string resule = System.BitConverter.ToString(hash_byte);
   resule = resule.Replace("-", "");
   return resule;
   }
   catch (Exception e)
   {
   return e.Message;
   }
   }
   }
  }
  FileMD5.aspx
  <%@ Page Language="C#" AutoEventWireup="true" CodeBehind="FileMD5.aspx.cs" Inherits="Winsteps.FileMD5.FileMD5" %>
  <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
  <html xmlns="http://www.w3.org/1999/xhtml" >
  <head runat="server">
   <title>手机主题网:http://www.shouji138.com</title>
  </head>
  <body>
   <form id="form1" runat="server">
   <div>
  
   </div>
   </form>
  </body>
  </html>
  FileMD5.aspx.cs
  using System;
  using System.Data;
  using System.Configuration;
  using System.Collections;
  using System.Web;
  using System.Web.Security;
  using System.Web.UI;
  using System.Web.UI.WebControls;
  using System.Web.UI.WebControls.WebParts;
  using System.Web.UI.HtmlControls;
  using System.Xml;
  using System.Configuration;
  namespace Winsteps.FileMD5
  {
   public partial class FileMD5 : System.Web.UI.Page
   {
   protected void Page_Load(object sender, EventArgs e)
   {
   string sysno = "11111";
   string status = "False";
   string message = "未指定的错误";
   string net2sysno = ConfigurationManager.AppSettings["sysno"];
   XmlDocument doc = new XmlDocument();
   try
   {
  
   doc.Load(Request.InputStream);
   sysno = doc.SelectSingleNode("//sysno").InnerText.Trim();
   if (net2sysno != sysno)
   {
   message = "非法适用!";
   }
   else
   {
   string filename = Server.MapPath(doc.SelectSingleNode("//filename").InnerText.Trim());
   message = MD5.md5_hash(filename);
   status = "OK";
   }
   }
   catch(Exception ex)
   {
   message = ex.Message;
   }
   finally
   {
   if (doc != null)
   doc = null;
   }
   Response.Clear(); //清楚html字符
   Response.ContentType = "text/xml";
   Response.Charset = "GB2312";//如果xml字符串中包含中文
   Response.Write("<?xml version=\"1.0\" encoding=\"GB2312\"?>");
   Response.Write("<root>");
   Response.Write(" <status>" + status + "</status>");
   Response.Write(" <message>" + message + "</message>");
   Response.Write("</root>");
   Response.End();
   }
   }
  }
  Web.config
  <?xml version="1.0" encoding="utf-8"?>
  <configuration>
   <appSettings>
   <add key="sysno" value="k8n6g2b0m1a6b0f6e8"></add>
   </appSettings>
   <system.web>
   <httpRuntime executionTimeout="3600" maxRequestLength="1048576"/>
   <compilation debug="true" defaultLanguage="c#" />
   <customErrors mode="Off" />
   <identity impersonate="true"/>
   <authentication mode="Forms">
   <forms name="forums" path="/" loginUrl="Login.aspx" protection="All" timeout="40">
   </forms>
   </authentication>
   <pages validateRequest="false"></pages>
   <globalization requestEncoding="gb2312" responseEncoding="gb2312" culture="zh-CN" uiCulture="zh-CN"/>
   </system.web>
  </configuration>
  web.config的sysno要跟filemd5fun.asp里面的Apisysno保持一致,具体应用时应该要把这个key改成你自己的值来保证安全。
  演示地址:http://www.shouji138.com/aspnet2/filemd5.asp
  代码虽然长,但是原理简单,asp发送xml数据给asp.net(xml中包含了要md5的文件名)->asp.net接收xml对文件进行md5->asp.net将结果通过xml返回给asp(xml中包含了获取到的md5值)->asp获取返回的xml,解析出md5值。
  应用范围:
  1. 在两个系统之间传送文件时,可以在传送前进行文件md5,传送后进行文件md5,检查两值是否相等,如果相等则表示在传送过程中没有被修改。
  2. 做上传系统中,如果要求不能上传同文件的话,可以在上传之后的文件进行md5存入数据库中,这样下次上传同样文件,则md5会相同,拒绝上传。
  3. 在搜索引擎、迅雷本b2b软件中,对文件md5,具有相同md5的文件被认为是相同文件,而不管文件名是否相同,可以从多个源来分享文件。
  4. 其他应用。。。。。
  二、asp通过COM组件实现md5(需要在服务器上注册组件)
  注册一个asp的文件md5组件,下载地址:http://www.shouji138.com/aspnet2/files/aspmd5.rar
  然后将PARmf.dll文件拷贝到服务器的c:\WINDOWS\system32目录,运行regsvr32 parmf.dll进行注册,重启IIS。
  调用代码:
  <%
  Set DelphiASPObj = Server.CreateObject("PARmf.md5file")
   DelphiASPObj.in_path=Server.Mappath("Web.config") '文件路径
   Response.Write "web.config的md5值是:" & DelphiASPObj.get_path_md5 & "<br />"
   Set DelphiASPObj=nothing
  %>
  三、两种方式获取文件md5的对比
  第一种方法通过与asp.net程序交互xml数据来得到文件的md5,需要服务器支持asp.net,一般的虚拟主机都提供asp.net环境,但是价格高点;
  第二种方法通过注册COM组件实现,需要有服务器的权限,对于拥有服务器的比较合适。
  另外第一种方式的这种交互方法使得asp具有更大的灵活性,可以应用在2台不同的服务器上面进行数据交互,可广泛应用于各种异构平台。
  四、下载地址
  请到偶的小站,手机主题网查看演示和下载程序包
  演示地址:http://www.shouji138.com/aspnet2/filemd5.asp
  程序下载打包下载:http://www.shouji138.com/aspnet2/files/FileMD5.rar
  asp的文件md5组件:http://www.shouji138.com/aspnet2/files/aspmd5.rar