asp.net 2.0中的URL重写以及urlMappings问题

在asp.net2.0中的urlMappings倒是非常好用，可惜暂不支持正则表达式，不过，好在如果用IHttpModule的话

不管什么样的请求都会先经过IHttpModule这样就为URL重写提供了一个好机会：

下面是我写的一个IHttpModule:

using System;
using System.Web;

public class ReWriteModule:IHttpModule
{
 public ReWriteModule()
 {
 }
    public override string ToString()
    {
        return this.GetType().ToString();
    }

void  IHttpModule.Dispose()
{
  
}
    private static System.Xml.XmlDocument ruleDoc = null;
    private static System.Xml.XmlDocument GetRuleConfig(System.Web.HttpContext app)
    {
        if (ruleDoc == null)
        {
            ruleDoc = new System.Xml.XmlDocument();
            ruleDoc.Load(app.Server.MapPath("~/rule.xml"));
        }
        return ruleDoc;
    }
    public static string GetUrl(System.Web.HttpContext cxt,string path)
    {
       
       System.Xml.XmlDocument doc = GetRuleConfig(cxt);
       System.Xml.XmlNodeList lst= doc.GetElementsByTagName("RewriterRule");
       string pat="";
       foreach (System.Xml.XmlNode nd in lst)
       {
           System.Xml.XmlNodeList sub = nd.ChildNodes[0].ChildNodes;
           foreach(System.Xml.XmlNode chk in sub)
           {
               pat = "^" + chk.InnerText+"$";
               System.Text.RegularExpressions.Regex reg = new System.Text.RegularExpressions.Regex(pat, System.Text.RegularExpressions.RegexOptions.Compiled | System.Text.RegularExpressions.RegexOptions.IgnoreCase);
               if(reg.IsMatch(path))
               {
                  return reg.Replace(path, nd.ChildNodes[1].InnerText);
               }
           }
       }
       return null;

    }
void  IHttpModule.Init(HttpApplication context)
{
    context.BeginRequest += delegate(object sender, EventArgs e)
    {
       

        System.Web.HttpContext cxt = context.Context;
    
        if (cxt.Request.ContentType != "image/pjpeg")
        {
            string type = cxt.Request.ContentType.ToLower();
            string path = cxt.Request.Path;
            string apppath = cxt.Request.ApplicationPath;
            path = path.Remove(0, apppath.Length);
            path = "~" + path;
           
            string newUrl = GetUrl(cxt, path.TrimEnd().TrimStart());
            if (newUrl != null)
            {
                cxt.Response.Filter = new ResponseFilter(cxt.Response.Filter,cxt.Request.Path);
                cxt.Response.Write("请求的路径:" + path);
                cxt.Response.Write("<BR>");
                cxt.Response.Write("转向的目的URL：" + newUrl);
                cxt.Response.Write("<BR>");
                cxt.RewritePath(newUrl);
               
               
               
            }//如果要求处理所有的请求时用到
            //else
            //{
            //    cxt.Response.Write(cxt.Request.Path + "<BR>");
            //    cxt.Response.Write("你请求的资源不存在或无权访问！");
            //    cxt.Response.Flush();
            //    cxt.Response.End();
            //}
        }
    
    };
   }

}

由于一旦进行了URL重写，原先的WEBFORM中的Action会发生改变，容易造成：请求的资源不存在问题

具体怎么样？各位DX看看就清楚了！！！

所有才有了这个ResponseFilter了，实现如下，

public class ResponseFilter:System.IO.Stream
{
        public ResponseFilter(System.IO.Stream sink,string _str)
  {
   _sink = sink;
   //
   // TODO: 在此处添加构造函数逻辑
   //
            this.str = _str;
  }
    private string str = "";
  private System.IO.Stream _sink;
  private long _position;
  private System.Text.Encoding end=System.Text.Encoding.GetEncoding("GB18030");
  private System.Text.StringBuilder  oOutput = new System.Text.StringBuilder();
   // The following members of Stream must be overriden.
  public override bool CanRead
  {
   get { return true; }
  }

  public override bool CanSeek
  {
   get { return true; }
  }

  public override bool CanWrite
  {
   get { return true; }
  }

  public override long Length
  {
   get { return 0; }
  }

  public override long Position
  {
   get { return _position; }
   set { _position = value; }
  }

  public override long Seek(long offset, System.IO.SeekOrigin direction)
  {
   return _sink.Seek(offset, direction);
  }

  public override void SetLength(long length)
  {
   _sink.SetLength(length);
  }

  public override void Close()
  {
   _sink.Close();
  }

  public override void Flush()
  {
   _sink.Flush();
  }

  public override int Read(byte[] buffer, int offset, int count)
  {
   return _sink.Read(buffer, offset, count);
  }

  // The Write method actually does the filtering.
    public override void Write(byte[] buffer, int offset, int count)
    {
        string szBuffer = System.Text.UTF8Encoding.UTF8.GetString(buffer, offset, count);
        string ap="action=\"";
        int pos=-1;
        if ((pos=szBuffer.IndexOf(ap) )!= -1)
        {
            int epos = szBuffer.IndexOf("\"", pos + ap.Length+1);
            if (epos != -1)
            {
              szBuffer=  szBuffer.Remove(pos + ap.Length, epos - pos - ap.Length);
            }

            szBuffer = szBuffer.Insert(pos + ap.Length, this.str);

            byte[] data = System.Text.UTF8Encoding.UTF8.GetBytes(szBuffer);
            _sink.Write(data, 0, data.Length);
           
        }
        else
        {
            oOutput.Append(szBuffer);
        }

        //下面的这一段可以用来修改<Head></head>之间的内容；
        //Regex oEndFile = new Regex("</head>", RegexOptions.IgnoreCase|RegexOptions.Compiled);
        //if (oEndFile.IsMatch(szBuffer))
        //{
        //    //Append the last buffer of data
        //    //附加上缓冲区中的最后一部分数据
        //    oOutput.Append(szBuffer);
        //    //Get back the complete response for the client
        //    //传回完整的客户端返回数据
        //    string szCompleteBuffer = oOutput.ToString().ToLower();
        //    int ipos = szCompleteBuffer.IndexOf("<title>");
        //    int epos = szCompleteBuffer.IndexOf("</title>",ipos+7);
        //    string sp = szCompleteBuffer.Substring(ipos+7, epos - ipos );
        //    szCompleteBuffer = szCompleteBuffer.Remove(ipos+7,sp.Length-7);
        //    szCompleteBuffer = szCompleteBuffer.Insert(ipos + 7, "dhz");
        // //   szCompleteBuffer = szCompleteBuffer.Replace(sp, "dhz");
        //    //No match, so write out original data
        //    //没有匹配，因此写入源代码
        //    byte[] data = System.Text.UTF8Encoding.UTF8.GetBytes(szCompleteBuffer);
        //    _sink.Write(data, 0, data.Length);
        //}
        //else
        //{
        //    oOutput.Append(szBuffer);
        //}
    }
}

//////而重候规则呢则是用xml文件配置如下；

当然在web.config通过自定义配置节做也可以的

<?xml version="1.0" encoding="utf-8" ?>
<Rules>
  <RewriterRule>
    <LookFors>
      <LookFor>~/(\d{4})/(\d{2})\.html</LookFor>
      <LookFor>~/(\d{4})/(\d{2})/</LookFor>
      <LookFor>~/(\d{4})/(\d{2})</LookFor>
      <LookFor>~/(\d{4})/(\d{2})/index.html</LookFor>
    </LookFors>
    <SendTo>~/Pro.aspx?year=$1&amp;month=$2</SendTo>
  </RewriterRule>
  <RewriterRule>
    <LookFors>
      <LookFor>~/pc</LookFor>
    </LookFors>
    <SendTo>~/Test2.aspx</SendTo>
  </RewriterRule>
</Rules>
//这个规则写的不好，如第一个就可以用一个正则表达式来做。但是一时不知道怎么写好，好像要用到什么反捕获组的概念，正在思考这个东东！！