asp.net 2.0中的URL重写以及urlMappings问题---流行第一线

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&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！！