asp.net 使用Response.Filter 过滤非法词汇

另一种解决方案是在输出时过滤掉非常词汇，优点是只要写一次就好了，可以过滤整站的非法词汇，缺点是，非法词汇仍然存入到了数据库中，呵呵，大家可以有针对性的选择，本例用的是后者，起因在于当初没有做此功能，后来需要添加，这时又不想改原来代码，所以就想了这个办法，主要是采用了HttpResponse.Filter属性来处理。具体代码如下：

首先自定义一个类，来作为非法词汇的过滤器
代码如下:

public class ResponseFilter:Stream 
{ 
#region properties 
Stream responseStream; 
long position; 
StringBuilder html = new StringBuilder(); 
#endregion 
#region constructor 
public ResponseFilter(Stream inputStream) 
{ 
responseStream = inputStream; 
} 
#endregion 
#region implemented abstract members 
public override bool CanRead 
{ 
get { return true; } 
} 
public override bool CanSeek 
{ 
get { return true; } 
} 
public override bool CanWrite 
{ 
get { return true; } 
} 
public override void Close() 
{ 
responseStream.Close(); 
} 
public override void Flush() 
{ 
responseStream.Flush(); 
} 
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 responseStream.Seek(offset, direction); 
} 
public override void SetLength(long length) 
{ 
responseStream.SetLength(length); 
} 
public override int Read(byte[] buffer, int offset, int count) 
{ 
return responseStream.Read(buffer, offset, count); 
} 
#endregion 
#region write method 
public override void Write(byte[] buffer, int offset, int count) 
{ 
string sBuffer = System.Text.UTF8Encoding.UTF8.GetString(buffer, offset, count); 
//得到非法词汇列表，这个可以在数据库或Web.Config中读取出来 
string pattern = @"(非法词汇1|非法词汇2|非法词汇3)"; 
string[] s = pattern.Split(new string[] { "|" }, StringSplitOptions.RemoveEmptyEntries); 
foreach (string s1 in s) 
{ 
sBuffer = sBuffer.Replace(s1, "**"); 
} 
byte[] data = System.Text.UTF8Encoding.UTF8.GetBytes(sBuffer); 
responseStream.Write(data, 0, data.Length); 
} 
#endregion 
} 

然后再Global.asax文件中，添加如下代码： 
[code] 
public void Application_BeginRequest(){ 
Response.Filter = new ResponseFilter(Response.Filter); 
} 
OK,测试一下吧！