asp.net 使用Response.Filter 过滤非法词汇

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
}