asp.net c非法词汇的过滤器

asp教程.net c非法词汇的过滤器

using system;
using system.text;
using system.io;
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，这个可以在数据库教程或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：

//这个适合多个页一次过处理
public void application_beginrequest()
{
    string path = httpcontext.current.request.path.tolower();
    string[] paths = new string[]
    {
        "/aa/","/bb/"
    };
    foreach (string item in paths)
    {
        if (path.startswith(item))
        {
            response.filter = new responsefilter(response.filter);
            break;
        }
    }
}

或者重写某页的render方法

protected override void render(htmltextwriter writer)
{
    stringwriter strwriter = new stringwriter();
    base.render(new htmltextwriter(strwriter));
    string html = strwriter.tostring();
    html = util.replaceinvalidkeyword(html);
    writer.write(html);
}

补充：asp.net教程,C语言