危险字符过滤的类

using System;


using System.IO;


using System.Text;


using System.Text.RegularExpressions;


using System.Runtime.Remoting;


using System.Runtime.Remoting.Proxies;


using System.Runtime.Remoting.Messaging;


using System.Reflection;




namespace FilterRealProxy






{




/**//// <summary>


/// FilterRealProxy类：一个真实代理, 拦截它所代理对象中方法的返回值，并对需要过滤的返回值进行过滤。


/// </summary>


public class FilterRealProxy:RealProxy






{


private MarshalByRefObject target;


public FilterRealProxy(MarshalByRefObject target):base(target.GetType())






{


this.target=target;


}


public override IMessage Invoke(IMessage msg)






{


IMethodCallMessage callMsg=msg as IMethodCallMessage;


IMethodReturnMessage returnMsg = RemotingServices.ExecuteMessage(target,callMsg);


//检查返回值是否为String,如果不是String,就没必要进行过滤


if(this.IsMatchType(returnMsg.ReturnValue))






{


string returnValue=this.Filter(returnMsg.ReturnValue.ToString(),returnMsg.MethodName);


return new ReturnMessage(returnValue,null,0,null,callMsg);


}


return returnMsg;


　　　　 }


protected string Filter(string ReturnValue,string MethodName)






{


MethodInfo methodInfo=target.GetType().GetMethod(MethodName);


object[] attributes=methodInfo.GetCustomAttributes(typeof(StringFilter),true);


foreach (object attrib in attributes)






{


return FilterHandler.Process(((StringFilter)attrib).FilterType,ReturnValue);


}


return ReturnValue;


}


protected bool IsMatchType(object obj)






{


return obj is System.String;


}


}






/**////<summary>


/// StringFilter类：自定义属性类, 定义目标元素的过滤类型


///</summary>


public class StringFilter:Attribute






{


protected FilterType _filterType;




public StringFilter(FilterType filterType)






{


this._filterType=filterType;


}


public FilterType FilterType






{


get






{


return _filterType;


}


}


}






/**//// <summary>


/// 枚举类：用于指定过滤类型，例如：对script过滤还是对html进行过滤？


/// </summary>


[Flags()]


public enum FilterType






{


Script = 1,


Html =2,


Object=3,


AHrefScript=4,


Iframe=5,


Frameset=6,


Src=7,


BadWords=8,


//Include=9,


All=16


}






/**////<summary>


/// 过滤处理类：根据过滤类型，调用相应的过滤处理方法。


///</summary>




public class FilterHandler






{


private FilterHandler()






{


}


public static string Process(FilterType filterType,string filterContent)






{


switch(filterType)






{


case FilterType.Script:


filterContent=FilterScript(filterContent);


break;


case FilterType.Html:


filterContent=FilterHtml(filterContent);


break;


case FilterType.Object:


filterContent=FilterObject(filterContent);


break;


case FilterType.AHrefScript:


filterContent=FilterAHrefScript(filterContent);


break;


case FilterType.Iframe:


filterContent=FilterIframe(filterContent);


break;


case FilterType.Frameset:


filterContent=FilterFrameset(filterContent);


break;


case FilterType.Src:


filterContent=FilterSrc(filterContent);


break;


//case FilterType.Include:


// filterContent=FilterInclude(filterContent);


// break;


case FilterType.BadWords:


filterContent=FilterBadWords(filterContent);


break;


case FilterType.All:


filterContent=FilterAll(filterContent);


break;


default:


//do nothing


break;


}


return filterContent;


}




public static string FilterScript(string content)






{


string commentPattern = @"(?'comment'<!--.*?--[ /n/r]*>)" ;


string embeddedScriptComments = @"(///*.*?/*//|////.*?[/n/r])" ;


string scriptPattern = String.Format(@"(?'script'<[ /n/r]*script[^>]*>(.*?{0}?)*<[ /n/r]*/script[^>]*>)", embeddedScriptComments ) ;


// 包含注释和Script语句


string pattern = String.Format(@"(?s)({0}|{1})", commentPattern, scriptPattern) ;




return StripScriptAttributesFromTags(Regex.Replace(content,pattern,string.Empty,RegexOptions.IgnoreCase));


}




private static string StripScriptAttributesFromTags( string content )






{


string eventAttribs = @"on(blur|c(hange|lick)|dblclick|focus|keypress|(key|mouse)(down|up)|(un)?load


|mouse(move|o(ut|ver))|reset|s(elect|ubmit))" ;




string pattern = String.Format(@"(?inx)


/<(/w+)/s+


(


(?'attribute'


(?'attributeName'{0})/s*=/s*


(?'delim'['""]?)


(?'attributeValue'[^'"">]+)


(/3)


)


|


(?'attribute'


(?'attributeName'href)/s*=/s*


(?'delim'['""]?)


(?'attributeValue'javascript[^'"">]+)


(/3)


)


|


[^>]


)*


/>", eventAttribs ) ;


Regex re = new Regex( pattern ) ;


// 使用MatchEvaluator的委托


return re.Replace( content, new MatchEvaluator( StripAttributesHandler ) ) ;


}




private static string StripAttributesHandler( Match m )






{


if( m.Groups["attribute"].Success )






{


return m.Value.Replace( m.Groups["attribute"].Value, "") ;


}


else






{


return m.Value ;


}


}




public static string FilterAHrefScript(string content)






{


string newstr=FilterScript(content);


string regexstr=@" href[ ^=]*= *[/s/S]*script *:";


return Regex.Replace(newstr,regexstr,string.Empty,RegexOptions.IgnoreCase);


}




public static string FilterSrc(string content)






{


string newstr=FilterScript(content);


string regexstr=@" src *= *['""]?[^/.]+/.(js|vbs|asp|aspx|php|jsp)['""]";


return Regex.Replace(newstr,regexstr,@"",RegexOptions.IgnoreCase);


}




/**//*


public static string FilterInclude(string content)


{


string newstr=FilterScript(content);


string regexstr=@"<[/s/S]*include *(file|virtual) *= *[/s/S]*/.(js|vbs|asp|aspx|php|jsp)[^>]*>";


return Regex.Replace(newstr,regexstr,string.Empty,RegexOptions.IgnoreCase);


}


*/


public static string FilterHtml(string content)






{


string newstr=FilterScript(content);


string regexstr=@"<[^>]*>";


return Regex.Replace(newstr,regexstr,string.Empty,RegexOptions.IgnoreCase);


}




public static string FilterObject(string content)






{


string regexstr=@"(?i)<Object([^>])*>(/w|/W)*</Object([^>])*>";


return Regex.Replace(content,regexstr,string.Empty,RegexOptions.IgnoreCase);


}




public static string FilterIframe(string content)






{


string regexstr=@"(?i)<Iframe([^>])*>(/w|/W)*</Iframe([^>])*>";


return Regex.Replace(content,regexstr,string.Empty,RegexOptions.IgnoreCase);


}




public static string FilterFrameset(string content)






{


string regexstr=@"(?i)<Frameset([^>])*>(/w|/W)*</Frameset([^>])*>";


return Regex.Replace(content,regexstr,string.Empty,RegexOptions.IgnoreCase);


}




//移除非法或不友好字符


private static string FilterBadWords(string chkStr)






{


//这里的非法和不友好字符由你任意加，用“|”分隔，支持正则表达式,由于本Blog禁止贴非法和不友好字符，所以这里无法加上。


string BadWords=@"

";


if (chkStr == "")






{


return "";


}




string[] bwords = BadWords.Split('#');


int i,j;


string str;


StringBuilder sb = new StringBuilder();


for(i = 0; i< bwords.Length; i++)






{


str=bwords[i].ToString().Trim();


string regStr,toStr;


regStr=str;


Regex r=new Regex(regStr,RegexOptions.IgnoreCase | RegexOptions.Singleline| RegexOptions.Multiline);


Match m=r.Match(chkStr);


if(m.Success)






{


j=m.Value.Length;


sb.Insert(0,"*",j);


toStr=sb.ToString();


chkStr=Regex.Replace(chkStr,regStr,toStr,RegexOptions.IgnoreCase | RegexOptions.Singleline| RegexOptions.Multiline);


}


sb.Remove(0,sb.Length);


}


return chkStr;


}




public static string FilterAll(string content)






{


content = FilterHtml(content);


content = FilterScript(content);


content = FilterAHrefScript(content);


content = FilterObject(content);


content = FilterIframe(content);


content = FilterFrameset(content);


content = FilterSrc(content);


content = FilterBadWords(content);


//content = FilterInclude(content);


return content;


}


}


}