危險字元過濾的類(最新完善版)（1）

大可山發表於2009-01-06
字元

前兩天在一個Blog中看到過濾危險字元的類（網址記不清楚了，如果原作者來信告知，本文將加上其連結），現將其完善一下：

/*原作者：(請與我聯絡)
*改進者：Johnsuna(阿山NET msn:a3news(AT)hotmail.com)  http://www.vcsharp.com
*/
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
{
 ///


 ///  FilterRealProxy類：一個真實代理, 攔截它所代理物件中方法的返回值，並對需要過濾的返回值進行過濾。
 ///
 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);
   //檢查返回值是否為String,如果不是String,就沒必要進行過濾
   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;
  }
 }

 ///


 ///  StringFilter類：自定義屬性類, 定義目標元素的過濾型別
 ///
 public class StringFilter:Attribute
 {
  protected FilterType _filterType;

  public StringFilter(FilterType filterType)
  {
   this._filterType=filterType;
  }
  public FilterType FilterType
  {
   get
   {
    return _filterType;
   }
  }
 }

 ///


 /// 列舉類：用於指定過濾型別，例如：對script過濾還是對html進行過濾？
 ///
 [Flags()]
 public enum FilterType
 {
  Script. = 1,
  Html =2,
  bject=3,
  AHrefScript=4,
  Iframe=5,
  Frameset=6,
  Src=7,
  BadWords=8,
  //Include=9,
  All=16
 }

 ///


 /// 過濾處理類：根據過濾型別，呼叫相應的過濾處理方法。
 ///
 
 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']*>(.*?{0}?)*]*>)", embeddedScriptComments ) ;
   // 包含註釋和Script語句
   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)
        \            (
                (?'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的委託
   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 ([^>])*>";
   return Regex.Replace(content,regexstr,string.Empty,RegexOptions.IgnoreCase);
  }

  public static string FilterIframe(string content)
  {
   string ([^>])*>";
   return Regex.Replace(content,regexstr,string.Empty,RegexOptions.IgnoreCase);
  }

  //移除非法或不友好字元
  private static string FilterBadWords(string chkStr)
  {
    //這裡的非法和不友好字元由你任意加，用“|”分隔，支援正規表示式,由於本Blog禁止貼非法和不友好字元，所以這裡無法加上。
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;
  }
 }
}

 

來自 “ ITPUB部落格 ” ，連結：http://blog.itpub.net/14601556/viewspace-528585/，如需轉載，請註明出處，否則將追究法律責任。

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