package com.xss;

import java.util.regex.Pattern;


/**
 * XssUtil 工具類
 */
public class XssUtil {

    static Pattern scriptPattern = Pattern.compile("<script>(.*?)</script>", Pattern.CASE_INSENSITIVE);


    static Pattern scriptPatternSrc = Pattern.compile("src=\"(.*?)",Pattern.CASE_INSENSITIVE );

    
 
static Pattern scriptPatternHref = Pattern.compile("href=\"(.*?)",Pattern.CASE_INSENSITIVE );

    static Pattern singleScriptPattern = scriptPattern = Pattern.compile("</script>", Pattern.CASE_INSENSITIVE);
    static Pattern singleBeginScriptPattern = Pattern.compile("<script(.*?)>",
            Pattern.CASE_INSENSITIVE 
 
| Pattern.MULTILINE | Pattern.DOTALL);

    static Pattern singleBeginIframePattern = Pattern.compile("<iframe(.*?)>",
            Pattern.CASE_INSENSITIVE | Pattern.MULTILINE | Pattern.DOTALL);

    static Pattern criptPattern = Pattern.compile("eval\\((.*?)\\)",
            Pattern.CASE_INSENSITIVE 
 
| Pattern.MULTILINE | Pattern.DOTALL);
    static Pattern expressionPattern = Pattern.compile("expression\\((.*?)\\)",
            Pattern.CASE_INSENSITIVE | Pattern.MULTILINE | Pattern.DOTALL);

    static Pattern javascriptPattern = Pattern.compile("javascript:", Pattern.CASE_INSENSITIVE);
    //alert
    static Pattern alertPattern = Pattern.compile("(.*?)alert(.*?)", Pattern.CASE_INSENSITIVE);

    static Pattern importPattern = Pattern.compile("(.*?)import(.*?)", Pattern.CASE_INSENSITIVE);

    static Pattern functionPattern = Pattern.compile("(.*?)function(.*?)", Pattern.CASE_INSENSITIVE);

    static Pattern vbscriptPattern = Pattern.compile("vbscript:", Pattern.CASE_INSENSITIVE);

    static Pattern onScriptPattern = Pattern.compile("on(.*?)=['|\"](.*?)['|\"]",
            Pattern.CASE_INSENSITIVE | Pattern.MULTILINE | Pattern.DOTALL);



    /**
     * 清理xss特殊字元
     * @param value 過濾的字串
     * @return: String
     */
    public static String cleanXSS(String value) {
        if (value != null) {
            // 避免script 標籤
            value = scriptPattern.matcher(value).replaceAll("");

            // 避免src形式的表示式
            value = scriptPatternSrc.matcher(value).replaceAll("");

            // 避免href形式的表示式
            value = scriptPatternHref.matcher(value).replaceAll("");
            // 刪除單個的 </script> 標籤
            value = singleScriptPattern.matcher(value).replaceAll("");

            // 刪除單個的<script ...> 標籤
            value = singleBeginScriptPattern.matcher(value).replaceAll("");
            // 刪除單個的<iframe ...> 標籤
            value = singleBeginIframePattern.matcher(value).replaceAll("");
            // 避免 eval(...) 形式表示式
            value = criptPattern.matcher(value).replaceAll("");

            // 避免 e­xpression(...) 表示式
            value = expressionPattern.matcher(value).replaceAll("");

            // 避免 javascript: 表示式
            value = javascriptPattern.matcher(value).replaceAll("");

            value = alertPattern.matcher(value).replaceAll("");

            value = importPattern.matcher(value).replaceAll("");

            value = functionPattern.matcher(value).replaceAll("");

            // 避免 vbscript: 表示式
            value = vbscriptPattern.matcher(value).replaceAll("");
            // 避免 onXX= 表示式
            value = onScriptPattern.matcher(value).replaceAll("");

        }
        return value;
    }


}