    001package org.apache.turbine.util;
    002
    003
    004/*
    005 * Licensed to the Apache Software Foundation (ASF) under one
    006 * or more contributor license agreements.  See the NOTICE file
    007 * distributed with this work for additional information
    008 * regarding copyright ownership.  The ASF licenses this file
    009 * to you under the Apache License, Version 2.0 (the
    010 * "License"); you may not use this file except in compliance
    011 * with the License.  You may obtain a copy of the License at
    012 *
    013 *   http://www.apache.org/licenses/LICENSE-2.0
    014 *
    015 * Unless required by applicable law or agreed to in writing,
    016 * software distributed under the License is distributed on an
    017 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
    018 * KIND, either express or implied.  See the License for the
    019 * specific language governing permissions and limitations
    020 * under the License.
    021 */
    022
    023
    024import org.apache.ecs.Entities;
    025
    026import org.apache.ecs.filter.CharacterFilter;
    027
    028/**
    029 * Some filter methods that have been orphaned in the Screen class.
    030 *
    031 *
    032 * @author <a href="mailto:mbryson@mont.mindspring.com">Dave Bryson</a>
    033 * @author <a href="mailto:hps@intermeta.de">Henning P. Schmiedehausen</a>
    034 * @version $Id: InputFilterUtils.java 615328 2008-01-25 20:25:05Z tv $
    035 */
    036
    037public abstract class InputFilterUtils
    038{
    039    /** A HtmlFilter Object for the normal input filter */
    040    private static final CharacterFilter filter = htmlFilter();
    041
    042    /** A HtmlFilter Object for the minimal input filter */
    043    private static final CharacterFilter minFilter = htmlMinFilter();
    044
    045    /**
    046     * This function can/should be used in any screen that will output
    047     * User entered text.  This will help prevent users from entering
    048     * html (<SCRIPT>) tags that will get executed by the browser.
    049     *
    050     * @param s The string to prepare.
    051     * @return A string with the input already prepared.
    052     */
    053    public static String prepareText(String s)
    054    {
    055        return filter.process(s);
    056    }
    057
    058    /**
    059     * This function can/should be used in any screen that will output
    060     * User entered text.  This will help prevent users from entering
    061     * html (<SCRIPT>) tags that will get executed by the browser.
    062     *
    063     * @param s The string to prepare.
    064     * @return A string with the input already prepared.
    065     */
    066    public static String prepareTextMinimum(String s)
    067    {
    068        return minFilter.process(s);
    069    }
    070
    071    /**
    072     * These attributes are supposed to be the default, but they are
    073     * not, at least in ECS 1.2.  Include them all just to be safe.
    074     *
    075     * @return A CharacterFilter to do HTML filtering.
    076     */
    077    private static CharacterFilter htmlFilter()
    078    {
    079        CharacterFilter filter = new CharacterFilter();
    080        filter.addAttribute("\"", Entities.QUOT);
    081        filter.addAttribute("'", Entities.LSQUO);
    082        filter.addAttribute("&", Entities.AMP);
    083        filter.addAttribute("<", Entities.LT);
    084        filter.addAttribute(">", Entities.GT);
    085        return filter;
    086    }
    087
    088    /*
    089     * We would like to filter user entered text that might be
    090     * dynamically added, using javascript for example.  But we do not
    091     * want to filter all the above chars, so we will just disallow
    092     * <.
    093     *
    094     * @return A CharacterFilter to do minimal HTML filtering.
    095     */
    096    private static CharacterFilter htmlMinFilter()
    097    {
    098        CharacterFilter filter = new CharacterFilter();
    099        filter.removeAttribute(">");
    100        filter.removeAttribute("\"");
    101        filter.removeAttribute("'");
    102        filter.removeAttribute("&");
    103        filter.addAttribute("<", Entities.LT);
    104        return filter;
    105    }
    106}