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This project contains some of the configurable modules used within the Heritrix application to crawl the web. The modules in this project can be used in applications other than Heritrix, however.

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/*
 *  This file is part of the Heritrix web crawler (crawler.archive.org).
 *
 *  Licensed to the Internet Archive (IA) by one or more individual 
 *  contributors. 
 *
 *  The IA licenses this file to You under the Apache License, Version 2.0
 *  (the "License"); you may not use this file except in compliance with
 *  the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 */
package org.archive.modules.canonicalize;

/**
 * Strip any trailing question mark.
 * @author stack
 * @version $Date$, $Revision$
 */
public class FixupQueryString
extends BaseRule {

    private static final long serialVersionUID = 3L;

    /*
    private static final String DESCRIPTION =
        "Fixup the question mark that leads off the query string. " +
        "This rule returns 'http://www.archive.org/index.html' if passed" +
        " 'http://www.archive.org/index.html?'.  It will also strip '?&'" +
        " if '?&' is all that comprises the query string.  Also strips" +
        " extraneous leading '&': Returns 'http://archive.org/index.html?x=y" +
        " if passed 'http://archive.org/index.html?&x=y." +
        " Will also strip '&' if last thing in query string." +
        " Operates on all schemes.  This is a good rule to run toward the" +
        " end of canonicalization processing.";
        */
    
    public FixupQueryString() {
    }

    public String canonicalize(String url) {
        if (url == null || url.length() <= 0) {
            return url;
        }
        
        int index = url.lastIndexOf('?');
        if (index > 0) {
            if (index == (url.length() - 1)) {
                // '?' is last char in url.  Strip it.
                url = url.substring(0, url.length() - 1);
            } else if (url.charAt(index + 1) == '&') {
                // Next char is '&'. Strip it.
                if (url.length() == (index + 2)) {
                    // Then url ends with '?&'.  Strip them.
                    url = url.substring(0, url.length() - 2);
                } else {
                    // The '&' is redundant.  Strip it.
                    url = url.substring(0, index + 1) +
                    url.substring(index + 2);
                }
            } else if (url.charAt(url.length() - 1) == '&') {
                // If we have a lone '&' on end of query str,
                // strip it.
                url = url.substring(0, url.length() - 1);
            }
        }
        return url;
    }
}