OfflineContentHandler.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF 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.apache.tika.sax;

import org.xml.sax.ContentHandler;
import org.xml.sax.InputSource;

import org.apache.tika.parser.ParseContext;

/**
 * Content handler decorator that always returns an empty stream from the
 * {@link #resolveEntity(String, String)} method to prevent potential
 * network or other external resources from being accessed by an XML parser.
 *
 * @see <a href="https://issues.apache.org/jira/browse/TIKA-185">TIKA-185</a>
 */
public class OfflineContentHandler extends ContentHandlerDecorator {

    private final OfflineEntityResolver resolver;

    public OfflineContentHandler(ContentHandler handler) {
        this(handler, null);
    }

    /**
     * @param context records refused external references on the document's metadata
     *                when it holds a {@link org.apache.tika.parser.ParseRecord}; may be null
     */
    public OfflineContentHandler(ContentHandler handler, ParseContext context) {
        super(handler);
        this.resolver = new OfflineEntityResolver(context);
    }

    /**
     * Returns an empty stream. This will make an XML parser silently
     * ignore any external entities.
     */
    @Override
    public InputSource resolveEntity(String publicId, String systemId) {
        return resolver.resolveEntity(publicId, systemId);
    }

}