org.apache.jackrabbit.webdav.xml.DavDocumentBuilderFactory Maven / Gradle / Ivy
/*
* 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.jackrabbit.webdav.xml;
import java.io.IOException;
import javax.xml.XMLConstants;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.xml.sax.EntityResolver;
import org.xml.sax.InputSource;
import org.xml.sax.helpers.DefaultHandler;
/**
* Custom {@link DocumentBuilderFactory} extended for use in WebDAV.
*/
public class DavDocumentBuilderFactory {
private static final Logger LOG = LoggerFactory.getLogger(DavDocumentBuilderFactory.class);
private final DocumentBuilderFactory DEFAULT_FACTORY = createFactory();
private DocumentBuilderFactory BUILDER_FACTORY = DEFAULT_FACTORY;
private DocumentBuilderFactory createFactory() {
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
factory.setNamespaceAware(true);
factory.setIgnoringComments(true);
factory.setIgnoringElementContentWhitespace(true);
factory.setCoalescing(true);
try {
factory.setFeature(XMLConstants.FEATURE_SECURE_PROCESSING, true);
} catch (ParserConfigurationException e) {
LOG.warn("Secure XML processing is not supported", e);
} catch (AbstractMethodError e) {
LOG.warn("Secure XML processing is not supported", e);
}
return factory;
}
public void setFactory(DocumentBuilderFactory documentBuilderFactory) {
LOG.debug("DocumentBuilderFactory changed to: " + documentBuilderFactory);
BUILDER_FACTORY = documentBuilderFactory != null ? documentBuilderFactory : DEFAULT_FACTORY;
}
/**
* An entity resolver that does not allow external entity resolution. See
* RFC 4918, Section 20.6
*/
private static final EntityResolver DEFAULT_ENTITY_RESOLVER = new EntityResolver() {
@Override
public InputSource resolveEntity(String publicId, String systemId) throws IOException {
LOG.debug("Resolution of external entities in XML payload not supported - publicId: " + publicId + ", systemId: "
+ systemId);
throw new IOException("This parser does not support resolution of external entities (publicId: " + publicId
+ ", systemId: " + systemId + ")");
}
};
public DocumentBuilder newDocumentBuilder() throws ParserConfigurationException {
DocumentBuilder db = BUILDER_FACTORY.newDocumentBuilder();
if (BUILDER_FACTORY == DEFAULT_FACTORY) {
// if this is the default factory: set the default entity resolver as well
db.setEntityResolver(DEFAULT_ENTITY_RESOLVER);
}
db.setErrorHandler(new DefaultHandler());
return db;
}
}