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This is the core Apache Tika™ toolkit library from which all other modules inherit functionality. It also
includes the core facades for the Tika API.
/*
* 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.parser;
import javax.xml.XMLConstants;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.parsers.SAXParser;
import javax.xml.parsers.SAXParserFactory;
import javax.xml.stream.XMLInputFactory;
import javax.xml.stream.XMLResolver;
import javax.xml.stream.XMLStreamException;
import java.io.IOException;
import java.io.Serializable;
import java.io.StringReader;
import java.lang.reflect.Method;
import java.util.HashMap;
import java.util.Map;
import org.apache.tika.exception.TikaException;
import org.xml.sax.EntityResolver;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;
import org.xml.sax.SAXNotRecognizedException;
import org.xml.sax.SAXNotSupportedException;
import org.xml.sax.XMLReader;
/**
* Parse context. Used to pass context information to Tika parsers.
*
* @since Apache Tika 0.5
* @see TIKA-275
*/
public class ParseContext implements Serializable {
/** Serial version UID. */
private static final long serialVersionUID = -5921436862145826534L;
/** Map of objects in this context */
private final Map context = new HashMap();
private static final EntityResolver IGNORING_SAX_ENTITY_RESOLVER = new EntityResolver() {
public InputSource resolveEntity(String publicId, String systemId) throws SAXException, IOException {
return new InputSource(new StringReader(""));
}
};
private static final XMLResolver IGNORING_STAX_ENTITY_RESOLVER =
new XMLResolver() {
@Override
public Object resolveEntity(String publicID, String systemID, String baseURI, String namespace) throws
XMLStreamException {
return "";
}
};
/**
* Adds the given value to the context as an implementation of the given
* interface.
*
* @param key the interface implemented by the given value
* @param value the value to be added, or null to remove
*/
public void set(Class key, T value) {
if (value != null) {
context.put(key.getName(), value);
} else {
context.remove(key.getName());
}
}
/**
* Returns the object in this context that implements the given interface.
*
* @param key the interface implemented by the requested object
* @return the object that implements the given interface,
* or null if not found
*/
@SuppressWarnings("unchecked")
public T get(Class key) {
return (T) context.get(key.getName());
}
/**
* Returns the object in this context that implements the given interface,
* or the given default value if such an object is not found.
*
* @param key the interface implemented by the requested object
* @param defaultValue value to return if the requested object is not found
* @return the object that implements the given interface,
* or the given default value if not found
*/
public T get(Class key, T defaultValue) {
T value = get(key);
if (value != null) {
return value;
} else {
return defaultValue;
}
}
/**
* Returns the XMLReader specified in this parsing context. If a reader
* is not explicitly specified, then one is created using the specified
* or the default SAX parser.
*
* @see #getSAXParser()
* @since Apache Tika 1.13
* @return XMLReader
* @throws TikaException
*/
public XMLReader getXMLReader() throws TikaException {
XMLReader reader = get(XMLReader.class);
if (reader != null) {
return reader;
}
try {
reader = getSAXParser().getXMLReader();
} catch (SAXException e) {
throw new TikaException("Unable to create an XMLReader", e);
}
reader.setEntityResolver(IGNORING_SAX_ENTITY_RESOLVER);
return reader;
}
/**
* Returns the SAX parser specified in this parsing context. If a parser
* is not explicitly specified, then one is created using the specified
* or the default SAX parser factory.
*
* @see #getSAXParserFactory()
* @since Apache Tika 0.8
* @return SAX parser
* @throws TikaException if a SAX parser could not be created
*/
public SAXParser getSAXParser() throws TikaException {
SAXParser parser = get(SAXParser.class);
if (parser != null) {
return parser;
} else {
try {
return getSAXParserFactory().newSAXParser();
} catch (ParserConfigurationException e) {
throw new TikaException("Unable to configure a SAX parser", e);
} catch (SAXException e) {
throw new TikaException("Unable to create a SAX parser", e);
}
}
}
/**
* Returns the SAX parser factory specified in this parsing context.
* If a factory is not explicitly specified, then a default factory
* instance is created and returned. The default factory instance is
* configured to be namespace-aware, not validating, and to use
* {@link XMLConstants#FEATURE_SECURE_PROCESSING secure XML processing}.
*
* @since Apache Tika 0.8
* @return SAX parser factory
*/
public SAXParserFactory getSAXParserFactory() {
SAXParserFactory factory = get(SAXParserFactory.class);
if (factory == null) {
factory = SAXParserFactory.newInstance();
factory.setNamespaceAware(true);
factory.setValidating(false);
try {
factory.setFeature(
XMLConstants.FEATURE_SECURE_PROCESSING, true);
} catch (ParserConfigurationException e) {
} catch (SAXNotSupportedException e) {
} catch (SAXNotRecognizedException e) {
// TIKA-271: Some XML parsers do not support the
// secure-processing feature, even though it's required by
// JAXP in Java 5. Ignoring the exception is fine here, as
// deployments without this feature are inherently vulnerable
// to XML denial-of-service attacks.
}
}
return factory;
}
/**
* Returns the DOM builder factory specified in this parsing context.
* If a factory is not explicitly specified, then a default factory
* instance is created and returned. The default factory instance is
* configured to be namespace-aware and to apply reasonable security
* features.
*
* @since Apache Tika 1.13
* @return DOM parser factory
*/
private DocumentBuilderFactory getDocumentBuilderFactory() {
//borrowed from Apache POI
DocumentBuilderFactory documentBuilderFactory = get(DocumentBuilderFactory.class);
if (documentBuilderFactory != null) {
return documentBuilderFactory;
}
documentBuilderFactory = DocumentBuilderFactory.newInstance();
documentBuilderFactory.setNamespaceAware(true);
documentBuilderFactory.setValidating(false);
tryToSetSAXFeatureOnDOMFactory(documentBuilderFactory,
XMLConstants.FEATURE_SECURE_PROCESSING, true);
tryToSetXercesManager(documentBuilderFactory);
return documentBuilderFactory;
}
/**
* Returns the DOM builder specified in this parsing context.
* If a builder is not explicitly specified, then a builder
* instance is created and returned. The builder instance is
* configured to apply an {@link #IGNORING_SAX_ENTITY_RESOLVER},
* and it sets the ErrorHandler to null.
*
* @since Apache Tika 1.13
* @return DOM Builder
*/
public DocumentBuilder getDocumentBuilder() throws TikaException {
DocumentBuilder documentBuilder = get(DocumentBuilder.class);
if (documentBuilder != null) {
return documentBuilder;
}
try {
DocumentBuilderFactory documentBuilderFactory = getDocumentBuilderFactory();
documentBuilder = documentBuilderFactory.newDocumentBuilder();
documentBuilder.setEntityResolver(IGNORING_SAX_ENTITY_RESOLVER);
documentBuilder.setErrorHandler(null);
return documentBuilder;
} catch (ParserConfigurationException e) {
throw new TikaException("XML parser not available", e);
}
}
/**
* Returns the StAX input factory specified in this parsing context.
* If a factory is not explicitly specified, then a default factory
* instance is created and returned. The default factory instance is
* configured to be namespace-aware and to apply reasonable security
* using the {@link #IGNORING_STAX_ENTITY_RESOLVER}.
*
* @since Apache Tika 1.13
* @return StAX input factory
*/
public XMLInputFactory getXMLInputFactory() {
XMLInputFactory factory = get(XMLInputFactory.class);
if (factory != null) {
return factory;
}
factory = XMLInputFactory.newFactory();
tryToSetStaxProperty(factory, XMLInputFactory.IS_NAMESPACE_AWARE, true);
tryToSetStaxProperty(factory, XMLInputFactory.IS_VALIDATING, false);
factory.setXMLResolver(IGNORING_STAX_ENTITY_RESOLVER);
return factory;
}
private static void tryToSetSAXFeatureOnDOMFactory(DocumentBuilderFactory dbf, String feature, boolean value) {
try {
dbf.setFeature(feature, value);
} catch (Exception|AbstractMethodError e) {
}
}
private static void tryToSetXercesManager(DocumentBuilderFactory dbf) {
// Try built-in JVM one first, standalone if not
for (String securityManagerClassName : new String[] {
"com.sun.org.apache.xerces.internal.util.SecurityManager",
"org.apache.xerces.util.SecurityManager"
}) {
try {
Object mgr = Class.forName(securityManagerClassName).newInstance();
Method setLimit = mgr.getClass().getMethod("setEntityExpansionLimit", Integer.TYPE);
setLimit.invoke(mgr, 4096);
dbf.setAttribute("http://apache.org/xml/properties/security-manager", mgr);
// Stop once one can be setup without error
return;
} catch (Throwable t) {
}
}
}
private void tryToSetStaxProperty(XMLInputFactory factory, String key, boolean value) {
try {
factory.setProperty(key, value);
} catch (IllegalArgumentException e) {
//swallow
}
}
}