/**********************************************************************************
* $URL: https://source.sakaiproject.org/svn/kernel/trunk/kernel-util/src/main/java/org/sakaiproject/util/Xml.java $
* $Id: Xml.java 90064 2011-03-19 12:04:59Z david.horwitz@uct.ac.za $
***********************************************************************************
*
* Copyright (c) 2003, 2004, 2005, 2006, 2007, 2008 Sakai Foundation
*
* Licensed under the Educational Community 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.opensource.org/licenses/ECL-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.sakaiproject.util;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.Reader;
import java.io.StringReader;
import java.io.StringWriter;
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 org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.w3c.dom.DOMImplementation;
import org.w3c.dom.Document;
import org.w3c.dom.ls.DOMImplementationLS;
import org.w3c.dom.ls.LSOutput;
import org.w3c.dom.ls.LSSerializer;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;
import org.xml.sax.helpers.DefaultHandler;
/**
* Special utils used in the storage utils
* (some duplication from the other kernel Xml utils)
*/
public class StorageUtils {
private static Log M_log = LogFactory.getLog(StorageUtils.class);
private static SAXParserFactory parserFactory;
/**
* Create a new DOM Document.
*
* @return A new DOM document.
*/
public static Document createDocument()
{
try
{
DocumentBuilder builder = getDocumentBuilder();
Document doc = builder.newDocument();
return doc;
}
catch (Exception any)
{
M_log.warn("createDocument: " + any.toString());
return null;
}
}
/**
* Read a DOM Document from xml in a file.
*
* @param name
* The file name for the xml file.
* @return A new DOM Document with the xml contents.
*/
public static Document readDocument(String name)
{
Document doc = null;
// first try using whatever character encoding the XML itself specifies
InputStream fis = null;
try
{
DocumentBuilder docBuilder = getDocumentBuilder();
fis = new FileInputStream(name);
doc = docBuilder.parse(fis);
}
catch (Exception e)
{
doc = null;
}
finally {
if (fis != null) {
try {
fis.close();
} catch (IOException e) {
}
}
}
if (doc != null) return doc;
// OK, that didn't work - the document is probably ISO-8859-1
try
{
DocumentBuilder docBuilder = getDocumentBuilder();
InputStreamReader in = new InputStreamReader(new FileInputStream(name), "ISO-8859-1");
InputSource inputSource = new InputSource(in);
doc = docBuilder.parse(inputSource);
}
catch (Exception any)
{
doc = null;
}
if (doc != null) return doc;
// try forcing UTF-8
try
{
DocumentBuilder docBuilder = getDocumentBuilder();
InputStreamReader in = new InputStreamReader(new FileInputStream(name), "UTF-8");
InputSource inputSource = new InputSource(in);
doc = docBuilder.parse(inputSource);
}
catch (Exception any)
{
M_log.warn("readDocument failed on file: " + name + " with exception: " + any.toString());
doc = null;
}
return doc;
}
/**
* Read a DOM Document from xml in a string.
*
* @param in
* The string containing the XML
* @return A new DOM Document with the xml contents.
*/
public static Document readDocumentFromString(String in)
{
try
{
DocumentBuilder docBuilder = getDocumentBuilder();
InputSource inputSource = new InputSource(new StringReader(in));
Document doc = docBuilder.parse(inputSource);
return doc;
}
catch (Exception any)
{
M_log.warn("readDocumentFromString: " + any.toString());
return null;
}
}
/**
* Process a string of XML using SAX and a default handler
* @param in
* @param dh
* @throws SAXException
* @throws IOException
*/
public static void processString( String in, DefaultHandler dh ) throws SAXException, IOException {
Reader r = new StringReader(in);
processReader(r,dh);
r.close();
}
/**
* SAX Process a Reader using the Default handler
* @param in
* @param dh
* @throws SAXException
* @throws IOException
*/
public static void processReader(Reader in, DefaultHandler dh) throws SAXException,
IOException
{
InputSource ss = new InputSource(in);
SAXParser p = null;
if (parserFactory == null)
{
parserFactory = SAXParserFactory.newInstance();
parserFactory.setNamespaceAware(false);
parserFactory.setValidating(false);
}
try
{
p = parserFactory.newSAXParser();
}
catch (ParserConfigurationException e)
{
throw new SAXException("Failed to get a parser ", e);
}
p.parse(ss, dh);
}
/**
* Write a DOM Document to an xml file.
*
* @param doc
* The DOM Document to write.
* @param fileName
* The complete file name path.
*/
public static void writeDocument(Document doc, String fileName)
{
OutputStream out = null;
try
{
out = new FileOutputStream(fileName);
// get an instance of the DOMImplementation registry
DocumentBuilderFactory factory
= DocumentBuilderFactory.newInstance();
DocumentBuilder builder = factory.newDocumentBuilder();
DOMImplementation impl = builder.getDOMImplementation();
DOMImplementationLS feature = (DOMImplementationLS) impl.getFeature("LS","3.0");
LSSerializer serializer = feature.createLSSerializer();
LSOutput output = feature.createLSOutput();
output.setByteStream(out);
output.setEncoding("UTF-8");
serializer.write(doc, output);
out.close();
}
catch (Exception any)
{
M_log.warn("writeDocument: " + any.toString());
}
finally {
if (out != null) {
try {
out.close();
} catch (IOException e) {
}
}
}
}
/**
* Write a DOM Document to an output stream.
*
* @param doc
* The DOM Document to write.
* @param out
* The output stream.
*/
public static String writeDocumentToString(Document doc)
{
try
{
StringWriter sw = new StringWriter();
DocumentBuilderFactory factory
= DocumentBuilderFactory.newInstance();
DocumentBuilder builder = factory.newDocumentBuilder();
DOMImplementation impl = builder.getDOMImplementation();
DOMImplementationLS feature = (DOMImplementationLS) impl.getFeature("LS",
"3.0");
LSSerializer serializer = feature.createLSSerializer();
LSOutput output = feature.createLSOutput();
output.setCharacterStream(sw);
output.setEncoding("UTF-8");
serializer.write(doc, output);
sw.flush();
return sw.toString();
}
catch (Exception any)
{
M_log.warn("writeDocumentToString: " + any.toString());
return null;
}
}
/**
* Escape the SQL to ensure it is valid (and protect against SQL injection attacks)
* @param value SQL string or fragment
* @return escaped SQL string
*/
public static String escapeSql(String value) {
if (value == null) return "";
try {
StringBuilder buf = new StringBuilder();
for (int i = 0; i < value.length(); i++) {
char c = value.charAt(i);
if (c == '\'') {
buf.append("''");
} else {
buf.append(c);
}
}
String rv = buf.toString();
return rv;
} catch (Exception e) {
M_log.warn("Validator.escapeSql: "+e, e);
return "";
}
}
/**
* @return a DocumentBuilder object for XML parsing.
*/
private static DocumentBuilder getDocumentBuilder() throws ParserConfigurationException
{
DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
return dbf.newDocumentBuilder();
}
}