Java tutorial
/** * 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.xml.security.transforms.implementations; import java.io.ByteArrayInputStream; import java.io.ByteArrayOutputStream; import java.io.IOException; import java.io.OutputStream; import javax.xml.transform.Source; import javax.xml.transform.Transformer; import javax.xml.transform.TransformerConfigurationException; import javax.xml.transform.TransformerException; import javax.xml.transform.TransformerFactory; import javax.xml.transform.dom.DOMSource; import javax.xml.transform.stream.StreamResult; import javax.xml.transform.stream.StreamSource; import org.apache.xml.security.exceptions.XMLSecurityException; import org.apache.xml.security.signature.XMLSignatureInput; import org.apache.xml.security.transforms.Transform; import org.apache.xml.security.transforms.TransformSpi; import org.apache.xml.security.transforms.TransformationException; import org.apache.xml.security.transforms.Transforms; import org.apache.xml.security.utils.XMLUtils; import org.w3c.dom.Element; /** * Class TransformXSLT * * Implements the <CODE>http://www.w3.org/TR/1999/REC-xslt-19991116</CODE> * transform. * * @author Christian Geuer-Pollmann */ public class TransformXSLT extends TransformSpi { /** Field implementedTransformURI */ public static final String implementedTransformURI = Transforms.TRANSFORM_XSLT; static final String XSLTSpecNS = "http://www.w3.org/1999/XSL/Transform"; static final String defaultXSLTSpecNSprefix = "xslt"; static final String XSLTSTYLESHEET = "stylesheet"; private static org.apache.commons.logging.Log log = org.apache.commons.logging.LogFactory .getLog(TransformXSLT.class); /** * Method engineGetURI * * @inheritDoc */ protected String engineGetURI() { return implementedTransformURI; } protected XMLSignatureInput enginePerformTransform(XMLSignatureInput input, OutputStream baos, Transform transformObject) throws IOException, TransformationException { try { Element transformElement = transformObject.getElement(); Element xsltElement = XMLUtils.selectNode(transformElement.getFirstChild(), XSLTSpecNS, "stylesheet", 0); if (xsltElement == null) { Object exArgs[] = { "xslt:stylesheet", "Transform" }; throw new TransformationException("xml.WrongContent", exArgs); } TransformerFactory tFactory = TransformerFactory.newInstance(); // Process XSLT stylesheets in a secure manner tFactory.setFeature("http://javax.xml.XMLConstants/feature/secure-processing", Boolean.TRUE); /* * This transform requires an octet stream as input. If the actual * input is an XPath node-set, then the signature application should * attempt to convert it to octets (apply Canonical XML]) as described * in the Reference Processing Model (section 4.3.3.2). */ Source xmlSource = new StreamSource(new ByteArrayInputStream(input.getBytes())); Source stylesheet; /* * This complicated transformation of the stylesheet itself is necessary * because of the need to get the pure style sheet. If we simply say * Source stylesheet = new DOMSource(this.xsltElement); * whereby this.xsltElement is not the rootElement of the Document, * this causes problems; * so we convert the stylesheet to byte[] and use this as input stream */ { ByteArrayOutputStream os = new ByteArrayOutputStream(); Transformer transformer = tFactory.newTransformer(); DOMSource source = new DOMSource(xsltElement); StreamResult result = new StreamResult(os); transformer.transform(source, result); stylesheet = new StreamSource(new ByteArrayInputStream(os.toByteArray())); } Transformer transformer = tFactory.newTransformer(stylesheet); // Force Xalan to use \n as line separator on all OSes. This // avoids OS specific signature validation failures due to line // separator differences in the transformed output. Unfortunately, // this is not a standard JAXP property so will not work with non-Xalan // implementations. try { transformer.setOutputProperty("{http://xml.apache.org/xalan}line-separator", "\n"); } catch (Exception e) { log.warn("Unable to set Xalan line-separator property: " + e.getMessage()); } if (baos == null) { ByteArrayOutputStream baos1 = new ByteArrayOutputStream(); StreamResult outputTarget = new StreamResult(baos1); transformer.transform(xmlSource, outputTarget); return new XMLSignatureInput(baos1.toByteArray()); } StreamResult outputTarget = new StreamResult(baos); transformer.transform(xmlSource, outputTarget); XMLSignatureInput output = new XMLSignatureInput((byte[]) null); output.setOutputStream(baos); return output; } catch (XMLSecurityException ex) { Object exArgs[] = { ex.getMessage() }; throw new TransformationException("generic.EmptyMessage", exArgs, ex); } catch (TransformerConfigurationException ex) { Object exArgs[] = { ex.getMessage() }; throw new TransformationException("generic.EmptyMessage", exArgs, ex); } catch (TransformerException ex) { Object exArgs[] = { ex.getMessage() }; throw new TransformationException("generic.EmptyMessage", exArgs, ex); } } }