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- /*
- * Copyright 1999-2005 The Apache Software Foundation.
- *
- * Licensed 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.
- */
-
- /* $Id$ */
-
- package org.apache.fop.servlet;
-
- import java.io.ByteArrayOutputStream;
- import java.io.File;
- import java.io.PrintWriter;
-
- import javax.servlet.ServletException;
- import javax.servlet.http.HttpServlet;
- import javax.servlet.http.HttpServletRequest;
- import javax.servlet.http.HttpServletResponse;
- import javax.xml.transform.Result;
- import javax.xml.transform.Source;
- import javax.xml.transform.Transformer;
- import javax.xml.transform.TransformerException;
- import javax.xml.transform.TransformerFactory;
- import javax.xml.transform.sax.SAXResult;
- import javax.xml.transform.stream.StreamSource;
-
- import org.apache.commons.logging.impl.SimpleLog;
-
- //FOP
- import org.apache.fop.apps.Fop;
- import org.apache.fop.apps.FOPException;
- import org.apache.fop.apps.MimeConstants;
-
- /**
- * Example servlet to generate a PDF from a servlet.
- * <br/>
- * Servlet param is:
- * <ul>
- * <li>fo: the path to a XSL-FO file to render
- * </ul>
- * or
- * <ul>
- * <li>xml: the path to an XML file to render</li>
- * <li>xslt: the path to an XSLT file that can transform the above XML to XSL-FO</li>
- * </ul>
- * <br/>
- * Example URL: http://servername/fop/servlet/FopServlet?fo=readme.fo
- * <br/>
- * Example URL: http://servername/fop/servlet/FopServlet?xml=data.xml&xslt=format.xsl
- * <br/>
- * For this to work with Internet Explorer, you might need to append "&ext=.pdf"
- * to the URL.
- *
- * @author <a href="mailto:fop-dev@xml.apache.org">Apache XML FOP Development Team</a>
- * @version $Id$
- * (todo) Ev. add caching mechanism for Templates objects
- */
- public class FopServlet extends HttpServlet {
-
- /** Name of the parameter used for the XSL-FO file */
- protected static final String FO_REQUEST_PARAM = "fo";
- /** Name of the parameter used for the XML file */
- protected static final String XML_REQUEST_PARAM = "xml";
- /** Name of the parameter used for the XSLT file */
- protected static final String XSLT_REQUEST_PARAM = "xslt";
-
- /** Logger to give to FOP */
- protected SimpleLog log = null;
- /** The TransformerFactory to use to create Transformer instances */
- protected TransformerFactory transFactory = null;
-
- /**
- * @see javax.servlet.GenericServlet#init()
- */
- public void init() throws ServletException {
- this.log = new SimpleLog("FOP/Servlet");
- log.setLevel(SimpleLog.LOG_LEVEL_WARN);
- this.transFactory = TransformerFactory.newInstance();
- }
-
- /**
- * @see javax.servlet.http.HttpServlet#doGet(HttpServletRequest, HttpServletResponse)
- */
- public void doGet(HttpServletRequest request,
- HttpServletResponse response) throws ServletException {
- try {
- //Get parameters
- String foParam = request.getParameter(FO_REQUEST_PARAM);
- String xmlParam = request.getParameter(XML_REQUEST_PARAM);
- String xsltParam = request.getParameter(XSLT_REQUEST_PARAM);
-
- //Analyze parameters and decide with method to use
- byte[] content = null;
- if (foParam != null) {
- content = renderFO(foParam);
- } else if ((xmlParam != null) && (xsltParam != null)) {
- content = renderXML(xmlParam, xsltParam);
- } else {
- PrintWriter out = response.getWriter();
- out.println("<html><head><title>Error</title></head>\n"
- + "<body><h1>FopServlet Error</h1><h3>No 'fo' "
- + "request param given.</body></html>");
- }
-
- if (content != null) {
- //Send the result back to the client
- response.setContentType("application/pdf");
- response.setContentLength(content.length);
- response.getOutputStream().write(content);
- response.getOutputStream().flush();
- }
-
- } catch (Exception ex) {
- throw new ServletException(ex);
- }
- }
-
- /**
- * Converts a String parameter to a JAXP Source object.
- * @param param a String parameter
- * @return Source the generated Source object
- */
- protected Source convertString2Source(String param) {
- return new StreamSource(new File(param));
- }
-
- /**
- * Renders an XSL-FO file into a PDF file. The PDF is written to a byte
- * array that is returned as the method's result.
- * @param fo the XSL-FO file
- * @return byte[] the rendered PDF file
- * @throws FOPException If an error occurs during the rendering of the
- * XSL-FO
- * @throws TransformerException If an error occurs while parsing the input
- * file
- */
- protected byte[] renderFO(String fo)
- throws FOPException, TransformerException {
-
- //Setup source
- Source foSrc = convertString2Source(fo);
-
- //Setup the identity transformation
- Transformer transformer = this.transFactory.newTransformer();
-
- //Start transformation and rendering process
- return render(foSrc, transformer);
- }
-
- /**
- * Renders an XML file into a PDF file by applying a stylesheet
- * that converts the XML to XSL-FO. The PDF is written to a byte array
- * that is returned as the method's result.
- * @param xml the XML file
- * @param xslt the XSLT file
- * @return byte[] the rendered PDF file
- * @throws FOPException If an error occurs during the rendering of the
- * XSL-FO
- * @throws TransformerException If an error occurs during XSL
- * transformation
- */
- protected byte[] renderXML(String xml, String xslt)
- throws FOPException, TransformerException {
-
- //Setup sources
- Source xmlSrc = convertString2Source(xml);
- Source xsltSrc = convertString2Source(xslt);
-
- //Setup the XSL transformation
- Transformer transformer = this.transFactory.newTransformer(xsltSrc);
-
- //Start transformation and rendering process
- return render(xmlSrc, transformer);
- }
-
- /**
- * Renders an input file (XML or XSL-FO) into a PDF file. It uses the JAXP
- * transformer given to optionally transform the input document to XSL-FO.
- * The transformer may be an identity transformer in which case the input
- * must already be XSL-FO. The PDF is written to a byte array that is
- * returned as the method's result.
- * @param src Input XML or XSL-FO
- * @param transformer Transformer to use for optional transformation
- * @return byte[] the rendered PDF file
- * @throws FOPException If an error occurs during the rendering of the
- * XSL-FO
- * @throws TransformerException If an error occurs during XSL
- * transformation
- */
- protected byte[] render(Source src, Transformer transformer)
- throws FOPException, TransformerException {
-
- //Setup FOP
- Fop fop = new Fop(MimeConstants.MIME_PDF);
-
- //Setup output
- ByteArrayOutputStream out = new ByteArrayOutputStream();
- fop.setOutputStream(out);
-
- //Make sure the XSL transformation's result is piped through to FOP
- Result res = new SAXResult(fop.getDefaultHandler());
-
- //Start the transformation and rendering process
- transformer.transform(src, res);
-
- //Return the result
- return out.toByteArray();
- }
-
- }
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