/* * 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. */ /* $Id$ */ package org.apache.fop.servlet; import java.io.File; import java.io.IOException; 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.URIResolver; import javax.xml.transform.sax.SAXResult; import javax.xml.transform.stream.StreamSource; import org.xml.sax.SAXException; import org.apache.commons.io.output.ByteArrayOutputStream; import org.apache.commons.logging.impl.SimpleLog; import org.apache.batik.*; import org.apache.fop.apps.FOPException; import org.apache.fop.apps.FOUserAgent; import org.apache.fop.apps.Fop; import org.apache.fop.apps.FopFactory; import org.apache.fop.apps.MimeConstants; import org.apache.avalon.framework.configuration.Configuration; import org.apache.avalon.framework.configuration.DefaultConfigurationBuilder; /** * Example servlet to generate a PDF from a servlet. *
* Servlet param is: * * or * *
* Example URL: http://servername/fop/servlet/FopServlet?fo=readme.fo *
* Example URL: http://servername/fop/servlet/FopServlet?xml=data.xml&xslt=format.xsl *
* For this to work with Internet Explorer, you might need to append "&ext=.pdf" * to the URL. * (todo) Ev. add caching mechanism for Templates objects */ public class FopServlet extends HttpServlet { private static final long serialVersionUID = -908918093488215264L; /** 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"; /** Name of the parameter used for the Config file */ protected static final String FO_CONFIG_PARAM = "cfg"; /** The TransformerFactory used to create Transformer instances */ protected TransformerFactory transFactory = null; /** The FopFactory used to create Fop instances */ protected FopFactory fopFactory = null; /** URIResolver for use by this servlet */ protected URIResolver uriResolver; /** Config for use by a request */ protected File foConfig = null; /* Logger */ protected SimpleLog log = null; /** * {@inheritDoc} */ public void init() throws ServletException { this.log = new SimpleLog("foplet"); log.setLevel(SimpleLog.LOG_LEVEL_DEBUG); this.uriResolver = new ServletContextURIResolver(getServletContext()); this.transFactory = TransformerFactory.newInstance(); this.transFactory.setURIResolver(this.uriResolver); //Configure FopFactory as desired this.fopFactory = FopFactory.newInstance(); this.fopFactory.setURIResolver(this.uriResolver); configureFopFactory(); } /** * This method is called right after the FopFactory is instantiated and can be overridden * by subclasses to perform additional configuration. */ protected void configureFopFactory() { //Subclass and override this method to perform additional configuration } /** * {@inheritDoc} */ public void doPost(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); String foCfg = request.getParameter(FO_CONFIG_PARAM); //Analyze config if (foCfg != null) { this.foConfig = new File(foCfg); } //Analyze parameters and decide with method to use if (foParam != null) { renderFO(foParam, response); } else if ((xmlParam != null) && (xsltParam != null)) { renderXML(xmlParam, xsltParam, response); } else { response.setContentType("text/html"); PrintWriter out = response.getWriter(); out.println("Error\n" + "

FopServlet Error

No 'fo' " + "request param given."); } } 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) { Source src; try { src = uriResolver.resolve(param, null); } catch (TransformerException e) { src = null; } if (src == null) { src = new StreamSource(new File(param)); } return src; } private void sendPDF(byte[] content, HttpServletResponse response) throws IOException { //Send the result back to the client response.setContentType("application/pdf"); response.setContentLength(content.length); response.getOutputStream().write(content); response.getOutputStream().flush(); } /** * 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 * @param response HTTP response object * @throws FOPException If an error occurs during the rendering of the * XSL-FO * @throws TransformerException If an error occurs while parsing the input * file * @throws IOException In case of an I/O problem * @throws SAXException In case of a config problem */ protected void renderFO(String fo, HttpServletResponse response) throws FOPException, TransformerException, IOException, SAXException { //Setup source Source foSrc = convertString2Source(fo); //Setup the identity transformation Transformer transformer = this.transFactory.newTransformer(); transformer.setURIResolver(this.uriResolver); //Start transformation and rendering process render(foSrc, transformer, response); } /** * 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 * @param response HTTP response object * @throws FOPException If an error occurs during the rendering of the * XSL-FO * @throws TransformerException If an error occurs during XSL * transformation * @throws IOException In case of an I/O problem * @throws SAXException In case of a config problem */ protected void renderXML(String xml, String xslt, HttpServletResponse response) throws FOPException, TransformerException, IOException, SAXException { //Setup sources Source xmlSrc = convertString2Source(xml); Source xsltSrc = convertString2Source(xslt); //Setup the XSL transformation Transformer transformer = this.transFactory.newTransformer(xsltSrc); transformer.setURIResolver(this.uriResolver); //Start transformation and rendering process render(xmlSrc, transformer, response); } /** * 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 * @param response HTTP response object * @throws FOPException If an error occurs during the rendering of the * XSL-FO * @throws TransformerException If an error occurs during XSL * transformation * @throws IOException In case of an I/O problem * @throws SAXException In case of a config problem */ protected void render(Source src, Transformer transformer, HttpServletResponse response) throws FOPException, TransformerException, IOException, SAXException { FOUserAgent foUserAgent = getFOUserAgent(); if (foConfig != null) { fopFactory.setUserConfig(foConfig); } fopFactory.setBaseURL(getBaseURLfromConfig(fopFactory.getUserConfig(),"base")); foUserAgent.setBaseURL(getBaseURLfromConfig(fopFactory.getUserConfig(),"base")); //Setup output ByteArrayOutputStream out = new ByteArrayOutputStream(); //Setup FOP Fop fop = fopFactory.newFop(MimeConstants.MIME_PDF, foUserAgent, 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 sendPDF(out.toByteArray(), response); } /** @return a new FOUserAgent for FOP */ protected FOUserAgent getFOUserAgent() { FOUserAgent userAgent = fopFactory.newFOUserAgent(); //Configure foUserAgent as desired return userAgent; } /** * Retrieves and verifies a base URL. * @param cfg The Configuration object to retrieve the base URL from * @param name the element name for the base URL * @return the requested base URL or null if not available */ public static String getBaseURLfromConfig(Configuration cfg, String name) { if (cfg.getChild(name, false) != null) { String cfgBaseDir = cfg.getChild(name).getValue(null); return cfgBaseDir; } return null; } }