src/java/org/apache/fop/servlet/FopServlet.java - xmlgraphics-fop - Git at Google

 /*
  * 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.OutputStream;
 import java.io.PrintWriter;
 import java.net.URI;
 import java.net.URL;

 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.apache.commons.io.output.ByteArrayOutputStream;

 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.FopFactoryBuilder;
 import org.apache.fop.apps.MimeConstants;
 import org.apache.fop.apps.io.Resource;
 import org.apache.fop.apps.io.ResourceResolver;

 /**
  * 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.
  * (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";

     /** 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;

     /**
      * {@inheritDoc}
      */
     public void init() throws ServletException {
         this.uriResolver = new ServletContextURIResolver(getServletContext());
         this.transFactory = TransformerFactory.newInstance();
         this.transFactory.setURIResolver(this.uriResolver);
         //Configure FopFactory as desired
         // TODO: Double check this behaves properly!!
         ResourceResolver resolver = new ResourceResolver() {
             public OutputStream getOutputStream(URI uri) throws IOException {
                 URL url = getServletContext().getResource(uri.toASCIIString());
                 return url.openConnection().getOutputStream();
             }

             public Resource getResource(URI uri) throws IOException {
                 return new Resource(getServletContext().getResourceAsStream(uri.toASCIIString()));
             }
         };
         FopFactoryBuilder builder = new FopFactoryBuilder(new File(".").toURI(), resolver);
         configureFopFactory(builder);
         fopFactory = builder.build();
     }

     /**
      * This method is called right after the FopFactory is instantiated and can be overridden
      * by subclasses to perform additional configuration.
      */
     protected void configureFopFactory(FopFactoryBuilder builder) {
         //Subclass and override this method to perform additional configuration
     }

     /**
      * {@inheritDoc}
      */
     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
             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("<html><head><title>Error</title></head>\n"
                           + "<body><h1>FopServlet Error</h1><h3>No 'fo' "
                           + "request param given.</body></html>");
             }
         } 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
      */
     protected void renderFO(String fo, HttpServletResponse response)
                 throws FOPException, TransformerException, IOException {

         //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
      */
     protected void renderXML(String xml, String xslt, HttpServletResponse response)
                 throws FOPException, TransformerException, IOException {

         //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
      */
     protected void render(Source src, Transformer transformer, HttpServletResponse response)
                 throws FOPException, TransformerException, IOException {

         FOUserAgent foUserAgent = getFOUserAgent();

         //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;
     }

 }
	/*
	* 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.OutputStream;
	import java.io.PrintWriter;
	import java.net.URI;
	import java.net.URL;

	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.apache.commons.io.output.ByteArrayOutputStream;

	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.FopFactoryBuilder;
	import org.apache.fop.apps.MimeConstants;
	import org.apache.fop.apps.io.Resource;
	import org.apache.fop.apps.io.ResourceResolver;

	/**
	* 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.
	* (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";

	/** 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;

	/**
	* {@inheritDoc}
	*/
	public void init() throws ServletException {
	this.uriResolver = new ServletContextURIResolver(getServletContext());
	this.transFactory = TransformerFactory.newInstance();
	this.transFactory.setURIResolver(this.uriResolver);
	//Configure FopFactory as desired
	// TODO: Double check this behaves properly!!
	ResourceResolver resolver = new ResourceResolver() {
	public OutputStream getOutputStream(URI uri) throws IOException {
	URL url = getServletContext().getResource(uri.toASCIIString());
	return url.openConnection().getOutputStream();
	}

	public Resource getResource(URI uri) throws IOException {
	return new Resource(getServletContext().getResourceAsStream(uri.toASCIIString()));
	}
	};
	FopFactoryBuilder builder = new FopFactoryBuilder(new File(".").toURI(), resolver);
	configureFopFactory(builder);
	fopFactory = builder.build();
	}

	/**
	* This method is called right after the FopFactory is instantiated and can be overridden
	* by subclasses to perform additional configuration.
	*/
	protected void configureFopFactory(FopFactoryBuilder builder) {
	//Subclass and override this method to perform additional configuration
	}

	/**
	* {@inheritDoc}
	*/
	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
	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("<html><head><title>Error</title></head>\n"
	+ "<body><h1>FopServlet Error</h1><h3>No 'fo' "
	+ "request param given.</body></html>");
	}
	} 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
	*/
	protected void renderFO(String fo, HttpServletResponse response)
	throws FOPException, TransformerException, IOException {

	//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
	*/
	protected void renderXML(String xml, String xslt, HttpServletResponse response)
	throws FOPException, TransformerException, IOException {

	//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
	*/
	protected void render(Source src, Transformer transformer, HttpServletResponse response)
	throws FOPException, TransformerException, IOException {

	FOUserAgent foUserAgent = getFOUserAgent();

	//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;
	}

	}