franta-hg@1: /* ================================================================
franta-hg@1:  * Cewolf : Chart enabling Web Objects Framework
franta-hg@1:  * ================================================================
franta-hg@1:  *
franta-hg@1:  * Project Info:  http://cewolf.sourceforge.net
franta-hg@1:  * Project Lead:  Guido Laures (guido@laures.de);
franta-hg@1:  *
franta-hg@1:  * (C) Copyright 2002, by Guido Laures
franta-hg@1:  *
franta-hg@1:  * This library is free software; you can redistribute it and/or modify it under the terms
franta-hg@1:  * of the GNU Lesser General Public License as published by the Free Software Foundation;
franta-hg@1:  * either version 2.1 of the License, or (at your option) any later version.
franta-hg@1:  *
franta-hg@1:  * This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
franta-hg@1:  * without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
franta-hg@1:  * See the GNU Lesser General Public License for more details.
franta-hg@1:  *
franta-hg@1:  * You should have received a copy of the GNU Lesser General Public License along with this
franta-hg@1:  * library; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330,
franta-hg@1:  * Boston, MA 02111-1307, USA.
franta-hg@1:  */
franta-hg@1: 
franta-hg@1: package de.laures.cewolf;
franta-hg@1: 
franta-hg@1: import java.io.IOException;
franta-hg@1: import java.io.OutputStream;
franta-hg@1: import java.io.Writer;
franta-hg@1: import java.util.Enumeration;
franta-hg@1: 
franta-hg@1: import javax.servlet.ServletConfig;
franta-hg@1: import javax.servlet.ServletException;
franta-hg@1: import javax.servlet.http.HttpServlet;
franta-hg@1: import javax.servlet.http.HttpServletRequest;
franta-hg@1: import javax.servlet.http.HttpServletResponse;
franta-hg@1: 
franta-hg@1: import de.laures.cewolf.util.RenderingHelper;
franta-hg@1: 
franta-hg@1: /**
franta-hg@1:  * The rendering servlet of Cewolf. It is resposible for writing an entire chart
franta-hg@1:  * img into the response stream of the client. Everything needed for this is
franta-hg@1:  * prepared already by the ChartImgTag resp. LegendTag. The ID of a chart image
franta-hg@1:  * is passed to this servlet as a request parameter. After that the image object
franta-hg@1:  * is retrieved from the server side session based image cache. This servlet
franta-hg@1:  * must be configured in web.xml of the web application in order to use Cewolf
franta-hg@1:  * services. The servlet's URL relative to the web apps root is used as the
franta-hg@1:  * renderer attribute of the ChartImgTag resp. LegendTag in the JSP page.
franta-hg@1:  * 
franta-hg@1:  * @see de.laures.cewolf.taglib.tags.ChartImgTag
franta-hg@1:  * @see de.laures.cewolf.taglib.tags.LegendTag
franta-hg@1:  * @author Guido Laures
franta-hg@1:  * @since 0.1
franta-hg@1:  */
franta-hg@1: public class CewolfRenderer extends HttpServlet implements WebConstants
franta-hg@1: {
franta-hg@1: 
franta-hg@1:   public static final String  INIT_CONFIG  = "CewolfRenderer_Init_Config";
franta-hg@1:   private static final String STATE        = "state";
franta-hg@1:   private boolean             debugged     = false;
franta-hg@1:   private int                 requestCount = 0;
franta-hg@1:   private Byte 					lock = Byte.valueOf("0");
franta-hg@1:   private Configuration       config       = null;
franta-hg@1: 
franta-hg@1:   public void init( ServletConfig servletCfg ) throws ServletException
franta-hg@1:   {
franta-hg@1:     super.init(servletCfg);
franta-hg@1:     
franta-hg@1:     //Store init config params for processing by the Configuration
franta-hg@1:     servletCfg.getServletContext().setAttribute(INIT_CONFIG, servletCfg);
franta-hg@1:     config = Configuration.getInstance(servletCfg.getServletContext());
franta-hg@1:     
franta-hg@1:     if (config != null)
franta-hg@1:       this.debugged = config.isDebugged();
franta-hg@1:     else
franta-hg@1:       this.debugged = false;
franta-hg@1:   }
franta-hg@1: 
franta-hg@1:   /**
franta-hg@1:    * Processes HTTP <code>GET</code> request. Renders the chart or the lengend
franta-hg@1:    * into the client's response stream.
franta-hg@1:    * 
franta-hg@1:    * @param request
franta-hg@1:    *          servlet request
franta-hg@1:    * @param response
franta-hg@1:    *          servlet response
franta-hg@1:    * @throws ServletException
franta-hg@1:    *           when the production of data could not be handled by the
franta-hg@1:    *           configured DatasetProcuder
franta-hg@1:    */
franta-hg@1:   
franta-hg@1:   public void printParameters(HttpServletRequest request)
franta-hg@1:   {
franta-hg@1:     Enumeration enumeration = request.getParameterNames();
franta-hg@1:     while (enumeration.hasMoreElements())
franta-hg@1:     {
franta-hg@1:       String cur = (String)enumeration.nextElement();
franta-hg@1:       Object obj = request.getParameter(cur);
franta-hg@1:       
franta-hg@1:       log("Request Parameter -> " + cur + " Value -> " + obj.toString());
franta-hg@1:     }
franta-hg@1:   }
franta-hg@1:   
franta-hg@1:   protected void doGet( HttpServletRequest request, HttpServletResponse response ) throws ServletException, IOException
franta-hg@1:   {
franta-hg@1:     if ( debugged )
franta-hg@1:     {
franta-hg@1:       logRequest(request);
franta-hg@1:     }
franta-hg@1:     addHeaders(response);
franta-hg@1:     if ( request.getParameter(STATE) != null || !request.getParameterNames().hasMoreElements() )
franta-hg@1:     {
franta-hg@1:       requestState(response);
franta-hg@1:       return;
franta-hg@1:     }
franta-hg@1:     synchronized (lock) {
franta-hg@1:     	requestCount++;
franta-hg@1: 	}
franta-hg@1:     
franta-hg@1:     int width = 400;
franta-hg@1:     int height = 400;
franta-hg@1:     boolean removeAfterRendering = false;
franta-hg@1:     if ( request.getParameter(REMOVE_AFTER_RENDERING) != null )
franta-hg@1:     {
franta-hg@1:     	removeAfterRendering = true;
franta-hg@1:     }
franta-hg@1:     if ( request.getParameter(WIDTH_PARAM) != null )
franta-hg@1:     {
franta-hg@1:       width = Integer.parseInt(request.getParameter(WIDTH_PARAM));
franta-hg@1:     }
franta-hg@1:     if ( request.getParameter(HEIGHT_PARAM) != null )
franta-hg@1:     {
franta-hg@1:       height = Integer.parseInt(request.getParameter(HEIGHT_PARAM));
franta-hg@1:     }
franta-hg@1: 
franta-hg@1:     // determine the cache key
franta-hg@1:     String imgKey = request.getParameter(IMG_PARAM);
franta-hg@1:     if ( imgKey == null )
franta-hg@1:     {
franta-hg@1:       logAndRenderException(new ServletException("no '" + IMG_PARAM + "' parameter provided for Cewolf servlet."), response, width, height);
franta-hg@1:       return;
franta-hg@1:     }
franta-hg@1:     Storage storage = config.getStorage();
franta-hg@1:     ChartImage chartImage = storage.getChartImage(imgKey, request);
franta-hg@1:     if ( chartImage == null )
franta-hg@1:     {
franta-hg@1:       renderImageExpiry(response, width, height);
franta-hg@1:       return;
franta-hg@1:     }
franta-hg@1:     // send the img
franta-hg@1:     try
franta-hg@1:     {
franta-hg@1:       long start = System.currentTimeMillis();
franta-hg@1:       // response.setContentType(cid.getMimeType());
franta-hg@1:       final int size = chartImage.getSize();
franta-hg@1:       response.setContentType(chartImage.getMimeType());
franta-hg@1:       response.setContentLength(size);
franta-hg@1:       response.setBufferSize(size);
franta-hg@1:       response.setStatus(HttpServletResponse.SC_OK);
franta-hg@1:       response.getOutputStream().write(chartImage.getBytes());
franta-hg@1:       long last = System.currentTimeMillis() - start;
franta-hg@1:       if ( debugged )
franta-hg@1:       {
franta-hg@1:         log("creation time for chart " + imgKey + ": " + last + "ms.");
franta-hg@1:       }
franta-hg@1:     }
franta-hg@1:     catch (Throwable t)
franta-hg@1:     {
franta-hg@1:       logAndRenderException(t, response, width, height);
franta-hg@1:     }
franta-hg@1:     finally
franta-hg@1:     {
franta-hg@1:     	if (removeAfterRendering)
franta-hg@1:     	{
franta-hg@1:     		try {
franta-hg@1: 				storage.removeChartImage(imgKey , request);
franta-hg@1: 			} catch (CewolfException e) {
franta-hg@1: 				log("Removal of image failed", e);
franta-hg@1: 			}
franta-hg@1:     	}
franta-hg@1:     }
franta-hg@1:   }
franta-hg@1: 
franta-hg@1:   /**
franta-hg@1:    * Method addHeaders.
franta-hg@1:    * 
franta-hg@1:    * @param response
franta-hg@1:    */
franta-hg@1:   private void addHeaders( HttpServletResponse response )
franta-hg@1:   {
franta-hg@1:     response.setDateHeader("Expires", System.currentTimeMillis());
franta-hg@1:   }
franta-hg@1: 
franta-hg@1:   /**
franta-hg@1:    * Method requestState.
franta-hg@1:    * 
franta-hg@1:    * @param request
franta-hg@1:    * @param response
franta-hg@1:    */
franta-hg@1:   private void requestState( HttpServletResponse response ) throws IOException
franta-hg@1:   {
franta-hg@1:     Writer writer = response.getWriter();
franta-hg@1:     writer.write("<HTML><BODY>");
franta-hg@1:     /*
franta-hg@1:      * StateDescriptor sd = (StateDescriptor)
franta-hg@1:      * ChartImageCacheFactory.getChartImageBase( getServletContext());
franta-hg@1:      * writer.write(HTMLStateTable.getStateTable(sd));
franta-hg@1:      */
franta-hg@1:     writer.write("<b>Cewolf servlet up and running.</b><br>");
franta-hg@1:     writer.write("Requests served so far: " + requestCount);
franta-hg@1:     writer.write("</HTML></BODY>");
franta-hg@1:     writer.close();
franta-hg@1:   }
franta-hg@1: 
franta-hg@1:   private void logAndRenderException( Throwable ex, HttpServletResponse response, int width, int height ) throws IOException
franta-hg@1:   {
franta-hg@1:     log(ex.getMessage(), ex);
franta-hg@1:     response.setContentType("image/jpg");
franta-hg@1:     OutputStream out = response.getOutputStream();
franta-hg@1:     RenderingHelper.renderException(ex, width, height, out);
franta-hg@1:     out.close();
franta-hg@1:   }
franta-hg@1: 
franta-hg@1:   /**
franta-hg@1:    * Method renderImageExpiry.
franta-hg@1:    * 
franta-hg@1:    * @param response
franta-hg@1:    * @param width
franta-hg@1:    * @param height
franta-hg@1:    */
franta-hg@1:   private void renderImageExpiry( HttpServletResponse response, int width, int height ) throws IOException
franta-hg@1:   {
franta-hg@1:     response.setContentType("image/jpg");
franta-hg@1:     OutputStream out = response.getOutputStream();
franta-hg@1:     RenderingHelper.renderMessage("This chart has expired. Please reload.", width, height, out);
franta-hg@1:     out.close();
franta-hg@1:   }
franta-hg@1: 
franta-hg@1:   private void logRequest( HttpServletRequest request ) throws IOException
franta-hg@1:   {
franta-hg@1:     log("Cewolf request:");
franta-hg@1:     log("Actual Request values:");
franta-hg@1:     printParameters(request);
franta-hg@1:     Enumeration headerNames = request.getHeaderNames();
franta-hg@1:     while ( headerNames.hasMoreElements() )
franta-hg@1:     {
franta-hg@1:       String name = (String) headerNames.nextElement();
franta-hg@1:       Enumeration values = request.getHeaders(name);
franta-hg@1:       StringBuffer value = new StringBuffer();
franta-hg@1:       while ( values.hasMoreElements() )
franta-hg@1:       {
franta-hg@1:         value.append((String) values.nextElement() + ",");
franta-hg@1:       }
franta-hg@1:       // cut last comma
franta-hg@1:       if ( value.length() > 0 )
franta-hg@1:         value.setLength(value.length() - 1);
franta-hg@1:       log(name + ": " + value);
franta-hg@1:     }
franta-hg@1:   //  InputStream body = request.getInputStream();
franta-hg@1:  //   byte[] bodyData = new byte[body.available()];
franta-hg@1:  //   body.read(bodyData);
franta-hg@1:  //   body.close();
franta-hg@1:  //   log(new String(bodyData));
franta-hg@1: 
franta-hg@1:   }
franta-hg@1: 
franta-hg@1: }