/* ====================================================================== Parts Copyright 2006 University of Leeds, Oxford University, University of the Highlands and Islands. 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. ====================================================================== */ package org.bodington.servlet; import javax.servlet.http.*; import javax.servlet.*; import java.io.*; import java.awt.Color; import java.awt.color.*; import java.util.Enumeration; import java.util.StringTokenizer; import org.apache.log4j.Level; import org.apache.log4j.Logger; import org.bodington.servlet.gif.*; import org.bodington.util.ColourPreferenceMapper; /** * * @author jrm */ public class ProcessedGifServlet extends javax.servlet.http.HttpServlet { private static Logger log = Logger.getLogger(ProcessedGifServlet.class); /** Creates a new instance of ProcessedGifServlet */ public ProcessedGifServlet() { } public void init() throws ServletException { super.init(); } public void doGet( HttpServletRequest req, HttpServletResponse resp ) throws ServletException, IOException { doPost( req, resp ); } public void doPost( HttpServletRequest req, HttpServletResponse res ) throws ServletException, IOException { String path_info = req.getPathInfo(); String path_translated = req.getPathTranslated(); String code; if ( !path_info.startsWith( "templates" ) && !path_info.startsWith( "/templates" ) ) { res.sendError( HttpServletResponse.SC_FORBIDDEN , "No access to files in requested area." ); return; } if ( path_info.indexOf( ".." ) >= 0 ) { res.sendError( HttpServletResponse.SC_FORBIDDEN, "Use of '..' in URLs is not allowed in requested area." ); return; } File file = new File( path_translated ); if ( !path_translated.endsWith( ".gif" ) ) { res.sendError( HttpServletResponse.SC_FORBIDDEN, "Access in this area is restricted to GIF files only." ); return; } if ( !file.exists() || !file.isFile() ) { res.sendError( HttpServletResponse.SC_NOT_FOUND, "GIF file not found." ); return; } GifDescriptor gd = GifDescriptor.getGifDescriptor( file ); code = req.getParameter( "code" ); ColourPreferenceMapper mapper = null; if ( code != null && code.length()>0 ) mapper = new ColourPreferenceMapper( code ); // at this point the servlet will either forward to the plain file // or programatically output a modified GIF. if ( mapper == null || gd.getGifColourStatements() == null ) forwardToOriginal( req, res ); else sendProcessedGif( req, res, mapper, gd ); } public void forwardToOriginal( HttpServletRequest req, HttpServletResponse res ) throws ServletException, IOException { String path_info = req.getPathInfo(); ServletContext context=getServletContext(); RequestDispatcher dispatcher=context.getRequestDispatcher( path_info ); if ( dispatcher==null ) { res.sendError( HttpServletResponse.SC_INTERNAL_SERVER_ERROR, "Technical problem fetching file - couldn't find dispatcher." ); return; } // will it set up all the appropriate headers including those for cache control? dispatcher.forward( req, res ); } public void sendProcessedGif( HttpServletRequest req, HttpServletResponse resp, ColourPreferenceMapper mapper, GifDescriptor gd ) throws ServletException, IOException { Response res = new Response( resp ); res.setContentType( "image/gif" ); if ( ServletUtils.isModified(req, resp, gd.getLastModified(), 0) ) { res.setStatus( HttpServletResponse.SC_NOT_MODIFIED ); return; } ServletOutputStream out = res.getOutputStream(); // output first part of header unmodified int count = gd.getColourCount(); byte[] data = gd.getData(); GifColourStatement[] statements = gd.getGifColourStatements(); out.write( data, 0, 13 ); if ( statements == null || statements.length == 0 ) out.write( data, 13, 3*count ); else sendProcessedGifColourTable( req, out, mapper, gd ); if ( gd.isDataCached() ) out.write( data, 13 + (count*3), data.length - (13 + (count*3)) ); else { int n; FileInputStream fin = new FileInputStream( gd.getFile() ); byte[] buffer = new byte[16*1024]; fin.read( buffer, 0, 13 + (count*3) ); while ( (n = fin.read( buffer, 0, 16*1024 ))> 0 ) out.write( buffer, 0, n ); } out.close(); } public void sendProcessedGifColourTable( HttpServletRequest req, OutputStream out, ColourPreferenceMapper colour_mapper, GifDescriptor gd ) throws java.io.IOException { Color b = colour_mapper.getReferenceBackgroundColor(); Color f = colour_mapper.getReferenceForegroundColor(); Color preferred_foreground = colour_mapper.getPreferredForegroundColor( f ); Color preferred_background = colour_mapper.getPreferredBackgroundColor(); Color active, gif_colour; int i, j, first, last; int count = gd.getColourCount(); byte[] data = gd.getData(); byte[] colourbuf = new byte[count*3]; GifColourStatement[] statements = gd.getGifColourStatements(); System.arraycopy( data, 13, colourbuf, 0, count*3 ); for ( i=0; i= count ) continue; if ( !statements[i].author_can_modify && !statements[i].user_can_modify ) continue; if ( statements[i].index == GifColourStatement.ALL ) { first = 0; last = count-1; } else { first = statements[i].index; last = statements[i].index; } if ( statements[i].user_can_modify ) { active = preferred_foreground; if ( statements[i].plane == GifColourStatement.BACKGROUND ) active = preferred_background; } else { active = f; if ( statements[i].plane == GifColourStatement.BACKGROUND ) active = b; } for ( j=first; j<=last; j++ ) { // if the author can't change the colour but the user cam, // then we have to adjust the actual GIF colour entry // against the reference background. This could preserve // colour GIFs. (Bit of a fudge because the reference // background is provided by the author but we assume that // it reflects the actual page background rather than the GIF // background and so is a good reference for deciding whether // the user wants the foreground adjusted.) if ( !statements[i].author_can_modify && statements[i].plane != GifColourStatement.BACKGROUND ) { gif_colour = new Color( ((int)colourbuf[(3*j) ]) & 0xff, ((int)colourbuf[(3*j)+1]) & 0xff, ((int)colourbuf[(3*j)+2]) & 0xff ); active = colour_mapper.getPreferredForegroundColor( gif_colour ); } colourbuf[(3*j) ] = (byte)active.getRed(); colourbuf[(3*j)+1] = (byte)active.getGreen(); colourbuf[(3*j)+2] = (byte)active.getBlue(); } } out.write( colourbuf, 0, 3*count ); } }