1 // ======================================================================== 2 // Copyright (c) 2004-2009 Mort Bay Consulting Pty. Ltd. 3 // ------------------------------------------------------------------------ 4 // All rights reserved. This program and the accompanying materials 5 // are made available under the terms of the Eclipse Public License v1.0 6 // and Apache License v2.0 which accompanies this distribution. 7 // The Eclipse Public License is available at 8 // http://www.eclipse.org/legal/epl-v10.html 9 // The Apache License v2.0 is available at 10 // http://www.opensource.org/licenses/apache2.0.php 11 // You may elect to redistribute this code under either of these licenses. 12 // ======================================================================== 13 14 package org.eclipse.jetty.servlets; 15 16 import java.io.IOException; 17 18 import javax.servlet.RequestDispatcher; 19 import javax.servlet.ServletContext; 20 import javax.servlet.ServletException; 21 import javax.servlet.http.HttpServlet; 22 import javax.servlet.http.HttpServletRequest; 23 import javax.servlet.http.HttpServletResponse; 24 25 /* ------------------------------------------------------------ */ 26 /** Concatenation Servlet 27 * This servlet may be used to concatenate multiple resources into 28 * a single response. It is intended to be used to load multiple 29 * javascript or css files, but may be used for any content of the 30 * same mime type that can be meaningfully concatenated. 31 * <p> 32 * The servlet uses {@link RequestDispatcher#include(javax.servlet.ServletRequest, javax.servlet.ServletResponse)} 33 * to combine the requested content, so dynamically generated content 34 * may be combined (Eg engine.js for DWR). 35 * <p> 36 * The servlet uses parameter names of the query string as resource names 37 * relative to the context root. So these script tags: 38 * <pre> 39 * <script type="text/javascript" src="../js/behaviour.js"></script> 40 * <script type="text/javascript" src="../js/ajax.js&/chat/chat.js"></script> 41 * <script type="text/javascript" src="../chat/chat.js"></script> 42 * </pre> can be replaced with the single tag (with the ConcatServlet mapped to /concat): 43 * <pre> 44 * <script type="text/javascript" src="../concat?/js/behaviour.js&/js/ajax.js&/chat/chat.js"></script> 45 * </pre> 46 * The {@link ServletContext#getMimeType(String)} method is used to determine the 47 * mime type of each resource. If the types of all resources do not match, then a 415 48 * UNSUPPORTED_MEDIA_TYPE error is returned. 49 * <p> 50 * If the init parameter "development" is set to "true" then the servlet will run in 51 * development mode and the content will be concatenated on every request. Otherwise 52 * the init time of the servlet is used as the lastModifiedTime of the combined content 53 * and If-Modified-Since requests are handled with 206 NOT Modified responses if 54 * appropriate. This means that when not in development mode, the servlet must be 55 * restarted before changed content will be served. 56 * 57 * 58 * 59 */ 60 public class ConcatServlet extends HttpServlet 61 { 62 boolean _development; 63 long _lastModified; 64 ServletContext _context; 65 66 /* ------------------------------------------------------------ */ 67 public void init() throws ServletException 68 { 69 _lastModified=System.currentTimeMillis(); 70 _context=getServletContext(); 71 _development="true".equals(getInitParameter("development")); 72 } 73 74 /* ------------------------------------------------------------ */ 75 /* 76 * @return The start time of the servlet unless in development mode, in which case -1 is returned. 77 */ 78 protected long getLastModified(HttpServletRequest req) 79 { 80 return _development?-1:_lastModified; 81 } 82 83 /* ------------------------------------------------------------ */ 84 protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException 85 { 86 String q=req.getQueryString(); 87 if (q==null) 88 { 89 resp.sendError(HttpServletResponse.SC_NO_CONTENT); 90 return; 91 } 92 93 String[] parts = q.split("\\&"); 94 String type=null; 95 for (int i=0;i<parts.length;i++) 96 { 97 String t = _context.getMimeType(parts[i]); 98 if (t!=null) 99 { 100 if (type==null) 101 type=t; 102 else if (!type.equals(t)) 103 { 104 resp.sendError(HttpServletResponse.SC_UNSUPPORTED_MEDIA_TYPE); 105 return; 106 } 107 } 108 } 109 110 if (type!=null) 111 resp.setContentType(type); 112 113 for (int i=0;i<parts.length;i++) 114 { 115 RequestDispatcher dispatcher=_context.getRequestDispatcher(parts[i]); 116 if (dispatcher!=null) 117 dispatcher.include(req,resp); 118 } 119 } 120 }