DSpaceServlet


1   /*
2    * DSpaceServlet.java
3    *
4    * Version: $Revision: 1.13 $
5    *
6    * Date: $Date: 2005/10/17 03:35:45 $
7    *
8    * Copyright (c) 2002-2005, Hewlett-Packard Company and Massachusetts
9    * Institute of Technology.  All rights reserved.
10   *
11   * Redistribution and use in source and binary forms, with or without
12   * modification, are permitted provided that the following conditions are
13   * met:
14   *
15   * - Redistributions of source code must retain the above copyright
16   * notice, this list of conditions and the following disclaimer.
17   *
18   * - Redistributions in binary form must reproduce the above copyright
19   * notice, this list of conditions and the following disclaimer in the
20   * documentation and/or other materials provided with the distribution.
21   *
22   * - Neither the name of the Hewlett-Packard Company nor the name of the
23   * Massachusetts Institute of Technology nor the names of their
24   * contributors may be used to endorse or promote products derived from
25   * this software without specific prior written permission.
26   *
27   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
28   * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
29   * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
30   * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
31   * HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
32   * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
33   * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
34   * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
35   * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR
36   * TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
37   * USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
38   * DAMAGE.
39   */
40  package org.dspace.app.webui.servlet;
41  
42  import java.io.IOException  ;
43  import java.sql.SQLException  ;
44  
45  import javax.servlet.ServletException  ;
46  import javax.servlet.http.HttpServlet  ;
47  import javax.servlet.http.HttpServletRequest  ;
48  import javax.servlet.http.HttpServletResponse  ;
49  
50  import org.apache.log4j.Logger;
51  import org.dspace.app.webui.util.Authenticate;
52  import org.dspace.app.webui.util.JSPManager;
53  import org.dspace.app.webui.util.UIUtil;
54  import org.dspace.authorize.AuthorizeException;
55  import org.dspace.core.Context;
56  import org.dspace.core.LogManager;
57  
58  /**
59   * Base class for DSpace servlets. This manages the initialisation of a context,
60   * if a context has not already been initialised by an authentication filter. It
61   * also grabs the original request URL for later use.
62   * <P>
63   * Unlike regular servlets, DSpace servlets should override the
64   * <code>doDSGet</code> and <code>doDSPost</code> methods, which provide a
65   * DSpace context to work with, and handle the common exceptions
66   * <code>SQLException</code> and <code>AuthorizeException</code>.
67   * <code>doGet</code> and <code>doPost</code> should be overridden only in
68   * special circumstances.
69   * <P>
70   * Note that if all goes well, the context object passed in to
71   * <code>doDSGet</code> and <code>doDSPut</code> must be completed
72   * <em>after</em> a JSP has been displayed, but <code>before</code> the
73   * method returns. If an error occurs (an exception is thrown, or the context is
74   * not completed) the context is aborted after <code>doDSGet</code> or
75   * <code>doDSPut</code> return.
76   * 
77   * @see org.dspace.core.Context
78   * 
79   * @author Robert Tansley
80   * @version $Revision: 1.13 $
81   */
82  public class DSpaceServlet extends HttpServlet  
83  {
84      /*
85       * Because the error handling is indentical for GET and POST requests, to
86       * make things easier, doGet and doPost are folded into one method which
87       * then "re-separates" to GET and POST. We do not override "service" since
88       * we wish to allow doGet and doPost to be overridden if necessary (for
89       * example, by lightweight servlets that do not need a DSpace context
90       * object).
91       */
92  
93      /** log4j category */
94      private static Logger log = Logger.getLogger(DSpaceServlet.class);
95  
96      protected void doGet(HttpServletRequest   request,
97              HttpServletResponse   response) throws ServletException  , IOException  
98      {
99          processRequest(request, response);
100     }
101 
102     protected void doPost(HttpServletRequest   request,
103             HttpServletResponse   response) throws ServletException  , IOException  
104     {
105         processRequest(request, response);
106     }
107 
108     /**
109      * Process an incoming request
110      * 
111      * @param request
112      *            the request object
113      * @param response
114      *            the response object
115      */
116     private void processRequest(HttpServletRequest   request,
117             HttpServletResponse   response) throws ServletException  , IOException  
118     {
119         Context context = null;
120 
121         // set all incoming encoding to UTF-8
122         request.setCharacterEncoding("UTF-8");
123 
124         // Get the URL from the request immediately, since forwarding
125         // loses that information
126         UIUtil.storeOriginalURL(request);
127 
128         try
129         {
130             // Obtain a context - either create one, or get the one created by
131             // an authentication filter
132             context = UIUtil.obtainContext(request);
133 
134             // Are we resuming a previous request that was interrupted for
135             // authentication?
136             request = Authenticate.getRealRequest(request);
137 
138             if (log.isDebugEnabled())
139             {
140                 log.debug(LogManager.getHeader(context, "http_request", UIUtil
141                         .getRequestLogInfo(request)));
142             }
143 
144             // Invoke the servlet code
145             if (request.getMethod().equals("POST"))
146             {
147                 doDSPost(context, request, response);
148             }
149             else
150             {
151                 doDSGet(context, request, response);
152             }
153         }
154         catch (SQLException   se)
155         {
156             // For database errors, we log the exception and show a suitably
157             // apologetic error
158             log.warn(LogManager.getHeader(context, "database_error", se
159                     .toString()), se);
160 
161             // Also email an alert
162             UIUtil.sendAlert(request, se);
163 
164             JSPManager.showInternalError(request, response);
165         }
166         catch (AuthorizeException ae)
167         {
168             /*
169              * If no user is logged in, we will start authentication, since if
170              * they authenticate, they might be allowed to do what they tried to
171              * do. If someone IS logged in, and we got this exception, we know
172              * they tried to do something they aren't allowed to, so we display
173              * an error in that case.
174              */
175             if (context.getCurrentUser() != null ||
176                 Authenticate.startAuthentication(context, request, response))
177             {
178                 // FIXME: Log the right info?
179                 // Log the error
180                 log.info(LogManager.getHeader(context, "authorize_error", ae
181                         .toString()));
182 
183                 JSPManager.showAuthorizeError(request, response, ae);
184             }
185         }
186         catch (RuntimeException   e)
187         {
188             // Catch and re-throw to ensure context aborted (via "finally")
189             throw e;
190         }
191         catch (IOException   ioe)
192         {
193             // Catch and re-throw to ensure context aborted (via "finally")
194             throw ioe;
195         }
196         catch (ServletException   sve)
197         {
198             // Catch and re-throw to ensure context aborted (via "finally")
199             throw sve;
200         }
201         finally
202         {
203             // Abort the context if it's still valid
204             if ((context != null) && context.isValid())
205             {
206                 context.abort();
207             }
208         }
209     }
210 
211     /**
212      * Process an incoming HTTP GET. If an exception is thrown, or for some
213      * other reason the passed in context is not completed, it will be aborted
214      * and any changes made by this method discarded when this method returns.
215      * 
216      * @param context
217      *            a DSpace Context object
218      * @param request
219      *            the HTTP request
220      * @param response
221      *            the HTTP response
222      * 
223      * @throws SQLException
224      *             if a database error occurs
225      * @throws AuthorizeException
226      *             if some authorization error occurs
227      */
228     protected void doDSGet(Context context, HttpServletRequest   request,
229             HttpServletResponse   response) throws ServletException  , IOException  ,
230             SQLException  , AuthorizeException
231     {
232         // If this is not overridden, we invoke the raw HttpServlet "doGet" to
233         // indicate that GET is not supported by this servlet.
234         super.doGet(request, response);
235     }
236 
237     /**
238      * Process an incoming HTTP POST. If an exception is thrown, or for some
239      * other reason the passed in context is not completed, it will be aborted
240      * and any changes made by this method discarded when this method returns.
241      * 
242      * @param context
243      *            a DSpace Context object
244      * @param request
245      *            the HTTP request
246      * @param response
247      *            the HTTP response
248      * 
249      * @throws SQLException
250      *             if a database error occurs
251      * @throws AuthorizeException
252      *             if some authorization error occurs
253      */
254     protected void doDSPost(Context context, HttpServletRequest   request,
255             HttpServletResponse   response) throws ServletException  , IOException  ,
256             SQLException  , AuthorizeException
257     {
258         // If this is not overridden, we invoke the raw HttpServlet "doGet" to
259         // indicate that POST is not supported by this servlet.
260         super.doGet(request, response);
261     }
262 }
263
A to Z: JavaDoc & Examples Daily Java News & Articles Open Source Projects Open Source Codes Free Computer Books Remove Frame
Popular Tags