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1   /*
2    * $Id: PerformForward.java 471754 2006-11-06 14:55:09Z husted $
3    *
4    * Licensed to the Apache Software Foundation (ASF) under one
5    * or more contributor license agreements.  See the NOTICE file
6    * distributed with this work for additional information
7    * regarding copyright ownership.  The ASF licenses this file
8    * to you under the Apache License, Version 2.0 (the
9    * "License"); you may not use this file except in compliance
10   * with the License.  You may obtain a copy of the License at
11   *
12   *  http://www.apache.org/licenses/LICENSE-2.0
13   *
14   * Unless required by applicable law or agreed to in writing,
15   * software distributed under the License is distributed on an
16   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
17   * KIND, either express or implied.  See the License for the
18   * specific language governing permissions and limitations
19   * under the License.
20   */
21  package org.apache.struts.chain.commands.servlet;
22  
23  import java.io.IOException;
24  
25  import org.apache.commons.logging.Log;
26  import org.apache.commons.logging.LogFactory;
27  import org.apache.struts.action.ActionServlet;
28  import org.apache.struts.chain.commands.AbstractPerformForward;
29  import org.apache.struts.chain.contexts.ActionContext;
30  import org.apache.struts.chain.contexts.ServletActionContext;
31  import org.apache.struts.config.ForwardConfig;
32  import org.apache.struts.config.ModuleConfig;
33  import org.apache.struts.util.MessageResources;
34  import org.apache.struts.util.RequestUtils;
35  import org.apache.struts.util.ModuleUtils;
36  
37  import javax.servlet.RequestDispatcher;
38  import javax.servlet.ServletContext;
39  import javax.servlet.ServletException;
40  import javax.servlet.http.HttpServletRequest;
41  import javax.servlet.http.HttpServletResponse;
42  
43  /**
44   * <p>Perform forwarding or redirection based on the specified
45   * <code>ForwardConfig</code> (if any).</p>
46   *
47   * @version $Rev: 471754 $ $Date: 2006-11-06 08:55:09 -0600 (Mon, 06 Nov 2006) $
48   */
49  public class PerformForward extends AbstractPerformForward {
50      private static final Log LOG = LogFactory.getLog(PerformForward.class);
51  
52      // ------------------------------------------------------- Protected Methods
53  
54      /**
55       * <p>Perform the appropriate processing on the specified
56       * <code>ForwardConfig</code>.</p>
57       *
58       * @param context       The context for this request
59       * @param forwardConfig The forward to be performed
60       */
61      protected void perform(ActionContext context, ForwardConfig forwardConfig)
62          throws Exception {
63          ServletActionContext sacontext = (ServletActionContext) context;
64          String uri = forwardConfig.getPath();
65  
66          if (uri == null) {
67              ActionServlet servlet = sacontext.getActionServlet();
68              MessageResources resources = servlet.getInternal();
69  
70              throw new IllegalArgumentException(resources.getMessage("forwardPathNull"));
71          }
72  
73          HttpServletRequest request = sacontext.getRequest();
74          ServletContext servletContext = sacontext.getContext();
75          HttpServletResponse response = sacontext.getResponse();
76  
77          // If the forward can be unaliased into an action, then use the path of the action
78          String actionIdPath = RequestUtils.actionIdURL(forwardConfig, sacontext.getRequest(), sacontext.getActionServlet());
79          if (actionIdPath != null) {
80              uri = actionIdPath;
81              ForwardConfig actionIdForwardConfig = new ForwardConfig(forwardConfig);
82              actionIdForwardConfig.setPath(actionIdPath);
83              forwardConfig = actionIdForwardConfig;
84          }
85  
86          if (uri.startsWith("/")) {
87              uri = resolveModuleRelativePath(forwardConfig, servletContext, request);
88          }
89  
90  
91          if (response.isCommitted() && !forwardConfig.getRedirect()) {
92              handleAsInclude(uri, servletContext, request, response);
93          } else if (forwardConfig.getRedirect()) {
94              handleAsRedirect(uri, request, response);
95          } else {
96              handleAsForward(uri, servletContext, request, response);
97          }
98      }
99  
100     private String resolveModuleRelativePath(ForwardConfig forwardConfig, ServletContext servletContext, HttpServletRequest request) {
101         String prefix = forwardConfig.getModule();
102         ModuleConfig moduleConfig = ModuleUtils.getInstance().getModuleConfig(prefix, request, servletContext);
103         return RequestUtils.forwardURL(request,forwardConfig, moduleConfig);
104     }
105 
106     private void handleAsForward(String uri, ServletContext servletContext, HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
107         RequestDispatcher rd = servletContext.getRequestDispatcher(uri);
108 
109         if (LOG.isDebugEnabled()) {
110             LOG.debug("Forwarding to " + uri);
111         }
112 
113         rd.forward(request, response);
114     }
115 
116     private void handleAsRedirect(String uri, HttpServletRequest request, HttpServletResponse response) throws IOException {
117         if (uri.startsWith("/")) {
118             uri = request.getContextPath() + uri;
119         }
120 
121         if (LOG.isDebugEnabled()) {
122             LOG.debug("Redirecting to " + uri);
123         }
124 
125         response.sendRedirect(response.encodeRedirectURL(uri));
126     }
127 
128     private void handleAsInclude(String uri, ServletContext servletContext, HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException {
129         RequestDispatcher rd = servletContext.getRequestDispatcher(uri);
130 
131         if (rd == null) {
132             response.sendError(HttpServletResponse.SC_INTERNAL_SERVER_ERROR,
133                 "Error getting RequestDispatcher for " + uri);
134             return;
135         }
136 
137         if (LOG.isDebugEnabled()) {
138             LOG.debug("Including " + uri);
139         }
140 
141         rd.include(request, response);
142     }
143 }