001 /*
002 $Id: ServletBinding.java,v 1.5 2005/06/10 10:57:28 cstein Exp $
003
004 Copyright 2005 (C) Guillaume Laforge. All Rights Reserved.
005
006 Redistribution and use of this software and associated documentation
007 ("Software"), with or without modification, are permitted provided
008 that the following conditions are met:
009
010 1. Redistributions of source code must retain copyright
011 statements and notices. Redistributions must also contain a
012 copy of this document.
013
014 2. Redistributions in binary form must reproduce the
015 above copyright notice, this list of conditions and the
016 following disclaimer in the documentation and/or other
017 materials provided with the distribution.
018
019 3. The name "groovy" must not be used to endorse or promote
020 products derived from this Software without prior written
021 permission of The Codehaus. For written permission,
022 please contact info@codehaus.org.
023
024 4. Products derived from this Software may not be called "groovy"
025 nor may "groovy" appear in their names without prior written
026 permission of The Codehaus. "groovy" is a registered
027 trademark of The Codehaus.
028
029 5. Due credit should be given to The Codehaus -
030 http://groovy.codehaus.org/
031
032 THIS SOFTWARE IS PROVIDED BY THE CODEHAUS AND CONTRIBUTORS
033 ``AS IS'' AND ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT
034 NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
035 FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
036 THE CODEHAUS OR ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
037 INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
038 (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
039 SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
040 HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
041 STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
042 ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
043 OF THE POSSIBILITY OF SUCH DAMAGE.
044
045 */
046 package groovy.servlet;
047
048 import groovy.lang.Binding;
049 import groovy.xml.MarkupBuilder;
050
051 import java.io.IOException;
052 import java.util.Enumeration;
053 import java.util.HashMap;
054 import java.util.Map;
055
056 import javax.servlet.ServletContext;
057 import javax.servlet.http.HttpServletRequest;
058 import javax.servlet.http.HttpServletResponse;
059
060 /**
061 * Servlet-specific binding extension to lazy load the writer or the output
062 * stream from the response.
063 *
064 * <p>
065 * <h3>Default variables bound</h3>
066 * <ul>
067 * <li><tt>"request"</tt> : the HttpServletRequest object</li>
068 * <li><tt>"response"</tt> : the HttpServletResponse object</li>
069 * <li><tt>"context"</tt> : the ServletContext object </li>
070 * <li><tt>"application"</tt> : same as context</li>
071 * <li><tt>"session"</tt> : convenient for <code>request.getSession(<b>false</b>)</code> - can be null!</li>
072 * <li><tt>"params"</tt> : map of all form parameters - can be empty</li>
073 * <li><tt>"headers"</tt> : map of all <b>request</b> header fields</li>
074 * </ul>
075 *
076 * <p>
077 * <h3>Implicite bound variables</h3>
078 * <ul>
079 * <li><tt>"out"</tt> : response.getWriter() </li>
080 * <li><tt>"sout"</tt> : response.getOutputStream() </li>
081 * <li><tt>"html"</tt> : new MarkupBuilder(response.getWriter()) </li>
082 * </ul>
083 * </p>
084 *
085 * @author Guillaume Laforge
086 * @author Christian Stein
087 */
088 public class ServletBinding extends Binding {
089
090 private final Binding binding;
091
092 private final ServletContext context;
093
094 private final HttpServletRequest request;
095
096 private final HttpServletResponse response;
097
098 private MarkupBuilder html;
099
100 /**
101 * Initializes a servlet binding.
102 */
103 public ServletBinding(HttpServletRequest request, HttpServletResponse response, ServletContext context) {
104 this.binding = new Binding();
105 this.request = request;
106 this.response = response;
107 this.context = context;
108
109 /*
110 * Bind the default variables.
111 */
112 binding.setVariable("request", request);
113 binding.setVariable("response", response);
114 binding.setVariable("context", context);
115 binding.setVariable("application", context);
116
117 /*
118 * Bind the HTTP session object - if there is one.
119 * Note: we don't create one here!
120 */
121 binding.setVariable("session", request.getSession(false));
122
123 /*
124 * Bind form parameter key-value hash map.
125 *
126 * If there are multiple, they are passed as an array.
127 */
128 Map params = new HashMap();
129 for (Enumeration names = request.getParameterNames(); names.hasMoreElements();) {
130 String name = (String) names.nextElement();
131 if (!binding.getVariables().containsKey(name)) {
132 String[] values = request.getParameterValues(name);
133 if (values.length == 1) {
134 params.put(name, values[0]);
135 } else {
136 params.put(name, values);
137 }
138 }
139 }
140 binding.setVariable("params", params);
141
142 /*
143 * Bind request header key-value hash map.
144 */
145 Map headers = new HashMap();
146 for (Enumeration names = request.getHeaderNames(); names.hasMoreElements();) {
147 String headerName = (String) names.nextElement();
148 String headerValue = request.getHeader(headerName);
149 headers.put(headerName, headerValue);
150 }
151 binding.setVariable("headers", headers);
152 }
153
154 public void setVariable(String name, Object value) {
155 /*
156 * Check sanity.
157 */
158 if (name == null) {
159 throw new IllegalArgumentException("Can't bind variable to null key.");
160 }
161 if (name.length() == 0) {
162 throw new IllegalArgumentException("Can't bind variable to blank key name. [length=0]");
163 }
164 /*
165 * Check implicite key names. See getVariable(String)!
166 */
167 if ("out".equals(name)) {
168 throw new IllegalArgumentException("Can't bind variable to key named '" + name + "'.");
169 }
170 if ("sout".equals(name)) {
171 throw new IllegalArgumentException("Can't bind variable to key named '" + name + "'.");
172 }
173 if ("html".equals(name)) {
174 throw new IllegalArgumentException("Can't bind variable to key named '" + name + "'.");
175 }
176 /*
177 * TODO Check default key names. See constructor(s).
178 */
179
180 /*
181 * All checks passed, set the variable.
182 */
183 binding.setVariable(name, value);
184 }
185
186 public Map getVariables() {
187 return binding.getVariables();
188 }
189
190 /**
191 * @return a writer, an output stream, a markup builder or another requested object
192 */
193 public Object getVariable(String name) {
194 /*
195 * Check sanity.
196 */
197 if (name == null) {
198 throw new IllegalArgumentException("Can't bind variable to null key.");
199 }
200 if (name.length() == 0) {
201 throw new IllegalArgumentException("Can't bind variable to blank key name. [length=0]");
202 }
203 /*
204 * Check implicite key names. See setVariable(String, Object)!
205 */
206 try {
207 if ("out".equals(name)) {
208 return response.getWriter();
209 }
210 if ("sout".equals(name)) {
211 return response.getOutputStream();
212 }
213 if ("html".equals(name)) {
214 if (html == null) {
215 html = new MarkupBuilder(response.getWriter());
216 }
217 return html;
218 }
219 } catch (IOException e) {
220 String message = "Failed to get writer or output stream from response.";
221 context.log(message, e);
222 throw new RuntimeException(message, e);
223 }
224 /*
225 * Still here? Delegate to the binding object.
226 */
227 return binding.getVariable(name);
228 }
229 }