Classes in this File | Line Coverage | Branch Coverage | Complexity | ||||
ConfigServlet |
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1 | /* | |
2 | * $Source: /usr/cvsroot/melati/melati/src/site/resources/withWebmacro/org.melati.servlet.ConfigServlet.html,v $ | |
3 | * $Revision: 1.1 $ | |
4 | * | |
5 | * Copyright (C) 2000 Tim Joyce | |
6 | * | |
7 | * Part of Melati (http://melati.org), a framework for the rapid | |
8 | * development of clean, maintainable web applications. | |
9 | * | |
10 | * Melati is free software; Permission is granted to copy, distribute | |
11 | * and/or modify this software under the terms either: | |
12 | * | |
13 | * a) the GNU General Public License as published by the Free Software | |
14 | * Foundation; either version 2 of the License, or (at your option) | |
15 | * any later version, | |
16 | * | |
17 | * or | |
18 | * | |
19 | * b) any version of the Melati Software License, as published | |
20 | * at http://melati.org | |
21 | * | |
22 | * You should have received a copy of the GNU General Public License and | |
23 | * the Melati Software License along with this program; | |
24 | * if not, write to the Free Software Foundation, Inc., | |
25 | * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA to obtain the | |
26 | * GNU General Public License and visit http://melati.org to obtain the | |
27 | * Melati Software License. | |
28 | * | |
29 | * Feel free to contact the Developers of Melati (http://melati.org), | |
30 | * if you would like to work out a different arrangement than the options | |
31 | * outlined here. It is our intention to allow Melati to be used by as | |
32 | * wide an audience as possible. | |
33 | * | |
34 | * This program is distributed in the hope that it will be useful, | |
35 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
36 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
37 | * GNU General Public License for more details. | |
38 | * | |
39 | * Contact details for copyright holder: | |
40 | * | |
41 | * Tim Joyce <timj At paneris.org> | |
42 | * http://paneris.org/ | |
43 | * 68 Sandbanks Rd, Poole, Dorset. BH14 8BY. UK | |
44 | */ | |
45 | ||
46 | package org.melati.servlet; | |
47 | ||
48 | import java.io.PrintWriter; | |
49 | import java.io.IOException; | |
50 | ||
51 | import javax.servlet.ServletConfig; | |
52 | import javax.servlet.ServletException; | |
53 | import javax.servlet.http.HttpServlet; | |
54 | import javax.servlet.http.HttpServletRequest; | |
55 | import javax.servlet.http.HttpServletResponse; | |
56 | ||
57 | import org.melati.Melati; | |
58 | import org.melati.PoemContext; | |
59 | import org.melati.MelatiConfig; | |
60 | import org.melati.poem.AccessPoemException; | |
61 | import org.melati.poem.NoSuchRowPoemException; | |
62 | import org.melati.util.ConnectionPendingException; | |
63 | import org.melati.util.MelatiWriter; | |
64 | ||
65 | /** | |
66 | * Config Servlet is the simplest way to use Melati. | |
67 | * | |
68 | * All a ConfigServlet does is to configure a melati and combine the | |
69 | * doGet and doPost methods. Importantly it does not establish a poem session | |
70 | * leaving you to do this for yourself. | |
71 | * | |
72 | * If you want a poem session established, please extend PoemServlet. | |
73 | * | |
74 | * ConfigServlet does set up a basic PoemContext with the Method set, | |
75 | * but not the POEM logicaldatabase, table or troid. | |
76 | * | |
77 | * The URL is expected to take one of the following form: | |
78 | * | |
79 | * <BLOCKQUOTE><TT> | |
80 | * http://<I>h</I>/<I>s</I>/<I>meth</I> | |
81 | * </TT></BLOCKQUOTE> | |
82 | * | |
83 | * the method is broken out of the path info and passed to | |
84 | * your application code in the <TT>Melati</TT> and | |
85 | * <TT>PoemContext</TT> parameter | |
86 | * | |
87 | * <TABLE> | |
88 | * <TR> | |
89 | * <TD><TT><I>h</I></TT></TD> | |
90 | * <TD>host name, such as <TT>www.melati.org</TT></TD> | |
91 | * </TR> | |
92 | * <TR> | |
93 | * <TD><TT><I>s</I></TT></TD> | |
94 | * <TD> | |
95 | * servlet-determining part, such as | |
96 | * <TT>melati/org.melati.admin.Admin</TT> | |
97 | * </TD> | |
98 | * </TR> | |
99 | * <TR> | |
100 | * <TD><TT><I>meth</I></TT></TD> | |
101 | * <TD> | |
102 | * A freeform string telling your servlet what it is meant to do. This | |
103 | * is automatically made available in templates as | |
104 | * <TT>$melati.Method</TT>. | |
105 | * </TD> | |
106 | * </TR> | |
107 | * </TABLE> | |
108 | * | |
109 | * You can change the way these things are determined by overriding | |
110 | * <TT>poemContext(Melati)</TT>. | |
111 | */ | |
112 | ||
113 | 156 | public abstract class ConfigServlet extends HttpServlet { |
114 | ||
115 | /** | |
116 | * Eclipse generated. | |
117 | */ | |
118 | private static final long serialVersionUID = 8995954958766276122L; | |
119 | ||
120 | protected MelatiConfig melatiConfig; | |
121 | 78 | protected String sysAdminName = "nobody"; |
122 | 78 | protected String sysAdminEmail = "nobody@nobody.com";; |
123 | ||
124 | /** | |
125 | * Inititialise Melati. | |
126 | * | |
127 | * @param config a <code>ServletConfig</code> | |
128 | * @throws ServletException is anything goes wrong | |
129 | */ | |
130 | public void init(ServletConfig config) throws ServletException { | |
131 | 78 | super.init(config); |
132 | 78 | melatiConfig = melatiConfig(); |
133 | 76 | } |
134 | ||
135 | /** | |
136 | * Handles GET. | |
137 | * | |
138 | * @param request the incoming <code>HttpServletRequest</code> | |
139 | * @param response the outgoing <code>HttpServletResponse</code> | |
140 | */ | |
141 | public void doGet(HttpServletRequest request, | |
142 | HttpServletResponse response) { | |
143 | 1041 | doGetPostRequest(request, response); |
144 | 1039 | } |
145 | ||
146 | /** | |
147 | * Handle a POST. | |
148 | * | |
149 | * @param request the incoming <code>HttpServletRequest</code> | |
150 | * @param response the outgoing <code>HttpServletResponse</code> | |
151 | */ | |
152 | public void doPost(HttpServletRequest request, | |
153 | HttpServletResponse response) { | |
154 | 132 | doGetPostRequest(request, response); |
155 | 132 | } |
156 | ||
157 | /** | |
158 | * Process the request. | |
159 | * | |
160 | * Exceptions are presented to the user if practicable, or written to the log. | |
161 | * | |
162 | * @param request the incoming <code>HttpServletRequest</code> | |
163 | * @param response the outgoing <code>HttpServletResponse</code> | |
164 | */ | |
165 | private void doGetPostRequest(final HttpServletRequest request, | |
166 | final HttpServletResponse response) { | |
167 | 1173 | Melati melati = new Melati(melatiConfig, request, response); |
168 | try { | |
169 | 1173 | melati.establishCharsets(); |
170 | 1173 | melati.setPoemContext(poemContext(melati)); |
171 | 1173 | doConfiguredRequest(melati); |
172 | // send the output to the client | |
173 | 1147 | melati.write(); |
174 | } | |
175 | 28 | catch (Exception e) { |
176 | 28 | error(melati,e); |
177 | 1145 | } |
178 | 1171 | } |
179 | ||
180 | /** | |
181 | * Send an error message. | |
182 | * | |
183 | * @param melati the {@link Melati} | |
184 | * @param e the {@link Exception} to report | |
185 | */ | |
186 | public void error(Melati melati, Exception e) { | |
187 | 20 | melati.getResponse().setStatus(httpStatusCode(e)); |
188 | ||
189 | // has it been trapped already, if so, we don't need to relog it here | |
190 | 20 | if (! (e instanceof TrappedException)) { |
191 | try { | |
192 | // log it | |
193 | 16 | e.printStackTrace(System.err); |
194 | // and put it on the page | |
195 | 16 | melati.setResponseContentType ("text/html"); |
196 | 16 | MelatiWriter mw = melati.getWriter(); |
197 | // get rid of anything that has been written so far | |
198 | 16 | mw.reset(); |
199 | 16 | PrintWriter out = new PrintWriter(mw.getWriter()); |
200 | 16 | if (e instanceof ConnectionPendingException) { |
201 | 2 | writeConnectionPendingException(out,e); |
202 | } else { | |
203 | 14 | writeError(out,e); |
204 | } | |
205 | 16 | melati.write(); |
206 | 0 | } catch (IOException f) { |
207 | 0 | e.printStackTrace(System.err); |
208 | 0 | throw new TrappedException("Problem logging error", f); |
209 | 14 | } |
210 | } | |
211 | 18 | } |
212 | ||
213 | protected int httpStatusCode(Exception e) { | |
214 | 50 | if (e instanceof AccessPoemException) |
215 | 2 | return 401; // Not Authorized |
216 | 48 | if (e instanceof InvalidUsageException) |
217 | 2 | return 400; // Client error |
218 | 46 | if (e instanceof NoSuchRowPoemException) |
219 | 0 | return 404; // Not found |
220 | 46 | return 500; // Server error |
221 | } | |
222 | ||
223 | /** | |
224 | * Print an error directly to the client. | |
225 | * | |
226 | * This is rarely called, eg when the template engine | |
227 | * fails to render the default error template. | |
228 | * | |
229 | * @param out the <code>PrintWriter</code> to print to | |
230 | * @param e the {@link Exception} to report | |
231 | */ | |
232 | public void writeError(PrintWriter out, Exception e) { | |
233 | 14 | out.println("<html><head><title>Melati Error</title></head>"); |
234 | 14 | out.println("<!-- HTML generated in " + |
235 | "org.melati.servlet.ConfigServlet.java -->"); | |
236 | 14 | out.println("<body><h2>Melati Error</h2>"); |
237 | 14 | out.println("<h3>Reported from ConfigServlet</h3>"); |
238 | 14 | out.println("<p>An error has occured in the application"); |
239 | 14 | out.println("that runs this website, please contact <a href='mailto:"); |
240 | 14 | out.println(getSysAdminEmail() + "'>" + getSysAdminName() + "</a>"); |
241 | 14 | out.println(", with the information given below.</p>"); |
242 | 14 | out.println("<h4><font color='red'><pre>"); |
243 | 14 | e.printStackTrace(out); |
244 | 14 | out.println("</pre></font></h4></body></html>"); |
245 | 14 | } |
246 | ||
247 | /** | |
248 | * Print the <code>ConnectionPendingException</code> directly to the client. | |
249 | * | |
250 | * This is called if a request is made whilst the system is | |
251 | * still being initialised. | |
252 | * | |
253 | * @param out the <code>PrintWriter</code> to print to | |
254 | * @param e the {@link Exception} to report | |
255 | */ | |
256 | public void writeConnectionPendingException(PrintWriter out, Exception e) { | |
257 | 2 | out.println("<html><head><title>Database Initialising</title>\n"); |
258 | 2 | out.println("<META HTTP-EQUIV='Refresh' CONTENT='30'>\n</head>\n"); |
259 | 2 | out.println("<!-- Generated in org.melati.servlet.ConfigServlet.java -->"); |
260 | 2 | out.println("<body><center><h2>Database Initialising</h2><p> </p>"); |
261 | 2 | out.println("<p><b>Sorry</b>, "); |
262 | 2 | out.println("the database that runs this website is just starting up."); |
263 | 2 | out.println("This takes a few seconds, "); |
264 | 2 | out.println("so you should be able to use the site in a moment."); |
265 | 2 | out.println("<p>This page will refresh in 30 seconds, "); |
266 | 2 | out.println("and you will be able to continue.</p>"); |
267 | 2 | out.println("<!--"); |
268 | 2 | e.printStackTrace(out); |
269 | 2 | out.println("--></center></body></html>"); |
270 | 2 | } |
271 | ||
272 | /** | |
273 | * This method <b>SHOULD</b> be overidden. | |
274 | * @return the System Administrators name. | |
275 | */ | |
276 | public String getSysAdminName () { | |
277 | 8 | return sysAdminName; |
278 | } | |
279 | ||
280 | /** | |
281 | * This method <b>SHOULD</b> be overidden. | |
282 | * @return the System Administrators email address. | |
283 | */ | |
284 | public String getSysAdminEmail () { | |
285 | 8 | return sysAdminEmail; |
286 | } | |
287 | ||
288 | /** | |
289 | * @param sysAdminEmail The sysAdminEmail to set. | |
290 | */ | |
291 | protected void setSysAdminEmail(String sysAdminEmail) { | |
292 | 1121 | this.sysAdminEmail = sysAdminEmail; |
293 | 1121 | } |
294 | ||
295 | ||
296 | /** | |
297 | * @param sysAdminName The sysAdminName to set. | |
298 | */ | |
299 | protected void setSysAdminName(String sysAdminName) { | |
300 | 1121 | this.sysAdminName = sysAdminName; |
301 | 1121 | } |
302 | ||
303 | protected PoemContext poemContext(Melati melati) | |
304 | throws PathInfoException { | |
305 | 52 | PoemContext it = new PoemContext(); |
306 | 52 | String[] parts = melati.getPathInfoParts(); |
307 | 52 | if (parts.length > 0) |
308 | 32 | it.setMethod(parts[parts.length - 1]); |
309 | 52 | return it; |
310 | } | |
311 | ||
312 | /** | |
313 | * To override any setting from org.melati.MelatiConfig.properties, | |
314 | * simply override this method and return a valid MelatiConfig. | |
315 | * | |
316 | * eg to use a different AccessHandler from the default: | |
317 | * | |
318 | * <PRE> | |
319 | * protected MelatiConfig melatiConfig() throws MelatiException { | |
320 | * MelatiConfig config = super.melatiConfig(); | |
321 | * config.setAccessHandler(new YourAccessHandler()); | |
322 | * return config; | |
323 | * } | |
324 | * </PRE> | |
325 | * | |
326 | * @return a new {@link MelatiConfig} | |
327 | */ | |
328 | protected MelatiConfig melatiConfig() { | |
329 | 74 | MelatiConfig m = new MelatiConfig(); |
330 | 74 | String realPath = getServletConfig().getServletContext().getRealPath("/"); |
331 | 74 | if (realPath == null) |
332 | 0 | throw new NullPointerException(); |
333 | 74 | m.setRealPath(realPath); |
334 | 74 | return m; |
335 | } | |
336 | ||
337 | /** | |
338 | * Instantiate this method to build up your own output. | |
339 | * @param melati | |
340 | * @throws Exception if anything goes wrong | |
341 | */ | |
342 | protected abstract void doConfiguredRequest(Melati melati) | |
343 | throws Exception; | |
344 | ||
345 | ||
346 | } |