src/main/java/de/uapcore/lightpit/AbstractLightPITServlet.java@276ef00a336d
src/main/java/de/uapcore/lightpit/AbstractLightPITServlet.java
Wed, 13 May 2020 18:31:52 +0200
- author
- Mike Becker <universe@uap-core.de>
- date
- Wed, 13 May 2020 18:31:52 +0200
- changeset 40
- 276ef00a336d
- parent 39
- e722861558bb
- child 42
- f962ff9dd44e
- permissions
- -rw-r--r--
fixes handler signatures and one compile error for AbstractDao.setForeignKeyOrNull()
1 /*
2 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
3 *
4 * Copyright 2018 Mike Becker. All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions are met:
8 *
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 *
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
17 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
20 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
21 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
22 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
23 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
24 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
25 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
26 * POSSIBILITY OF SUCH DAMAGE.
27 *
28 */
29 package de.uapcore.lightpit;
31 import de.uapcore.lightpit.dao.DataAccessObjects;
32 import de.uapcore.lightpit.dao.postgres.PGDataAccessObjects;
33 import org.slf4j.Logger;
34 import org.slf4j.LoggerFactory;
36 import javax.servlet.ServletException;
37 import javax.servlet.http.HttpServlet;
38 import javax.servlet.http.HttpServletRequest;
39 import javax.servlet.http.HttpServletResponse;
40 import javax.servlet.http.HttpSession;
41 import java.io.IOException;
42 import java.lang.reflect.Method;
43 import java.lang.reflect.Modifier;
44 import java.sql.Connection;
45 import java.sql.SQLException;
46 import java.util.*;
48 /**
49 * A special implementation of a HTTPServlet which is focused on implementing
50 * the necessary functionality for {@link LightPITModule}s.
51 */
52 public abstract class AbstractLightPITServlet extends HttpServlet {
54 private static final Logger LOG = LoggerFactory.getLogger(AbstractLightPITServlet.class);
56 private static final String HTML_FULL_DISPATCHER = Functions.jspPath("html_full");
58 /**
59 * The EL proxy is necessary, because the EL resolver cannot handle annotation properties.
60 */
61 private LightPITModule.ELProxy moduleInfo = null;
63 /**
64 * Invocation mapping gathered from the {@link RequestMapping} annotations.
65 * <p>
66 * Paths in this map must always start with a leading slash, although
67 * the specification in the annotation must not start with a leading slash.
68 * <p>
69 * The reason for this is the different handling of empty paths in
70 * {@link HttpServletRequest#getPathInfo()}.
71 */
72 private final Map<HttpMethod, Map<String, Method>> mappings = new HashMap<>();
74 /**
75 * Gives implementing modules access to the {@link ModuleManager}.
76 *
77 * @return the module manager
78 */
79 protected final ModuleManager getModuleManager() {
80 return (ModuleManager) getServletContext().getAttribute(ModuleManager.SC_ATTR_NAME);
81 }
84 /**
85 * Creates a set of data access objects for the specified connection.
86 *
87 * @param connection the SQL connection
88 * @return a set of data access objects
89 */
90 private DataAccessObjects createDataAccessObjects(Connection connection) throws SQLException {
91 final var df = (DatabaseFacade) getServletContext().getAttribute(DatabaseFacade.SC_ATTR_NAME);
92 if (df.getSQLDialect() == DatabaseFacade.Dialect.Postgres) {
93 return new PGDataAccessObjects(connection);
94 }
95 throw new AssertionError("Non-exhaustive if-else - this is a bug.");
96 }
98 private ResponseType invokeMapping(Method method, HttpServletRequest req, HttpServletResponse resp, DataAccessObjects dao) throws IOException {
99 try {
100 LOG.trace("invoke {}#{}", method.getDeclaringClass().getName(), method.getName());
101 return (ResponseType) method.invoke(this, req, resp, dao);
102 } catch (ReflectiveOperationException | ClassCastException ex) {
103 LOG.error("invocation of method {} failed: {}", method.getName(), ex.getMessage());
104 LOG.debug("Details: ", ex);
105 resp.sendError(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
106 return ResponseType.NONE;
107 }
108 }
110 @Override
111 public void init() throws ServletException {
112 moduleInfo = Optional.ofNullable(this.getClass().getAnnotation(LightPITModule.class))
113 .map(LightPITModule.ELProxy::new).orElse(null);
115 if (moduleInfo != null) {
116 scanForRequestMappings();
117 }
119 LOG.trace("{} initialized", getServletName());
120 }
122 private void scanForRequestMappings() {
123 try {
124 Method[] methods = getClass().getDeclaredMethods();
125 for (Method method : methods) {
126 Optional<RequestMapping> mapping = Optional.ofNullable(method.getAnnotation(RequestMapping.class));
127 if (mapping.isPresent()) {
128 if (!Modifier.isPublic(method.getModifiers())) {
129 LOG.warn("{} is annotated with {} but is not public",
130 method.getName(), RequestMapping.class.getSimpleName()
131 );
132 continue;
133 }
134 if (Modifier.isAbstract(method.getModifiers())) {
135 LOG.warn("{} is annotated with {} but is abstract",
136 method.getName(), RequestMapping.class.getSimpleName()
137 );
138 continue;
139 }
140 if (!ResponseType.class.isAssignableFrom(method.getReturnType())) {
141 LOG.warn("{} is annotated with {} but has the wrong return type - 'ResponseType' required",
142 method.getName(), RequestMapping.class.getSimpleName()
143 );
144 continue;
145 }
147 Class<?>[] params = method.getParameterTypes();
148 if (params.length == 3
149 && HttpServletRequest.class.isAssignableFrom(params[0])
150 && HttpServletResponse.class.isAssignableFrom(params[1])
151 && DataAccessObjects.class.isAssignableFrom(params[2])) {
153 final String requestPath = "/" + mapping.get().requestPath();
155 if (mappings
156 .computeIfAbsent(mapping.get().method(), k -> new HashMap<>())
157 .putIfAbsent(requestPath, method) != null) {
158 LOG.warn("{} {} has multiple mappings",
159 mapping.get().method(),
160 mapping.get().requestPath()
161 );
162 }
164 LOG.debug("{} {} maps to {}::{}",
165 mapping.get().method(),
166 requestPath,
167 getClass().getSimpleName(),
168 method.getName()
169 );
170 } else {
171 LOG.warn("{} is annotated with {} but has the wrong parameters - (HttpServletRequest,HttpServletResponse,DataAccessObjects) required",
172 method.getName(), RequestMapping.class.getSimpleName()
173 );
174 }
175 }
176 }
177 } catch (SecurityException ex) {
178 LOG.error("Scan for request mappings on declared methods failed.", ex);
179 }
180 }
182 @Override
183 public void destroy() {
184 mappings.clear();
185 LOG.trace("{} destroyed", getServletName());
186 }
188 /**
189 * Sets the name of the dynamic fragment.
190 * <p>
191 * It is sufficient to specify the name without any extension. The extension
192 * is added automatically if not specified.
193 * <p>
194 * The fragment must be located in the dynamic fragments folder.
195 *
196 * @param req the servlet request object
197 * @param fragmentName the name of the fragment
198 * @see Constants#DYN_FRAGMENT_PATH_PREFIX
199 */
200 public void setDynamicFragment(HttpServletRequest req, String fragmentName) {
201 req.setAttribute(Constants.REQ_ATTR_FRAGMENT, Functions.dynFragmentPath(fragmentName));
202 }
204 /**
205 * Specifies the name of an additional stylesheet used by the module.
206 * <p>
207 * Setting an additional stylesheet is optional, but quite common for HTML
208 * output.
209 * <p>
210 * It is sufficient to specify the name without any extension. The extension
211 * is added automatically if not specified.
212 *
213 * @param req the servlet request object
214 * @param stylesheet the name of the stylesheet
215 */
216 public void setStylesheet(HttpServletRequest req, String stylesheet) {
217 req.setAttribute(Constants.REQ_ATTR_STYLESHEET, Functions.enforceExt(stylesheet, ".css"));
218 }
220 private void forwardToFullView(HttpServletRequest req, HttpServletResponse resp)
221 throws IOException, ServletException {
223 req.setAttribute(Constants.REQ_ATTR_MENU, getModuleManager().getMainMenu());
224 req.getRequestDispatcher(HTML_FULL_DISPATCHER).forward(req, resp);
225 }
227 private Optional<Method> findMapping(HttpMethod method, HttpServletRequest req) {
228 return Optional.ofNullable(mappings.get(method))
229 .map(rm -> rm.get(Optional.ofNullable(req.getPathInfo()).orElse("/"))
230 );
231 }
233 private void forwardAsSpecified(ResponseType type, HttpServletRequest req, HttpServletResponse resp)
234 throws ServletException, IOException {
235 switch (type) {
236 case NONE:
237 return;
238 case HTML_FULL:
239 forwardToFullView(req, resp);
240 return;
241 // TODO: implement remaining response types
242 default:
243 throw new AssertionError("ResponseType switch is not exhaustive - this is a bug!");
244 }
245 }
247 private void doProcess(HttpMethod method, HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
249 // choose the requested language as session language (if available) or fall back to english, otherwise
250 HttpSession session = req.getSession();
251 if (session.getAttribute(Constants.SESSION_ATTR_LANGUAGE) == null) {
252 Optional<List<String>> availableLanguages = Functions.availableLanguages(getServletContext()).map(Arrays::asList);
253 Optional<Locale> reqLocale = Optional.of(req.getLocale());
254 Locale sessionLocale = reqLocale.filter((rl) -> availableLanguages.map((al) -> al.contains(rl.getLanguage())).orElse(false)).orElse(Locale.ENGLISH);
255 session.setAttribute(Constants.SESSION_ATTR_LANGUAGE, sessionLocale);
256 LOG.debug("Setting language for new session {}: {}", session.getId(), sessionLocale.getDisplayLanguage());
257 } else {
258 Locale sessionLocale = (Locale) session.getAttribute(Constants.SESSION_ATTR_LANGUAGE);
259 resp.setLocale(sessionLocale);
260 LOG.trace("Continuing session {} with language {}", session.getId(), sessionLocale);
261 }
263 // set some internal request attributes
264 req.setAttribute(Constants.REQ_ATTR_PATH, Functions.fullPath(req));
265 req.setAttribute(Constants.REQ_ATTR_MODULE_CLASSNAME, this.getClass().getName());
266 Optional.ofNullable(moduleInfo).ifPresent((proxy) -> req.setAttribute(Constants.REQ_ATTR_MODULE_INFO, proxy));
268 // obtain a connection and create the data access objects
269 final var db = (DatabaseFacade) req.getServletContext().getAttribute(DatabaseFacade.SC_ATTR_NAME);
270 try (final var connection = db.getDataSource().getConnection()) {
271 final var dao = createDataAccessObjects(connection);
272 try {
273 connection.setAutoCommit(false);
274 // call the handler, if available, or send an HTTP 404 error
275 final var mapping = findMapping(method, req);
276 if (mapping.isPresent()) {
277 forwardAsSpecified(invokeMapping(mapping.get(), req, resp, dao), req, resp);
278 } else {
279 resp.sendError(HttpServletResponse.SC_NOT_FOUND);
280 }
281 connection.commit();
282 } catch (SQLException ex) {
283 LOG.warn("Database transaction failed (Code {}): {}", ex.getErrorCode(), ex.getMessage());
284 LOG.debug("Details: ", ex);
285 resp.sendError(HttpServletResponse.SC_INTERNAL_SERVER_ERROR, "Unhandled Transaction Error - Code:" + ex.getErrorCode());
286 connection.rollback();
287 }
288 } catch (SQLException ex) {
289 LOG.error("Severe Database Exception (Code {}): {}", ex.getErrorCode(), ex.getMessage());
290 LOG.debug("Details: ", ex);
291 resp.sendError(HttpServletResponse.SC_INTERNAL_SERVER_ERROR, "Database Error - Code:" + ex.getErrorCode());
292 }
293 }
295 @Override
296 protected final void doGet(HttpServletRequest req, HttpServletResponse resp)
297 throws ServletException, IOException {
298 doProcess(HttpMethod.GET, req, resp);
299 }
301 @Override
302 protected final void doPost(HttpServletRequest req, HttpServletResponse resp)
303 throws ServletException, IOException {
304 doProcess(HttpMethod.POST, req, resp);
305 }
306 }
