1.1 --- a/src/java/de/uapcore/lightpit/AbstractLightPITServlet.java Sun Apr 08 16:51:15 2018 +0200
1.2 +++ /dev/null Thu Jan 01 00:00:00 1970 +0000
1.3 @@ -1,296 +0,0 @@
1.4 -/*
1.5 - * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
1.6 - *
1.7 - * Copyright 2018 Mike Becker. All rights reserved.
1.8 - *
1.9 - * Redistribution and use in source and binary forms, with or without
1.10 - * modification, are permitted provided that the following conditions are met:
1.11 - *
1.12 - * 1. Redistributions of source code must retain the above copyright
1.13 - * notice, this list of conditions and the following disclaimer.
1.14 - *
1.15 - * 2. Redistributions in binary form must reproduce the above copyright
1.16 - * notice, this list of conditions and the following disclaimer in the
1.17 - * documentation and/or other materials provided with the distribution.
1.18 - *
1.19 - * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
1.20 - * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
1.21 - * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
1.22 - * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
1.23 - * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
1.24 - * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
1.25 - * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
1.26 - * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
1.27 - * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
1.28 - * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
1.29 - * POSSIBILITY OF SUCH DAMAGE.
1.30 - *
1.31 - */
1.32 -package de.uapcore.lightpit;
1.33 -
1.34 -import java.io.IOException;
1.35 -import java.lang.reflect.Method;
1.36 -import java.lang.reflect.Modifier;
1.37 -import java.util.Arrays;
1.38 -import java.util.HashMap;
1.39 -import java.util.List;
1.40 -import java.util.Locale;
1.41 -import java.util.Map;
1.42 -import java.util.Optional;
1.43 -import javax.servlet.ServletException;
1.44 -import javax.servlet.http.HttpServlet;
1.45 -import javax.servlet.http.HttpServletRequest;
1.46 -import javax.servlet.http.HttpServletResponse;
1.47 -import javax.servlet.http.HttpSession;
1.48 -import org.slf4j.Logger;
1.49 -import org.slf4j.LoggerFactory;
1.50 -
1.51 -/**
1.52 - * A special implementation of a HTTPServlet which is focused on implementing
1.53 - * the necessary functionality for {@link LightPITModule}s.
1.54 - */
1.55 -public abstract class AbstractLightPITServlet extends HttpServlet {
1.56 -
1.57 - private static final Logger LOG = LoggerFactory.getLogger(AbstractLightPITServlet.class);
1.58 -
1.59 - private static final String HTML_FULL_DISPATCHER = Functions.jspPath("html_full");
1.60 -
1.61 - /**
1.62 - * Store a reference to the annotation for quicker access.
1.63 - */
1.64 - private Optional<LightPITModule> moduleInfo = Optional.empty();
1.65 -
1.66 - /**
1.67 - * The EL proxy is necessary, because the EL resolver cannot handle annotation properties.
1.68 - */
1.69 - private Optional<LightPITModule.ELProxy> moduleInfoELProxy = Optional.empty();
1.70 -
1.71 -
1.72 - @FunctionalInterface
1.73 - private static interface HandlerMethod {
1.74 - ResponseType apply(HttpServletRequest t, HttpServletResponse u) throws IOException, ServletException;
1.75 - }
1.76 -
1.77 - /**
1.78 - * Invocation mapping gathered from the {@link RequestMapping} annotations.
1.79 - *
1.80 - * Paths in this map must always start with a leading slash, although
1.81 - * the specification in the annotation must not start with a leading slash.
1.82 - *
1.83 - * The reason for this is the different handling of empty paths in
1.84 - * {@link HttpServletRequest#getPathInfo()}.
1.85 - */
1.86 - private final Map<HttpMethod, Map<String, HandlerMethod>> mappings = new HashMap<>();
1.87 -
1.88 - /**
1.89 - * Gives implementing modules access to the {@link ModuleManager}.
1.90 - * @return the module manager
1.91 - */
1.92 - protected final ModuleManager getModuleManager() {
1.93 - return (ModuleManager) getServletContext().getAttribute(ModuleManager.SC_ATTR_NAME);
1.94 - }
1.95 -
1.96 - /**
1.97 - * Gives implementing modules access to the {@link DatabaseFacade}.
1.98 - * @return the database facade
1.99 - */
1.100 - protected final DatabaseFacade getDatabaseFacade() {
1.101 - return (DatabaseFacade) getServletContext().getAttribute(DatabaseFacade.SC_ATTR_NAME);
1.102 - }
1.103 -
1.104 - private ResponseType invokeMapping(Method method, HttpServletRequest req, HttpServletResponse resp)
1.105 - throws IOException, ServletException {
1.106 - try {
1.107 - LOG.trace("invoke {}#{}", method.getDeclaringClass().getName(), method.getName());
1.108 - return (ResponseType) method.invoke(this, req, resp);
1.109 - } catch (ReflectiveOperationException | ClassCastException ex) {
1.110 - LOG.error(String.format("invocation of method %s failed", method.getName()), ex);
1.111 - resp.sendError(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
1.112 - return ResponseType.NONE;
1.113 - }
1.114 - }
1.115 -
1.116 - @Override
1.117 - public void init() throws ServletException {
1.118 - moduleInfo = Optional.ofNullable(this.getClass().getAnnotation(LightPITModule.class));
1.119 - moduleInfoELProxy = moduleInfo.map(LightPITModule.ELProxy::convert);
1.120 -
1.121 - if (moduleInfo.isPresent()) {
1.122 - scanForRequestMappings();
1.123 - }
1.124 -
1.125 - LOG.trace("{} initialized", getServletName());
1.126 - }
1.127 -
1.128 - private void scanForRequestMappings() {
1.129 - try {
1.130 - Method[] methods = getClass().getDeclaredMethods();
1.131 - for (Method method : methods) {
1.132 - Optional<RequestMapping> mapping = Optional.ofNullable(method.getAnnotation(RequestMapping.class));
1.133 - if (mapping.isPresent()) {
1.134 - if (!Modifier.isPublic(method.getModifiers())) {
1.135 - LOG.warn("{} is annotated with {} but is not public",
1.136 - method.getName(), RequestMapping.class.getSimpleName()
1.137 - );
1.138 - continue;
1.139 - }
1.140 - if (Modifier.isAbstract(method.getModifiers())) {
1.141 - LOG.warn("{} is annotated with {} but is abstract",
1.142 - method.getName(), RequestMapping.class.getSimpleName()
1.143 - );
1.144 - continue;
1.145 - }
1.146 - if (!ResponseType.class.isAssignableFrom(method.getReturnType())) {
1.147 - LOG.warn("{} is annotated with {} but has the wrong return type - 'ResponseType' required",
1.148 - method.getName(), RequestMapping.class.getSimpleName()
1.149 - );
1.150 - continue;
1.151 - }
1.152 -
1.153 - Class<?>[] params = method.getParameterTypes();
1.154 - if (params.length == 2
1.155 - && HttpServletRequest.class.isAssignableFrom(params[0])
1.156 - && HttpServletResponse.class.isAssignableFrom(params[1])) {
1.157 -
1.158 - final String requestPath = "/"+mapping.get().requestPath();
1.159 -
1.160 - if (mappings.computeIfAbsent(mapping.get().method(), k -> new HashMap<>()).
1.161 - putIfAbsent(requestPath,
1.162 - (req, resp) -> invokeMapping(method, req, resp)) != null) {
1.163 - LOG.warn("{} {} has multiple mappings",
1.164 - mapping.get().method(),
1.165 - mapping.get().requestPath()
1.166 - );
1.167 - }
1.168 -
1.169 - LOG.debug("{} {} maps to {}::{}",
1.170 - mapping.get().method(),
1.171 - requestPath,
1.172 - getClass().getSimpleName(),
1.173 - method.getName()
1.174 - );
1.175 - } else {
1.176 - LOG.warn("{} is annotated with {} but has the wrong parameters - (HttpServletRequest,HttpServletResponse) required",
1.177 - method.getName(), RequestMapping.class.getSimpleName()
1.178 - );
1.179 - }
1.180 - }
1.181 - }
1.182 - } catch (SecurityException ex) {
1.183 - LOG.error("Scan for request mappings on declared methods failed.", ex);
1.184 - }
1.185 - }
1.186 -
1.187 - @Override
1.188 - public void destroy() {
1.189 - mappings.clear();
1.190 - LOG.trace("{} destroyed", getServletName());
1.191 - }
1.192 -
1.193 - /**
1.194 - * Sets the name of the dynamic fragment.
1.195 - *
1.196 - * It is sufficient to specify the name without any extension. The extension
1.197 - * is added automatically if not specified.
1.198 - *
1.199 - * The fragment must be located in the dynamic fragments folder.
1.200 - *
1.201 - * @param req the servlet request object
1.202 - * @param fragmentName the name of the fragment
1.203 - * @see Constants#DYN_FRAGMENT_PATH_PREFIX
1.204 - */
1.205 - public void setDynamicFragment(HttpServletRequest req, String fragmentName) {
1.206 - req.setAttribute(Constants.REQ_ATTR_FRAGMENT, Functions.dynFragmentPath(fragmentName));
1.207 - }
1.208 -
1.209 - /**
1.210 - * Specifies the name of an additional stylesheet used by the module.
1.211 - *
1.212 - * Setting an additional stylesheet is optional, but quite common for HTML
1.213 - * output.
1.214 - *
1.215 - * It is sufficient to specify the name without any extension. The extension
1.216 - * is added automatically if not specified.
1.217 - *
1.218 - * @param req the servlet request object
1.219 - * @param stylesheet the name of the stylesheet
1.220 - */
1.221 - public void setStylesheet(HttpServletRequest req, String stylesheet) {
1.222 - req.setAttribute(Constants.REQ_ATTR_STYLESHEET, Functions.enforceExt(stylesheet, ".css"));
1.223 - }
1.224 -
1.225 - private void forwardToFullView(HttpServletRequest req, HttpServletResponse resp)
1.226 - throws IOException, ServletException {
1.227 -
1.228 - req.setAttribute(Constants.REQ_ATTR_MENU, getModuleManager().getMainMenu(getDatabaseFacade()));
1.229 - req.getRequestDispatcher(HTML_FULL_DISPATCHER).forward(req, resp);
1.230 - }
1.231 -
1.232 - private Optional<HandlerMethod> findMapping(HttpMethod method, HttpServletRequest req) {
1.233 - return Optional.ofNullable(mappings.get(method)).map(
1.234 - (rm) -> rm.get(Optional.ofNullable(req.getPathInfo()).orElse("/"))
1.235 - );
1.236 - }
1.237 -
1.238 - private void forwardAsSepcified(ResponseType type, HttpServletRequest req, HttpServletResponse resp)
1.239 - throws ServletException, IOException {
1.240 - switch (type) {
1.241 - case NONE: return;
1.242 - case HTML_FULL:
1.243 - forwardToFullView(req, resp);
1.244 - return;
1.245 - // TODO: implement remaining response types
1.246 - default:
1.247 - // this code should be unreachable
1.248 - LOG.error("ResponseType switch is not exhaustive - this is a bug!");
1.249 - throw new UnsupportedOperationException();
1.250 - }
1.251 - }
1.252 -
1.253 - private void doProcess(HttpMethod method, HttpServletRequest req, HttpServletResponse resp)
1.254 - throws ServletException, IOException {
1.255 -
1.256 - // Synchronize module information with database
1.257 - getModuleManager().syncWithDatabase(getDatabaseFacade());
1.258 -
1.259 - // choose the requested language as session language (if available) or fall back to english, otherwise
1.260 - HttpSession session = req.getSession();
1.261 - if (session.getAttribute(Constants.SESSION_ATTR_LANGUAGE) == null) {
1.262 - Optional<List<String>> availableLanguages = Functions.availableLanguages(getServletContext()).map(Arrays::asList);
1.263 - Optional<Locale> reqLocale = Optional.of(req.getLocale());
1.264 - Locale sessionLocale = reqLocale.filter((rl) -> availableLanguages.map((al) -> al.contains(rl.getLanguage())).orElse(false)).orElse(Locale.ENGLISH);
1.265 - session.setAttribute(Constants.SESSION_ATTR_LANGUAGE, sessionLocale);
1.266 - LOG.debug("Settng language for new session {}: {}", session.getId(), sessionLocale.getDisplayLanguage());
1.267 - } else {
1.268 - Locale sessionLocale = (Locale) session.getAttribute(Constants.SESSION_ATTR_LANGUAGE);
1.269 - resp.setLocale(sessionLocale);
1.270 - LOG.trace("Continuing session {} with language {}", session.getId(), sessionLocale);
1.271 - }
1.272 -
1.273 - // set some internal request attributes
1.274 - req.setAttribute(Constants.REQ_ATTR_PATH, Functions.fullPath(req));
1.275 - req.setAttribute(Constants.REQ_ATTR_MODULE_CLASSNAME, this.getClass().getName());
1.276 - moduleInfoELProxy.ifPresent((proxy) -> req.setAttribute(Constants.REQ_ATTR_MODULE_INFO, proxy));
1.277 -
1.278 -
1.279 - // call the handler, if available, or send an HTTP 404 error
1.280 - Optional<HandlerMethod> mapping = findMapping(method, req);
1.281 - if (mapping.isPresent()) {
1.282 - forwardAsSepcified(mapping.get().apply(req, resp), req, resp);
1.283 - } else {
1.284 - resp.sendError(HttpServletResponse.SC_NOT_FOUND);
1.285 - }
1.286 - }
1.287 -
1.288 - @Override
1.289 - protected final void doGet(HttpServletRequest req, HttpServletResponse resp)
1.290 - throws ServletException, IOException {
1.291 - doProcess(HttpMethod.GET, req, resp);
1.292 - }
1.293 -
1.294 - @Override
1.295 - protected final void doPost(HttpServletRequest req, HttpServletResponse resp)
1.296 - throws ServletException, IOException {
1.297 - doProcess(HttpMethod.POST, req, resp);
1.298 - }
1.299 -}
