Java tutorial
/* * Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements. The ASF licenses this file to You * under the Apache License, Version 2.0 (the "License"); you may not * use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. For additional information regarding * copyright in this work, please see the NOTICE file in the top level * directory of this distribution. */ package org.apache.roller.weblogger.ui.rendering.servlets; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.apache.roller.weblogger.WebloggerException; import org.apache.roller.weblogger.business.WebloggerFactory; import org.apache.roller.weblogger.config.WebloggerConfig; import org.apache.roller.weblogger.config.WebloggerRuntimeConfig; import org.apache.roller.weblogger.pojos.*; import org.apache.roller.weblogger.ui.core.RollerContext; import org.apache.roller.weblogger.ui.rendering.Renderer; import org.apache.roller.weblogger.ui.rendering.RendererManager; import org.apache.roller.weblogger.ui.rendering.model.ModelLoader; import org.apache.roller.weblogger.ui.rendering.util.WeblogPreviewRequest; import org.apache.roller.weblogger.util.cache.CachedContent; import javax.servlet.ServletConfig; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import javax.servlet.jsp.JspFactory; import javax.servlet.jsp.PageContext; import java.io.IOException; import java.util.HashMap; import java.util.Map; import org.apache.roller.weblogger.ui.rendering.mobile.MobileDeviceRepository; /** * Responsible for rendering weblog page previews. * * This servlet is used as part of the authoring interface to provide previews * of what a weblog will look like with a given theme. It is not available * outside of the authoring interface. */ public class PreviewServlet extends HttpServlet { private static Log log = LogFactory.getLog(PreviewServlet.class); /** * Init method for this servlet */ public void init(ServletConfig servletConfig) throws ServletException { super.init(servletConfig); log.info("Initializing PreviewServlet"); } /** * Handle GET requests for weblog pages. */ public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { log.debug("Entering"); Weblog weblog = null; WeblogPreviewRequest previewRequest = null; String type = null; try { previewRequest = new WeblogPreviewRequest(request); // type of the page we are going to preview type = previewRequest.getType(); // lookup weblog specified by preview request weblog = previewRequest.getWeblog(); if (weblog == null) { throw new WebloggerException("unable to lookup weblog: " + previewRequest.getWeblogHandle()); } } catch (Exception e) { // some kind of error parsing the request or getting weblog log.debug("error creating preview request", e); response.sendError(HttpServletResponse.SC_NOT_FOUND); return; } // Get the deviceType from user agent MobileDeviceRepository.DeviceType deviceType = MobileDeviceRepository.getRequestType(request); // for previews we explicitly set the deviceType attribute if (request.getParameter("type") != null) { deviceType = request.getParameter("type").equals("standard") ? MobileDeviceRepository.DeviceType.standard : MobileDeviceRepository.DeviceType.mobile; } Weblog tmpWebsite = weblog; if (previewRequest.getThemeName() != null) { // only create temporary weblog object if theme name was specified // in request, which indicates we're doing a theme preview // try getting the preview theme log.debug("preview theme = " + previewRequest.getThemeName()); Theme previewTheme = previewRequest.getTheme(); // construct a temporary Website object for this request // and set the EditorTheme to our previewTheme tmpWebsite = new Weblog(); tmpWebsite.setData(weblog); if (previewTheme != null && previewTheme.isEnabled()) { tmpWebsite.setEditorTheme(previewTheme.getId()); } else if (WeblogTheme.CUSTOM.equals(previewRequest.getThemeName())) { tmpWebsite.setEditorTheme(WeblogTheme.CUSTOM); } // we've got to set the weblog in our previewRequest because that's // the object that gets referenced during rendering operations previewRequest.setWeblog(tmpWebsite); } // do we need to force a specific locale for the request? if (previewRequest.getLocale() == null && !weblog.isShowAllLangs()) { previewRequest.setLocale(weblog.getLocale()); } Template page = null; if ("page".equals(previewRequest.getContext())) { page = previewRequest.getWeblogPage(); // If request specified tags section index, then look for custom template } else if ("tags".equals(previewRequest.getContext()) && previewRequest.getTags() == null) { try { page = weblog.getTheme().getTemplateByAction(ThemeTemplate.ACTION_TAGSINDEX); } catch (Exception e) { log.error("Error getting weblog page for action 'tagsIndex'", e); } // if we don't have a custom tags page then 404, we don't let // this one fall through to the default template if (page == null) { if (!response.isCommitted()) response.reset(); response.sendError(HttpServletResponse.SC_NOT_FOUND); return; } // If this is a permalink then look for a permalink template } else if (previewRequest.getWeblogAnchor() != null) { try { page = weblog.getTheme().getTemplateByAction(ThemeTemplate.ACTION_PERMALINK); } catch (Exception e) { log.error("Error getting weblog page for action 'permalink'", e); } } if (page == null) { try { page = tmpWebsite.getTheme().getDefaultTemplate(); } catch (WebloggerException re) { log.error("Error getting default page for preview", re); } } // Still no page? Then that is a 404 if (page == null) { if (!response.isCommitted()) response.reset(); response.sendError(HttpServletResponse.SC_NOT_FOUND); return; } log.debug("preview page found, dealing with it"); // set the content type String pageLink = previewRequest.getWeblogPageName(); String mimeType = pageLink != null ? RollerContext.getServletContext().getMimeType(pageLink) : null; String contentType = "text/html; charset=utf-8"; if (mimeType != null) { // we found a match ... set the content type contentType = mimeType + "; charset=utf-8"; } else if ("_css".equals(previewRequest.getWeblogPageName())) { // TODO: store content-type for each page so this hack is unnecessary contentType = "text/css; charset=utf-8"; } // looks like we need to render content Map model = new HashMap(); try { PageContext pageContext = JspFactory.getDefaultFactory().getPageContext(this, request, response, "", false, 8192, true); // special hack for menu tag request.setAttribute("pageRequest", previewRequest); // populate the rendering model Map initData = new HashMap(); initData.put("parsedRequest", previewRequest); initData.put("pageContext", pageContext); // define url strategy initData.put("urlStrategy", WebloggerFactory.getWeblogger().getUrlStrategy() .getPreviewURLStrategy(previewRequest.getThemeName())); // Load models for page previewing String pageModels = WebloggerConfig.getProperty("rendering.previewModels"); ModelLoader.loadModels(pageModels, model, initData, true); // Load special models for site-wide blog if (WebloggerRuntimeConfig.isSiteWideWeblog(weblog.getHandle())) { String siteModels = WebloggerConfig.getProperty("rendering.siteModels"); ModelLoader.loadModels(siteModels, model, initData, true); } // Load weblog custom models ModelLoader.loadCustomModels(weblog, model, initData); // ick, gotta load pre-3.0 model stuff as well :( ModelLoader.loadOldModels(model, request, response, pageContext, previewRequest, WebloggerFactory .getWeblogger().getUrlStrategy().getPreviewURLStrategy(previewRequest.getThemeName())); } catch (WebloggerException ex) { log.error("ERROR loading model for page", ex); if (!response.isCommitted()) response.reset(); response.sendError(HttpServletResponse.SC_INTERNAL_SERVER_ERROR); return; } // lookup Renderer we are going to use Renderer renderer = null; try { log.debug("Looking up renderer"); renderer = RendererManager.getRenderer(page, deviceType); } catch (Exception e) { // nobody wants to render my content :( log.error("Couldn't find renderer for page " + page.getId(), e); if (!response.isCommitted()) response.reset(); response.sendError(HttpServletResponse.SC_NOT_FOUND); return; } // render content. use default size of about 24K for a standard page CachedContent rendererOutput = new CachedContent(24567); try { log.debug("Doing rendering"); renderer.render(model, rendererOutput.getCachedWriter()); // flush rendered output and close rendererOutput.flush(); rendererOutput.close(); } catch (Exception e) { // bummer, error during rendering log.error("Error during rendering for page " + page.getId(), e); if (!response.isCommitted()) response.reset(); response.sendError(HttpServletResponse.SC_NOT_FOUND); return; } // post rendering process // flush rendered content to response log.debug("Flushing response output"); response.setContentType(contentType); response.setContentLength(rendererOutput.getContent().length); response.getOutputStream().write(rendererOutput.getContent()); log.debug("Exiting"); } }