MainServlet.java

/*
 * Copyright (c) 2006-2009 by Dirk Riehle, http://dirkriehle.com
 *
 * This file is part of the Wahlzeit photo rating application.
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as
 * published by the Free Software Foundation, either version 3 of the
 * License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public
 * License along with this program. If not, see
 * <http://www.gnu.org/licenses/>.
 */

package org.wahlzeit.servlets;

import com.google.api.client.util.Charsets;
import com.google.appengine.api.images.Image;
import com.google.appengine.api.images.ImagesServiceFactory;
import com.google.common.io.CharStreams;
import org.apache.commons.fileupload.FileItemIterator;
import org.apache.commons.fileupload.FileItemStream;
import org.apache.commons.fileupload.servlet.ServletFileUpload;
import org.wahlzeit.handlers.PartUtil;
import org.wahlzeit.handlers.WebFormHandler;
import org.wahlzeit.handlers.WebPageHandler;
import org.wahlzeit.handlers.WebPartHandlerManager;
import org.wahlzeit.model.User;
import org.wahlzeit.model.UserSession;
import org.wahlzeit.services.LogBuilder;
import org.wahlzeit.services.SessionManager;
import org.wahlzeit.webparts.WebPart;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.HashMap;
import java.util.Map;
import java.util.logging.Logger;


/**
 * The main servlet class for handling incoming and outgoing requests.
 */
public class MainServlet extends AbstractServlet {

	private static final Logger log = Logger.getLogger(MainServlet.class.getName());
	/**
	 *
	 */
	private static final long serialVersionUID = 42L; // any one does; class never serialized

	/**
	 *
	 */
	public void myPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		long startTime = System.currentTimeMillis();

		UserSession us = (UserSession) SessionManager.getThreadLocalSession();
		String link = request.getRequestURI();
		int linkStart = link.lastIndexOf("/") + 1;
		int linkEnd = link.indexOf(".form");
		if (linkEnd != -1) {
			link = link.substring(linkStart, linkEnd);
		} else {
			link = PartUtil.NULL_FORM_NAME;
		}
		log.info(LogBuilder.createUserMessage().addParameter("posted to", link).toString());

		Map args = getRequestArgs(request, us);
		log.info(LogBuilder.createSystemMessage().
				addParameter("POST arguments", getRequestArgsAsString(us, args)).toString());

		WebFormHandler formHandler = WebPartHandlerManager.getWebFormHandler(link);
		link = PartUtil.DEFAULT_PAGE_NAME;
		if (formHandler != null) {
			link = formHandler.handlePost(us, args);
		}

		redirectRequest(response, link);
		us.addProcessingTime(System.currentTimeMillis() - startTime);
		SessionManager.dropThreadLocalSession();
	}

	/**
	 *
	 */
	public void myGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		long startTime = System.currentTimeMillis();

		UserSession us = (UserSession) SessionManager.getThreadLocalSession();
		String link = request.getRequestURI();
		int linkStart = link.lastIndexOf("/") + 1;
		int linkEnd = link.indexOf(".html");
		if (linkEnd == -1) {
			linkEnd = link.length();
		}

		link = link.substring(linkStart, linkEnd);
		log.info(LogBuilder.createUserMessage().addParameter("requested URI", request.getRequestURI()).toString());


		WebPageHandler handler = WebPartHandlerManager.getWebPageHandler(link);
		String newLink = PartUtil.DEFAULT_PAGE_NAME;
		if (handler != null) {
			Map args = getRequestArgs(request, us);
			log.info(LogBuilder.createSystemMessage().
					addParameter("GET arguments", getRequestArgsAsString(us, args)).toString());
			newLink = handler.handleGet(us, link, args);
		}

		if (newLink.equals(link)) { // no redirect necessary
			WebPart result = handler.makeWebPart(us);
			us.addProcessingTime(System.currentTimeMillis() - startTime);
			configureResponse(us, response, result);
			us.clearSavedArgs(); // saved args go from post to next get
			us.resetProcessingTime();
		} else {
			redirectRequest(response, newLink);
			us.addProcessingTime(System.currentTimeMillis() - startTime);
		}
		SessionManager.dropThreadLocalSession();
	}

	/**
	 *
	 */
	protected Map getRequestArgs(HttpServletRequest request, UserSession us) throws IOException, ServletException {
		String contentType = request.getContentType();
		if ((contentType != null) && contentType.startsWith("multipart/form-data")) {
			return getMultiPartRequestArgs(request, us);
		} else {
			return request.getParameterMap();
		}
	}

	/**
	 * Searches for files in the request and puts them in the resulting map with the key "fileName". When a file is
	 * found, you can access its path by searching for elements with the key "fileName".
	 */
	protected Map getMultiPartRequestArgs(HttpServletRequest request, UserSession us) throws IOException,
			ServletException {
		Map<String, String> result = new HashMap<String, String>();
		result.putAll(request.getParameterMap());
		try {
			ServletFileUpload upload = new ServletFileUpload();
			FileItemIterator iterator = upload.getItemIterator(request);

			while (iterator.hasNext()) {
				FileItemStream fileItemStream = iterator.next();
				String filename = fileItemStream.getName();

				if (!fileItemStream.isFormField()) {
					InputStream inputStream = fileItemStream.openStream();
					Image image = getImage(inputStream);
					User user = (User) us.getClient();
					user.setUploadedImage(image);
					result.put("fileName", filename);
					log.config(LogBuilder.createSystemMessage().addParameter("Uploaded image", filename).toString());
				} else {
					String key = fileItemStream.getFieldName();
					InputStream is = fileItemStream.openStream();
					String value = CharStreams.toString(new InputStreamReader(is, Charsets.UTF_8));
					result.put(key, value);
					log.config(LogBuilder.createSystemMessage().
							addParameter("Key of uploaded parameter", key).
							addParameter("value", value).toString());
				}
			}
		} catch (Exception ex) {
			throw new ServletException(ex);
		}

		return result;
	}

	/**
	 * Create an Image object from the Input stream.
	 */
	private Image getImage(InputStream input) throws IOException {
		Image image;
		try {
			ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
			byte[] buffer = new byte[1024 * 1024];
			int bytesRead = input.read(buffer);
			while (bytesRead != -1) {
				outputStream.write(buffer, 0, bytesRead);
				bytesRead = input.read(buffer);
			}
			image = ImagesServiceFactory.makeImage(outputStream.toByteArray());
		} finally {
			input.close();
		}
		return image;
	}
}