Java tutorial
/** * Global Sensor Networks (GSN) Source Code * Copyright (c) 2006-2014, Ecole Polytechnique Federale de Lausanne (EPFL) * * This file is part of GSN. * * GSN is free software: you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation, either version 3 of the License, or * (at your option) any later version. * * GSN 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 General Public License for more details. * * You should have received a copy of the GNU General Public License * along with GSN. If not, see <http://www.gnu.org/licenses/>. * * File: src/gsn/http/GMLHandler.java * * @author Ionut Iosifescu * @author Ali Salehi * @author Timotee Maret * @author Sofiane Sarni * */ package gsn.http; import gsn.Main; import gsn.Mappings; import gsn.beans.DataField; import gsn.beans.StreamElement; import gsn.beans.VSensorConfig; import gsn.http.ac.DataSource; import gsn.http.ac.User; import gsn.storage.DataEnumerator; import java.io.IOException; import java.sql.SQLException; import java.text.SimpleDateFormat; import java.util.ArrayList; import java.util.Arrays; import java.util.HashSet; import java.util.Iterator; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import org.apache.commons.collections.KeyValue; import org.apache.commons.lang.StringEscapeUtils; import org.slf4j.LoggerFactory; import org.slf4j.Logger; import gsn.http.ac.UserUtils; public class GMLHandler implements RequestHandler { private static transient Logger logger = LoggerFactory.getLogger(GMLHandler.class); public void handle(HttpServletRequest request, HttpServletResponse response) throws IOException { response.setStatus(HttpServletResponse.SC_OK); String reqName = request.getParameter("name"); String reqGroup = request.getParameter("group"); String reqUsername = request.getParameter("username"); String reqPassword = request.getParameter("password"); response.getWriter().write(buildOutput(reqName, reqGroup, reqUsername, reqPassword)); } //return only the requested sensor(s) if specified (otherwise use null) public String buildOutput(String reqName, String reqGroup, String reqUsername, String reqPassword) { boolean authenticateUserFromURL = false; User user = null; if (Main.getContainerConfig().isAcEnabled()) { if ((reqUsername != null) && (reqPassword != null)) { authenticateUserFromURL = true; user = UserUtils.allowUserToLogin(reqUsername, reqPassword); } } SimpleDateFormat sdf = new SimpleDateFormat(Main.getContainerConfig().getTimeFormat()); StringBuilder outsb = new StringBuilder( "<gsn:FeatureCollection xmlns:xsi=\"http://www.w3.org/2001/XMLSchema-instance\" xsi:schemaLocation=\"./gsn.xsd\" xmlns:gsn=\"http://gsn.ch/\" xmlns:gml=\"http://www.opengis.net/gml\"> \n"); Iterator<VSensorConfig> vsIterator = Mappings.getAllVSensorConfigs(); HashSet<String> sensorsSet = new HashSet<String>(); if (reqName != null && reqName.contains(",")) sensorsSet = new HashSet<String>(Arrays.asList(reqName.split(","))); else sensorsSet.add(reqName); while (vsIterator.hasNext()) { StringBuilder sb = new StringBuilder(); String lat = null; String lon = null; VSensorConfig sensorConfig = vsIterator.next(); if (reqName != null && !sensorsSet.contains(sensorConfig.getName())) continue; if (reqGroup != null && !(sensorConfig.getName().startsWith(reqGroup + "_"))) continue; if (Main.getContainerConfig().isAcEnabled()) { if (user == null) { if (authenticateUserFromURL) continue; // means that username and password provided are rejected dince they don't map to a correct User object else // no username was provided, show only public sensors if (DataSource.isVSManaged(sensorConfig.getName())) continue; //skip sensor if it is managed by access control } else // user authenticated, verify that it has the right credentials if (!user.hasReadAccessRight(sensorConfig.getName()) && !user.isAdmin() && !DataSource.isVSManaged(sensorConfig.getName())) continue; } for (KeyValue df : sensorConfig.getAddressing()) { if (StringEscapeUtils.escapeXml(df.getKey().toString().toLowerCase()).contentEquals("latitude")) lat = new String(StringEscapeUtils.escapeXml(df.getValue().toString())); if (StringEscapeUtils.escapeXml(df.getKey().toString().toLowerCase()).contentEquals("longitude")) lon = new String(StringEscapeUtils.escapeXml(df.getValue().toString())); } if (lat != null && lon != null) { sb.append("<gml:featureMember>\n"); sb.append("<gsn:sensors"); sb.append(" fid=\"").append(sensorConfig.getName()).append("\""); sb.append(">\n"); sb.append("\t<gsn:geometryProperty><gml:Point><gml:coordinates>").append(lon).append(",") .append(lat).append("</gml:coordinates></gml:Point></gsn:geometryProperty>\n"); } else continue; if (lat.isEmpty() || lon.isEmpty()) // skip sensors with empty coordinates continue; ArrayList<StreamElement> ses = getMostRecentValueFor(sensorConfig.getName()); int counter = 1; if (ses != null) { for (StreamElement se : ses) { sb.append("\t<gsn:sensor>").append(sensorConfig.getName()).append("</gsn:sensor>\n"); for (KeyValue df : sensorConfig.getAddressing()) { sb.append("\t<gsn:") .append(StringEscapeUtils.escapeXml(df.getKey().toString().toLowerCase())) .append(">"); sb.append(StringEscapeUtils.escapeXml(df.getValue().toString())); sb.append("</gsn:") .append(StringEscapeUtils.escapeXml(df.getKey().toString().toLowerCase())) .append(">\n"); } for (DataField df : sensorConfig.getOutputStructure()) { sb.append("\t<gsn:").append(df.getName().toLowerCase()).append(">"); if (se != null) if (df.getType().toLowerCase().trim().indexOf("binary") > 0) sb.append(se.getData(df.getName())); else sb.append(se.getData(StringEscapeUtils.escapeXml(df.getName()))); sb.append("</gsn:").append(df.getName().toLowerCase()).append(">\n"); } counter++; } } sb.append("</gsn:sensors>\n"); sb.append("</gml:featureMember>\n"); outsb.append(sb); } outsb.append("</gsn:FeatureCollection>\n"); return outsb.toString(); } public boolean isValid(HttpServletRequest request, HttpServletResponse response) throws IOException { return true; } /** * returns null if there is an error. * * @param virtual_sensor_name * @return */ public static ArrayList<StreamElement> getMostRecentValueFor(String virtual_sensor_name) { StringBuilder query = new StringBuilder("select * from ").append(virtual_sensor_name) .append(" where timed = (select max(timed) from ").append(virtual_sensor_name).append(")"); ArrayList<StreamElement> toReturn = new ArrayList<StreamElement>(); try { DataEnumerator result = Main.getStorage(virtual_sensor_name).executeQuery(query, true); while (result.hasMoreElements()) toReturn.add(result.nextElement()); } catch (SQLException e) { logger.error("ERROR IN EXECUTING, query: " + query + ": " + e.getMessage()); return null; } return toReturn; } }