/* * Copyright 2015 Anton Tananaev (anton.tananaev@gmail.com) * * Licensed 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. */ package org.traccar.http; import java.io.IOException; import java.util.Collection; import java.util.HashMap; import java.util.Map; import java.util.concurrent.TimeUnit; import javax.json.Json; import javax.json.JsonObjectBuilder; import javax.servlet.AsyncContext; import javax.servlet.ServletException; import javax.servlet.ServletResponse; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import org.jboss.netty.util.Timeout; import org.jboss.netty.util.TimerTask; import org.traccar.Context; import org.traccar.GlobalTimer; import org.traccar.database.DataCache; import org.traccar.helper.Log; import org.traccar.model.Position; public class AsyncServlet extends HttpServlet { private static final long ASYNC_TIMEOUT = 120000; @Override protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { async(req.startAsync()); } public class AsyncSession { private static final boolean DEBUG_ASYNC = true; private static final long SESSION_TIMEOUT = 30; private static final long REQUEST_TIMEOUT = 10; private boolean destroyed; private final long userId; private final Collection<Long> devices; private Timeout sessionTimeout; private Timeout requestTimeout; private final Map<Long, Position> positions = new HashMap<Long, Position>(); private AsyncContext activeContext; private void logEvent(String message) { if (DEBUG_ASYNC) { Log.debug("AsyncSession: " + this.hashCode() + " destroyed: " + destroyed + " " + message); } } public AsyncSession(long userId, Collection<Long> devices) { logEvent("create userId: " + userId + " devices: " + devices.size()); this.userId = userId; this.devices = devices; Collection<Position> initialPositions = Context.getDataCache().getInitialState(devices); for (Position position : initialPositions) { positions.put(position.getDeviceId(), position); } Context.getDataCache().addListener(devices, dataListener); } @Override protected void finalize() throws Throwable { super.finalize(); logEvent("finalize"); } private final DataCache.DataCacheListener dataListener = new DataCache.DataCacheListener() { @Override public void onUpdate(Position position) { synchronized (AsyncSession.this) { logEvent("onUpdate deviceId: " + position.getDeviceId()); if (!destroyed) { if (requestTimeout != null) { requestTimeout.cancel(); requestTimeout = null; } positions.put(position.getDeviceId(), position); if (activeContext != null) { response(); } } } } }; private final TimerTask sessionTimer = new TimerTask() { @Override public void run(Timeout tmt) throws Exception { synchronized (AsyncSession.this) { logEvent("sessionTimeout"); Context.getDataCache().removeListener(devices, dataListener); synchronized (asyncSessions) { asyncSessions.remove(userId); } destroyed = true; } } }; private final TimerTask requestTimer = new TimerTask() { @Override public void run(Timeout tmt) throws Exception { synchronized (AsyncSession.this) { logEvent("requestTimeout"); if (!destroyed) { if (activeContext != null) { response(); } } } } }; public synchronized void request(AsyncContext context) { logEvent("request context: " + context.hashCode()); if (!destroyed) { activeContext = context; if (sessionTimeout != null) { sessionTimeout.cancel(); sessionTimeout = null; } if (!positions.isEmpty()) { response(); } else { requestTimeout = GlobalTimer.getTimer().newTimeout( requestTimer, REQUEST_TIMEOUT, TimeUnit.SECONDS); } } } private synchronized void response() { logEvent("response context: " + activeContext.hashCode()); if (!destroyed) { ServletResponse response = activeContext.getResponse(); JsonObjectBuilder result = Json.createObjectBuilder(); result.add("success", true); result.add("data", JsonConverter.arrayToJson(positions.values())); positions.clear(); try { response.getWriter().println(result.build().toString()); } catch (IOException error) { Log.warning(error); } activeContext.complete(); activeContext = null; sessionTimeout = GlobalTimer.getTimer().newTimeout( sessionTimer, SESSION_TIMEOUT, TimeUnit.SECONDS); } } } private final Map<Long, AsyncSession> asyncSessions = new HashMap<Long, AsyncSession>(); private void async(final AsyncContext context) { context.setTimeout(ASYNC_TIMEOUT); HttpServletRequest req = (HttpServletRequest) context.getRequest(); long userId = (Long) req.getSession().getAttribute(MainServlet.USER_KEY); synchronized (asyncSessions) { if (!asyncSessions.containsKey(userId)) { Collection<Long> devices = Context.getPermissionsManager().allowedDevices(userId); asyncSessions.put(userId, new AsyncSession(userId, devices)); } asyncSessions.get(userId).request(context); } } }