/*
* Copyright 2014 Google Inc. All rights reserved.
*
* 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 com.google.samples.apps.iosched.server.gcm.device;
import com.google.samples.apps.iosched.server.gcm.db.ApiKeyInitializer;
import com.google.samples.apps.iosched.server.gcm.db.MessageStore;
import com.google.samples.apps.iosched.server.gcm.db.DeviceStore;
import com.google.samples.apps.iosched.server.gcm.db.models.Device;
import com.google.samples.apps.iosched.server.gcm.db.models.MulticastMessage;
import com.google.android.gcm.server.*;
import com.google.appengine.api.taskqueue.Queue;
import com.google.appengine.api.taskqueue.QueueFactory;
import com.google.appengine.api.taskqueue.TaskOptions;
import javax.servlet.ServletConfig;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.TimeUnit;
import java.util.logging.Level;
import java.util.logging.Logger;
/** Utility class for sending individual messages to devices.
*
* This class is responsible for communication with the GCM server for purposes of sending
* messages.
*
* @return true if success, false if
*/
public class MessageSender {
private String mApiKey;
private Sender mGcmService;
private static final int TTL = (int) TimeUnit.MINUTES.toSeconds(300);
protected final Logger mLogger = Logger.getLogger(getClass().getName());
/** Maximum devices in a multicast message */
private static final int MAX_DEVICES = 1000;
public MessageSender(ServletConfig config) {
mApiKey = (String) config.getServletContext().getAttribute(
ApiKeyInitializer.ATTRIBUTE_ACCESS_KEY);
mGcmService = new Sender(mApiKey);
}
public void multicastSend(List<Device> devices, String action, String extraData) {
Queue queue = QueueFactory.getQueue("MulticastMessagesQueue");
// Split messages into batches for multicast
// GCM limits maximum devices per multicast request. AppEngine also limits the size of
// lists stored in the datastore.
int total = devices.size();
List<String> partialDevices = new ArrayList<String>(total);
int counter = 0;
for (Device device : devices) {
counter ++;
partialDevices.add(device.getGcmId());
int partialSize = partialDevices.size();
if (partialSize == MAX_DEVICES || counter == total) {
// Send multicast message
Long multicastKey = MessageStore.createMulticast(partialDevices,
action,
extraData);
mLogger.fine("Queuing " + partialSize + " devices on multicast " + multicastKey);
TaskOptions taskOptions = TaskOptions.Builder
.withUrl("/queue/send")
.param("multicastKey", Long.toString(multicastKey))
.method(TaskOptions.Method.POST);
queue.add(taskOptions);
partialDevices.clear();
}
}
mLogger.fine("Queued message to " + total + " devices");
}
boolean sendMessage(Long multicastId) {
MulticastMessage msg = MessageStore.getMulticast(multicastId);
List<String> devices = msg.getDestinations();
String action = msg.getAction();
Message.Builder builder = new Message.Builder().delayWhileIdle(true);
if (action == null || action.length() == 0) {
throw new IllegalArgumentException("Message action cannot be empty.");
}
builder.collapseKey(action)
.addData("action", action)
.addData("extraData", msg.getExtraData())
.timeToLive(TTL);
Message message = builder.build();
MulticastResult multicastResult = null;
try {
// We occasionally see null messages. (Maybe due to squelch?)
// We should these from entering the send queue in the first place. In the meantime,
// here's a hack to prevent this.
if (devices != null) {
multicastResult = mGcmService.sendNoRetry(message, devices);
mLogger.info("Result: " + multicastResult);
} else {
mLogger.info("Null device list detected. Aborting.");
return true;
}
} catch (IOException e) {
mLogger.log(Level.SEVERE, "Exception posting " + message, e);
return true;
}
boolean allDone = true;
// check if any registration id must be updated
if (multicastResult.getCanonicalIds() != 0) {
List<Result> results = multicastResult.getResults();
for (int i = 0; i < results.size(); i++) {
String canonicalRegId = results.get(i).getCanonicalRegistrationId();
if (canonicalRegId != null) {
String regId = devices.get(i);
DeviceStore.updateRegistration(regId, canonicalRegId);
}
}
}
if (multicastResult.getFailure() != 0) {
// there were failures, check if any could be retried
List<Result> results = multicastResult.getResults();
List<String> retriableRegIds = new ArrayList<String>();
for (int i = 0; i < results.size(); i++) {
String error = results.get(i).getErrorCodeName();
if (error != null) {
String regId = devices.get(i);
mLogger.warning("Got error (" + error + ") for regId " + regId);
if (error.equals(Constants.ERROR_NOT_REGISTERED)) {
// application has been removed from device - unregister it
DeviceStore.unregister(regId);
}
if (error.equals(Constants.ERROR_UNAVAILABLE)) {
retriableRegIds.add(regId);
}
}
}
if (!retriableRegIds.isEmpty()) {
// update task
MessageStore.updateMulticast(multicastId, retriableRegIds);
allDone = false;
return false;
}
}
if (allDone) {
return true;
} else {
return false;
}
}
}