У меня простое клиентское приложение Paho MQTT Android:
public class PahoExampleActivity extends AppCompatActivity {
MqttAndroidClient mqttAndroidClient;
final String serverUri = "ssl://myserver:8887";
String clientId = "ExampleAndroidClient";
final String subscriptionTopic = "aaa/";
final String publishTopic = "exampleAndroidPublishTopic";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
Timber.plant(new Timber.DebugTree());
Timber.plant(new FileLoggingTree(this));
Timber.tag(Utils.TIMBER_TAG).v("starting");
setContentView(R.layout.activity_main);
mqttAndroidClient = new MqttAndroidClient(getApplicationContext(), serverUri, clientId);
mqttAndroidClient.setCallback(new MqttCallbackExtended() {
@Override
public void connectComplete(boolean reconnect, String serverURI) {
if (reconnect) {
Timber.tag(Utils.TIMBER_TAG).v("Reconnected to : " + serverURI);
// Because Clean Session is true, we need to re-subscribe
subscribeToTopic();
} else {
Timber.tag(Utils.TIMBER_TAG).v("Connected to: " + serverURI);
}
}
@Override
public void connectionLost(Throwable cause) {
Timber.tag(Utils.TIMBER_TAG).v("The Connection was lost.");
}
@Override
public void messageArrived(String topic, MqttMessage message) throws Exception {
Timber.tag(Utils.TIMBER_TAG).v("Incoming message: " + new String(message.getPayload()));
}
@Override
public void deliveryComplete(IMqttDeliveryToken token) {
}
});
MqttConnectOptions mqttConnectOptions = new MqttConnectOptions();
mqttConnectOptions.setAutomaticReconnect(true);
mqttConnectOptions.setCleanSession(false);
mqttConnectOptions.setKeepAliveInterval(300);
mqttConnectOptions.setUserName("a");
mqttConnectOptions.setPassword("a".toCharArray());
try {
mqttConnectOptions.setSocketFactory(SocketFactoryMQ.getSocketFactory(this,""));
} catch (KeyStoreException e) {
Timber.e ( e);
} catch (NoSuchAlgorithmException e) {
Timber.tag(Utils.TIMBER_TAG).e ( e);
} catch (IOException e) {
Timber.tag(Utils.TIMBER_TAG).e ( e);
} catch (KeyManagementException e) {
Timber.tag(Utils.TIMBER_TAG).e ( e);
} catch (CertificateException e) {
Timber.tag(Utils.TIMBER_TAG).e ( e);
} catch (UnrecoverableKeyException e) {
Timber.tag(Utils.TIMBER_TAG).e ( e);
}
try {
//addToHistory("Connecting to " + serverUri);
mqttAndroidClient.connect(mqttConnectOptions, null, new IMqttActionListener() {
@Override
public void onSuccess(IMqttToken asyncActionToken) {
DisconnectedBufferOptions disconnectedBufferOptions = new DisconnectedBufferOptions();
disconnectedBufferOptions.setBufferEnabled(true);
disconnectedBufferOptions.setBufferSize(100);
disconnectedBufferOptions.setPersistBuffer(false);
disconnectedBufferOptions.setDeleteOldestMessages(false);
mqttAndroidClient.setBufferOpts(disconnectedBufferOptions);
subscribeToTopic();
}
@Override
public void onFailure(IMqttToken asyncActionToken, Throwable exception) {
Timber.tag(Utils.TIMBER_TAG).v("Failed to connect to: " + serverUri);
}
});
} catch (MqttException ex){
ex.printStackTrace();
}
}
public void subscribeToTopic(){
try {
mqttAndroidClient.subscribe(subscriptionTopic, 0, null, new IMqttActionListener() {
@Override
public void onSuccess(IMqttToken asyncActionToken) {
Timber.tag(Utils.TIMBER_TAG).v("Subscribed!");
}
@Override
public void onFailure(IMqttToken asyncActionToken, Throwable exception) {
Timber.tag(Utils.TIMBER_TAG).v("Failed to subscribe");
}
});
mqttAndroidClient.subscribe(subscriptionTopic, 0, new IMqttMessageListener() {
@Override
public void messageArrived(String topic, MqttMessage message) throws Exception {
// message Arrived!
Timber.tag(Utils.TIMBER_TAG).v("Message: " + topic + " : " + new String(message.getPayload()));
sendNotification(topic,new String(message.getPayload()));
}
});
} catch (MqttException ex){
System.err.println("Exception whilst subscribing");
ex.printStackTrace();
}
}
public void sendNotification(String title, String message) {
...
}
}
Все отлично работает, когда телефон подключен к зарядному устройству или активен. Мое приложение пропускает сообщения MQTT, когда телефон отключен от зарядного устройства и закрыт (я называю это энергосберегающим режимом). В этой ситуации через некоторое время телефон начинает пропускать MQTT-сообщения. Согласно журналу, полученному с телефона, мы видим, что сообщения появляются при пробуждении телефона:
Thu Feb 20 2020 at 02:41:27:776 pm Message: aaa/ : 2
Thu Feb 20 2020 at 02:41:49:537 pm Message: aaa/ : 3
Thu Feb 20 2020 at 02:44:26:972 pm Message: aaa/ : 2
Thu Feb 20 2020 at 02:44:47:913 pm Message: aaa/ : 3
Thu Feb 20 2020 at 02:45:20:876 pm Message: aaa/ : 4
Thu Feb 20 2020 at 02:46:01:322 pm Message: aaa/ : 5
Thu Feb 20 2020 at 02:46:52:873 pm Message: aaa/ : 6
Thu Feb 20 2020 at 02:47:09:993 pm The Connection was lost.
Thu Feb 20 2020 at 02:54:44:263 pm Reconnected to : ssl://myserver:8887
Thu Feb 20 2020 at 02:54:44:357 pm Subscribed!
Thu Feb 20 2020 at 02:54:48:196 pm MainActivity.onStart
Thu Feb 20 2020 at 02:55:28:465 pm MainActivity.onStop
Thu Feb 20 2020 at 02:55:33:080 pm Message: aaa/ : 12
Thu Feb 20 2020 at 02:57:35:070 pm Message: aaa/ : 13
Thu Feb 20 2020 at 02:58:30:264 pm The Connection was lost.
Thu Feb 20 2020 at 03:02:54:001 pm Reconnected to : ssl://myserver:8887
Thu Feb 20 2020 at 03:02:54:103 pm Subscribed!
Сообщения 7-11 просто не дошли до моего устройства. Как решить эту проблему?
UPD
После изменения QOS 0 на QOS 1 я получил все сообщения. Сообщения, начинающиеся с 10, пришли одновременно с некоторой задержкой. С первого взгляда 5 мин. задержка не имеет значения, но я не уверен, насколько большой это может быть. Например 30 мин. задержка не подходит.
Thu Feb 20 2020 at 06:20:54:411 pm Message: aaa/ : 2
Thu Feb 20 2020 at 06:21:16:221 pm Message: aaa/ : 3
Thu Feb 20 2020 at 06:21:48:173 pm Message: aaa/ : 4
Thu Feb 20 2020 at 06:22:29:642 pm Message: aaa/ : 5
Thu Feb 20 2020 at 06:23:21:571 pm Message: aaa/ : 6
Thu Feb 20 2020 at 06:24:23:327 pm Message: aaa/ : 7
Thu Feb 20 2020 at 06:25:34:278 pm Message: aaa/ : 8
Thu Feb 20 2020 at 06:26:56:309 pm Message: aaa/ : 9
Thu Feb 20 2020 at 06:27:16:408 pm The Connection was lost.
Thu Feb 20 2020 at 06:32:27:667 pm MainActivity.onStart
Thu Feb 20 2020 at 06:32:37:320 pm Reconnected to : ssl://myserver:8887
Thu Feb 20 2020 at 06:32:37:390 pm Message: aaa/ : 10
Thu Feb 20 2020 at 06:32:37:442 pm Subscribed!
Thu Feb 20 2020 at 06:32:37:450 pm Message: aaa/ : 11
Thu Feb 20 2020 at 06:32:37:498 pm Message: aaa/ : 12
Thu Feb 20 2020 at 06:32:38:084 pm MainActivity.onStop
Thu Feb 20 2020 at 06:34:02:431 pm Message: aaa/ : 13