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Hi all! I am using MQTT connector to implement Subscribe/unsubscribe in my Mendix app with AWSIoTCore as Broker. I am using the following module. https://marketplace.mendix.com/link/component/2868 However, I am not able to get the data during the time when the connection is disconnected when I resume the subscribe. (For example, when I deploy and restart, or when I simply unsubscribe and then subscribe again. I can get the data from the point of resumption. I checked with Publisher, and they said that QoS is set to 1. My understanding is that when QoS is set to 1, if the subscriber has not received the data, when the connection is reconnected, it will receive the data from when the connection was disconnected. However, the above result means that this is not possible. I checked the java source for the [SubscribeToTopic] JavaAction, and checked the library [MqttClient] that is being used, and it seems that QoS is set to 1. I believe that the QoS setting on the Client side is also set to 1. /* */ public void subscribe(String topicFilter) throws MqttException { /* 297 */ this.subscribe(new String[]{topicFilter}, new int[]{1}); /* 298 */ } /* */ /* */ /* */ /* */ /* */ public void subscribe(String[] topicFilters) throws MqttException { /* 304 */ int[] qos = new int[topicFilters.length]; /* 305 */ for(int i = 0; i < qos.length; ++i) { /* 306 */ qos[i] = 1; /* */ } /* 308 */ this.subscribe(topicFilters, qos); /* 309 */ } /* */ /* */ /* */ /* */ /* */ public void subscribe(String topicFilter, int qos) throws MqttException { /* 315 */ this.subscribe(new String[]{topicFilter}, new int[]{qos}); /* 316 */ } /* */ /* */ /* */ /* */ /* */ public void subscribe(String[] topicFilters, int[] qos) throws MqttException { /* 322 */ IMqttToken tok = this.aClient.subscribe(topicFilters, qos, (Object)null, (IMqttActionListener)null); /* 323 */ tok.waitForCompletion(this.getTimeToWait()); /* 324 */ int[] grantedQos = tok.getGrantedQos(); /* 325 */ for(int i = 0; i < grantedQos.length; ++i) { /* 326 */ qos[i] = grantedQos[i]; /* */ } /* 328 */ if (grantedQos.length == 1 && qos[0] == 128) { /* 329 */ throw new MqttException(128); /* */ } /* 331 */ }   Is there something wrong with my usage? What else do I need to configure?   I use Mendix Studio Version:8.18.1. However, I can’t choose this version from list of this form. Thank you in advance:)  

asked 2021-02-26

0 answers