/**
* A PUBLISH Control Packet is sent from a Client to a Server or from Server to a Client to
* transport an Application Message.
*
* @throws RetriableException
* @throws UnRetriableException
*/
@Override
public void handle(PublishMessage publishMessage)
throws RetriableException, UnRetriableException {
log.debug(" handle : client attempting to publish a message.");
/**
* During an attempt to publish a message.
*
* <p>All Topic Names and Topic Filters MUST be at least one character long [MQTT-4.7.3-1]
*
* <p>The wildcard characters can be used in Topic Filters, but MUST NOT be used within a Topic
* Name [MQTT-4.7.1-1].
*
* <p>Topic Names and Topic Filters MUST NOT include the null character (Unicode U+0000)
* [Unicode] [MQTT-4.7.3-2]
*
* <p>Topic Names and Topic Filters are UTF-8 encoded strings, they MUST NOT encode to more than
* 65535 bytes [MQTT-4.7.3-3]. See Section 1.5.3
*/
String topic = publishMessage.getTopic();
if (null == topic
|| topic.isEmpty()
|| topic.contains(Constant.MULTI_LEVEL_WILDCARD)
|| topic.contains(Constant.SINGLE_LEVEL_WILDCARD)
|| topic.contains(Constant.SYS_PREFIX)) {
log.info(" handle : Invalid topic " + publishMessage.getTopic());
throw new ShutdownException(" Invalid topic name");
}
/** Before publishing we should get the current session and validate it. */
Observable<IOTClient> permissionObservable =
checkPermission(
publishMessage.getSessionId(),
publishMessage.getAuthKey(),
AuthorityRole.PUBLISH,
topic);
permissionObservable.subscribe(
(iotSession) -> {
try {
publishMessage.setPartitionId(iotSession.getPartitionId());
publishMessage.setClientId(iotSession.getSessionId());
publishMessage.setId(-1);
/** Message processing is based on 4.3 Quality of Service levels and protocol flows */
/**
* 4.3.1 QoS 0: At most once delivery Accepts ownership of the message when it receives
* the PUBLISH packet.
*/
if (MqttQoS.AT_MOST_ONCE.value() == publishMessage.getQos()) {
getMessenger().publish(iotSession.getPartitionId(), publishMessage);
}
/**
* 4.3.2 QoS 1: At least once delivery
*
* <p>MUST respond with a PUBACK Packet containing the Packet Identifier from the
* incoming PUBLISH Packet, having accepted ownership of the Application Message After
* it has sent a PUBACK Packet the Receiver MUST treat any incoming PUBLISH packet that
* contains the same Packet Identifier as being a new publication, irrespective of the
* setting of its DUP flag.
*/
if (MqttQoS.AT_LEAST_ONCE.value() == publishMessage.getQos()) {
getMessenger().publish(iotSession.getPartitionId(), publishMessage);
// We need to generate a puback message to close this conversation.
AcknowledgeMessage acknowledgeMessage =
AcknowledgeMessage.from(publishMessage.getMessageId());
acknowledgeMessage.copyTransmissionData(publishMessage);
pushToServer(acknowledgeMessage);
}
/**
* 4.3.3 QoS 2: Exactly once delivery
*
* <p>MUST respond with a PUBREC containing the Packet Identifier from the incoming
* PUBLISH Packet, having accepted ownership of the Application Message. Until it has
* received the corresponding PUBREL packet, the Receiver MUST acknowledge any
* subsequent PUBLISH packet with the same Packet Identifier by sending a PUBREC. It
* MUST NOT cause duplicate messages to be delivered to any onward recipients in this
* case.
*/
if (MqttQoS.EXACTLY_ONCE.value() == publishMessage.getQos()) {
queueQos2Message(publishMessage);
}
} catch (UnRetriableException | RetriableException e) {
disconnectDueToError(e, publishMessage);
}
},
throwable -> disconnectDueToError(throwable, publishMessage));
}
