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<?php |
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declare(strict_types=1); |
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namespace unreal4u\MQTT\Protocol; |
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use unreal4u\MQTT\Application\EmptyReadableResponse; |
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use unreal4u\MQTT\Application\PayloadInterface; |
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use unreal4u\MQTT\Client; |
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use unreal4u\MQTT\Internals\ProtocolBase; |
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use unreal4u\MQTT\Internals\ReadableContentInterface; |
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use unreal4u\MQTT\Internals\WritableContent; |
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use unreal4u\MQTT\Internals\WritableContentInterface; |
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use unreal4u\MQTT\Protocol\Subscribe\Topic; |
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final class Subscribe extends ProtocolBase implements WritableContentInterface |
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{ |
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use WritableContent; |
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const CONTROL_PACKET_VALUE = 8; |
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public $packetIdentifier = 0; |
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/** |
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* An array of topics on which to subscribe to |
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* @var Topic[] |
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*/ |
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private $topics = []; |
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public function createVariableHeader(): string |
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{ |
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// Subscribe must always send a 2 flag |
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$this->specialFlags = 2; |
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return \chr(0) . \chr($this->packetIdentifier); |
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} |
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public function createPayload(): string |
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{ |
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$output = ''; |
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foreach ($this->topics as $topic) { |
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// chr on QoS level is safe because it will create an 8-bit flag where the first 6 are only 0's |
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$output .= $this->createUTF8String($topic->getTopicName()) . \chr($topic->getTopicQoSLevel()); |
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} |
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return $output; |
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} |
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/** |
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* QoS level 0 does not have to wait for a answer, so return false. Any other QoS level returns true |
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* @return bool |
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*/ |
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public function shouldExpectAnswer(): bool |
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{ |
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return true; |
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} |
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public function expectAnswer(string $data): ReadableContentInterface |
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{ |
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$this->logger->info('String of incoming data confirmed, returning new object', ['class' => \get_class($this)]); |
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$subAck = new SubAck($this->logger); |
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$subAck->populate($data); |
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return $subAck; |
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} |
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/** |
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* Performs a check on the socket connection and returns either the contents or an empty object |
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* |
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* @param Client $client |
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* @param PayloadInterface $payloadType |
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* @return ReadableContentInterface |
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* @throws \unreal4u\MQTT\Exceptions\NotConnected |
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* @throws \unreal4u\MQTT\Exceptions\Connect\NoConnectionParametersDefined |
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* @throws \unreal4u\MQTT\Exceptions\ServerClosedConnection |
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*/ |
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public function checkForEvent(Client $client, PayloadInterface $payloadType): ReadableContentInterface |
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{ |
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$this->updateCommunication($client); |
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$publishPacketControlField = $client->readSocketData(1); |
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if ((\ord($publishPacketControlField) & 0xf0) > 0) { |
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$restOfBytes = $client->readSocketData(1); |
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$payload = $client->readSocketData(\ord($restOfBytes)); |
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$publish = new Publish($this->logger); |
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$publish->setPayloadType($payloadType); |
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$publish->populate($publishPacketControlField . $restOfBytes . $payload); |
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return $publish; |
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} |
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$this->logger->debug('No valid publish packet control field found, returning empty response'); |
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return new EmptyReadableResponse($this->logger); |
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} |
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/** |
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* Performs a simple loop and yields results back whenever they are available |
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* |
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* @param Client $client |
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* @param PayloadInterface $payloadObject |
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* @param int $idleMicroseconds |
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* @return \Generator |
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* @throws \unreal4u\MQTT\Exceptions\NotConnected |
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* @throws \unreal4u\MQTT\Exceptions\Connect\NoConnectionParametersDefined |
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* @throws \unreal4u\MQTT\Exceptions\ServerClosedConnection |
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*/ |
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public function loop(Client $client, PayloadInterface $payloadObject, int $idleMicroseconds = 100000): \Generator |
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{ |
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// First of all: subscribe |
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$client->sendData($this); |
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// After we are successfully subscribed, start to listen for events |
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while (true) { |
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$readableContent = $this->checkForEvent($client, $payloadObject); |
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// Only if we receive a Publish event from the broker, yield the contents |
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if ($readableContent instanceof Publish) { |
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yield $readableContent->getMessage(); |
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} else { |
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// Only wait for a certain amount of time if there was nothing in the queue |
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usleep($idleMicroseconds); |
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} |
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} |
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} |
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/** |
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* A subscription is based on filters, this function allows us to pass on filters |
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* |
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* @param Topic[] $topics |
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* @return Subscribe |
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*/ |
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public function addTopics(Topic ...$topics): Subscribe |
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{ |
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$this->topics = $topics; |
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return $this; |
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} |
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/** |
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* @param Client $client |
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* @return bool |
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* @throws \unreal4u\MQTT\Exceptions\NotConnected |
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* @throws \unreal4u\MQTT\Exceptions\Connect\NoConnectionParametersDefined |
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* @throws \unreal4u\MQTT\Exceptions\ServerClosedConnection |
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*/ |
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private function updateCommunication(Client $client): bool |
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{ |
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$this->logger->debug('Checking ping'); |
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if ($client->needsCommunication()) { |
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$this->logger->notice('Sending ping'); |
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$client->setBlocking(true); |
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$client->sendData(new PingReq($this->logger)); |
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$client->setBlocking(false); |
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} |
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return true; |
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} |
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} |
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