Publish::checkForValidPacketIdentifier() - Code Metrics - Inspection of "Don't use deprecated syntax" - unreal4u/mqtt - Measure and Improve Code Quality continuously with Scrutinizer

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Push — master ( 578a67...de03ca )

by Camilo

created 2020-09-22 09:37 UTC

Publish::checkForValidPacketIdentifier() A

↳ Parent: Publish

Complexity

Conditions	2
Paths	2

Size

Total Lines	8
Code Lines	4

Duplication

Lines	0
Ratio	0 %

Code Coverage

Tests	5
CRAP Score	2

Importance

Changes

Metric	Value
eloc	4
dl	0
loc	8
c	0
b	0
f	0
ccs	5
cts	5
cp	1
rs	10
cc	2
nc	2
nop	0
crap	2

<?php

declare(strict_types=1);

namespace unreal4u\MQTT\Protocol;

use InvalidArgumentException;
use OutOfBoundsException;
use OutOfRangeException;
use unreal4u\MQTT\Application\EmptyReadableResponse;
use unreal4u\MQTT\DataTypes\Message;
use unreal4u\MQTT\DataTypes\PacketIdentifier;
use unreal4u\MQTT\DataTypes\QoSLevel;
use unreal4u\MQTT\DataTypes\TopicName;
use unreal4u\MQTT\Exceptions\Connect\NoConnectionParametersDefined;
use unreal4u\MQTT\Exceptions\InvalidQoSLevel;
use unreal4u\MQTT\Exceptions\InvalidRequest;
use unreal4u\MQTT\Exceptions\InvalidResponseType;
use unreal4u\MQTT\Exceptions\MessageTooBig;
use unreal4u\MQTT\Exceptions\MissingTopicName;
use unreal4u\MQTT\Exceptions\NotConnected;
use unreal4u\MQTT\Internals\ClientInterface;
use unreal4u\MQTT\Internals\PacketIdentifierFunctionality;
use unreal4u\MQTT\Internals\ProtocolBase;
use unreal4u\MQTT\Internals\ReadableContent;
use unreal4u\MQTT\Internals\ReadableContentInterface;
use unreal4u\MQTT\Internals\WritableContent;
use unreal4u\MQTT\Internals\WritableContentInterface;
use unreal4u\MQTT\Utilities;

use function decbin;
use function ord;
use function sprintf;
use function strlen;
use function substr;

/**
 * A PUBLISH Control Packet is sent from a Client to a Server or vice-versa to transport an Application Message.
 *
 * @see http://docs.oasis-open.org/mqtt/mqtt/v3.1.1/os/mqtt-v3.1.1-os.html#_Toc398718037
 *
 * QoS lvl1:
 *   First packet: PUBLISH
 *   Second packet: PUBACK
 *
 * QoS lvl2:
 *   First packet: PUBLISH
 *   Second packet: PUBREC
 *   Third packet: PUBREL
 *   Fourth packet: PUBCOMP
 *
 * @see https://go.gliffy.com/go/publish/12498076
 */
final class Publish extends ProtocolBase implements ReadableContentInterface, WritableContentInterface
{
    use ReadableContent;
    use /** @noinspection TraitsPropertiesConflictsInspection */
        WritableContent;
    use PacketIdentifierFunctionality;

    private const CONTROL_PACKET_VALUE = 3;

    /**
     * Contains the message to be sent
     * @var Message
     */
    private $message;

    /**
     * Flag to check whether a message is a redelivery (DUP flag)
     * @see http://docs.oasis-open.org/mqtt/mqtt/v3.1.1/os/mqtt-v3.1.1-os.html#_Toc398718038
     * @var bool
     */
    public $isRedelivery = false;

    /**
     * @return string
     * @throws InvalidQoSLevel
     * @throws MissingTopicName
     * @throws OutOfRangeException
     * @throws InvalidArgumentException
     */
    public function createVariableHeader(): string
    {
        if ($this->message === null) {
            throw new InvalidArgumentException('You must at least provide a message object with a topic name');
        }

        $variableHeaderContents = $this->createUTF8String($this->message->getTopicName());
        // Reset the special flags should the same object be reused with another message
        $this->specialFlags = 0;

        $variableHeaderContents .= $this->createVariableHeaderFlags();

        return $variableHeaderContents;
    }

    /**
     * Sets some common flags and returns the variable header string should there be one
     *
     * @return string
     * @throws OutOfRangeException
     * @throws InvalidQoSLevel
     */
    private function createVariableHeaderFlags(): string
    {
        if ($this->isRedelivery) {
            // DUP flag: if the message is a re-delivery, mark it as such
            $this->specialFlags |= 8;
            $this->logger->debug('Activating redelivery bit');
        }

        if ($this->message->isRetained()) {
            // RETAIN flag: should the server retain the message?
            $this->specialFlags |= 1;
            $this->logger->debug('Activating retain flag');
        }

        // Check QoS level and perform the corresponding actions
        if ($this->message->getQoSLevel() !== 0) {
            // 0 for QoS lvl2 for QoS lvl1 and 4 for QoS lvl2
            $this->specialFlags |= ($this->message->getQoSLevel() * 2);
            $this->logger->debug(sprintf('Activating QoS level %d bit', $this->message->getQoSLevel()));
            return $this->getPacketIdentifierBinaryRepresentation();
        }

        return '';
    }

    /**
     * @return string
     * @throws MissingTopicName
     * @throws MessageTooBig
     * @throws InvalidArgumentException
     */
    public function createPayload(): string
    {
        if ($this->message === null) {
            throw new InvalidArgumentException('A message must be set before publishing');
        }
        return $this->message->getPayload();
    }

    /**
     * QoS level 0 does not have to wait for a answer, so return false. Any other QoS level returns true
     * @return bool
     * @throws InvalidQoSLevel
     */
    public function shouldExpectAnswer(): bool
    {
        $shouldExpectAnswer = !($this->message->getQoSLevel() === 0);
        $this->logger->debug('Checking whether we should expect an answer or not', [
            'shouldExpectAnswer' => $shouldExpectAnswer,
        ]);
        return $shouldExpectAnswer;
    }

    /**
     * @param string $brokerBitStream
     * @param ClientInterface $client
     * @return ReadableContentInterface
     * @throws InvalidResponseType
     */
    public function expectAnswer(string $brokerBitStream, ClientInterface $client): ReadableContentInterface
    {
        switch ($this->message->getQoSLevel()) {
            case 1:
                $pubAck = new PubAck($this->logger);
                $pubAck->instantiateObject($brokerBitStream, $client);
                return $pubAck;
            case 2:
                $pubRec = new PubRec($this->logger);
                $pubRec->instantiateObject($brokerBitStream, $client);
                return $pubRec;
            case 0:
            default:
                return new EmptyReadableResponse($this->logger);
        }
    }

    /**
     * Sets the to be sent message
     *
     * @param Message $message
     * @return WritableContentInterface
     */
    public function setMessage(Message $message): WritableContentInterface
    {
        $this->message = $message;
        return $this;
    }

    /**
     * Gets the set message
     *
     * @return Message
     */
    public function getMessage(): Message
    {
        return $this->message;
    }

    /**
     * Sets several bits and pieces from the first byte of the fixed header for the Publish packet
     *
     * @param int $firstByte
     * @param QoSLevel $qoSLevel
     * @return Publish
     * @throws InvalidQoSLevel
     */
    private function analyzeFirstByte(int $firstByte, QoSLevel $qoSLevel): Publish
    {
        $this->logger->debug('Analyzing first byte', [sprintf('%08d', decbin($firstByte))]);
        // Retained bit is bit 0 of first byte
        $this->message->setRetainFlag(false);
        if (($firstByte & 1) === 1) {
            $this->logger->debug('Setting retain flag to true');
            $this->message->setRetainFlag(true);
        }
        // QoS level is already been taken care of, assign it to the message at this point
        $this->message->setQoSLevel($qoSLevel);

        // Duplicate message must be checked only on QoS > 0, else set it to false
        $this->isRedelivery = false;
        if (($firstByte & 8) === 8 && $this->message->getQoSLevel() !== 0) {
            // Is a duplicate is always bit 3 of first byte
            $this->isRedelivery = true;
            $this->logger->debug('Setting redelivery bit');
        }

        return $this;
    }

    /**
     * Finds out the QoS level in a fixed header for the Publish object
     *
     * @param int $bitString
     * @return QoSLevel
     * @throws InvalidQoSLevel
     */
    private function determineIncomingQoSLevel(int $bitString): QoSLevel
    {
        // QoS lvl are in bit positions 1-2. Shifting is strictly speaking not needed, but increases human comprehension
        $shiftedBits = $bitString >> 1;
        $incomingQoSLevel = 0;
        if (($shiftedBits & 1) === 1) {
            $incomingQoSLevel = 1;
        }
        if (($shiftedBits & 2) === 2) {
            $incomingQoSLevel = 2;
        }

        $this->logger->debug('Setting QoS level', ['bitString' => $bitString, 'incomingQoSLevel' => $incomingQoSLevel]);
        return new QoSLevel($incomingQoSLevel);
    }

    /**
     * Gets the full message in case this object needs to
     *
     * @param string $rawMQTTHeaders
     * @param ClientInterface $client
     * @return string
     * @throws OutOfBoundsException
     * @throws InvalidArgumentException
     * @throws MessageTooBig
     * @throws InvalidQoSLevel
     */
    private function completePossibleIncompleteMessage(string $rawMQTTHeaders, ClientInterface $client): string
    {
        // Read at least one extra byte from the stream if we know that the message is too short
        if (strlen($rawMQTTHeaders) < 2) {
            $rawMQTTHeaders .= $client->readBrokerData(1);
        }

        $restOfBytes = $this->performRemainingLengthFieldOperations($rawMQTTHeaders, $client);

        /*
         * A complete message consists of:
         *  - The very first byte
         *  - The size of the remaining length field (from 1 to 4 bytes)
         *  - The $restOfBytes
         *
         * So we have to compare what we already have vs the above calculation
         *
         * More information:
         * http://docs.oasis-open.org/mqtt/mqtt/v3.1.1/errata01/os/mqtt-v3.1.1-errata01-os-complete.html#_Toc442180832
         */
        if (strlen($rawMQTTHeaders) < ($restOfBytes + $this->sizeOfRemainingLengthField + 1)) {
            // Read only the portion of data we have left from the socket
            $readableDataLeft = ($restOfBytes + $this->sizeOfRemainingLengthField + 1) - strlen($rawMQTTHeaders);
            $rawMQTTHeaders .= $client->readBrokerData($readableDataLeft);
        }

        return $rawMQTTHeaders;
    }

    /**
     * Will perform sanity checks and fill in the Readable object with data
     * @param string $rawMQTTHeaders
     * @param ClientInterface $client
     * @return ReadableContentInterface
     * @throws MessageTooBig
     * @throws OutOfBoundsException
     * @throws InvalidQoSLevel
     * @throws InvalidArgumentException
     * @throws OutOfRangeException
     */
    public function fillObject(string $rawMQTTHeaders, ClientInterface $client): ReadableContentInterface
    {
        // Retrieve full message first
        $fullMessage = $this->completePossibleIncompleteMessage($rawMQTTHeaders, $client);
        // Handy to maintain for debugging purposes
        #$this->logger->debug('Bin data', [\unreal4u\MQTT\DebugTools::convertToBinaryRepresentation($rawMQTTHeaders)]);

        // Handy to have: the first byte
        $firstByte = ord($fullMessage{0});
        // TopicName size is always on the second position after the size of the remaining length field (1 to 4 bytes)
        $topicSize = ord($fullMessage[$this->sizeOfRemainingLengthField + 2]);
        // With the first byte, we can determine the QoS level of the incoming message
        $qosLevel = $this->determineIncomingQoSLevel($firstByte);

        $messageStartPosition = $this->sizeOfRemainingLengthField + 3;
        // If we have a QoS level present, we must retrieve the packet identifier as well
        if ($qosLevel->getQoSLevel() > 0) {
            $this->logger->debug('QoS level above 0, shifting message start position and getting packet identifier');
            // [2 (fixed header) + 2 (topic size) + $topicSize] marks the beginning of the 2 packet identifier bytes
            $this->setPacketIdentifier(new PacketIdentifier(Utilities::convertBinaryStringToNumber(
                $fullMessage[$this->sizeOfRemainingLengthField + 3 + $topicSize] .
                $fullMessage[$this->sizeOfRemainingLengthField + 4 + $topicSize]
            )));
            $this->logger->debug('Determined packet identifier', ['PI' => $this->getPacketIdentifier()]);
            $messageStartPosition += 2;
        }

        // At this point $rawMQTTHeaders will be always 1 byte long, initialize a Message object with dummy data for now
        $this->message = new Message(
            // Save to assume a constant here: first 2 bytes will always be fixed header, next 2 bytes are topic size
            substr($fullMessage, $messageStartPosition + $topicSize),
            new TopicName(substr($fullMessage, $this->sizeOfRemainingLengthField + 3, $topicSize))
        );
        $this->analyzeFirstByte($firstByte, $qosLevel);

        $this->logger->debug('Determined headers', [
            'topicSize' => $topicSize,
            'QoSLevel' => $this->message->getQoSLevel(),
            'isDuplicate' => $this->isRedelivery,
            'isRetained' => $this->message->isRetained(),
            #'packetIdentifier' => $this->packetIdentifier->getPacketIdentifierValue(), // This is not always set!
        ]);

        return $this;
    }

    /**
     * @inheritdoc
     * @throws InvalidRequest
     * @throws InvalidQoSLevel
     * @throws NotConnected
     * @throws NoConnectionParametersDefined
     */
    public function performSpecialActions(ClientInterface $client, WritableContentInterface $originalRequest): bool
    {
        $qosLevel = $this->message->getQoSLevel();
        if ($qosLevel === 0) {
            $this->logger->debug('No response needed', ['qosLevel', $qosLevel]);
        } else {
            if ($qosLevel === 1) {
                $this->logger->debug('Responding with PubAck', ['qosLevel' => $qosLevel]);
                $client->processObject($this->composePubAckAnswer());
            } elseif ($qosLevel === 2) {
                $this->logger->debug('Responding with PubRec', ['qosLevel' => $qosLevel]);
                $client->processObject($this->composePubRecAnswer());
            }
        }

        return true;
    }

    /**
     * Composes a PubRec answer with the same packetIdentifier as what we received
     *
     * @return PubRec
     * @throws InvalidRequest
     */
    private function composePubRecAnswer(): PubRec
    {
        $this->checkForValidPacketIdentifier();
        $pubRec = new PubRec($this->logger);
        $pubRec->setPacketIdentifier($this->packetIdentifier);
        return $pubRec;
    }

    /**
     * Composes a PubAck answer with the same packetIdentifier as what we received
     *
     * @return PubAck
     * @throws InvalidRequest
     */
    private function composePubAckAnswer(): PubAck
    {
        $this->checkForValidPacketIdentifier();
        $pubAck = new PubAck($this->logger);
        $pubAck->setPacketIdentifier($this->packetIdentifier);
        return $pubAck;
    }

    /**
     * Will check whether the current object has a packet identifier set. If not, we are in serious problems!
     *
     * @return Publish
     * @throws InvalidRequest
     */
    private function checkForValidPacketIdentifier(): self
    {
        if ($this->packetIdentifier === null) {
            $this->logger->critical('No valid packet identifier found at a stage where there MUST be one set');
            throw new InvalidRequest('You are trying to send a request without a valid packet identifier');
        }

        return $this;
    }

    /**
     * PUBLISH packet is the exception to the rule: it is not started on base of a packet that gets sent by us
     */
    public function getOriginControlPacket(): int
    {
        return 0;
    }
}


1		<?php
2
3		declare(strict_types=1);
4
5		namespace unreal4u\MQTT\Protocol;
6
7		use InvalidArgumentException;
8		use OutOfBoundsException;
9		use OutOfRangeException;
10		use unreal4u\MQTT\Application\EmptyReadableResponse;
11		use unreal4u\MQTT\DataTypes\Message;
12		use unreal4u\MQTT\DataTypes\PacketIdentifier;
13		use unreal4u\MQTT\DataTypes\QoSLevel;
14		use unreal4u\MQTT\DataTypes\TopicName;
15		use unreal4u\MQTT\Exceptions\Connect\NoConnectionParametersDefined;
16		use unreal4u\MQTT\Exceptions\InvalidQoSLevel;
17		use unreal4u\MQTT\Exceptions\InvalidRequest;
18		use unreal4u\MQTT\Exceptions\InvalidResponseType;
19		use unreal4u\MQTT\Exceptions\MessageTooBig;
20		use unreal4u\MQTT\Exceptions\MissingTopicName;
21		use unreal4u\MQTT\Exceptions\NotConnected;
22		use unreal4u\MQTT\Internals\ClientInterface;
23		use unreal4u\MQTT\Internals\PacketIdentifierFunctionality;
24		use unreal4u\MQTT\Internals\ProtocolBase;
25		use unreal4u\MQTT\Internals\ReadableContent;
26		use unreal4u\MQTT\Internals\ReadableContentInterface;
27		use unreal4u\MQTT\Internals\WritableContent;
28		use unreal4u\MQTT\Internals\WritableContentInterface;
29		use unreal4u\MQTT\Utilities;
30
31		use function decbin;
32		use function ord;
33		use function sprintf;
34		use function strlen;
35		use function substr;
36
37		/**
38		* A PUBLISH Control Packet is sent from a Client to a Server or vice-versa to transport an Application Message.
39		*
40		* @see http://docs.oasis-open.org/mqtt/mqtt/v3.1.1/os/mqtt-v3.1.1-os.html#_Toc398718037
41		*
42		* QoS lvl1:
43		* First packet: PUBLISH
44		* Second packet: PUBACK
45		*
46		* QoS lvl2:
47		* First packet: PUBLISH
48		* Second packet: PUBREC
49		* Third packet: PUBREL
50		* Fourth packet: PUBCOMP
51		*
52		* @see https://go.gliffy.com/go/publish/12498076
53		*/
54		final class Publish extends ProtocolBase implements ReadableContentInterface, WritableContentInterface
55		{
56	1	use ReadableContent;
57		use /** @noinspection TraitsPropertiesConflictsInspection */
58	1	WritableContent;
59	1	use PacketIdentifierFunctionality;
60
61		private const CONTROL_PACKET_VALUE = 3;
62
63		/**
64		* Contains the message to be sent
65		* @var Message
66		*/
67		private $message;
68
69		/**
70		* Flag to check whether a message is a redelivery (DUP flag)
71		* @see http://docs.oasis-open.org/mqtt/mqtt/v3.1.1/os/mqtt-v3.1.1-os.html#_Toc398718038
72		* @var bool
73		*/
74		public $isRedelivery = false;
75
76		/**
77		* @return string
78		* @throws InvalidQoSLevel
79		* @throws MissingTopicName
80		* @throws OutOfRangeException
81		* @throws InvalidArgumentException
82		*/
83	5	public function createVariableHeader(): string
84		{
85	5	if ($this->message === null) {
86	1	throw new InvalidArgumentException('You must at least provide a message object with a topic name');
87		}
88
89	4	$variableHeaderContents = $this->createUTF8String($this->message->getTopicName());
90		// Reset the special flags should the same object be reused with another message
91	4	$this->specialFlags = 0;
92
93	4	$variableHeaderContents .= $this->createVariableHeaderFlags();
94
95	4	return $variableHeaderContents;
96		}
97
98		/**
99		* Sets some common flags and returns the variable header string should there be one
100		*
101		* @return string
102		* @throws OutOfRangeException
103		* @throws InvalidQoSLevel
104		*/
105	4	private function createVariableHeaderFlags(): string
106		{
107	4	if ($this->isRedelivery) {
108		// DUP flag: if the message is a re-delivery, mark it as such
109		$this->specialFlags \|= 8;
110		$this->logger->debug('Activating redelivery bit');
111		}
112
113	4	if ($this->message->isRetained()) {
114		// RETAIN flag: should the server retain the message?
115	1	$this->specialFlags \|= 1;
116	1	$this->logger->debug('Activating retain flag');
117		}
118
119		// Check QoS level and perform the corresponding actions
120	4	if ($this->message->getQoSLevel() !== 0) {
121		// 0 for QoS lvl2 for QoS lvl1 and 4 for QoS lvl2
122	3	$this->specialFlags \|= ($this->message->getQoSLevel() * 2);
123	3	$this->logger->debug(sprintf('Activating QoS level %d bit', $this->message->getQoSLevel()));
124	3	return $this->getPacketIdentifierBinaryRepresentation();
125		}
126
127	1	return '';
128		}
129
130		/**
131		* @return string
132		* @throws MissingTopicName
133		* @throws MessageTooBig
134		* @throws InvalidArgumentException
135		*/
136	2	public function createPayload(): string
137		{
138	2	if ($this->message === null) {
139	1	throw new InvalidArgumentException('A message must be set before publishing');
140		}
141	1	return $this->message->getPayload();
142		}
143
144		/**
145		* QoS level 0 does not have to wait for a answer, so return false. Any other QoS level returns true
146		* @return bool
147		* @throws InvalidQoSLevel
148		*/
149	2	public function shouldExpectAnswer(): bool
150		{
151	2	$shouldExpectAnswer = !($this->message->getQoSLevel() === 0);
152	2	$this->logger->debug('Checking whether we should expect an answer or not', [
153	2	'shouldExpectAnswer' => $shouldExpectAnswer,
154		]);
155	2	return $shouldExpectAnswer;
156		}
157
158		/**
159		* @param string $brokerBitStream
160		* @param ClientInterface $client
161		* @return ReadableContentInterface
162		* @throws InvalidResponseType
163		*/
164	3	public function expectAnswer(string $brokerBitStream, ClientInterface $client): ReadableContentInterface
165		{
166	3	switch ($this->message->getQoSLevel()) {
167	3	case 1:
168	1	$pubAck = new PubAck($this->logger);
169	1	$pubAck->instantiateObject($brokerBitStream, $client);
170	1	return $pubAck;
171	2	case 2:
172	1	$pubRec = new PubRec($this->logger);
173	1	$pubRec->instantiateObject($brokerBitStream, $client);
174	1	return $pubRec;
175	1	case 0:
176		default:
177	1	return new EmptyReadableResponse($this->logger);
178		}
179		}
180
181		/**
182		* Sets the to be sent message
183		*
184		* @param Message $message
185		* @return WritableContentInterface
186		*/
187	19	public function setMessage(Message $message): WritableContentInterface
188		{
189	19	$this->message = $message;
190	19	return $this;
191		}
192
193		/**
194		* Gets the set message
195		*
196		* @return Message
197		*/
198	15	public function getMessage(): Message
199		{
200	15	return $this->message;
201		}
202
203		/**
204		* Sets several bits and pieces from the first byte of the fixed header for the Publish packet
205		*
206		* @param int $firstByte
207		* @param QoSLevel $qoSLevel
208		* @return Publish
209		* @throws InvalidQoSLevel
210		*/
211	14	private function analyzeFirstByte(int $firstByte, QoSLevel $qoSLevel): Publish
212		{
213	14	$this->logger->debug('Analyzing first byte', [sprintf('%08d', decbin($firstByte))]);
214		// Retained bit is bit 0 of first byte
215	14	$this->message->setRetainFlag(false);
216	14	if (($firstByte & 1) === 1) {
217	4	$this->logger->debug('Setting retain flag to true');
218	4	$this->message->setRetainFlag(true);
219		}
220		// QoS level is already been taken care of, assign it to the message at this point
221	14	$this->message->setQoSLevel($qoSLevel);
222
223		// Duplicate message must be checked only on QoS > 0, else set it to false
224	14	$this->isRedelivery = false;
225	14	if (($firstByte & 8) === 8 && $this->message->getQoSLevel() !== 0) {
226		// Is a duplicate is always bit 3 of first byte
227	2	$this->isRedelivery = true;
228	2	$this->logger->debug('Setting redelivery bit');
229		}
230
231	14	return $this;
232		}
233
234		/**
235		* Finds out the QoS level in a fixed header for the Publish object
236		*
237		* @param int $bitString
238		* @return QoSLevel
239		* @throws InvalidQoSLevel
240		*/
241	11	private function determineIncomingQoSLevel(int $bitString): QoSLevel
242		{
243		// QoS lvl are in bit positions 1-2. Shifting is strictly speaking not needed, but increases human comprehension
244	11	$shiftedBits = $bitString >> 1;
245	11	$incomingQoSLevel = 0;
246	11	if (($shiftedBits & 1) === 1) {
247	4	$incomingQoSLevel = 1;
248		}
249	11	if (($shiftedBits & 2) === 2) {
250	2	$incomingQoSLevel = 2;
251		}
252
253	11	$this->logger->debug('Setting QoS level', ['bitString' => $bitString, 'incomingQoSLevel' => $incomingQoSLevel]);
254	11	return new QoSLevel($incomingQoSLevel);
255		}
256
257		/**
258		* Gets the full message in case this object needs to
259		*
260		* @param string $rawMQTTHeaders
261		* @param ClientInterface $client
262		* @return string
263		* @throws OutOfBoundsException
264		* @throws InvalidArgumentException
265		* @throws MessageTooBig
266		* @throws InvalidQoSLevel
267		*/
268	11	private function completePossibleIncompleteMessage(string $rawMQTTHeaders, ClientInterface $client): string
269		{
270		// Read at least one extra byte from the stream if we know that the message is too short
271	11	if (strlen($rawMQTTHeaders) < 2) {
272	3	$rawMQTTHeaders .= $client->readBrokerData(1);
273		}
274
275	11	$restOfBytes = $this->performRemainingLengthFieldOperations($rawMQTTHeaders, $client);
276
277		/*
278		* A complete message consists of:
279		* - The very first byte
280		* - The size of the remaining length field (from 1 to 4 bytes)
281		* - The $restOfBytes
282		*
283		* So we have to compare what we already have vs the above calculation
284		*
285		* More information:
286		* http://docs.oasis-open.org/mqtt/mqtt/v3.1.1/errata01/os/mqtt-v3.1.1-errata01-os-complete.html#_Toc442180832
287		*/
288	11	if (strlen($rawMQTTHeaders) < ($restOfBytes + $this->sizeOfRemainingLengthField + 1)) {
289		// Read only the portion of data we have left from the socket
290	6	$readableDataLeft = ($restOfBytes + $this->sizeOfRemainingLengthField + 1) - strlen($rawMQTTHeaders);
291	6	$rawMQTTHeaders .= $client->readBrokerData($readableDataLeft);
292		}
293
294	11	return $rawMQTTHeaders;
295		}
296
297		/**
298		* Will perform sanity checks and fill in the Readable object with data
299		* @param string $rawMQTTHeaders
300		* @param ClientInterface $client
301		* @return ReadableContentInterface
302		* @throws MessageTooBig
303		* @throws OutOfBoundsException
304		* @throws InvalidQoSLevel
305		* @throws InvalidArgumentException
306		* @throws OutOfRangeException
307		*/
308	7	public function fillObject(string $rawMQTTHeaders, ClientInterface $client): ReadableContentInterface
309		{
310		// Retrieve full message first
311	7	$fullMessage = $this->completePossibleIncompleteMessage($rawMQTTHeaders, $client);
312		// Handy to maintain for debugging purposes
313		#$this->logger->debug('Bin data', [\unreal4u\MQTT\DebugTools::convertToBinaryRepresentation($rawMQTTHeaders)]);
314
315		// Handy to have: the first byte
316	7	$firstByte = ord($fullMessage{0});
317		// TopicName size is always on the second position after the size of the remaining length field (1 to 4 bytes)
318	7	$topicSize = ord($fullMessage[$this->sizeOfRemainingLengthField + 2]);
319		// With the first byte, we can determine the QoS level of the incoming message
320	7	$qosLevel = $this->determineIncomingQoSLevel($firstByte);
321
322	7	$messageStartPosition = $this->sizeOfRemainingLengthField + 3;
323		// If we have a QoS level present, we must retrieve the packet identifier as well
324	7	if ($qosLevel->getQoSLevel() > 0) {
325	3	$this->logger->debug('QoS level above 0, shifting message start position and getting packet identifier');
326		// [2 (fixed header) + 2 (topic size) + $topicSize] marks the beginning of the 2 packet identifier bytes
327	3	$this->setPacketIdentifier(new PacketIdentifier(Utilities::convertBinaryStringToNumber(
328	3	$fullMessage[$this->sizeOfRemainingLengthField + 3 + $topicSize] .
329	3	$fullMessage[$this->sizeOfRemainingLengthField + 4 + $topicSize]
330		)));
331	3	$this->logger->debug('Determined packet identifier', ['PI' => $this->getPacketIdentifier()]);
332	3	$messageStartPosition += 2;
333		}
334
335		// At this point $rawMQTTHeaders will be always 1 byte long, initialize a Message object with dummy data for now
336	7	$this->message = new Message(
337		// Save to assume a constant here: first 2 bytes will always be fixed header, next 2 bytes are topic size
338	7	substr($fullMessage, $messageStartPosition + $topicSize),
339	7	new TopicName(substr($fullMessage, $this->sizeOfRemainingLengthField + 3, $topicSize))
340		);
341	7	$this->analyzeFirstByte($firstByte, $qosLevel);
342
343	7	$this->logger->debug('Determined headers', [
344	7	'topicSize' => $topicSize,
345	7	'QoSLevel' => $this->message->getQoSLevel(),
346	7	'isDuplicate' => $this->isRedelivery,
347	7	'isRetained' => $this->message->isRetained(),
348		#'packetIdentifier' => $this->packetIdentifier->getPacketIdentifierValue(), // This is not always set!
349		]);
350
351	7	return $this;
352		}
353
354		/**
355		* @inheritdoc
356		* @throws InvalidRequest
357		* @throws InvalidQoSLevel
358		* @throws NotConnected
359		* @throws NoConnectionParametersDefined
360		*/
361	5	public function performSpecialActions(ClientInterface $client, WritableContentInterface $originalRequest): bool
362		{
363	5	$qosLevel = $this->message->getQoSLevel();
364	5	if ($qosLevel === 0) {
365	3	$this->logger->debug('No response needed', ['qosLevel', $qosLevel]);
366		} else {
367	2	if ($qosLevel === 1) {
368	1	$this->logger->debug('Responding with PubAck', ['qosLevel' => $qosLevel]);
369	1	$client->processObject($this->composePubAckAnswer());
370	1	} elseif ($qosLevel === 2) {
371	1	$this->logger->debug('Responding with PubRec', ['qosLevel' => $qosLevel]);
372	1	$client->processObject($this->composePubRecAnswer());
373		}
374		}
375
376	5	return true;
377		}
378
379		/**
380		* Composes a PubRec answer with the same packetIdentifier as what we received
381		*
382		* @return PubRec
383		* @throws InvalidRequest
384		*/
385	2	private function composePubRecAnswer(): PubRec
386		{
387	2	$this->checkForValidPacketIdentifier();
388	2	$pubRec = new PubRec($this->logger);
389	2	$pubRec->setPacketIdentifier($this->packetIdentifier);
390	2	return $pubRec;
391		}
392
393		/**
394		* Composes a PubAck answer with the same packetIdentifier as what we received
395		*
396		* @return PubAck
397		* @throws InvalidRequest
398		*/
399	2	private function composePubAckAnswer(): PubAck
400		{
401	2	$this->checkForValidPacketIdentifier();
402	2	$pubAck = new PubAck($this->logger);
403	2	$pubAck->setPacketIdentifier($this->packetIdentifier);
404	2	return $pubAck;
405		}
406
407		/**
408		* Will check whether the current object has a packet identifier set. If not, we are in serious problems!
409		*
410		* @return Publish
411		* @throws InvalidRequest
412		*/
413	5	private function checkForValidPacketIdentifier(): self
414		{
415	5	if ($this->packetIdentifier === null) {
416	1	$this->logger->critical('No valid packet identifier found at a stage where there MUST be one set');
417	1	throw new InvalidRequest('You are trying to send a request without a valid packet identifier');
418		}
419
420	4	return $this;
421		}
422
423		/**
424		* PUBLISH packet is the exception to the rule: it is not started on base of a packet that gets sent by us
425		*/
426	1	public function getOriginControlPacket(): int
427		{
428	1	return 0;
429		}
430		}
431

unreal4u / mqtt

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Publish::checkForValidPacketIdentifier() A

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