AsyncClient::subscribeOnChannel() - Code Metrics - Inspection of "Improvement handle disconnects and reconnect when..." - php-api-clients/pusher - Measure and Improve Code Quality continuously with Scrutinizer

Completed

Pull Request — master (#3)

by Cees-Jan

created 2017-05-22 20:29 UTC

AsyncClient::subscribeOnChannel() A

↳ Parent: AsyncClient

Complexity

Conditions	1
Paths	1

Size

Total Lines	4
Code Lines	2

Duplication

Lines	0
Ratio	0 %

Code Coverage

Tests	3
CRAP Score	1

Importance

Changes

Metric	Value
dl	0
loc	4
ccs	3
cts	3
cp	1
rs	10
c	0
b	0
f	0
cc	1
eloc	2
nc	1
nop	1
crap	1

<?php declare(strict_types=1);

namespace ApiClients\Client\Pusher;

use React\Dns\Resolver\Resolver;
use React\EventLoop\LoopInterface;
use RuntimeException;
use Rx\Disposable\CallbackDisposable;
use Rx\Observable;
use Rx\ObserverInterface;
use Rx\Scheduler;
use Rx\Websocket\Client as WebsocketClient;
use Rx\Websocket\MessageSubject;
use Rx\Websocket\WebsocketErrorException;
use Throwable;
use function React\Promise\reject;
use function React\Promise\resolve;

final class AsyncClient
{
    const DEFAULT_DELAY = 200;
    const NO_ACTIVITY_TIMEOUT = 120;
    const NO_PING_RESPONSE_TIMEOUT = 30;

    protected $noActivityTimeout = self::NO_ACTIVITY_TIMEOUT;

    /**
     * @var Observable\RefCountObservable
     */
    protected $client;

    /**
     * @var Observable\AnonymousObservable
     */
    protected $messages;

    /**
     * @var MessageSubject
     */
    protected $sendSubject;

    /**
     * @var array
     */
    protected $channels = [];

    /**
     * @var int
     */
    protected $delay = self::DEFAULT_DELAY;

    /**
     * @internal
     */
    public function __construct(Observable $client)
    {
        $this->messages = $client
            // Save this subject for sending stuff
            ->do(function (MessageSubject $ms) {
                $this->sendSubject = $ms;

                // Resubscribe to an channels we where subscribed to when disconnected
                foreach ($this->channels as $channel => $_) {
                    $this->subscribeOnChannel($channel);
                }
            })

            // Make sure if there is a disconnect or something
            // that we unset the sendSubject
            ->finally(function () {
                $this->sendSubject = null;
            })

            ->flatMap(function (MessageSubject $ms) {
                return $ms;
            })

            // This is the ping/timeout functionality
            ->flatMapLatest(function ($x) {
                // this Observable emits the current value immediately
                // if another value comes along, this all gets disposed (because we are using flatMapLatest)
                // before the timeouts start get triggered
                return Observable::never()
                    ->timeout($this->noActivityTimeout * 1000)
                    ->catch(function () use ($x) {
                        // ping (do something that causes incoming stream to get a message)
                        $this->send(['event' => 'pusher:ping']);
                        // this timeout will actually timeout with a TimeoutException - causing
                        //   everything above this to dispose
                        return Observable::never()->timeout(self::NO_PING_RESPONSE_TIMEOUT * 1000);
                    })
                    ->startWith($x);
            })

            // Decode JSON
            ->_ApiClients_jsonDecode()

            // Deal with connection established messages
            ->flatMap(function (array $message) {
                $this->delay = self::DEFAULT_DELAY;

                $event = Event::createFromMessage($message);

                if ($event->getEvent() === 'pusher:error') {
                    return Observable::fromPromise(reject(new PusherErrorException($event->getData()['message'], $event->getData()['code'])));
                }

                if ($event->getEvent() === 'pusher:connection_established') {
                    $this->setActivityTimeout($event);
                }

                return Observable::fromPromise(resolve($event));
            })

            // Handle connection level errors
            ->retryWhen(function (Observable $errors) {
                return $errors->flatMap(function (Throwable $throwable) {
                    return $this->handleLowLevelError($throwable);
                });
            })

        // Share client
        ->share();
    }

    /**
     * @param  LoopInterface $loop
     * @param  string        $app      Application ID
     * @param  Resolver      $resolver Optional DNS resolver
     * @return AsyncClient
     */
    public static function create(LoopInterface $loop, string $app, Resolver $resolver = null): AsyncClient
    {
        try {
            Scheduler::setAsyncFactory(function () use ($loop) {
                return new Scheduler\EventLoopScheduler($loop);
function acceptsInteger($int) { }

$x = '123'; // string "123"

// Instead of
acceptsInteger($x);

// we recommend to use
acceptsInteger((integer) $x);
            });
        } catch (Throwable $t) {

        }

        return new self(
            new WebsocketClient(
                ApiSettings::createUrl($app),
                false,
                [],
                $loop,
                $resolver
            )
        );
    }

    /**
     * Listen on a channel.
     *
     * @param  string     $channel Channel to listen on
     * @return Observable
     */
    public function channel(string $channel): Observable
    {
        if (isset($this->channels[$channel])) {
            return $this->channels[$channel];
        }

        // Ensure we only get messages for the given channel
        $channelMessages = $this->messages->filter(function (Event $event) use ($channel) {
            return $event->getChannel() !== '' && $event->getChannel() === $channel;
        });

        $events = Observable::create(function (
            ObserverInterface $observer
        ) use (
            $channel,
            $channelMessages
        ) {
            $subscription = $channelMessages
                ->filter(function (Event $event) {
                    return $event->getEvent() !== 'pusher_internal:subscription_succeeded';
                })
                ->subscribe($observer);
function acceptsInteger($int) { }

$x = '123'; // string "123"

// Instead of
acceptsInteger($x);

// we recommend to use
acceptsInteger((integer) $x);

            $this->subscribeOnChannel($channel);

            return new CallbackDisposable(function () use ($channel, $subscription) {
                // Send unsubscribe event
                $this->send(['event' => 'pusher:unsubscribe', 'data' => ['channel' => $channel]]);
                // Dispose our own subscription to messages
                $subscription->dispose();
                // Remove our channel from the channel list so we don't resubscribe in case we reconnect
                unset($this->channels[$channel]);
            });
        });

        // Share stream amount subscribers to this channel
        $this->channels[$channel] = $events->share();

        return $this->channels[$channel];
    }

    /**
     * Send a message through the client.
     *
     * @param array $message Message to send, will be json encoded
     *
     * @return A bool indicating whether or not the connection was active
     *           and the given message has been pass onto the connection.
     */
    public function send(array $message): bool
    {
        // Don't send messages when we aren't connected
        if ($this->sendSubject ===  null) {
            return false;
        }

        $this->sendSubject->onNext(json_encode($message));

        return true;
    }

    /**
     *  Handle errors as described at https://pusher.com/docs/pusher_protocol#error-codes.
     */
    private function handleLowLevelError(Throwable $throwable)
    {
        if (!($throwable instanceof WebsocketErrorException) && !($throwable instanceof RuntimeException) && !($throwable instanceof PusherErrorException)) {
            return Observable::fromPromise(reject($throwable));
        }

        $code = $throwable->getCode();
        $pusherError = ($throwable instanceof WebsocketErrorException || $throwable instanceof PusherErrorException);

        // Errors 4000-4099, don't retry connecting
        if ($pusherError && $code >= 4000 && $code <= 4099) {
            return Observable::fromPromise(reject($throwable));
        }

        // Errors 4100-4199 reconnect after 1 or more seconds, we do it after 1.001 second
        if ($pusherError && $code >= 4100 && $code <= 4199) {
            return Observable::timer(1001);
        }

        // Errors 4200-4299 connection closed by Pusher, reconnect immediately, we wait 0.001 second
        if ($pusherError && $code >= 4200 && $code <= 4299) {
            return Observable::timer(1);
        }

        $this->delay *= 2;

        return Observable::timer($this->delay);
    }

    /**
     * @param string $channel
     */
    private function subscribeOnChannel(string $channel)
    {
        $this->send(['event' => 'pusher:subscribe', 'data' => ['channel' => $channel]]);
    }

    /**
     * Get connection activity timeout from connection established event.
     *
     * @param Event $event
     */
    private function setActivityTimeout(Event $event)
    {
        $data = $event->getData();

        // No activity_timeout found on event
        if (!isset($data['activity_timeout'])) {
            return;
        }

        // activity_timeout holds zero or invalid value (we don't want to hammer Pusher)
        if ((int)$data['activity_timeout'] <= 0) {
            return;
        }

        $this->noActivityTimeout = (int)$data['activity_timeout'];
    }
}


1		<?php declare(strict_types=1);
2
3		namespace ApiClients\Client\Pusher;
4
5		use React\Dns\Resolver\Resolver;
6		use React\EventLoop\LoopInterface;
7		use RuntimeException;
8		use Rx\Disposable\CallbackDisposable;
9		use Rx\Observable;
10		use Rx\ObserverInterface;
11		use Rx\Scheduler;
12		use Rx\Websocket\Client as WebsocketClient;
13		use Rx\Websocket\MessageSubject;
14		use Rx\Websocket\WebsocketErrorException;
15		use Throwable;
16		use function React\Promise\reject;
17		use function React\Promise\resolve;
18
19		final class AsyncClient
20		{
21		const DEFAULT_DELAY = 200;
22		const NO_ACTIVITY_TIMEOUT = 120;
23		const NO_PING_RESPONSE_TIMEOUT = 30;
24
25		protected $noActivityTimeout = self::NO_ACTIVITY_TIMEOUT;
26
27		/**
28		* @var Observable\RefCountObservable
29		*/
30		protected $client;
31
32		/**
33		* @var Observable\AnonymousObservable
34		*/
35		protected $messages;
36
37		/**
38		* @var MessageSubject
39		*/
40		protected $sendSubject;
41
42		/**
43		* @var array
44		*/
45		protected $channels = [];
46
47		/**
48		* @var int
49		*/
50		protected $delay = self::DEFAULT_DELAY;
51
52		/**
53		* @internal
54		*/
55	5	public function __construct(Observable $client)
56		{
57	5	$this->messages = $client
58		// Save this subject for sending stuff
59		->do(function (MessageSubject $ms) {
60		$this->sendSubject = $ms;
61
62		// Resubscribe to an channels we where subscribed to when disconnected
63		foreach ($this->channels as $channel => $_) {
64		$this->subscribeOnChannel($channel);
65		}
66	5	})
67
68		// Make sure if there is a disconnect or something
69		// that we unset the sendSubject
70		->finally(function () {
71	2	$this->sendSubject = null;
72	5	})
73
74		->flatMap(function (MessageSubject $ms) {
75		return $ms;
76	5	})
77
78		// This is the ping/timeout functionality
79		->flatMapLatest(function ($x) {
80		// this Observable emits the current value immediately
81		// if another value comes along, this all gets disposed (because we are using flatMapLatest)
82		// before the timeouts start get triggered
83		return Observable::never()
84		->timeout($this->noActivityTimeout * 1000)
85		->catch(function () use ($x) {
86		// ping (do something that causes incoming stream to get a message)
87		$this->send(['event' => 'pusher:ping']);
88		// this timeout will actually timeout with a TimeoutException - causing
89		// everything above this to dispose
90		return Observable::never()->timeout(self::NO_PING_RESPONSE_TIMEOUT * 1000);
91		})
92		->startWith($x);
93	5	})
94
95		// Decode JSON
96	5	->_ApiClients_jsonDecode()
97
98		// Deal with connection established messages
99		->flatMap(function (array $message) {
100		$this->delay = self::DEFAULT_DELAY;
101
102		$event = Event::createFromMessage($message);
103
104		if ($event->getEvent() === 'pusher:error') {
105		return Observable::fromPromise(reject(new PusherErrorException($event->getData()['message'], $event->getData()['code'])));
106		}
107
108		if ($event->getEvent() === 'pusher:connection_established') {
109		$this->setActivityTimeout($event);
110		}
111
112		return Observable::fromPromise(resolve($event));
113	5	})
114
115		// Handle connection level errors
116		->retryWhen(function (Observable $errors) {
117		return $errors->flatMap(function (Throwable $throwable) {
118	2	return $this->handleLowLevelError($throwable);
119	2	});
120	5	})
121
122		// Share client
123	5	->share();
124	5	}
125
126		/**
127		* @param LoopInterface $loop
128		* @param string $app Application ID
129		* @param Resolver $resolver Optional DNS resolver
130		* @return AsyncClient
131		*/
132	4	public static function create(LoopInterface $loop, string $app, Resolver $resolver = null): AsyncClient
133		{
134		try {
135		Scheduler::setAsyncFactory(function () use ($loop) {
136	1	return new Scheduler\EventLoopScheduler($loop);
		0 ignored issues – show Documentation introduced 2017-04-05 19:21 UTC by Report Bug Copy Issue Report `$loop` is of type `object<React\EventLoop\LoopInterface>`, but the function expects a `callable`. It seems like the type of the argument is not accepted by the function/method which you are calling. In some cases, in particular if PHP’s automatic type-juggling kicks in this might be fine. In other cases, however this might be a bug. We suggest to add an explicit type cast like in the following example: function acceptsInteger($int) { } $x = '123'; // string "123" // Instead of acceptsInteger($x); // we recommend to use acceptsInteger((integer) $x); Loading history...
137	4	});
138	3	} catch (Throwable $t) {
		0 ignored issues – show Coding Style Comprehensibility introduced 2017-04-05 19:21 UTC by Report Bug Copy Issue Report Consider adding a comment why this CATCH block is empty. Loading history...
139		}
140
141	4	return new self(
142	4	new WebsocketClient(
143	4	ApiSettings::createUrl($app),
144	4	false,
145	4	[],
146		$loop,
147	4	$resolver
148		)
149		);
150		}
151
152		/**
153		* Listen on a channel.
154		*
155		* @param string $channel Channel to listen on
156		* @return Observable
157		*/
158	2	public function channel(string $channel): Observable
159		{
160	2	if (isset($this->channels[$channel])) {
161		return $this->channels[$channel];
162		}
163
164		// Ensure we only get messages for the given channel
165		$channelMessages = $this->messages->filter(function (Event $event) use ($channel) {
166		return $event->getChannel() !== '' && $event->getChannel() === $channel;
167	2	});
168
169		$events = Observable::create(function (
170		ObserverInterface $observer
171		) use (
172	2	$channel,
173	2	$channelMessages
174		) {
175		$subscription = $channelMessages
176		->filter(function (Event $event) {
177		return $event->getEvent() !== 'pusher_internal:subscription_succeeded';
178	2	})
179	2	->subscribe($observer);
		0 ignored issues – show Documentation introduced 2017-04-05 19:21 UTC by Report Bug Copy Issue Report `$observer` is of type `object<Rx\ObserverInterface>`, but the function expects a `callable\|null`. It seems like the type of the argument is not accepted by the function/method which you are calling. In some cases, in particular if PHP’s automatic type-juggling kicks in this might be fine. In other cases, however this might be a bug. We suggest to add an explicit type cast like in the following example: function acceptsInteger($int) { } $x = '123'; // string "123" // Instead of acceptsInteger($x); // we recommend to use acceptsInteger((integer) $x); Loading history...
180
181	2	$this->subscribeOnChannel($channel);
182
183	2	return new CallbackDisposable(function () use ($channel, $subscription) {
184		// Send unsubscribe event
185		$this->send(['event' => 'pusher:unsubscribe', 'data' => ['channel' => $channel]]);
186		// Dispose our own subscription to messages
187		$subscription->dispose();
188		// Remove our channel from the channel list so we don't resubscribe in case we reconnect
189		unset($this->channels[$channel]);
190	2	});
191	2	});
192
193		// Share stream amount subscribers to this channel
194	2	$this->channels[$channel] = $events->share();
195
196	2	return $this->channels[$channel];
197		}
198
199		/**
200		* Send a message through the client.
201		*
202		* @param array $message Message to send, will be json encoded
203		*
204		* @return A bool indicating whether or not the connection was active
205		* and the given message has been pass onto the connection.
206		*/
207	2	public function send(array $message): bool
208		{
209		// Don't send messages when we aren't connected
210	2	if ($this->sendSubject === null) {
211	2	return false;
212		}
213
214		$this->sendSubject->onNext(json_encode($message));
215
216		return true;
217		}
218
219		/**
220		* Handle errors as described at https://pusher.com/docs/pusher_protocol#error-codes.
221		*/
222	2	private function handleLowLevelError(Throwable $throwable)
223		{
224	2	if (!($throwable instanceof WebsocketErrorException) && !($throwable instanceof RuntimeException) && !($throwable instanceof PusherErrorException)) {
225		return Observable::fromPromise(reject($throwable));
226		}
227
228	2	$code = $throwable->getCode();
229	2	$pusherError = ($throwable instanceof WebsocketErrorException \|\| $throwable instanceof PusherErrorException);
230
231		// Errors 4000-4099, don't retry connecting
232	2	if ($pusherError && $code >= 4000 && $code <= 4099) {
233		return Observable::fromPromise(reject($throwable));
234		}
235
236		// Errors 4100-4199 reconnect after 1 or more seconds, we do it after 1.001 second
237	2	if ($pusherError && $code >= 4100 && $code <= 4199) {
238		return Observable::timer(1001);
239		}
240
241		// Errors 4200-4299 connection closed by Pusher, reconnect immediately, we wait 0.001 second
242	2	if ($pusherError && $code >= 4200 && $code <= 4299) {
243		return Observable::timer(1);
244		}
245
246	2	$this->delay *= 2;
247
248	2	return Observable::timer($this->delay);
249		}
250
251		/**
252		* @param string $channel
253		*/
254	2	private function subscribeOnChannel(string $channel)
255		{
256	2	$this->send(['event' => 'pusher:subscribe', 'data' => ['channel' => $channel]]);
257	2	}
258
259		/**
260		* Get connection activity timeout from connection established event.
261		*
262		* @param Event $event
263		*/
264		private function setActivityTimeout(Event $event)
265		{
266		$data = $event->getData();
267
268		// No activity_timeout found on event
269		if (!isset($data['activity_timeout'])) {
270		return;
271		}
272
273		// activity_timeout holds zero or invalid value (we don't want to hammer Pusher)
274		if ((int)$data['activity_timeout'] <= 0) {
275		return;
276		}
277
278		$this->noActivityTimeout = (int)$data['activity_timeout'];
279		}
280		}
281

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Pull Request — master (#3)

AsyncClient::subscribeOnChannel() A

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