Duplicate code is one of the most pungent code smells. A rule that is often used is to re-structure code once it is duplicated in three or more places.
Common duplication problems, and corresponding solutions are:
| 1 | <?php declare(strict_types=1); |
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| 24 | private string $key; |
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| 25 | |||
| 26 | private SubscriptionMap $subscriptions; |
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| 27 | |||
| 28 | private Closure $guard; |
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| 29 | |||
| 30 | private MetadataEnricherList $metadataEnrichers; |
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| 31 | |||
| 32 | 9 | public function __construct( |
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| 33 | string $key, |
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| 34 | SubscriptionMap $subscriptions, |
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| 35 | Closure $guard = null, |
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| 36 | MetadataEnricherList $metadataEnrichers = null |
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| 37 | ) { |
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| 38 | 9 | $this->key = $key; |
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| 39 | 9 | $this->subscriptions = $subscriptions; |
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| 40 | 9 | $this->guard = $guard ?? fn(): bool => true; |
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| 41 | 9 | $metadataEnrichers = $metadataEnrichers ?? new MetadataEnricherList; |
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| 42 | 9 | $this->metadataEnrichers = $metadataEnrichers->prependEnricher(self::METADATA_KEY, $this->key); |
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| 43 | 9 | } |
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| 44 | |||
| 45 | 3 | public function publish(EnvelopeInterface $envelope, MessageBusInterface $messageBus): void |
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| 46 | { |
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| 47 | 3 | $envelope = $this->enrichMetadata($envelope); |
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| 48 | 3 | if ($this->accepts($envelope)) { |
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| 49 | 2 | foreach ($this->subscriptions as $subscription) { |
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| 50 | 2 | $subscription->publish($envelope, $messageBus); |
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| 51 | } |
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| 52 | } |
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| 53 | 3 | } |
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| 54 | |||
| 55 | 5 | public function receive(EnvelopeInterface $envelope): void |
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| 56 | { |
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| 57 | 5 | $this->verify($envelope); |
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| 58 | 2 | $subscriptionKey = (string)$envelope->getMetadata()->get(SubscriptionInterface::METADATA_KEY); |
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| 59 | 2 | if (!$this->subscriptions->has($subscriptionKey)) { |
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| 60 | 1 | throw new SubscriptionUnknown( |
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| 61 | 1 | "Channel '{$this->key}' has no subscription '$subscriptionKey' and thus ". |
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| 62 | 1 | "Envelope '{$envelope->getUuid()->toString()}' cannot be handled." |
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| 63 | ); |
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| 64 | } |
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| 65 | /** @var SubscriptionInterface $subscription */ |
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| 66 | 1 | $subscription = $this->subscriptions->get($subscriptionKey); |
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| 67 | 1 | $subscription->receive($envelope); |
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| 68 | 1 | } |
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| 69 | |||
| 70 | 1 | public function getKey(): string |
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| 71 | { |
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| 72 | 1 | return $this->key; |
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| 73 | } |
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| 74 | |||
| 75 | 3 | private function enrichMetadata(EnvelopeInterface $envelope): EnvelopeInterface |
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| 76 | { |
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| 77 | 3 | return $envelope->withMetadata(array_reduce( |
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| 78 | 3 | $this->metadataEnrichers->unwrap(), |
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| 79 | function (MetadataInterface $metadata, MetadataEnricherInterface $metadataEnricher): MetadataInterface { |
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| 80 | 3 | return $metadataEnricher->enrich($metadata); |
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| 81 | 3 | }, |
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| 82 | 3 | $envelope->getMetadata() |
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| 83 | )); |
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| 84 | } |
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| 85 | |||
| 86 | 3 | private function accepts(EnvelopeInterface $envelope): bool |
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| 87 | { |
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| 88 | 3 | return (bool)call_user_func($this->guard, $envelope); |
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| 89 | } |
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| 90 | |||
| 91 | 5 | private function verify(EnvelopeInterface $envelope): void |
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| 92 | { |
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| 93 | 5 | $metadata = $envelope->getMetadata(); |
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| 94 | 5 | if (!$metadata->has(self::METADATA_KEY)) { |
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| 95 | 1 | throw new EnvelopeNotAcceptable( |
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| 96 | 1 | "Channel key '".self::METADATA_KEY."' missing in metadata of Envelope ". |
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| 97 | 1 | "'{$envelope->getUuid()->toString()}' received on channel '{$this->key}'.", |
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| 98 | 1 | EnvelopeNotAcceptable::CHANNEL_KEY_MISSING |
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| 99 | ); |
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| 100 | } |
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| 101 | 4 | $channelKey = $metadata->get(self::METADATA_KEY); |
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| 102 | 4 | if ($channelKey !== $this->key) { |
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| 103 | 1 | throw new EnvelopeNotAcceptable( |
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| 104 | 1 | "Channel '{$this->key}' inadvertently received Envelope ". |
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| 105 | 1 | "'{$envelope->getUuid()->toString()}' for channel '$channelKey'.", |
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| 106 | 1 | EnvelopeNotAcceptable::CHANNEL_KEY_UNEXPECTED |
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| 107 | ); |
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| 108 | } |
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| 109 | 3 | if (!$metadata->has(SubscriptionInterface::METADATA_KEY)) { |
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| 110 | 1 | throw new EnvelopeNotAcceptable( |
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| 111 | 1 | "Subscription key '".SubscriptionInterface::METADATA_KEY."' missing in metadata of ". |
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| 112 | 1 | "Envelope '{$envelope->getUuid()->toString()}' received on channel '{$this->key}'.", |
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| 113 | 1 | EnvelopeNotAcceptable::SUBSCRIPTION_KEY_MISSING |
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| 114 | ); |
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| 115 | } |
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| 116 | 2 | } |
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| 117 | } |
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| 118 |