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 |