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:
Complex classes like Queue often do a lot of different things. To break such a class down, we need to identify a cohesive component within that class. A common approach to find such a component is to look for fields/methods that share the same prefixes, or suffixes. You can also have a look at the cohesion graph to spot any un-connected, or weakly-connected components.
Once you have determined the fields that belong together, you can apply the Extract Class refactoring. If the component makes sense as a sub-class, Extract Subclass is also a candidate, and is often faster.
While breaking up the class, it is a good idea to analyze how other classes use Queue, and based on these observations, apply Extract Interface, too.
1 | <?php |
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16 | final class Queue implements QueueInterface |
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17 | { |
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18 | /** |
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19 | * Maximum millisecond value to use for UTCDateTime creation. |
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20 | * |
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21 | * @var integer |
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22 | */ |
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23 | const MONGO_INT32_MAX = PHP_INT_MAX; |
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24 | |||
25 | /** |
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26 | * mongo collection to use for queue. |
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27 | * |
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28 | * @var \MongoDB\Collection |
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29 | */ |
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30 | private $collection; |
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31 | |||
32 | /** |
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33 | * Construct queue. |
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34 | * |
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35 | * @param \MongoDB\Collection|string $collectionOrUrl A MongoCollection instance or the mongo connection url. |
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36 | * @param string $db the mongo db name |
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37 | * @param string $collection the collection name to use for the queue |
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38 | * |
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39 | * @throws \InvalidArgumentException $collectionOrUrl, $db or $collection was not a string |
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40 | */ |
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41 | public function __construct($collectionOrUrl, $db = null, $collection = null) |
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42 | { |
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43 | if ($collectionOrUrl instanceof \MongoDB\Collection) { |
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44 | $this->collection = $collectionOrUrl; |
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45 | return; |
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46 | } |
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47 | |||
48 | if (!is_string($collectionOrUrl)) { |
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49 | throw new \InvalidArgumentException('$collectionOrUrl was not a string'); |
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50 | } |
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51 | |||
52 | if (!is_string($db)) { |
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53 | throw new \InvalidArgumentException('$db was not a string'); |
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54 | } |
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55 | |||
56 | if (!is_string($collection)) { |
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57 | throw new \InvalidArgumentException('$collection was not a string'); |
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58 | } |
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59 | |||
60 | $mongo = new \MongoDB\Client($collectionOrUrl, [], ['typeMap' => ['root' => 'array', 'document' => 'array', 'array' => 'array']]); |
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61 | $mongoDb = $mongo->selectDatabase($db); |
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62 | $this->collection = $mongoDb->selectCollection($collection); |
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63 | } |
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64 | |||
65 | /** |
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66 | * Ensure an index for the get() method. |
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67 | * |
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68 | * @param array $beforeSort Fields in get() call to index before the sort field in same format |
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69 | * as \MongoDB\Collection::ensureIndex() |
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70 | * @param array $afterSort Fields in get() call to index after the sort field in same format as |
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71 | * \MongoDB\Collection::ensureIndex() |
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72 | * |
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73 | * @return void |
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74 | * |
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75 | * @throws \InvalidArgumentException value of $beforeSort or $afterSort is not 1 or -1 for ascending and descending |
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76 | * @throws \InvalidArgumentException key in $beforeSort or $afterSort was not a string |
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77 | */ |
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78 | public function ensureGetIndex(array $beforeSort = [], array $afterSort = []) |
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79 | { |
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80 | //using general rule: equality, sort, range or more equality tests in that order for index |
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81 | $completeFields = ['earliestGet' => 1]; |
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82 | |||
83 | self::verifySort($beforeSort, 'beforeSort', $completeFields); |
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84 | |||
85 | $completeFields['priority'] = 1; |
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86 | $completeFields['created'] = 1; |
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87 | |||
88 | self::verifySort($afterSort, 'afterSort', $completeFields); |
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89 | |||
90 | //for the main query in get() |
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91 | $this->ensureIndex($completeFields); |
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92 | } |
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93 | |||
94 | /** |
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95 | * Ensure an index for the count() method. |
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96 | * Is a no-op if the generated index is a prefix of an existing one. If you have a similar ensureGetIndex call, |
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97 | * call it first. |
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98 | * |
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99 | * @param array $fields fields in count() call to index in same format as \MongoDB\Collection::createIndex() |
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100 | * @param bool $includeRunning whether to include the running field in the index |
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101 | * |
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102 | * @return void |
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103 | * |
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104 | * @throws \InvalidArgumentException $includeRunning was not a boolean |
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105 | * @throws \InvalidArgumentException key in $fields was not a string |
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106 | * @throws \InvalidArgumentException value of $fields is not 1 or -1 for ascending and descending |
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107 | */ |
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108 | public function ensureCountIndex(array $fields, $includeRunning) |
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109 | { |
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110 | if (!is_bool($includeRunning)) { |
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111 | throw new \InvalidArgumentException('$includeRunning was not a boolean'); |
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112 | } |
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113 | |||
114 | $completeFields = []; |
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115 | |||
116 | if ($includeRunning) { |
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117 | $completeFields['earliestGet'] = 1; |
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118 | } |
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119 | |||
120 | self::verifySort($fields, 'fields', $completeFields); |
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121 | |||
122 | $this->ensureIndex($completeFields); |
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123 | } |
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124 | |||
125 | /** |
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126 | * Get a non running message from the queue. |
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127 | * |
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128 | * @param array $query in same format as \MongoDB\Collection::find() where top level fields do not contain operators. |
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129 | * Lower level fields can however. eg: valid {a: {$gt: 1}, "b.c": 3}, |
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130 | * invalid {$and: [{...}, {...}]} |
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131 | * @param int $runningResetDuration second duration the message can stay unacked before it resets and can be |
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132 | * retreived again. |
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133 | * @param int $waitDurationInMillis millisecond duration to wait for a message. |
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134 | * @param int $pollDurationInMillis millisecond duration to wait between polls. |
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135 | * |
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136 | * @return array|null the message or null if one is not found |
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137 | * |
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138 | * @throws \InvalidArgumentException $runningResetDuration, $waitDurationInMillis or $pollDurationInMillis was not |
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139 | * an int |
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140 | * @throws \InvalidArgumentException key in $query was not a string |
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141 | */ |
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142 | public function get(array $query, $runningResetDuration, $waitDurationInMillis = 3000, $pollDurationInMillis = 200) |
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143 | { |
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144 | if (!is_int($runningResetDuration)) { |
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145 | throw new \InvalidArgumentException('$runningResetDuration was not an int'); |
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146 | } |
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147 | |||
148 | if (!is_int($waitDurationInMillis)) { |
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149 | throw new \InvalidArgumentException('$waitDurationInMillis was not an int'); |
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150 | } |
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151 | |||
152 | if (!is_int($pollDurationInMillis)) { |
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153 | throw new \InvalidArgumentException('$pollDurationInMillis was not an int'); |
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154 | } |
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155 | |||
156 | if ($pollDurationInMillis < 0) { |
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157 | $pollDurationInMillis = 0; |
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158 | } |
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159 | |||
160 | $completeQuery = ['earliestGet' => ['$lte' => new UTCDateTime((int)(microtime(true) * 1000))]]; |
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161 | foreach ($query as $key => $value) { |
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162 | if (!is_string($key)) { |
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163 | throw new \InvalidArgumentException('key in $query was not a string'); |
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164 | } |
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165 | |||
166 | $completeQuery["payload.{$key}"] = $value; |
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167 | } |
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168 | |||
169 | $resetTimestamp = time() + $runningResetDuration; |
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170 | //ints overflow to floats |
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171 | if (!is_int($resetTimestamp)) { |
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172 | $resetTimestamp = $runningResetDuration > 0 ? self::MONGO_INT32_MAX : 0; |
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173 | } |
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174 | |||
175 | $resetTimestamp = min(max(0, $resetTimestamp * 1000), self::MONGO_INT32_MAX); |
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176 | |||
177 | $update = ['$set' => ['earliestGet' => new UTCDateTime($resetTimestamp)]]; |
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178 | $findOneAndUpdateOptions = ['sort' => ['priority' => 1, 'created' => 1]]; |
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179 | $findOneOptions = ['typeMap' => ['root' => 'array', 'document' => 'array', 'array' => 'array']], |
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180 | |||
181 | //ints overflow to floats, should be fine |
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182 | $end = microtime(true) + ($waitDurationInMillis / 1000.0); |
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183 | |||
184 | $sleepTime = $pollDurationInMillis * 1000; |
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185 | //ints overflow to floats and already checked $pollDurationInMillis was positive |
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186 | if (!is_int($sleepTime)) { |
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187 | //ignore since testing a giant sleep takes too long |
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188 | //@codeCoverageIgnoreStart |
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189 | $sleepTime = PHP_INT_MAX; |
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190 | } //@codeCoverageIgnoreEnd |
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191 | |||
192 | while (true) { |
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193 | $id = $this->getIdFromMessage( |
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194 | $this->collection->findOneAndUpdate($completeQuery, $update, $findOneAndUpdateOptions) |
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195 | ); |
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196 | if ($id !== null) { |
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197 | // findOneAndUpdate does not correctly return result according to typeMap options so just refetch. |
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198 | $message = $this->collection->findOne(['_id' => $id], $findOneOptions); |
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199 | //id on left of union operator so a possible id in payload doesnt wipe it out the generated one |
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200 | return ['id' => $id] + $message['payload']; |
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201 | } |
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202 | |||
203 | if (microtime(true) >= $end) { |
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204 | return null; |
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205 | } |
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206 | |||
207 | usleep($sleepTime); |
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208 | } |
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209 | |||
210 | //ignore since always return from the function from the while loop |
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211 | //@codeCoverageIgnoreStart |
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212 | } |
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213 | //@codeCoverageIgnoreEnd |
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214 | |||
215 | private function getIdFromMessage($message) |
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216 | { |
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217 | if (is_array($message)) { |
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218 | return array_key_exists('_id', $message) ? $message['_id'] : null; |
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219 | } |
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220 | |||
221 | if (is_object($message)) { |
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222 | return isset($message->_id) ? $message->_id : null; |
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223 | } |
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224 | |||
225 | return null; |
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226 | } |
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227 | |||
228 | /** |
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229 | * Count queue messages. |
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230 | * |
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231 | * @param array $query in same format as \MongoDB\Collection::find() where top level fields do not contain operators. |
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232 | * Lower level fields can however. eg: valid {a: {$gt: 1}, "b.c": 3}, invalid {$and: [{...}, {...}]} |
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233 | * @param bool|null $running query a running message or not or all |
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234 | * |
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235 | * @return int the count |
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236 | * |
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237 | * @throws \InvalidArgumentException $running was not null and not a bool |
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238 | * @throws \InvalidArgumentException key in $query was not a string |
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239 | */ |
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240 | public function count(array $query, $running = null) |
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241 | { |
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242 | if ($running !== null && !is_bool($running)) { |
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243 | throw new \InvalidArgumentException('$running was not null and not a bool'); |
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244 | } |
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245 | |||
246 | $totalQuery = []; |
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247 | |||
248 | if ($running === true || $running === false) { |
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249 | $key = $running ? '$gt' : '$lte'; |
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250 | $totalQuery['earliestGet'] = [$key => new UTCDateTime((int)(microtime(true) * 1000))]; |
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251 | } |
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252 | |||
253 | foreach ($query as $key => $value) { |
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254 | if (!is_string($key)) { |
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255 | throw new \InvalidArgumentException('key in $query was not a string'); |
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256 | } |
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257 | |||
258 | $totalQuery["payload.{$key}"] = $value; |
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259 | } |
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260 | |||
261 | return $this->collection->count($totalQuery); |
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262 | } |
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263 | |||
264 | /** |
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265 | * Acknowledge a message was processed and remove from queue. |
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266 | * |
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267 | * @param array $message message received from get() |
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268 | * |
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269 | * @return void |
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270 | * |
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271 | * @throws \InvalidArgumentException $message does not have a field "id" that is a MongoDB\BSON\ObjectID |
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272 | */ |
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273 | public function ack(array $message) |
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274 | { |
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275 | $id = null; |
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276 | if (array_key_exists('id', $message)) { |
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277 | $id = $message['id']; |
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278 | } |
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279 | |||
280 | if (!(is_a($id, 'MongoDB\BSON\ObjectID'))) { |
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281 | throw new \InvalidArgumentException('$message does not have a field "id" that is a ObjectID'); |
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282 | } |
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283 | |||
284 | $this->collection->deleteOne(['_id' => $id]); |
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285 | } |
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286 | |||
287 | /** |
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288 | * Atomically acknowledge and send a message to the queue. |
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289 | * |
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290 | * @param array $message the message to ack received from get() |
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291 | * @param array $payload the data to store in the message to send. Data is handled same way |
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292 | * as \MongoDB\Collection::insertOne() |
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293 | * @param int $earliestGet earliest unix timestamp the message can be retreived. |
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294 | * @param float $priority priority for order out of get(). 0 is higher priority than 1 |
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295 | * @param bool $newTimestamp true to give the payload a new timestamp or false to use given message timestamp |
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296 | * |
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297 | * @return void |
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298 | * |
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299 | * @throws \InvalidArgumentException $message does not have a field "id" that is a ObjectID |
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300 | * @throws \InvalidArgumentException $earliestGet was not an int |
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301 | * @throws \InvalidArgumentException $priority was not a float |
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302 | * @throws \InvalidArgumentException $priority is NaN |
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303 | * @throws \InvalidArgumentException $newTimestamp was not a bool |
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304 | */ |
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305 | public function ackSend(array $message, array $payload, $earliestGet = 0, $priority = 0.0, $newTimestamp = true) |
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306 | { |
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307 | $id = null; |
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308 | if (array_key_exists('id', $message)) { |
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309 | $id = $message['id']; |
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310 | } |
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311 | |||
312 | if (!(is_a($id, 'MongoDB\BSON\ObjectID'))) { |
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313 | throw new \InvalidArgumentException('$message does not have a field "id" that is a ObjectID'); |
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314 | } |
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315 | |||
316 | if (!is_int($earliestGet)) { |
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317 | throw new \InvalidArgumentException('$earliestGet was not an int'); |
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318 | } |
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319 | |||
320 | if (!is_float($priority)) { |
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321 | throw new \InvalidArgumentException('$priority was not a float'); |
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322 | } |
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323 | |||
324 | if (is_nan($priority)) { |
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325 | throw new \InvalidArgumentException('$priority was NaN'); |
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326 | } |
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327 | |||
328 | if ($newTimestamp !== true && $newTimestamp !== false) { |
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329 | throw new \InvalidArgumentException('$newTimestamp was not a bool'); |
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330 | } |
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331 | |||
332 | //Ensure $earliestGet is between 0 and MONGO_INT32_MAX |
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333 | $earliestGet = min(max(0, $earliestGet * 1000), self::MONGO_INT32_MAX); |
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334 | |||
335 | $toSet = [ |
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336 | 'payload' => $payload, |
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337 | 'earliestGet' => new UTCDateTime($earliestGet), |
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338 | 'priority' => $priority, |
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339 | ]; |
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340 | if ($newTimestamp) { |
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341 | $toSet['created'] = new UTCDateTime((int)(microtime(true) * 1000)); |
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342 | } |
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343 | |||
344 | //using upsert because if no documents found then the doc was removed (SHOULD ONLY HAPPEN BY SOMEONE MANUALLY) |
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345 | //so we can just send |
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346 | $this->collection->updateOne(['_id' => $id], ['$set' => $toSet], ['upsert' => true]); |
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347 | } |
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348 | |||
349 | /** |
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350 | * Requeue message to the queue. Same as ackSend() with the same message. |
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351 | * |
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352 | * @param array $message message received from get(). |
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353 | * @param int $earliestGet earliest unix timestamp the message can be retreived. |
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354 | * @param float $priority priority for order out of get(). 0 is higher priority than 1 |
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355 | * @param bool $newTimestamp true to give the payload a new timestamp or false to use given message timestamp |
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356 | * |
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357 | * @return void |
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358 | * |
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359 | * @throws \InvalidArgumentException $message does not have a field "id" that is a ObjectID |
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360 | * @throws \InvalidArgumentException $earliestGet was not an int |
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361 | * @throws \InvalidArgumentException $priority was not a float |
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362 | * @throws \InvalidArgumentException priority is NaN |
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363 | * @throws \InvalidArgumentException $newTimestamp was not a bool |
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364 | */ |
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365 | public function requeue(array $message, $earliestGet = 0, $priority = 0.0, $newTimestamp = true) |
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366 | { |
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367 | $forRequeue = $message; |
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368 | unset($forRequeue['id']); |
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369 | $this->ackSend($message, $forRequeue, $earliestGet, $priority, $newTimestamp); |
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370 | } |
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371 | |||
372 | /** |
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373 | * Send a message to the queue. |
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374 | * |
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375 | * @param array $payload the data to store in the message. Data is handled same way as \MongoDB\Collection::insertOne() |
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376 | * @param int $earliestGet earliest unix timestamp the message can be retreived. |
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377 | * @param float $priority priority for order out of get(). 0 is higher priority than 1 |
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378 | * |
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379 | * @return void |
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380 | * |
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381 | * @throws \InvalidArgumentException $earliestGet was not an int |
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382 | * @throws \InvalidArgumentException $priority was not a float |
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383 | * @throws \InvalidArgumentException $priority is NaN |
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384 | */ |
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385 | public function send(array $payload, $earliestGet = 0, $priority = 0.0) |
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386 | { |
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387 | if (!is_int($earliestGet)) { |
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388 | throw new \InvalidArgumentException('$earliestGet was not an int'); |
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389 | } |
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390 | |||
391 | if (!is_float($priority)) { |
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392 | throw new \InvalidArgumentException('$priority was not a float'); |
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393 | } |
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394 | |||
395 | if (is_nan($priority)) { |
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396 | throw new \InvalidArgumentException('$priority was NaN'); |
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397 | } |
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398 | |||
399 | //Ensure $earliestGet is between 0 and MONGO_INT32_MAX |
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400 | $earliestGet = min(max(0, $earliestGet * 1000), self::MONGO_INT32_MAX); |
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401 | |||
402 | $message = [ |
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403 | 'payload' => $payload, |
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404 | 'earliestGet' => new UTCDateTime($earliestGet), |
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405 | 'priority' => $priority, |
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406 | 'created' => new UTCDateTime((int)(microtime(true) * 1000)), |
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407 | ]; |
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408 | |||
409 | $this->collection->insertOne($message); |
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410 | } |
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411 | |||
412 | /** |
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413 | * Ensure index of correct specification and a unique name whether the specification or name already exist or not. |
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414 | * Will not create index if $index is a prefix of an existing index |
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415 | * |
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416 | * @param array $index index to create in same format as \MongoDB\Collection::createIndex() |
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417 | * |
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418 | * @return void |
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419 | * |
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420 | * @throws \Exception couldnt create index after 5 attempts |
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421 | */ |
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422 | private function ensureIndex(array $index) |
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423 | { |
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424 | //if $index is a prefix of any existing index we are good |
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425 | foreach ($this->collection->listIndexes() as $existingIndex) { |
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426 | $slice = array_slice($existingIndex['key'], 0, count($index), true); |
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427 | if ($slice === $index) { |
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428 | return; |
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429 | } |
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430 | } |
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431 | |||
432 | for ($i = 0; $i < 5; ++$i) { |
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433 | for ($name = uniqid(); strlen($name) > 0; $name = substr($name, 0, -1)) { |
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434 | //creating an index with same name and different spec does nothing. |
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435 | //creating an index with same spec and different name does nothing. |
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436 | //so we use any generated name, and then find the right spec after we have called, |
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437 | //and just go with that name. |
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438 | try { |
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439 | $this->collection->createIndex($index, ['name' => $name, 'background' => true]); |
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440 | } catch (\MongoDB\Exception\Exception $e) { |
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441 | //this happens when the name was too long, let continue |
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442 | } |
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443 | |||
444 | foreach ($this->collection->listIndexes() as $existingIndex) { |
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445 | if ($existingIndex['key'] === $index) { |
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446 | return; |
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447 | } |
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448 | } |
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449 | } |
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450 | } |
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451 | |||
452 | throw new \Exception('couldnt create index after 5 attempts'); |
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453 | //@codeCoverageIgnoreEnd |
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454 | } |
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455 | |||
456 | /** |
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457 | * Helper method to validate keys and values for the given sort array |
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458 | * |
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459 | * @param array $sort The proposed sort for a mongo index. |
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460 | * @param string $label The name of the variable given to the public ensureXIndex method. |
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461 | * @param array &$completedFields The final index array with payload. prefix added to fields. |
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462 | * |
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463 | * @return void |
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464 | */ |
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465 | private static function verifySort(array $sort, $label, &$completeFields) |
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466 | { |
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467 | foreach ($sort as $key => $value) { |
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468 | if (!is_string($key)) { |
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482 |