Complex classes like JsonApiSerializer 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 JsonApiSerializer, and based on these observations, apply Extract Interface, too.
1 | <?php |
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18 | class JsonApiSerializer extends ArraySerializer |
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19 | { |
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20 | /** @var string|null */ |
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21 | protected $baseUrl; |
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22 | |||
23 | /** @var array */ |
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24 | protected $rootObjects; |
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25 | |||
26 | 14 | public function __construct(? string $baseUrl = null) |
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31 | |||
32 | /** |
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33 | * Serialize a collection. |
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34 | * |
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35 | * @param string $resourceKey |
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36 | * @param array $data |
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37 | * |
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38 | * @return array |
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39 | */ |
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40 | 1 | public function collection($resourceKey, array $data) : array |
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41 | { |
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42 | 1 | $resources = []; |
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43 | |||
44 | 1 | foreach ($data as $resource) { |
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45 | $resources[] = $this->serializeItem($resourceKey, $resource)['data']; |
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46 | } |
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47 | |||
48 | 1 | return ['data' => $resources]; |
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49 | } |
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50 | |||
51 | /** |
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52 | * Serialize an item. |
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53 | * |
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54 | * @param string $resourceKey |
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55 | * @param array $data |
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56 | * |
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57 | * @return array |
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58 | */ |
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59 | 14 | public function item($resourceKey, array $data) : array |
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60 | { |
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61 | 14 | $id = $this->getIdFromData($data); |
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62 | |||
63 | $resource = [ |
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64 | 'data' => [ |
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65 | 13 | 'type' => $resourceKey, |
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66 | 13 | 'id' => "$id", |
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67 | 13 | 'attributes' => $data, |
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68 | ], |
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69 | ]; |
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70 | |||
71 | 13 | unset($resource['data']['attributes']['id']); |
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72 | |||
73 | |||
74 | 13 | if (isset($resource['data']['attributes']['links'])) { |
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75 | 1 | $custom_links = $data['links']; |
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76 | 1 | unset($resource['data']['attributes']['links']); |
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77 | } |
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78 | |||
79 | 13 | if (isset($resource['data']['attributes']['meta'])) { |
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80 | 1 | $resource['data']['meta'] = $data['meta']; |
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81 | 1 | unset($resource['data']['attributes']['meta']); |
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82 | } |
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83 | |||
84 | 13 | if (empty($resource['data']['attributes'])) { |
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85 | 1 | $resource['data']['attributes'] = (object) []; |
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86 | } |
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87 | |||
88 | 13 | if ($this->shouldIncludeLinks()) { |
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89 | 4 | $resource['data']['links'] = [ |
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90 | 4 | 'self' => "{$this->baseUrl}/$resourceKey/$id", |
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91 | ]; |
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92 | 4 | if (isset($custom_links)) { |
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93 | 1 | $resource['data']['links'] = array_merge($resource['data']['links'], $custom_links); |
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94 | } |
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95 | } |
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96 | |||
97 | 13 | return $resource; |
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98 | } |
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99 | |||
100 | /** |
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101 | * Serialize the paginator. |
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102 | * |
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103 | * @param PaginatorInterface $paginator |
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104 | * |
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105 | * @return array |
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106 | */ |
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107 | public function paginator(PaginatorInterface $paginator) : array |
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108 | { |
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109 | $currentPage = (int)$paginator->getCurrentPage(); |
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110 | $lastPage = (int)$paginator->getLastPage(); |
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111 | |||
112 | $pagination = [ |
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113 | 'total' => (int)$paginator->getTotal(), |
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114 | 'count' => (int)$paginator->getCount(), |
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115 | 'per_page' => (int)$paginator->getPerPage(), |
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116 | 'current_page' => $currentPage, |
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117 | 'total_pages' => $lastPage, |
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118 | ]; |
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119 | |||
120 | $pagination['links'] = []; |
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121 | |||
122 | $pagination['links']['self'] = $paginator->getUrl($currentPage); |
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123 | $pagination['links']['first'] = $paginator->getUrl(1); |
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124 | |||
125 | if ($currentPage > 1) { |
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126 | $pagination['links']['prev'] = $paginator->getUrl($currentPage - 1); |
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127 | } |
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128 | |||
129 | if ($currentPage < $lastPage) { |
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130 | $pagination['links']['next'] = $paginator->getUrl($currentPage + 1); |
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131 | } |
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132 | |||
133 | $pagination['links']['last'] = $paginator->getUrl($lastPage); |
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134 | |||
135 | return ['pagination' => $pagination]; |
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136 | } |
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137 | |||
138 | 13 | public function meta(array $meta) : array |
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139 | { |
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140 | 13 | if (empty($meta)) { |
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141 | 11 | return []; |
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142 | } |
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143 | |||
144 | 3 | $result['meta'] = $meta; |
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145 | |||
146 | 3 | if (array_key_exists('pagination', $result['meta'])) { |
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147 | $result['links'] = $result['meta']['pagination']['links']; |
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148 | unset($result['meta']['pagination']['links']); |
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149 | } |
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150 | |||
151 | 3 | return $result; |
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152 | } |
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153 | |||
154 | 1 | public function null() : array |
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160 | |||
161 | 13 | public function includedData(ResourceInterface $resource, array $data) : array |
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178 | |||
179 | /** |
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180 | * Indicates if includes should be side-loaded. |
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181 | * |
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182 | * @return bool |
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183 | */ |
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184 | 14 | public function sideloadIncludes() |
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188 | |||
189 | /** |
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190 | * @param array $data |
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191 | * @param array $includedData |
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192 | * |
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193 | * @return array |
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194 | */ |
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195 | 13 | public function injectData($data, $includedData) : array |
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205 | |||
206 | /** |
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207 | * Hook to manipulate the final sideloaded includes. |
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208 | * The JSON API specification does not allow the root object to be included |
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209 | * into the sideloaded `included`-array. We have to make sure it is |
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210 | * filtered out, in case some object links to the root object in a |
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211 | * relationship. |
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212 | * |
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213 | * @param array $includedData |
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214 | * @param array $data |
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215 | * |
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216 | * @return array |
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217 | */ |
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218 | 13 | public function filterIncludes($includedData, $data) : array |
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235 | |||
236 | /** |
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237 | * Get the mandatory fields for the serializer |
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238 | * |
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239 | * @return array |
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240 | */ |
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241 | public function getMandatoryFields() : array |
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242 | { |
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243 | return ['id']; |
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244 | } |
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245 | |||
246 | /** |
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247 | * Filter function to delete root objects from array. |
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248 | * |
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249 | * @param array $object |
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250 | * |
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251 | * @return bool |
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252 | */ |
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253 | 4 | protected function filterRootObject($object) : bool |
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257 | |||
258 | /** |
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259 | * Set the root objects of the JSON API tree. |
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260 | * |
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261 | * @param array $objects |
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262 | */ |
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263 | 4 | protected function setRootObjects(array $objects = []) : void |
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269 | |||
270 | /** |
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271 | * Determines whether an object is a root object of the JSON API tree. |
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272 | * |
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273 | * @param array $object |
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274 | * |
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275 | * @return bool |
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276 | */ |
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277 | 4 | protected function isRootObject($object) : bool |
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282 | |||
283 | /** |
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284 | * @param array|null $data |
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285 | * |
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286 | * @return bool |
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287 | */ |
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288 | 9 | protected function isCollection($data) : bool |
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297 | |||
298 | /** |
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299 | * @param array|null $data |
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300 | * |
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301 | * @return bool |
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302 | */ |
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303 | 6 | protected function isNull($data) : bool |
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311 | |||
312 | /** |
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313 | * @param array|null $data |
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314 | * |
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315 | * @return bool |
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316 | */ |
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317 | 5 | protected function isEmpty($data) : bool |
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325 | |||
326 | /** |
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327 | * @param array $data |
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328 | * @param array $relationships |
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329 | * |
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330 | * @return array |
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331 | */ |
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332 | 6 | protected function fillRelationships($data, $relationships) : array |
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333 | { |
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334 | 6 | if ($this->isCollection($data)) { |
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335 | foreach ($relationships as $key => $relationship) { |
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336 | $data = $this->fillRelationshipAsCollection($data, $relationship, $key); |
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337 | } |
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338 | } else { // Single resource |
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339 | 6 | foreach ($relationships as $key => $relationship) { |
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340 | 6 | $data = $this->fillRelationshipAsSingleResource($data, $relationship, $key); |
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341 | } |
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342 | } |
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343 | |||
344 | 6 | return $data; |
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345 | } |
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346 | |||
347 | /** |
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348 | * @param array $includedData |
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349 | * |
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350 | * @return array |
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351 | */ |
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352 | 13 | protected function parseRelationships($includedData) : array |
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353 | { |
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354 | 13 | $relationships = []; |
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355 | |||
356 | 13 | foreach ($includedData as $key => $inclusion) { |
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357 | 13 | foreach ($inclusion as $includeKey => $includeObject) { |
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358 | 6 | $relationships = $this->buildRelationships($includeKey, $relationships, $includeObject, $key); |
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359 | 6 | if (isset($includedData[0][$includeKey]['meta'])) { |
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360 | 1 | $relationships[$includeKey][0]['meta'] = $includedData[0][$includeKey]['meta']; |
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361 | } |
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362 | } |
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363 | } |
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364 | |||
365 | 13 | return $relationships; |
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366 | } |
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367 | |||
368 | /** |
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369 | * @param array $data |
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370 | * |
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371 | * @return integer |
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372 | */ |
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373 | 14 | protected function getIdFromData(array $data) : int |
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374 | { |
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375 | 14 | if (!array_key_exists('id', $data)) { |
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376 | 1 | throw new InvalidArgumentException( |
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377 | 1 | 'JSON API resource objects MUST have a valid id' |
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378 | ); |
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379 | } |
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380 | 13 | return $data['id']; |
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381 | } |
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382 | |||
383 | /** |
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384 | * Keep all sideloaded inclusion data on the top level. |
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385 | * |
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386 | * @param array $data |
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387 | * |
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388 | * @return array |
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389 | */ |
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390 | 13 | protected function pullOutNestedIncludedData(array $data) : array |
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405 | |||
406 | /** |
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407 | * Whether or not the serializer should include `links` for resource objects. |
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408 | * |
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409 | * @return bool |
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410 | */ |
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411 | 13 | protected function shouldIncludeLinks() : bool |
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415 | |||
416 | /** |
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417 | * Check if the objects are part of a collection or not |
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418 | * |
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419 | * @param array $includeObject |
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420 | * |
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421 | * @return array |
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422 | */ |
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423 | 4 | private function createIncludeObjects($includeObject) : array |
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435 | |||
436 | /** |
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437 | * Sets the RootObjects, either as collection or not. |
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438 | * |
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439 | * @param array $data |
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440 | */ |
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441 | 4 | private function createRootObjects(array $data) : void |
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449 | |||
450 | private function fillRelationshipAsCollection($data, $relationship, $key) : array |
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451 | { |
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452 | foreach ($relationship as $index => $relationshipData) { |
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453 | $data['data'][$index]['relationships'][$key] = $relationshipData; |
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454 | } |
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455 | |||
456 | return $data; |
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457 | } |
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458 | |||
459 | 6 | private function fillRelationshipAsSingleResource($data, $relationship, $key) : array |
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465 | |||
466 | 6 | private function buildRelationships(string $includeKey, array $relationships, array $includeObject, string $key) : array |
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492 | |||
493 | 6 | private function addIncludeKeyToRelationsIfNotSet(string $includeKey, array $relationships) : array |
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494 | { |
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495 | 6 | if (!array_key_exists($includeKey, $relationships)) { |
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496 | 6 | $relationships[$includeKey] = []; |
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497 | 6 | return $relationships; |
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498 | } |
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499 | |||
500 | return $relationships; |
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501 | } |
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502 | |||
503 | /** |
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504 | * @param array $includeObject |
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505 | * @param array $relationship |
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506 | * |
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507 | * @return array |
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508 | */ |
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509 | private function addIncludedDataToRelationship(array $includeObject, array $relationship) : array |
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510 | { |
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511 | foreach ($includeObject['data'] as $object) { |
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512 | $relationship['data'][] = [ |
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513 | 'type' => $object['type'], |
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514 | 'id' => $object['id'], |
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515 | ]; |
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516 | } |
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517 | |||
518 | return $relationship; |
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519 | } |
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520 | |||
521 | 12 | public function injectAvailableIncludeData($data, $availableIncludes) : array |
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522 | { |
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523 | 12 | if (!$this->shouldIncludeLinks()) { |
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524 | 8 | return $data; |
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525 | } |
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526 | |||
527 | 4 | if ($this->isCollection($data)) { |
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528 | $data['data'] = array_map(function ($resource) use ($availableIncludes) { |
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529 | foreach ($availableIncludes as $relationshipKey) { |
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530 | $resource = $this->addRelationshipLinks($resource, $relationshipKey); |
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531 | } |
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532 | return $resource; |
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533 | }, $data['data']); |
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534 | } else { |
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535 | 4 | foreach ($availableIncludes as $relationshipKey) { |
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536 | 4 | $data['data'] = $this->addRelationshipLinks($data['data'], $relationshipKey); |
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537 | } |
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538 | } |
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539 | |||
540 | 4 | return $data; |
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541 | } |
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542 | |||
543 | 4 | private function addRelationshipLinks(array $resource, string $relationshipKey) : array |
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561 | |||
562 | 4 | private function serializeIncludedObjectsWithCacheKey(array $includeObjects, array $linkedIds, array $serializedData) : array |
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575 | } |
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576 |
Adding an explicit array definition is generally preferable to implicit array definition as it guarantees a stable state of the code.
Let’s take a look at an example:
As you can see in this example, the array
$myArray
is initialized the first time when the foreach loop is entered. You can also see that the value of thebar
key is only written conditionally; thus, its value might result from a previous iteration.This might or might not be intended. To make your intention clear, your code more readible and to avoid accidental bugs, we recommend to add an explicit initialization $myArray = array() either outside or inside the foreach loop.