Complex classes like JsonApiController 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 JsonApiController, and based on these observations, apply Extract Interface, too.
| 1 | <?php  | 
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| 15 | abstract class JsonApiController extends Controller  | 
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| 16 | { | 
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| 17 | use JsonApiErrors;  | 
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| 18 | |||
| 19 | /**  | 
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| 20 | * Return the Eloquent Model for the resource.  | 
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| 21 | *  | 
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| 22 | * @return Model  | 
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| 23 | */  | 
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| 24 | abstract protected function getModel();  | 
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| 25 | |||
| 26 | /**  | 
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| 27 | * Return the type name of the resource.  | 
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| 28 | *  | 
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| 29 | * @return string  | 
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| 30 | */  | 
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| 31 | protected function getModelType()  | 
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| 35 | |||
| 36 | /**  | 
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| 37 | * The model relationships that can be updated.  | 
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| 38 | *  | 
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| 39 | * @return string  | 
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| 40 | */  | 
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| 41 | protected function getModelRelationships()  | 
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| 45 | |||
| 46 | /**  | 
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| 47 | * Return a listing of the resource.  | 
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| 48 | *  | 
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| 49 | * @param Request $request  | 
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| 50 | *  | 
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| 51 | * @return JsonApiResponse  | 
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| 52 | */  | 
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| 53 | public function indexAction(Request $request)  | 
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| 85 | |||
| 86 | /**  | 
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| 87 | * Store a new record.  | 
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| 88 | *  | 
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| 89 | * @param Request $request  | 
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| 90 | *  | 
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| 91 | * @return JsonApiResponse  | 
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| 92 | */  | 
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| 93 | public function storeAction(Request $request)  | 
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| 103 | |||
| 104 | /**  | 
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| 105 | * Return a specified record.  | 
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| 106 | *  | 
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| 107 | * @param Request $request  | 
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| 108 | * @param Model|int $record  | 
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| 109 | *  | 
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| 110 | * @return JsonApiResponse  | 
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| 111 | */  | 
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| 112 | public function showAction(Request $request, $record)  | 
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| 119 | |||
| 120 | /**  | 
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| 121 | * Update a specified record.  | 
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| 122 | *  | 
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| 123 | * @param Request $request  | 
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| 124 | * @param Model|int $record  | 
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| 125 | *  | 
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| 126 | * @return JsonApiResponse  | 
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| 127 | */  | 
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| 128 | public function updateAction(Request $request, $record)  | 
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| 139 | |||
| 140 | /**  | 
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| 141 | * Destroy a specified record.  | 
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| 142 | *  | 
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| 143 | * @param Request $request  | 
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| 144 | * @param Model|int $record  | 
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| 145 | *  | 
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| 146 | * @return JsonApiResponse  | 
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| 147 | */  | 
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| 148 | public function destroyAction(Request $request, $record)  | 
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| 155 | |||
| 156 | /**  | 
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| 157 | * Return a specified record relationship.  | 
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| 158 | *  | 
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| 159 | * @param Request $request  | 
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| 160 | * @param Model|int $record  | 
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| 161 | * @param string $relation  | 
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| 162 | *  | 
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| 163 | * @throws \Symfony\Component\HttpKernel\Exception\NotFoundHttpException  | 
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| 164 | *  | 
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| 165 | * @return JsonApiResponse  | 
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| 166 | */  | 
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| 167 | public function relationshipAction(Request $request, $record, $relation)  | 
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| 185 | |||
| 186 | /**  | 
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| 187 | * Update a named many-to-one relationship association on a specified record.  | 
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| 188 | * http://jsonapi.org/format/#crud-updating-to-one-relationships  | 
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| 189 | *  | 
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| 190 | * @param Request $request  | 
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| 191 | * @param Model|int $record  | 
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| 192 | * @param string $relation  | 
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| 193 | * @param string|null $foreignKey  | 
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| 194 | *  | 
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| 195 | * @throws \Symfony\Component\HttpKernel\Exception\NotFoundHttpException  | 
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| 196 | *  | 
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| 197 | * @return JsonApiResponse  | 
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| 198 | */  | 
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| 199 | public function updateToOneRelationshipAction(Request $request, $record, $relation, $foreignKey = null)  | 
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| 210 | |||
| 211 | /**  | 
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| 212 | * Update named many-to-many relationship entries on a specified record.  | 
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| 213 | * http://jsonapi.org/format/#crud-updating-to-many-relationships  | 
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| 214 | *  | 
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| 215 | * @param Request $request  | 
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| 216 | * @param Model|int $record  | 
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| 217 | * @param string $relation  | 
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| 218 | *  | 
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| 219 | * @throws \Symfony\Component\HttpKernel\Exception\NotFoundHttpException  | 
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| 220 | *  | 
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| 221 | * @return JsonApiResponse  | 
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| 222 | */  | 
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| 223 | public function updateToManyRelationshipAction(Request $request, $record, $relation)  | 
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| 248 | |||
| 249 | /**  | 
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| 250 | * Return an instance of the resource by primary key.  | 
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| 251 | *  | 
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| 252 | * @param int $key  | 
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| 253 | *  | 
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| 254 | * @throws \Illuminate\Database\Eloquent\ModelNotFoundException  | 
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| 255 | *  | 
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| 256 | * @return Model  | 
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| 257 | */  | 
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| 258 | protected function findModelInstance($key)  | 
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| 262 | |||
| 263 | /**  | 
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| 264 | * Return any JSON API resource parameters from a request.  | 
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| 265 | *  | 
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| 266 | * @param Request $request  | 
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| 267 | *  | 
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| 268 | * @return array  | 
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| 269 | */  | 
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| 270 | protected function getRequestParameters($request)  | 
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| 279 | |||
| 280 | /**  | 
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| 281 | * Return any comma separated values in a request query field as an array.  | 
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| 282 | *  | 
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| 283 | * @param Request $request  | 
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| 284 | * @param string $key  | 
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| 285 | *  | 
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| 286 | * @return array  | 
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| 287 | */  | 
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| 288 | protected function getRequestQuerySet($request, $key)  | 
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| 292 | |||
| 293 | /**  | 
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| 294 | * Transform a model instance into a JSON API object.  | 
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| 295 | *  | 
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| 296 | * @param Model $record  | 
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| 297 | * @param array|null $fields Field names of attributes to limit to  | 
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| 298 | * @param array|null $include Relations to include  | 
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| 299 | *  | 
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| 300 | * @return array  | 
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| 301 | */  | 
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| 302 | protected function transformRecord($record, array $fields = [], array $include = [])  | 
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| 343 | |||
| 344 | /**  | 
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| 345 | * Transform a set of models into a JSON API collection.  | 
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| 346 | *  | 
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| 347 | * @param \Illuminate\Support\Collection $records  | 
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| 348 | * @param array $fields  | 
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| 349 | *  | 
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| 350 | * @return array  | 
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| 351 | */  | 
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| 352 | protected function transformCollection($records, array $fields = [])  | 
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| 360 | |||
| 361 | /**  | 
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| 362 | * Transform a set of models into a collection of JSON API resource  | 
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| 363 | * identifier objects.  | 
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| 364 | *  | 
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| 365 | * @param \Illuminate\Support\Collection $records  | 
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| 366 | *  | 
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| 367 | * @return array  | 
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| 368 | */  | 
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| 369 | protected function transformCollectionIds($records)  | 
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| 380 | |||
| 381 | /**  | 
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| 382 | * Update one or more relationships on a model instance.  | 
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| 383 | *  | 
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| 384 | * @param Model $record  | 
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| 385 | * @param array $relationships  | 
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| 386 | */  | 
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| 387 | protected function updateRecordRelationships($record, array $relationships)  | 
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| 402 | }  | 
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| 403 | 
It is generally a best practice as it is often more readable to use concatenation instead of interpolation for variables inside strings.