Issue #3232265: Allow the user to specify a path to the data within JSON.

src/Plugin/DatasetSource/JsonSource.php

@@ -4,9 +4,14 @@ declare(strict_types=1);
 
 namespace Drupal\data_pipelines\Plugin\DatasetSource;
 
+use Drupal\Core\Field\BaseFieldDefinition;
+use Drupal\Core\StringTranslation\TranslatableMarkup;
 use Drupal\data_pipelines\DatasetData;
+use Drupal\data_pipelines\Entity\Dataset;
 use Drupal\data_pipelines\Entity\DatasetInterface;
 use Drupal\data_pipelines\Source\DatasetSourceBase;
+use Drupal\data_pipelines\Traits\FieldValueTrait;
+use Drupal\data_pipelines\Traits\JsonPathTrait;
 
 /**
  * A class for providing json as a source.
@@ -19,6 +24,9 @@ use Drupal\data_pipelines\Source\DatasetSourceBase;
  */
 class JsonSource extends DatasetSourceBase {
 
+  use FieldValueTrait;
+  use JsonPathTrait;
+
   /**
    * {@inheritDoc}
    */
@@ -26,6 +34,9 @@ class JsonSource extends DatasetSourceBase {
     try {
       $resource = $this->getResource($dataset);
       $json = json_decode(stream_get_contents($resource), TRUE);
+      if (!empty($json_path_to_data = $this->getJsonPathToData($dataset))) {
+        $json = $this->createJsonPath($json)->find($json_path_to_data)->getData();
+      }
       if (array_values($json) === $json) {
         foreach ($json as $record) {
           yield new DatasetData($record);
@@ -42,4 +53,45 @@ class JsonSource extends DatasetSourceBase {
     }
   }
 
+  /**
+   * A method to get the field value of the plugins path to the data.
+   *
+   * @param \Drupal\data_pipelines\Entity\Dataset $dataset
+   *   The dataset.
+   *
+   * @return string|null
+   *   The path to the data or null.
+   */
+  private function getJsonPathToData(Dataset $dataset): ?string {
+    return self::getFieldValue($dataset, $this->getJsonPathToDataField());
+  }
+
+  /**
+   * A method the get the field name of the plugins path to the data.
+   *
+   * @return string
+   *   The field name.
+   */
+  private function getJsonPathToDataField(): string {
+    return sprintf('%s_path_to_data', $this->getBaseId());
+  }
+
+  /**
+   * {@inheritDoc}
+   */
+  public function buildFieldDefinitions(): array {
+    $base_field_definitions = parent::buildFieldDefinitions();
+    $extra_field_definitions = [
+      $this->getJsonPathToDataField() => BaseFieldDefinition::create('string')
+        ->setLabel(new TranslatableMarkup('Path to data'))
+        ->setDescription(new TranslatableMarkup("This value must be a <a href='@link' target='_blank'>JSON path</a> query expression. Follow the link for examples.", ['@link' => 'https://github.com/SoftCreatR/JSONPath']))
+        ->setSetting('max_length', 255)
+        ->setDisplayOptions('form', [
+          'type' => 'string_textfield',
+        ])
+        ->setPropertyConstraints('value', ['JsonPath' => []])
+    ];
+    return $extra_field_definitions + $base_field_definitions;
+  }
+
 }