Json.php in Migrate Plus 8

Contains Drupal\migrate_plus\Plugin\migrate_plus\data_parser\JSON.

This parser can traverse multidimensional arrays and retrieve results by locating subarrays that contain a known identifier field at a known depth. It can locate id fields that are nested in the results and pull out all other content that is at the same level. If that content contains additional nested arrays or needs other manipulation, extend this class and massage the data further in the getSourceFields() method.

For example, a file that adheres to the JSON API might look like this:

Source: [ links [ self: http://example.com/this_path.json ], data [ entry [ id: 1 value1: 'something' value2: [ 0: green 1: blue ] ] entry [ id: 2 value1: 'something else' value2: [ 0: yellow 1: purple ] ] ] ]

The resulting source fields array, using identifier = 'id' and identifierDepth = 2, would be: [ 0 [ id: 1 value1: 'something' value2: [ 0: green 1: blue ] ] 1 [ id: 2, value1: 'something else' value2: [ 0: yellow 1: purple ] ] ]

In the above example, the id field and the value1 field would be transformed to top-level key/value pairs, as required by Migrate. The value2 field, if needed, might require further manipulation by extending this class.

Namespace

Drupal\migrate_plus\Plugin\migrate_plus\data_parser

See also

http://php.net/manual/en/class.recursiveiteratoriterator.php

File

src/Plugin/migrate_plus/data_parser/Json.php

<?php

/**
 * @file
 * Contains Drupal\migrate_plus\Plugin\migrate_plus\data_parser\JSON.
 *
 * This parser can traverse multidimensional arrays and retrieve results
 * by locating subarrays that contain a known identifier field at a known depth.
 * It can locate id fields that are nested in the results and pull out all other
 * content that is at the same level. If that content contains additional nested
 * arrays or needs other manipulation, extend this class and massage the data further
 * in the getSourceFields() method.
 *
 * For example, a file that adheres to the JSON API might look like this:
 *
 * Source:
 * [
 *   links [
 *     self: http://example.com/this_path.json
 *   ],
 *   data [
 *     entry [
 *       id: 1
 *       value1: 'something'
 *       value2: [
 *         0: green
 *         1: blue
 *       ]
 *     ]
 *     entry [
 *       id: 2
 *       value1: 'something else'
 *       value2: [
 *         0: yellow
 *         1: purple
 *       ]
 *     ]
 *   ]
 * ]
 *
 * The resulting source fields array, using identifier = 'id' and identifierDepth = 2, would be:
 * [
 *   0 [
 *     id: 1
 *     value1: 'something'
 *     value2: [
 *       0: green
 *       1: blue
 *     ]
 *   ]
 *   1 [
 *     id: 2,
 *     value1: 'something else'
 *     value2: [
 *       0: yellow
 *       1: purple
 *     ]
 *   ]
 * ]
 *
 * In the above example, the id field and the value1 field would be transformed
 * to top-level key/value pairs, as required by Migrate. The value2 field,
 * if needed, might require further manipulation by extending this class.
 *
 * @see http://php.net/manual/en/class.recursiveiteratoriterator.php
 */
namespace Drupal\migrate_plus\Plugin\migrate_plus\data_parser;

use Drupal\Core\Plugin\ContainerFactoryPluginInterface;
use Drupal\migrate\MigrateException;
use Drupal\migrate_plus\DataParserPluginBase;
use GuzzleHttp\Exception\RequestException;

/**
 * Obtain JSON data for migration.
 *
 * @DataParser(
 *   id = "json",
 *   title = @Translation("JSON")
 * )
 */
class Json extends DataParserPluginBase implements ContainerFactoryPluginInterface {

  /**
   * The request headers passed to the data fetcher.
   *
   * @var array
   */
  protected $headers = [];

  /**
   * Iterator over the JSON data.
   *
   * @var \Iterator
   */
  protected $iterator;

  /**
   * {@inheritdoc}
   */
  public function __construct(array $configuration, $plugin_id, $plugin_definition) {
    parent::__construct($configuration, $plugin_id, $plugin_definition);
  }

  /**
   * {@inheritdoc}
   */
  protected function getSourceData($url) {
    $iterator = $this
      ->getSourceIterator($url);

    // Recurse through the result array. When there is an array of items at the
    // expected depth, pull that array out as a distinct item.
    $identifierDepth = $this->itemSelector;
    $items = [];
    while ($iterator
      ->valid()) {
      $iterator
        ->next();
      $item = $iterator
        ->current();
      if (is_array($item) && $iterator
        ->getDepth() == $identifierDepth) {
        $items[] = $item;
      }
    }
    return $items;
  }

  /**
   * Get the source data for reading.
   *
   * @param string $url
   *   The URL to read the source data from.
   *
   * @return \RecursiveIteratorIterator|resource
   *
   * @throws \Drupal\migrate\MigrateException
   */
  protected function getSourceIterator($url) {
    try {
      $response = $this
        ->getDataFetcherPlugin()
        ->getResponseContent($url);

      // The TRUE setting means decode the response into an associative array.
      $array = json_decode($response, TRUE);

      // Return the results in a recursive iterator that
      // can traverse multidimensional arrays.
      return new \RecursiveIteratorIterator(new \RecursiveArrayIterator($array), \RecursiveIteratorIterator::SELF_FIRST);
    } catch (RequestException $e) {
      throw new MigrateException($e
        ->getMessage(), $e
        ->getCode(), $e);
    }
  }

  /**
   * {@inheritdoc}
   */
  protected function openSourceUrl($url) {

    // (Re)open the provided URL.
    $source_data = $this
      ->getSourceData($url);
    $this->iterator = new \ArrayIterator($source_data);
    return TRUE;
  }

  /**
   * {@inheritdoc}
   */
  protected function fetchNextRow() {
    $current = $this->iterator
      ->current();
    if ($current) {
      foreach ($this
        ->fieldSelectors() as $field_name => $selector) {
        $this->currentItem[$field_name] = $current[$selector];
      }
      $this->iterator
        ->next();
    }
  }

}

Classes

Name	Description
Json	Obtain JSON data for migration.