How to migrate content from json?

Question

I have a json file like this

{
  "online": false,
  "key": "123",
  "Product": {
    "name": "product name",
    "Id": 12,
  },
}

I have my json migration file

source:
  plugin: url
  data_fetcher_plugin: file
  data_parser_plugin: json
  urls:
    - 'json_path/data.json'
  item_selector: /Product
  fields:
    - name: keyword
      label: 'Keyword'
      selector: name
  ids:
    product_key:
      type: string
  constants:
    vocabulary: tag
process:
  vid: constants/vocabulary
  name: keyword
destination:
  plugin: entity:taxonomy_term

but I am getting the following error.

Drupal\Core\Database\IntegrityConstraintViolationException: SQLSTATE[23000]: Integrity constraint violation: 1048 Column 'name' cannot be null

It means the xpath is not correct.

I have tried with the item_selector: $ and for the keyword selector selector: Product.name but then I am getting this error.

Passed variable is not an array or object

I have tried with item_selector: 0 and item_selector: / but nothing worked.

However when I use the following json.

{
  "online": false,
  "key": "123",
  "Product": [
    {
      "name": "product name",
      "Id": 12,
    }
  ],
}

Notice the [] brackets.

What is the issue? How can I make it work without the [] brackets because I don't have any control on the json to change it.

Answer 1

The data_parser_plugin: json always expects an array with numeric keys as item_selector, there is no way you can get around this requirement in YAML. If you want to use a single object as item_selector, you have to create your own data_parser_plugin.

I've already had that problem in a previous object and creates my custom plugin and used my custom data_parser_plugin: single_json_object in YAML instead.

file MY_MODULE/src/Plugin/migrate_plus/data_parser/SingleJsonObject.php

<?php

namespace Drupal\MY_MODULE\Plugin\migrate_plus\data_parser;

use Drupal\migrate_plus\Plugin\migrate_plus\data_parser\Json;

/**
 * Obtain JSON data for migration.
 *
 * @DataParser(
 *   id = "single_json_object",
 *   title = @Translation("Single JSON object as root")
 * )
 */
class SingleJsonObject extends Json {

  protected function has_string_keys(array $array) {
    return count(array_filter(array_keys($array), 'is_string')) > 0;
  }

  protected function getSourceData($url) {
    $source_data = parent::getSourceData($url);

    if ($this->has_string_keys($source_data)) {
      $sequential_array = [];
      $sequential_array[] = $source_data;
      $source_data = $sequential_array;
    }

    return $source_data;
  }
}