Drupal 7 Scald Atom Source Plugin for Drupal 8 Migration

ScaldAtom.php

<?php
namespace Drupal\your_module\Plugin\migrate\source;

use Drupal\Core\Database\Query\Condition;
use Drupal\migrate\Row;
use Drupal\migrate_drupal\Plugin\migrate\source\d7\FieldableEntity;

/**
 * Processes Scald Media items to Drupal 8 Media entities.
 *
 * @MigrateSource(
 *   id = "d7_scald_atom",
 *   source_provider = "scald",
 *   source_module = "scald",
 * )
 */
class ScaldAtom extends FieldableEntity {

  /**
   * {@inheritdoc}
   */
  public function query() {
    $query = $this->select('scald_atoms', 's')
      ->fields('s', array(
        'sid',
        'provider',
        'type',
        'base_id',
        'language',
        'publisher',
        'actions',
        'title',
        'data',
        'created',
        'changed',
        'publisher',
      ));
    
    if (isset($this->configuration['atom_type'])) {
      if ($this->configuration['atom_type'] === 'image') {
        $query->fields('st', array(
          'scald_thumbnail_alt'
        ))
        ->fields('cred', array(
          'field_credit_value'
        ))
        ->fields('url', array(
          'field_photo_credit_url_url'
        ))
        ->fields('cap', array(
          'field_caption_long_value'
        ))
        ->fields('cop', array(
          'field_copyright_value'
        ))
        ->fields('fm', array(
          'uri'
        ));

        $query->leftJoin('field_data_scald_thumbnail', 'st', 'st.entity_id = s.sid');
        $query->leftJoin('field_data_field_credit', 'cred', 'cred.entity_id = s.sid');
        $query->leftJoin('field_data_field_photo_credit_url', 'url', 'url.entity_id = s.sid');
        $query->leftJoin('field_data_field_caption_long', 'cap', 'cap.entity_id = s.sid');
        $query->leftJoin('field_data_field_copyright', 'cop', 'cop.entity_id = s.sid');
        $query->leftJoin('file_managed', 'fm', 'fm.fid = s.base_id');
      } else if ($this->configuration['atom_type'] === 'video') {
        $query->fields('cred', array(
          'field_credit_value'
        ))
        ->fields('cap', array(
          'field_caption_long_value'
        ))
        ->fields('cop', array(
          'field_copyright_value'
        ));

        $query->leftJoin('field_data_field_credit', 'cred', 'cred.entity_id = s.sid');
        $query->leftJoin('field_data_field_caption_long', 'cap', 'cap.entity_id = s.sid');
        $query->leftJoin('field_data_field_copyright', 'cop', 'cop.entity_id = s.sid');
        $query->leftJoin('file_managed', 'fm', 'fm.fid = s.base_id');
      } else if ($this->configuration['atom_type'] === 'file') {
        // Exclude JS files for now.
        $query->fields('fm', array(
          'filemime',
          'uri',
          'uid'
        ));
        $query->leftJoin('file_managed', 'fm', 'fm.fid = s.base_id');
        $query->condition('fm.filemime', ['application/octet-stream', 'application/x-shockwave-flash', 'application/x-javascript', 'text/css', 'application/zip', 'text/html', 'application/xml', 'text/x-component', 'text/calendar', 'application/vnd.google-earth.kmz'], 'NOT IN');
      }

      $query->condition('s.type', $this->configuration['atom_type']);
    }

    if (isset($this->configuration['provider'])) {
      $query->condition('s.provider', $this->configuration['provider']);
    }

    return $query;
  }

  /**
   * {@inheritdoc}
   */
  public function prepareRow(Row $row) {

    $sid = $row->getSourceProperty('sid');
    $type = $row->getSourceProperty('type');

    // Get Field API field values.
    foreach (array_keys($this->getFields('scald_atoms', $type)) as $field) {
      $row->setSourceProperty($field, $this->getFieldValues('scald_atoms', $field, $sid));
    }

    if ($type === 'audio') {
      $data =  unserialize($row->getSourceProperty('data'));
      $row->setSourceProperty('permalink_url', isset($data['permalink_url']) ? $data['permalink_url'] : 'somthing');
    }

    return parent::prepareRow($row);
  }

  /**
   * {@inheritdoc}
   */
  public function fields() {
    return array(
      'sid' => $this->t('Scald Atom ID'),
      'provider' => $this->t('Provider module name'),
      'type' => $this->t('Scald Atom type'),
      'base_id' => $this->t('Scald Atom base ID'),
      'language' => $this->t('Scald Atom language'),
      'publisher' => $this->t('Scald Atom publisher (User ID)'),
      'actions' => $this->t('Available Scald actions'),
      'title' => $this->t('Scald Atom title'),
      'data' => $this->t('Scald Atom data'),
      'created' => $this->t('Created timestamp'),
      'changed' => $this->t('modified timestamp'),
      'scald_thumbnail_alt' => $this->t('Alternative text for images'),
      'field_credit_value' => $this->t('Credit text value'),
      'field_photo_credit_url_url' => $this->t('photo credit text value'),
      'field_caption_long_value' => $this->t('Caption text value'),
      'field_copyright_value' => $this->t('Copyright text value'),
      'publisher' => $this->t('the user id'),
      'uri' => $this->t('File uri'),
    );
  }

  /**
   * {@inheritdoc}
   */
  public function getIds() {
    $ids['sid']['type'] = 'integer';
    $ids['sid']['alias'] = 's';
    return $ids;
  }
}