class MigrationLookup

Same name in other branches
  1. 8.9.x core/modules/migrate/src/Plugin/migrate/process/MigrationLookup.php \Drupal\migrate\Plugin\migrate\process\MigrationLookup
  2. 10 core/modules/migrate/src/Plugin/migrate/process/MigrationLookup.php \Drupal\migrate\Plugin\migrate\process\MigrationLookup
  3. 11.x core/modules/migrate/src/Plugin/migrate/process/MigrationLookup.php \Drupal\migrate\Plugin\migrate\process\MigrationLookup

Looks up the value of a property based on a previous migration.

It is important to maintain relationships among content coming from the source site. For example, on the source site, a given user account may have an ID of 123, but the Drupal user account created from it may have a uid of 456. The migration process maintains the relationships between source and destination identifiers in map tables, and this information is leveraged by the migration_lookup process plugin.

Available configuration keys

  • migration: A single migration ID, or an array of migration IDs.
  • source_ids: (optional) An array keyed by migration IDs with values that are a list of source properties.
  • stub_id: (optional) Identifies the migration which will be used to create any stub entities.
  • no_stub: (optional) Prevents the creation of a stub entity when no relationship is found in the migration map.

Examples:

Consider a node migration, where you want to maintain authorship. Let's assume that users are previously migrated in a migration named 'users'. The 'users' migration saved the mapping between the source and destination IDs in a map table. The node migration example below maps the node 'uid' property so that we first take the source 'author' value and then do a lookup for the corresponding Drupal user ID from the map table.


process:
  uid:
    plugin: migration_lookup
    migration: users
    source: author

The value of 'migration' can be a list of migration IDs. When using multiple migrations it is possible each use different source identifiers. In this case one can use source_ids which is an array keyed by the migration IDs and the value is a list of source properties. See example below.


process:
  uid:
    plugin: migration_lookup
    migration:
      - users
      - members
    source_ids:
      users:
        - author
      members:
        - id

It's not required to describe source identifiers for each migration. If the source identifier for a migration is not specified, the default source value will be used. In the example below, the 'author' source property will be used to do a lookup in the 'users' migration, and the 'uid' property in the 'members' migration.


process:
  uid:
    plugin: migration_lookup
    source: uid
    migration:
      - users
      - members
    source_ids:
      users:
        - author

If the migration_lookup plugin does not find the source ID in the migration map it will create a stub entity for the relationship to use. This stub is generated by the migration provided. In the case of multiple migrations the first value of the migration list will be used, but you can select the migration you wish to use by using the stub_id configuration key. The example below uses 'members' migration to create stub entities.


process:
  uid:
    plugin: migration_lookup
    migration:
      - users
      - members
    stub_id: members

To prevent the creation of a stub entity when no relationship is found in the migration map, 'no_stub' configuration can be used as shown below.


process:
  uid:
    plugin: migration_lookup
    migration: users
    no_stub: true
    source: author

If the source value passed in to the plugin is NULL, boolean FALSE, an empty array or an empty string, the plugin will throw a MigrateSkipProcessException, causing further plugins in the process to be skipped.

Plugin annotation


@MigrateProcessPlugin(
  id = "migration_lookup"
)

Hierarchy

Expanded class hierarchy of MigrationLookup

See also

\Drupal\migrate\Plugin\MigrateProcessInterface

1 file declares its use of MigrationLookup
MigrationLookupTest.php in core/modules/migrate/tests/src/Unit/process/MigrationLookupTest.php

File

core/modules/migrate/src/Plugin/migrate/process/MigrationLookup.php, line 127

Namespace

Drupal\migrate\Plugin\migrate\process
View source
class MigrationLookup extends ProcessPluginBase implements ContainerFactoryPluginInterface {
    
    /**
     * The migration to be executed.
     *
     * @var \Drupal\migrate\Plugin\MigrationInterface
     */
    protected $migration;
    
    /**
     * The migrate lookup service.
     *
     * @var \Drupal\migrate\MigrateLookupInterface
     */
    protected $migrateLookup;
    
    /**
     * The migrate stub service.
     *
     * @var \Drupal\migrate\MigrateStubInterface
     */
    protected $migrateStub;
    
    /**
     * Constructs a MigrationLookup object.
     *
     * @param array $configuration
     *   A configuration array containing information about the plugin instance.
     * @param string $plugin_id
     *   The plugin_id for the plugin instance.
     * @param mixed $plugin_definition
     *   The plugin implementation definition.
     * @param \Drupal\migrate\Plugin\MigrationInterface $migration
     *   The Migration the plugin is being used in.
     * @param \Drupal\migrate\MigrateLookupInterface $migrate_lookup
     *   The migrate lookup service.
     * @param \Drupal\migrate\MigrateStubInterface $migrate_stub
     *   The migrate stub service.
     */
    public function __construct(array $configuration, $plugin_id, $plugin_definition, MigrationInterface $migration, MigrateLookupInterface $migrate_lookup, MigrateStubInterface $migrate_stub) {
        parent::__construct($configuration, $plugin_id, $plugin_definition);
        $this->migration = $migration;
        $this->migrateLookup = $migrate_lookup;
        $this->migrateStub = $migrate_stub;
    }
    
    /**
     * {@inheritdoc}
     */
    public static function create(ContainerInterface $container, array $configuration, $plugin_id, $plugin_definition, MigrationInterface $migration = NULL) {
        return new static($configuration, $plugin_id, $plugin_definition, $migration, $container->get('migrate.lookup'), $container->get('migrate.stub'));
    }
    
    /**
     * {@inheritdoc}
     *
     * @throws \Drupal\migrate\MigrateSkipProcessException
     * @throws \Drupal\migrate\MigrateException
     */
    public function transform($value, MigrateExecutableInterface $migrate_executable, Row $row, $destination_property) {
        $lookup_migration_ids = (array) $this->configuration['migration'];
        $self = FALSE;
        $destination_ids = NULL;
        $source_id_values = [];
        foreach ($lookup_migration_ids as $lookup_migration_id) {
            $lookup_value = $value;
            if ($lookup_migration_id == $this->migration
                ->id()) {
                $self = TRUE;
            }
            if (isset($this->configuration['source_ids'][$lookup_migration_id])) {
                $lookup_value = array_values($row->getMultiple($this->configuration['source_ids'][$lookup_migration_id]));
            }
            $lookup_value = (array) $lookup_value;
            $this->skipInvalid($lookup_value);
            $source_id_values[$lookup_migration_id] = $lookup_value;
            // Re-throw any PluginException as a MigrateException so the executable
            // can shut down the migration.
            try {
                $destination_id_array = $this->migrateLookup
                    ->lookup($lookup_migration_id, $lookup_value);
            } catch (PluginNotFoundException $e) {
                $destination_id_array = [];
            } catch (MigrateException $e) {
                throw $e;
            } catch (\Exception $e) {
                throw new MigrateException(sprintf('A %s was thrown while processing this migration lookup', gettype($e)), $e->getCode(), $e);
            }
            if ($destination_id_array) {
                $destination_ids = array_values(reset($destination_id_array));
                break;
            }
        }
        if (!$destination_ids && !empty($this->configuration['no_stub'])) {
            return NULL;
        }
        if (!$destination_ids && ($self || isset($this->configuration['stub_id']) || count($lookup_migration_ids) == 1)) {
            // If the lookup didn't succeed, figure out which migration will do the
            // stubbing.
            if ($self) {
                $stub_migration = $this->migration
                    ->id();
            }
            elseif (isset($this->configuration['stub_id'])) {
                $stub_migration = $this->configuration['stub_id'];
            }
            else {
                $stub_migration = reset($lookup_migration_ids);
            }
            // Rethrow any exception as a MigrateException so the executable can shut
            // down the migration.
            try {
                $destination_ids = $this->migrateStub
                    ->createStub($stub_migration, $source_id_values[$stub_migration], [], FALSE);
            } catch (\LogicException $e) {
                // For BC reasons, we must allow attempting to stub a derived migration.
            } catch (PluginNotFoundException $e) {
                // For BC reasons, we must allow attempting to stub a non-existent
                // migration.
            } catch (MigrateException $e) {
                throw $e;
            } catch (MigrateSkipRowException $e) {
                throw $e;
            } catch (\Exception $e) {
                throw new MigrateException(sprintf('%s was thrown while attempting to stub: %s', get_class($e), $e->getMessage()), $e->getCode(), $e);
            }
        }
        if ($destination_ids) {
            if (count($destination_ids) == 1) {
                return reset($destination_ids);
            }
            else {
                return $destination_ids;
            }
        }
    }
    
    /**
     * Skips the migration process entirely if the value is invalid.
     *
     * @param array $value
     *   The incoming value to check.
     *
     * @throws \Drupal\migrate\MigrateSkipProcessException
     */
    protected function skipInvalid(array $value) {
        if (!array_filter($value, [
            $this,
            'isValid',
        ])) {
            throw new MigrateSkipProcessException();
        }
    }
    
    /**
     * Determines if the value is valid for lookup.
     *
     * The only values considered invalid are: NULL, FALSE, [] and "".
     *
     * @param string $value
     *   The value to test.
     *
     * @return bool
     *   Return true if the value is valid.
     */
    protected function isValid($value) {
        return !in_array($value, [
            NULL,
            FALSE,
            [],
            "",
        ], TRUE);
    }

}

Members

Title Sort descending Modifiers Object type Summary Overriden Title Overrides
MigrationLookup::$migrateLookup protected property The migrate lookup service.
MigrationLookup::$migrateStub protected property The migrate stub service.
MigrationLookup::$migration protected property The migration to be executed.
MigrationLookup::create public static function Creates an instance of the plugin. Overrides ContainerFactoryPluginInterface::create
MigrationLookup::isValid protected function Determines if the value is valid for lookup.
MigrationLookup::skipInvalid protected function Skips the migration process entirely if the value is invalid.
MigrationLookup::transform public function Overrides ProcessPluginBase::transform
MigrationLookup::__construct public function Constructs a MigrationLookup object.
PluginInspectionInterface::getPluginDefinition public function Gets the definition of the plugin implementation. 6
PluginInspectionInterface::getPluginId public function Gets the plugin_id of the plugin instance. 2
ProcessPluginBase::multiple public function Indicates whether the returned value requires multiple handling. Overrides MigrateProcessInterface::multiple 3

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