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drupalcampbristol/web/core/modules/migrate/migrate.api.php
2017-02-13 15:31:17 +00:00

139 lines
6 KiB
PHP

<?php
/**
* @file
* Hooks provided by the Migrate module.
*/
use Drupal\migrate\Plugin\MigrationInterface;
use Drupal\migrate\Plugin\MigrateSourceInterface;
use Drupal\migrate\Row;
/**
* @defgroup migration Migration API
* @{
* Overview of the Migration API, which migrates data into Drupal.
*
* @section overview Overview of migration
* Migration is an
* @link http://wikipedia.org/wiki/Extract,_transform,_load Extract, Transform, Load @endlink
* (ETL) process. In the Drupal migration API the extract phase is called
* "source", the transform phase is called "process", and the load phase is
* called "destination". It is important to understand that the "load" in ETL
* means to load data into storage, while traditionally Drupal uses "load" to
* mean load data from storage into memory.
*
* In the source phase, a set of data, called the row, is retrieved from the
* data source, typically a database but it can be a CSV, JSON or XML file. The
* row is sent to the process phase where it is transformed as needed by the
* destination, or marked to be skipped. Processing can also determine that a
* stub needs to be created, for example, if a term has a parent term that does
* not yet exist. After processing the transformed row is passed to the
* destination phase where it is loaded (saved) into the Drupal 8 site.
*
* The ETL process is configured by the migration plugin. The different phases:
* source, process, and destination are also plugins, and are managed by the
* Migration plugin. So there are four types of plugins in the migration
* process: migration, source, process and destination.
*
* @section sec_migrations Migration plugins
* Migration plugin definitions are stored in a module's 'migrations' directory.
* For backwards compatibility we also scan the 'migration_templates' directory.
* Examples of migration plugin definitions can be found in
* 'core/modules/action/migration_templates'. The plugin class is
* \Drupal\migrate\Plugin\Migration, with interface
* \Drupal\migrate\Plugin\MigrationInterface. Migration plugins are managed by
* the \Drupal\migrate\Plugin\MigrationPluginManager class. Migration plugins
* are only available if the providers of their source plugins are installed.
*
* @section sec_source Source plugins
* Migration source plugins implement
* \Drupal\migrate\Plugin\MigrateSourceInterface and usually extend
* \Drupal\migrate\Plugin\migrate\source\SourcePluginBase. They are annotated
* with \Drupal\migrate\Annotation\MigrateSource annotation, and must be in
* namespace subdirectory Plugin\migrate\source under the namespace of the
* module that defines them. Migration source plugins are managed by the
* \Drupal\migrate\Plugin\MigrateSourcePluginManager class. Source plugin
* providers are determined by their and their parents namespaces.
*
* @section sec_process Process plugins
* Migration process plugins implement
* \Drupal\migrate\Plugin\MigrateProcessInterface and usually extend
* \Drupal\migrate\ProcessPluginBase. They are annotated
* with \Drupal\migrate\Annotation\MigrateProcessPlugin annotation, and must be
* in namespace subdirectory Plugin\migrate\process under the namespace of the
* module that defines them. Migration process plugins are managed by the
* \Drupal\migrate\Plugin\MigratePluginManager class. The Migrate module
* provides process plugins for common operations (setting default values,
* mapping values, etc.).
*
* @section sec_destination Destination plugins
* Migration destination plugins implement
* \Drupal\migrate\Plugin\MigrateDestinationInterface and usually extend
* \Drupal\migrate\Plugin\migrate\destination\DestinationBase. They are
* annotated with \Drupal\migrate\Annotation\MigrateDestination annotation, and
* must be in namespace subdirectory Plugin\migrate\destination under the
* namespace of the module that defines them. Migration destination plugins
* are managed by the \Drupal\migrate\Plugin\MigrateDestinationPluginManager
* class. The Migrate module provides destination plugins for Drupal core
* objects (configuration and entity).
*
* @section sec_more_info More information
* @link https://www.drupal.org/node/2127611 Migration API documentation. @endlink
*
* @see update_api
* @}
*/
/**
* @addtogroup hooks
* @{
*/
/**
* Allows adding data to a row before processing it.
*
* For example, filter module used to store filter format settings in the
* variables table which now needs to be inside the filter format config
* file. So, it needs to be added here.
*
* hook_migrate_MIGRATION_ID_prepare_row() is also available.
*
* @ingroup migration
*/
function hook_migrate_prepare_row(Row $row, MigrateSourceInterface $source, MigrationInterface $migration) {
if ($migration->id() == 'd6_filter_formats') {
$value = $source->getDatabase()->query('SELECT value FROM {variable} WHERE name = :name', array(':name' => 'mymodule_filter_foo_' . $row->getSourceProperty('format')))->fetchField();
if ($value) {
$row->setSourceProperty('settings:mymodule:foo', unserialize($value));
}
}
}
/**
* Allows altering the list of discovered migration plugins.
*
* Modules are able to alter specific migrations structures or even remove or
* append additional migrations to the discovery. For example, this
* implementation filters out Drupal 6 migrations from the discovered migration
* list. This is done by checking the migration tags.
*
* @param array[] $migrations
* An associative array of migrations keyed by migration ID. Each value is the
* migration array, obtained by decoding the migration YAML file and enriched
* with some meta information added during discovery phase, like migration
* 'class', 'provider' or '_discovered_file_path'.
*
* @ingroup migration
*/
function hook_migration_plugins_alter(array &$migrations) {
$migrations = array_filter($migrations, function (array $migration) {
$tags = isset($migration['migration_tags']) ? (array) $migration['migration_tags'] : [];
return !in_array('Drupal 6', $tags);
});
}
/**
* @} End of "addtogroup hooks".
*/