Migrate File Entities to Media Entities

Migrate File Entities to Media Entities This module allows you to migrate Drupal 8.0 file entities to Drupal 8.5 media entities using the migrate module.

Lately, also support for Drupal 7 entities was added.

Main features:
* While migrating the files, a binary hash of all images is calculated and duplicate files are recognized. If the same file was uploaded multiple times, only one media entity will be created.
* Migration of translated file/image fields is supported. Having different images per language will create a translated media entity with the corresponding image.
* Using migrate module allows drush processing, rollback and track changes.

Usage
* Install the module.
* If you want to migrate file fields for all content revisions then you have to fix the issues related to the content moderate and revisions. For this, you can use known core patches:
* #3052115: Mark an entity as 'syncing' during a migration update
* #2329253: Allow the ChangedItem to skip updating the entity's "changed" timestamp when synchronizing (f.e. when migrating)
* #3338260: Skip changing 'revision translation affected' field if the old revision is syncing
* Possible will be useful in some cases: #2859042: Impossible to update an entity revision if the field value you are updating matches the default revision.



Preparation: Install media core module Before you can start, you need to install the media module of Drupal Core. This will automatically create 4 (in Drupal 8.5) or 5 (in Drupal 8.6) media bundle types for you, namely image, video, file and audio.

Generate the target media fields Generate the media fields based on the existing file fields using the following drush command:

drush migrate:file-media-fields <entity_type> <bundle> <source_field_type> <target_media_bundle>

Example
drush migrate:file-media-fields node article image imageFor all file fields the corresponding media entity reference fields will be automatically created suffixed by _media.

Create a custom migration per content type based on the migrate_file_to_media_example module
* Create a custom module
* Create your custom migration templates using the included yml generator.
* The module supports nodes and also paragraphs and any other entity type as a source bundle.

There are two possible generators for that:


* Drupal code generator v1 (Drush 10) - drush generate migrate_file_to_media:media_migration_generator:v1
* Drupal code generator v2 (Drush 11) - drush generate migrate_file_to_media:media_migration_generator:v2

Welcome to migrate_file_to_media:media_migration_generator:v1 generator! ––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––– Module machine name: ➤ migrate_file_to_media_exampleThe generator will ask you several questions about the module, the source bundle and the target media entity. It will generate several files based on your answers, that can be used to migrate the files to media entity.

Refresh / check migrations If you created a new module with the generator, you can just enable the module and the migrations will be visible when running drush ms. If you generated the migration files into an existing module, you will have to install the module config_devel and update your mymodule.info.yml file. You can find a nice documentation about config_devel here: https://drupal.stackexchange.com/questions/191435/how-to-refresh-new-mig...

Prepare duplicate file detection In order to detect duplicate files / images, run the following drush command to calculate a binary hash for all files. The data will be saved to the table "migrate_file_to_media_mapping". You need to run this drush command before you can import media entities.

drush migrate:duplicate-file-detection <migration_name>(optional step): Check for existing medias Sometimes you already have media entities in your database or you have multiple migrations and would like to avoid duplicate media entities. Here is the solution:


Run the command drush migrate:duplicate-media-detection image --all. (see drush help migrate:duplicate-media-detection for extra options)
Run the duplicate file detection for step 1 of your file migration: drush migrate:duplicate-file-detection <migration_name> --check-existing-media
Run step 1 and 2 of your file migrations as described on the project page or the readme.

Migrate the images to media entities Check the migrations using
drush migrate:statusRun the migrations using
drush migrate:import <migration_name>Explanation of the generated migration files Step 1:
File config/install/migrate_plus.migration.migrate_file_to_media_example_article_images_step1.yml

This is the starting point. This migration creates a unique media entity from all files / images referenced by fields in the configuration field_names of the source plugin. In the example, we have two image fields called: "field_image" and "field_image2".

Important: The drush command to calculate the binary hash need to be run before you can use the media_entity_generator source plugin.

Using rokka.io on Step 1:
File config/install/migrate_plus.migration.migrate_file_to_media_example_article_images_step1_rokka.yml

This is an example migration, how to move all images to the rokka.io image cdn. You need to install the drupal rokka module.

Step 2:
File config/install/migrate_plus.migration.migrate_file_to_media_example_article_images_step1_de.yml

This migration adds a translation to existing media entities if a translated file / image field is found.

Step 3:
File config/install/migrate_plus.migration.migrate_file_to_media_example_article_images_step2.yml

This migration links the newly created media entities with entity reference field on the target bundle.