Migrate Source JCR

The Migrate Source JCR module provides a source plugin for migrating from Java Content Repository (JCR) storage. It leverages Jackalope, an implementation of PHPCR, for queries.

The general approach for using this plugin is:

1. Allow access to the JCR instance from Drupal.
2. Write a Drupal migration using the JCR source plugin.

Writing the migrations will require a working knowledge of how JCR data is structured and how to map it to the structure inside Drupal. Refer to the Resources below and related Documentation for help.

REQUIREMENTS

There are no additional requirements for using the JCR migration plugin. However, making sure the JCR source is setup and accessible to Drupal may have its own considerations.

INSTALLATION

This module is installed similar to other Drupal modules. Because there are composer dependencies it is important that this module be installed via composer. After requiring the module with composer, enable the module on the site.

CONFIGURATION

There is no additional configuration required to use the JCR source plugin.

USAGE

Please refer to the online documentation for detailed information about its usage: Migrating data from a JCR source.

RECOMMENDED MODULES

These two modules are useful for working with migrations:

• Migrate Plus - Allows migration plugins to be implemented as configuration entities, allowing them to flexibly be loaded, modified, and saved.
• Migrate Tools - Provides the ‘migrate:import’ Drush command that you can use to run the migration from the command line.

Given the complex nature of migrating from JCR it may be worth considering the use of a hierarchical data structure in Drupal using a module like Paragraphs and migrating into nested paragraph types.

RESOURCES

• #migration in the Drupal Slack
• Jackalope documentation, which links to the PHPCR Book
• The PHPCR Book, for understanding in detail how JCR queries work
• Magnolia CMS’ JCR Query Cheat Sheet
• Paul Rohrbeck’s Query Builder Cheat Sheet
• Wikipedia’s JCR page, shows a list of possible migration sources

ROADMAP

There are no planned improvements or changes. However, feel welcome to share ideas in the issue queue.

KNOWN PROBLEMS

• During a migration it may run out of memory, a temporary work around is to repeat the migration until it passes; see #2701121
• Paragraphs only: #3075039 Ability to map paragraphs to an entity
• Paragraphs only: #3075041 Ability to map subparagraphs to a paragraph

CONTRIBUTING

Migrating from JCR storage to Drupal is a complex process and having tangible examples for migrations would help us understand better what opportunities there are for improving it. If you are using Migrate Source JCR on a project, share with the community how you’re using it and what opportunities there are for improving it by submitting a case study.

If you have a bug or issue, please always feel welcome to reach out in the issue queue.