Content Repository for PHP

Jackalope is an open source implementation of the PHPCR API, which is a PHP adaption of the Java Content Repository (JCR) standard, an open API specification defined in JSR-170/283.
Jackalope implements the PHPCR interfaces and storage agnostic application code. You need to chose one of the transport implementations to get a functional application.

Jackalope-Jackrabbit is the most feature complete and reliable implementation, storing content into the Java server Apache Jackrabbit, the JCR reference implementation.
Jackalope-Doctrine-Dbal uses the Doctrine database abstraction layer to store data into postgres, mysql or sqlite so there is no Java backend involved.