Import and export dataΒΆ

As promised, here are some more details on importing and exporting data. There are two formats:

  • The document view translates the data into a XML document with node names

    as xml elements and properties as attributes and thus very readable. Type information is lost, and illegal XML characters are encoded.

  • The system view is a more strict XML document defining the exact structure

    of the repository with all type information. However, it is more verbose.

As an analogy, think about an SQL dump file with SQL statements and the dump of an SQL table into a csv file. You can restore the data from both, but the SQL dump knows every detail about your field types and so on while the CSV just knows the data.

When exporting, you explicitly call a method corresponding to the desired format:

<?php
$file = fopen('/tmp/document.xml', 'w+');

// dump the tree at /foo/bar into a document view file
$session->exportDocumentView(
    '/data/sibling',
    $file,
    true, // skip binary properties to not have large files in the dump
    false // recursivly output the child nodes as well
);

fclose($file);

$file = fopen('/tmp/system.xml', 'w+');
// export the tree at /foo/bar into a system view xml file
$session->exportSystemView(
    '/data/sibling',
    $file,
    false, // do not skip binary properties
    false
);

fclose($file);

Importing detects the format automatically. If the document is a valid JCR system view, it is interpreted according to that format, otherwise if it is a valid XML document it is imported as document:

<?php
$filename = 'dump.xml';
$session->getRootNode()->addNode('imported_data', 'nt:unstructured');
$session->importXML(
    '/imported_data', // attach the imported data at this node
    $filename,
    ImportUUIDBehaviorInterface::IMPORT_UUID_CREATE_NEW
);

When importing nodes with a uuid, a couple of different behaviors can be used:

  • IMPORT_UUID_CREATE_NEW: Create new UUIDs for nodes that are imported, so you never get collisions.
  • IMPORT_UUID_COLLISION_THROW: Throw an exception if a node with the same UUID already exists.
  • IMPORT_UUID_COLLISION_REMOVE_EXISTING: Remove an existing node if an imported node has the same UUID.
  • IMPORT_UUID_COLLISION_REPLACE_EXISTING: Replace existing node with the imported node. This can lead to the imported data being put in various places.