Trash Service

On user interface provided by Nuxeo, deleting a document involves several steps before the entire document is actually deleted from the database and disk. It implies to first trash it and then delete it permanently. The second action is only possible if document is in the trash.

Trash Management

Trash feature is managed by TrashService.

Trash / Untrash / Purge Document

When you trash or untrash a document, the TrashService renames it (to avoid any further collision), changes the isTrashed property and then fires the documentTrashed or documentUntrashed event. Once your document is in trashed state, you can untrash it or purge it (remove it permanently).

In order to perform these actions, trash management is exposed as Java API, Automation and REST API.

To use the Java API, as usual you can retrieve the service with Framework.getService(TrashService.class) and then access to the following APIs:

isTrashed
trashDocument / trashDocuments
untrashDocument / untrashDocuments
canPurgeOrUntrash
getAboveDocument - retrieve the first non trashed ancestor
purgeDocumentsUnder
getDocuments - retrieve all documents from the trash of the current document

To use the trash feature through the REST API, you need to use Automation. Several operations are available to perform trash actions:

TrashDocument / Document.Trash
UntrashDocument / Document.Untrash
EmptyTrash / Document.EmptyTrash

The enricher FirstAccessibleAncestorJsonEnricher / firstAccessibleAncestor allows you to get the the first non trashed ancestor of returned document during a REST call. This is useful when you trashed a document and want to know on which document you might redirect your user for instance.

Checking the State

When you're handling DocumentModel you can call isTrashed method to check the state. CoreSession also has this API for convenience.

When you're using the REST API, the return JSON document will have a isTrashed property, for instance:

{
  "entity-type":"document",
  "repository": "REPOSITORY_NAME",
  "uid": "DOCUMENT_UID",
  "path": "DOCUMENT_PATH",
  "type": "DOCUMENT_TYPE",
  "state": "DOCUMENT_STATE",
  "parentRef": "PARENT_DOCUMENT_UID",
  "isCheckedOut": true|false,
  "changeToken": null|"CHANGE_TOKEN",
  "isCheckedOut": true|false,
  "isTrashed": true|false,
  ...
  "properties": {
    ...
  },
  ...
}

You can also filter trashed document when running NXQL by using the ecm:isTrashed property. For instance, in order to get direct children not trashed:

SELECT * FROM Document
  WHERE ecm:parentId = 'DOCUMENT_UID'
  AND ecm:isProxy = 0
  AND ecm:mixinType != 'HiddenInNavigation'
  AND ecm:isVersion = 0
  AND ecm:isTrashed = 0

Permanently Deleting Document

A permanent delete is done by most Nuxeo APIs, typically CoreSession.removeDocument or the higher-level APIs that use it like the CMIS bindings or the Automation Document.Delete operation.

Soft-Delete

If soft-delete is enabled (this is not the case by default), then the document is marked as deleted in the database (using a simple boolean flag) but no rows are actually removed. A search will not be able to find any document marked deleted in this way. From the application's point of view, the document is already fully deleted.

A scheduled periodic process will then hard-delete the documents marked as deleted at a later time, for asynchronous cleanup in fixed-sized batches.

Using Soft-Delete

Soft-delete is available for VCS only.

Soft-delete can be enabled to relieve the database of expected heavy loads if many documents are deleted at the same time.

When Nuxeo has to hard-delete lots of documents, many rows in many tables, themselves related by foreign key constraints, have to be removed. On some databases this can use many resources (like undo segments for Oracle) and take a lot of time, so soft-delete is designed to spread these costly operations over time.

To activate soft-delete, you should change the repository configuration to add <softDelete enabled="true" />. See Configuration Templates for more about updating the default-repository-config.xml.nxftl file.

Please consult NXP-11335 for more details about soft-delete and the configuration of the periodic cleanup.

Hard-Delete

If soft-delete is not enabled, or when the periodic cleanup process for soft-delete happens, the document's data is actually physically deleted from the database by using DELETE SQL statements (or equivalent calls for non-VCS storages).

Trash Migration

As TrashService now leverages the system property ecm:isTrashed by default, you need to migrate your instance.

You need to replace all occurrences of ecm:currentLifeCycleState with deleted state by ecm:isTrashed in your NXQL/Page Provider/Content View, etc.
For instance ecm:currentLifeCycleState = 'deleted' is to replace by ecm:isTrashed = 1.
Add the contribution from section Keeping old trash implementation.
In JSF UI, go to Admin > System Information > Migration, click the button next to Migration of in the trash storage model field and wait until the migration is completed.
Then perform an Elasticsearch re-indexation of all repository. In JSF UI, go to Admin > Elasticsearch > Admin, click the button Re-index repository and wait until the re-indexation is completed.
Remove the contribution added at step 2.
You now need to remove deleted lifecycle state from your lifecycle policies as it is deprecated and not used anymore.

Keeping Old Trash Implementation

The trash implementation has changed in 10.2. If you want to keep previous implementation relying on lifecycle state, add the following contribution:

  <require>org.nuxeo.ecm.core.trash.service.migrator</require>
  <extension target="org.nuxeo.runtime.migration.MigrationService" point="configuration">

    <migration id="trash-storage">
      <defaultState>lifecycle</defaultState>
    </migration>

  </extension>

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