Restore capability

Contents

Site setting
Registration
Entity menu
View deleted items
- Custom views
Restore a deleted item
Events
ElggEntity functions
Show deleted items
Cleanup of deleted entities
More information

As of Elgg 6.0 it’s possible to set the restorable capability on an ElggEntity. Enabling this capability will mark an entity as deleted in the database when the ElggEntity::delete() function is called. The entity will then no longer show up in listings or work when viewing it directly.

Site setting 

A site administrator has the option to enable/disable all restore features. By default this feature is disabled. This means that even if an entity has the capability restorable it will always be permanently removed from the database.

Registration 

Just like any other entity capability you can enable the restorable capability in the elgg-plugin.php

'entities' => [
        [
                'type' => 'object',
                'subtype' => 'my_custom_subtype',
                'capabilities' => [
                        'restorable' => true,
                ],
        ],
]

Entity menu 

By default a menu item is added to the entity menu which allows a user to delete the entity when the user has the rights to do so.

If an entity has the restorable capability this menu item will be replaced with a menu item which will mark the entity as deleted.

Bemerkung

When the site administrator hasn’t enabled the feature no menu items will be replaced.

Bemerkung

There are 2 generic actions to help developers in case they need to add a delete link somewhere.

entity/delete: this will permanently delete the entity from the database, requires a guid to be submitted to the action
entity/trash: this will mark the entity as deleted in the database, requires a guid to be submitted to the action

View deleted items 

Once an entity has been marked as deleted it’ll no longer show up in the normal functionality of your Elgg website.

In order for a user to see the entities that have been deleted there is a link in the user settings to a list of all deleted items that are owned by the given user.

Group owners also have the ability to see the deleted content from their group. This is accessible from the group profile page. The list will show all deleted content contained by their group.

Bemerkung

The list will only show the deleted entities with the restorable capability. For example when a blog has been deleted which also has comments only the blog will show up in the deleted list of the owner (and in the deleted list of the group if the blog was posted in a group).

The comments will not show up in any list of deleted items.

Custom views 

When a developer needs to have a custom view of a deleted item a view trash/<entity_type>/<entity_subtype> can be made which will get provided the deleted entity in $vars['entity']. As a fallback trash/<entity_type>/default will be tried and ultimately trash/entity/default which is provided by Elgg core.

Different sub-elements can be found in the views trash/elements/*.

Bemerkung

When making a custom view for an entity make sure it doesn’t include links to the deleted entity as that link will not work. Also keep in mind other links to entities that could have been deleted.

Restore a deleted item 

From the deleted list the user (or group owner) has the ability to restore the deleted item to it’s original state. If the entity was contained in a group which was removed, the user has the option to restore the entity to a different container.

Events 

When an entity is being marked as deleted there is an event sequence 'trash', '<entity_type>' with which a developer can program additional action or logic.

ElggEntity functions 

There are 3 functions in an ElggEntity related to the deletion of that entity:

public function delete(bool $recursive = true, bool $persistent = null): bool
protected function persistentDelete(bool $recursive = true): bool
protected function trash(bool $recursive = true): bool
public function isDeleted(): bool

Function: delete 

This is the only public function to delete an entity. The $recursive parameter will determine whether or not other entities which have this entity as it’s owner or container will also be deleted (default true).

The $persistent parameter can force a persistent removal from the database or it being marked as deleted. The default value is null which means the restorable capability will be checked.

Warnung

It’s not recommended that a developer overrules this function as the developer will have to handle part of the logic of determining the correct value of the $persistent parameter.

Function: persistentDelete 

This function is called when the $persistent parameter is true in the delete() function. This function must handle cases where the entity is permanently removed from the database. An example of when a developer would overrule this function is an ElggFile where the physical file on disk needs to be removed when the entity is removed from the database, but the physical file shouldn’t be removed from the disk when the entity is only marked as deleted in the database.

This will trigger the 'delete', '<entity_type>' event sequence.

Function: trash 

This function is called when the $persistent parameter is false in the delete() function. This function must handle cases where the entity is marked as deleted in the database.

This will trigger the 'trash', '<entity_type>' event sequence.

Function: isDeleted 

To check if an entity is marked as deleted.

Show deleted items 

When a developer needs to be sure to include deleted entities when fetching/listing entities the code needs to be wrapped in an elgg_call() with the flag ELGG_SHOW_DELETED_ENTITIES.

The same applies when the developer needs to be sure to exclude all deleted items set the flag ELGG_HIDE_DELETED_ENTITIES.

Cleanup of deleted entities 

In order to cleanup the database of the deleted entities a cron job runs every hour. It’ll cleanup all the deleted entities that have been removed when a retention period has passed. A site administrator can set this retention period (default: 30 days).

In order to not put too much stress on the system the cron job will only run for a maximum of 5 minutes per hour. Entities that couldn’t be removed in that period will be removed in the next period. The oldest deleted entity (by when the entity was deleted) will be removed first.

More information 

Siehe auch

Check out the Capabilities documentation