mirror of
https://github.com/silverstripe/silverstripe-framework
synced 2024-08-26 12:36:07 +02:00
95 lines
3.0 KiB
Markdown
95 lines
3.0 KiB
Markdown
title: Extending DataObjects
|
|
summary: Modify the data model without using subclasses.
|
|
|
|
# Extending DataObjects
|
|
|
|
You can add properties and methods to existing [DataObject](api:SilverStripe\ORM\DataObject)s like [Member](api:SilverStripe\Security\Member) without hacking core code or sub
|
|
classing by using [DataExtension](api:SilverStripe\ORM\DataExtension). See the [Extending SilverStripe](../extending) guide for more information on
|
|
[DataExtension](api:SilverStripe\ORM\DataExtension).
|
|
|
|
The following documentation outlines some common hooks that the [Extension](api:SilverStripe\Core\Extension) API provides specifically for managing
|
|
data records.
|
|
|
|
## onBeforeWrite
|
|
|
|
You can customise saving-behavior for each DataObject, e.g. for adding workflow or data customization. The function is
|
|
triggered when calling *write()* to save the object to the database. This includes saving a page in the CMS or altering
|
|
a `ModelAdmin` record.
|
|
|
|
Example: Disallow creation of new players if the currently logged-in player is not a team-manager.
|
|
|
|
```php
|
|
use SilverStripe\Security\Security;
|
|
use SilverStripe\ORM\DataObject;
|
|
|
|
class Player extends DataObject
|
|
{
|
|
private static $has_many = [
|
|
"Teams" => "Team",
|
|
];
|
|
|
|
public function onBeforeWrite()
|
|
{
|
|
// check on first write action, aka "database row creation" (ID-property is not set)
|
|
if(!$this->isInDb()) {
|
|
$currentPlayer = Security::getCurrentUser();
|
|
|
|
if(!$currentPlayer->IsTeamManager()) {
|
|
user_error('Player-creation not allowed', E_USER_ERROR);
|
|
exit();
|
|
}
|
|
}
|
|
|
|
// check on every write action
|
|
if(!$this->record['TeamID']) {
|
|
user_error('Cannot save player without a valid team', E_USER_ERROR);
|
|
exit();
|
|
}
|
|
|
|
// CAUTION: You are required to call the parent-function, otherwise
|
|
// SilverStripe will not execute the request.
|
|
parent::onBeforeWrite();
|
|
}
|
|
}
|
|
|
|
```
|
|
|
|
## onBeforeDelete
|
|
|
|
Triggered before executing *delete()* on an existing object.
|
|
|
|
Example: Checking for a specific [permission](permissions) to delete this type of object. It checks if a
|
|
member is logged in who belongs to a group containing the permission "PLAYER_DELETE".
|
|
|
|
```php
|
|
use SilverStripe\Security\Permission;
|
|
use SilverStripe\Security\Security;
|
|
use SilverStripe\ORM\DataObject;
|
|
|
|
class Player extends DataObject
|
|
{
|
|
|
|
private static $has_many = [
|
|
"Teams" => "Team"
|
|
];
|
|
|
|
public function onBeforeDelete()
|
|
{
|
|
if(!Permission::check('PLAYER_DELETE')) {
|
|
Security::permissionFailure($this);
|
|
exit();
|
|
}
|
|
|
|
parent::onBeforeDelete();
|
|
}
|
|
}
|
|
```
|
|
|
|
<div class="notice" markdown='1'>
|
|
Note: There are no separate methods for *onBeforeCreate* and *onBeforeUpdate*. Please check `$this->isInDb()` to toggle
|
|
these two modes, as shown in the example above.
|
|
</div>
|
|
|
|
## Related Lessons
|
|
* [Working with data relationships - $has_many](https://www.silverstripe.org/learn/lessons/v4/working-with-data-relationships-has-many-1)
|