Customize Content Attribute Display

Context

In Open Orchestra the Content are composed of a set of base attributes and a collection of ContentAttribute (See content documentation for more information). The ContentAttribute are configured by the content type. In order to have minimum constraints on contents, Open Orchestra allows you to store any type of value in the ContentAttribute.

Sometimes, there is no easy way to render the value to the Back Office user. A custom ContentAttribute could be stored as an array, which cannot be displayed directly in the dataTables plugin. In that way the ContentAttribute class provides a specific attribute stringValue which is the representation of the value in an HTML string.

Transformers

Open Orchestra uses a ValueTransformer strategy manager to generate the HTML strings for multiple value types. Open Orchestra already provides some strategies located in OpenOrchestra\Backoffice\ValueTransformer\Strategies.

Strategy creation

Service used as ValueTransformer must be tagged as open_orchestra_backoffice.value_transformer.strategy.

tags:
    - { name: open_orchestra_backoffice.value_transformer.strategy }

Such services also need to implement OpenOrchestra\Backoffice\ValueTransformer\ValueTransformerInterface.

Strategy access

Open Orchestra uses the OpenOrchestra\Backoffice\ValueTransformer\ValueTransformerManager as an easy way to access every transformation strategies. All ValueTransformer strategies are registered in the ValueTransformerManager. The transform method of the manager:

• searches the first transformation strategy supporting the current fieldType and value of the ContentAttribute
• uses this strategy’s transform method to return the stringValue

Examples

Transformation available

Value	StringValue	Strategy
“string”	“string”	none
1	“1”	IntegerToHtmlStringTransformer
null	“none”	NullToHtmlStringTransformer
Object()	Object::__toString()	ObjectToHtmlStringTransformer
array(‘foo’ => array(‘bar’))	‘<ul><li><ul><li>bar</li></ul></li></ul>’	ArrayToHtmlStringTransformer

New transformation

Let’s say that the field with the type foo will store relation to the FooDocument. You will need to add a transformer in order to create a stringValue that could be displayed on the Back office. In our example the bar properties should be displayed.

You need to implement the three methods of the interface :

• getName : give the name of the transformer
• support : take the fieldType and the value to decide if the transformation should be applied
• transform : will transform the value

In our case, the support method will check the field type and if the value is null or not.

public function support($fieldType, $value)
{
    return $fieldType == 'foo' && $value != null;
}

The transform method will need the fooDocument repository to find the document then will return the bar properties.

/**
 * $value = mongoId;
 */
public function transform($value)
{
    $fooDocument = $this->fooRepository->find($value);

    return $fooDocument->getBar();
}