README

This extension provides a behavior that makes easy to add data-transformed attributes into Yii2 models. It does that by creating virtual attributes that automatically convert data back-and-forth upon set/get operations.

Common use cases:

• You store dates in the database using Unix timestamps and/or date strings, but want to manipulate them as DateTime objects

• Automatically data serialization

• Calculated attributes

See the Data Transformation section in the ActiveRecord documentation for more information about what problems this extensions helps you to solve.

Installation

composer require flaviovs/yii2-data-transformation

How to use

This extension provides an abstract class that you can use to create data transformation attributes. In other words, you need to define your own behavior class to do the transformations you want (or look for one created by somebody else).

To create a data transformation class, extend from \fv\yii\behaviors\DataTransformation and add the following methods:

• transform($value) (required) - apply data transformation to original model value $value (e.g. a Unix timestamp) and return the transformed result (e.g. a \DateTimeImmutable).

• transformBack($value) (optional) - apply data transformation to a transformed value $value (e.g. a \DateTimeImmutable) and return the original model representation (e.g. a Unix timestamp). This method is optional -- the inherited implementation just cast $value to string.

NULL handling

By default data transformation methods will never receive null values -- fv\yii\behaviors\DataTransformation will automatically intercept then, and automatically return null. You can change this behavior by setting $autoConvertNull to false in your class (in which case, of course, your conversion methods must be prepared to handle null values).

For example:

class MyBehavior extends \fv\yii\behaviors\DataTransformation
{
    public $autoConvertNull = false;

    // (...)
}

Model usage

When adding data-transformation behaviors to models, you should specify the attributes to be transformed in an attributes key in the configuration array. Attributes must be specified as key/value pair, where key is the transformed (virtual) attribute, and value is the original attribute.

Examples

Automatic date conversion

This behavior will allow \DateTime objects access to Unix timestamps-based attributes:

class DateTimeImmutableBehavior extends \fv\yii\behaviors\DataTransformation
{
	protected function transform($value)
	{
		return new \DateTimeImmutable('@' . $value);
	}

    protected function transformBack($value)
    {
        return $value->getTimestamp();
    }
}

Now on your model:

class MyModel extends \yii\base\Model
{
	/**
	 * Unix timestamp attributes.
	 *
	 * @var integer
	 */
	public $created;
	public $updated;

	function behaviors()
	{
		return [
			'datetime' => [
				'class' => \app\behaviors\DateTimeImmutableBehavior::class,
					'attributes' => [
					'createdDateTime' => 'created',
					'updatedDateTime' => 'updated',
				],
			],
		];
	}
}

In your code:

// Print our timestamp property.
print_r($mymodel->created);
/*
1547346253
*/

// Print our data transformation property.
echo $mymodel->createdDateTime;
/*
DateTimeImmutable Object
(
    [date] => 2019-01-13 02:24:13.000000
    [timezone_type] => 1
    [timezone] => +00:00
)
*/

// Set value using date transformation.
$mymodel->updatedDateTime = new DateTime('2018-12-01 00:00:00');

// Output transformed value.
echo $mymodel->updated;
/*
1543651200
*/

Support

Visit https://github.com/flaviovs/yii2-data-transformation