DataTransformer - split DateTime into two fields

Question

I recently build a DataTransformer that will accept a variety of different date formats in the end (like 12/12/2012 or 12.12.2012 or 2012-12-12).

Answer 1

I'm assuming you are using Symfony 2.0. I've read that form component has changed somewhat in 2.1.

I had a similar problem - I wanted to have a datetime field that uses separate widgets for date and time (hour) input.

First of all, you have to create a separate form type for this field (which actually is a form in itself).

My code looks similar to this (altered for this example):

class MyDateTimeType extends AbstractType
{
    public function buildForm(FormBuilder $builder, array $options)
    {
        $builder
        ->add('date', 'date', array(
            'label'  => 'label.form.date',
            'input'  => 'datetime',
            'widget' => 'single_text',
            'format' => 'yyyy-MM-dd',
            'error_bubbling' => true
        ))
        ->add('time', 'time', array(
            'label'  => 'label.form.time',
            'input'  => 'datetime',
            'widget' => 'choice',
            'error_bubbling' => true
        ));

        $builder->appendClientTransformer(new DateTimeToDateTimeArrayTransformer());
    }

    public function getDefaultOptions(array $options)
    {
        return array(
            'label' => 'label.form.date',
            'error_bubbling' => false
        );
    }

    public function getParent(array $options)
    {
        return 'form';
    }

    public function getName()
    {
        return 'my_datetime';
    }
}

As you can see it is a form (don't let it confuse you) but we will use it as a single logical field. That's where the data transformer comes in. It has to split a single DateTime instance into date and time to obtain data for the two subfields when displaying the form and vice-versa when the form is submitted.

The error_bubbling settings ensure that the errors generated by subfields attach to our new subfield and don't propagate to the top-level form, but you may have diferrent goal.

My data transformer looks like this:

class DateTimeToDateTimeArrayTransformer implements DataTransformerInterface
{
    public function transform($datetime)
    {
        if(null !== $datetime)
        {
            $date = clone $datetime;
            $date->setTime(12, 0, 0);

            $time = clone $datetime;
            $time->setDate(1970, 1, 1);
        }
        else
        {
            $date = null;
            $time = null;
        }

        $result = array(
            'date' => $date,
            'time' => $time
        );

        return $result;
    }

    public function reverseTransform($array)
    {
        $date = $array['date'];
        $time = $array['time'];

        if(null == $date || null == $time)
            return null;

        $date->setTime($time->format('G'), $time->format('i'));

        return $date;
    }
}

Finally you can use it like that:

$builder->add('startDate', 'my_datetime', array(
       'label' => 'label.form.date'
));

You have to register it as a service to use it by alias, otherwise instantiate it directly (new MyDateTimeType()).

This may not be the prettiest solution but so is the form component in Symfony 2.0.