在持久之前将表单数据绑定到变量-Symfony2 / Doctrine2

Question

Currently I am trying to bind a user selected option to a variable and then use that variable in a function BEFORE persisting the data.

My current entity code is this:

public function setUnit($unit)
{
    $this->unit = $unit;
    return $this;
}
public function getUnit()
{
    return $this->unit;
}
public function setSize($size)
{        
    $unit = $this->getUnit();
    $this->size = $size = new Mass($size, $unit);
    $this->size = $size->toUnit('mg');      
    return $this;
}

And my form:

    $builder
        ->add('size')
        ->add('unit')
        ;

And finally my controller:

 public function createAction(Request $request)
 {
    $entity = new Products();

    $form = $this->createCreateForm($entity);
    $form->handleRequest($request);


    if ($form->isValid()) {
        $em = $this->getDoctrine()->getManager();
        $entity->setUser($this->get('security.context')->getToken()->getUser());
        $em->persist($entity);
        $em->flush();

There is quite a bit more code but think I've removed all the non-related stuff.

SO.. Basically what I want to do it:

1. User enters Size and Unit (For example 100 grams) clicks submit.
2. new Mass($size, $unit); converts $size by $unit to Mg
3. Data is now persisted to the database.

If I specify set $unit variable myself, it works fine ($unit = 'g') but when I try to pass the unit by $this-getUnit; nothing is being sent leaving the $unit variable as null.

  Unknown unit of measure ()

If I try doing the same but updating a pre existing entry it works fine but is always one step behind eg:

So if its 'g' set in the database and I try to convert an 'oz' it converts the 'G' and then on the next try if say I enter kg it will then convert by the oz from before.

I'm assuming this is happening because the form is valid, so Symfony tries to persist the entity but then hits the new Mass function which throws an error because it has not been sent the $unit variable yet. How do I send the $unit variable BEFORE persistence so as to convert it to the new $size.

Have seriously spent so many hours on this now and last night I woke up thinking about it far too many times I just can't give up now I feel so close.

(( The Unit converter I am using is https://github.com/triplepoint/php-units-of-measure/ just incase anyone was wondering ))

Answer thanks to Jenechka

public function setSize($size)
{
    $this->size = $size;       
    return $this;
}

/**
 * @ORM\PrePersist
 * @ORM\PreUpdate
 */
public function fixSize()
{
    $unit = $this->getUnit();
    $size = $this->getSize();

    $mass = new Mass($size, $unit);
    $this->size = $mass->toUnit('mg');      
}

and in my orm.yml

    lifecycleCallbacks:
    prePersist: [ setCreatedAtValue, fixSize ]
    preUpdate: [ setUpdatedAtValue, fixSize ]

Happy now :) Thank you.

Answer 1

Try to "fix" size in prePersist or preUpdate events .

/**
 * @Entity
 * @HasLifecycleCallbacks
 */
class YourEntity {
    // ...

    public function setSize($size)
    {        
        $this->size = $size;
        return $this;
    }

    /**
     * @PrePersist
     * @PreUpdate
     */
    public function fixSize()
    {
        $unit = $this->getUnit();
        $size = $this->getSize();

        $mass = new Mass($size, $unit);
        $this->size = $mass->toUnit('mg');      
    }

Or another way

public function setUnit($unit)
{
    $this->unit = $unit;
    $this->updateSize();

    return $this;
}

public function setSize($size)
{        
    $this->size = $size;
    $this->updateSize();

    return $this;
}

public function updateSize()
{
    $unit = $this->getUnit();
    $size = $this->getSize();

    if ($unit && $size) {
        $mass = new Mass($size, $unit);
        $this->size = $mass->toUnit('mg');      
    }

    return $this;
}