Filtering doctrine collections

I recently ran into the following situation as defined:

An entity A with a OneToMany relation to entity B
FOS REST Bundle serializing entity and returning it in multiple API endpoints
A entity has a property hidden

I wanted to see what was the simplest and most efficient way for all those APIs and for anywhere using A->getBs() to retrieve the list of B related to A that have hidden = false.

Basically I needed something that would look like:

@OneToMany
@Where(!hidden)

Which is obviously not a feature.

1st idea

One possible way is to updated everywhere the collection is used and do the filtering. That means a lot of things to change, which is not really maintainable, and it does not happen on the database level so not really great performances.

2sd idea

The second though was to manually query what was needed wherever it was needed. This could have worked but a few things got in the way.

It’s still not maintainable, it’s a lot of changes in a lot of different places
So far the FOS REST bundle was serializing things automatically which is very convenient, definitely didn’t want to change that

Criteria

The first step towards the light was using criteria, changing the getter definition as follows:

 /**
  * Get Addresses
  *
  * @return B[]
  */
 public function getBs()
 {
     $criteria = Criteria::create();
     $criteria->where(Criteria::expr()->eq('hidden', false));

     return $this->b->matching($criteria);
}

Criteria are quite amazing as it’s a neat way to filter collections and, as said in the doctrine documentation:

Collections have a filtering API that allows to slice parts of data from a collection.
If the collection has not been loaded from the database yet,
the filtering API can work on the SQL level to make optimized access to large collections.

A good thing to note, is that the QueryBuilder can now takes Criteria as well.

After that I noted that the serialization was still going directly to the property instead of using the getter. The final key was the Accessor attribute that helps specify which getter and setter to use:

/**
* @var B[]
*
* @ORM\OneToMany(...)
* @Accessor(getter="getBs")
*
*/
private $b;

And that’s it, Working!

Posted with : PHP