In my previous post I wrote about uploading files to GridFS. Therefor I created a MongoDB Document with a $file property annotated with @MongoDB\File. Because I am using ORM entities more often then ODM documents, I was looking for a seamless way to access a Document from an Entity.

Because it isn’t possible to define a direct relationship between an Entity and a Document I thought it would be a solid solution to create a custom field type. By defining a custom field type I can control the way the reference to the Document will be stored and at the same time I will be able to restore the reference when retrieving the field. The steps needed to create a custom field type for ORM entities are very similar to the post of Matthias on how to create custom field types for ODM documents.

Almost at the same time, I silently celebrate the first birthday of my blog. My first article appeared a little over a year ago. It is great to see how Symfony2 has become more and more popular during these twelve months. Your comments and visits encourage me to keep posting articles. So, thank you all! And thanks, Dennis, for contributing.

GridFS is a specification for storing large files in MongoDB. In this post I will explain how you can easily upload a file to GridFS and then retrieve it from the database to serve it to the browser.

Just a quick post…

What seems to be missing from the DoctrineMongoDBBundle is a ParamConverter service which resolves request attributes to controller arguments by fetching a Document using the MongoDB DocumentManager. For entities, this would work:

/**
 * @Route("/blog/{id}
 */
public function showAction(Post $post)
{
    // $post will be the entity Post with the "id" taken from the route pattern
}

This works because of the DoctrineParamConverter, which is registered by default by the SensioFrameworkExtraBundle. But only for Doctrine ORM, and not for Doctrine MongoDB ODM. As Christophe Coevoet mentioned when someone tried to implement this missing feature, it can be added easily by yourself, without writing any PHP code, though it might not be so clear how to accomplish this. Still, the only thing you have to do is add a service to your services.xml file:

With Doctrine MongoDB ODM it is possible to add custom field types and define how its values should be converted from and to the database. But type management in the MongoDB ODM currently suffers from several design flaws. This makes it non-trivial to create a custom type, especially when your type conversion has any dependencies. This is how it works:

use Doctrine\ODM\MongoDB\Mapping\Types\Type;

Type::registerType('custom', 'Matthias\CustomTypeBundle\MongoDB\Type\CustomType');

$type = Type::getType('custom');
// $type is an instance of Matthias\CustomTypeBundle\MongoDB\Type\CustomType

As you will understand, the Type class is both a Registry and a Factory. Yet, it only allows you to define a type as a class, not as an object. This means: no constructor arguments can be passed. When using Symfony2, this implies that types can not be services, and you can use neither constructor nor setter injection.