Extract common features from normalizer to be able to decorate them easily

Currently JSON and JSON-LD are handled by two different normalizers, both of them extending ApiPlatform\Core\Serializer\AbstractItemNormalizer.

I wanted to add/modify properties on one of my resources (eg. setting URLs for images managed by LiipImagineBundle) and could not find a way to do it without decorating both api_platform.serializer.normalizer.item and api_platform.jsonld.normalizer.item:

    app.normalizer.image:
        class: AppBundle\Serializer\ImageNormalizer
        decorates: 'api_platform.serializer.normalizer.item'
        arguments:
            - '@app.normalizer.image.inner'
            (...)

    app.normalizer.jsonld.image:
        class: AppBundle\Serializer\ImageNormalizer
        decorates: 'api_platform.jsonld.normalizer.item'
        arguments:
            - '@app.normalizer.jsonld.image.inner'
            (...)

Wouldn’t it make sense to have a common item normalizer injected in every other item normalizers and be able to only decorate that one?

[Lyrkan]

@soyuka Wouldn’t it be possible to keep the normalizers separated but still having a “base” normalizer used by all of them ?

There is already a big part of the code that is shared between them (ApiPlatform\Core\Serializer\AbstractItemNormalizer) so at first I was expecting something like:

• api_platform.serializer.normalizer.item: do the common things, basically what AbstractItemNormalizer does nowadays
• api_platform.json.normalizer.item: uses api_platform.serializer.normalizer.item (the same way it calls parent::denormalize at the end of its own denormalize method) and does specific things
• api_platform.jsonld.normalizer.item: same thing but with jsonld specific parts
• api_platform.hal.normalizer.item: same thing but with hal specific parts

That would still allow people to only decorate json/jsonld/hal normalizers if needed, or decorate the common normalizer for properties that must be added/modified in every formats.

[teohhanhui]

If we can find a way of refactoring to extract out common functionality, I say go ahead. 😄