how to implement Sparse Fieldsets?

[hnakamur]

I would like the Sparse Fieldsets feature:
http://jsonapi.org/format/#fetching-sparse-fieldsets

I tried to implement it and thought creating a custom serializer and override rest_framework.serializers.Serializer.fields property.

However, we need the resource_name to get the fields[TYPE] query parameter value (TYPE=resource_name).
I find rest_framework_json_api.utils.get_resource_name, however its argument rendrerer_context is created after the serializer returns data. For example, in ListModelMixin, rendered_context is created in Response(serializer.data) at https://github.com/tomchristie/django-rest-framework/blob/8cae462b3a3d724cf83fd33572c0ea23f91f2278/rest_framework/mixins.py#L47-L48)

So how should we implement the Sparse Fieldsets feature?

[jerel]

utils.get_resource_name doesn't appear to need a serializer passed to it. It just fetches view off of whatever it is given. So we could call utils.get_resource_name anywhere that we have access to the view to get the same resource_name. Perhaps a filter backend would make sense for this?

A filter has access to the view and from there it may be possible to modify the serializer fields tuple for that request. It gets trickier with included or related serializers though, maybe someone else has additional ideas

[jerel]

@hnakamur I just merged a feature from @jsenecal that adds sparse fieldset support e56ef78. If you want to try it out use this serializer from rest_framework_json_api.serializers import HyperlinkedModelSerializer or use the SparseFieldsetsMixin in an existing serializer.

Let us know here or open a new issue for any problems.

[hnakamur]

@jerel @jsenecal Great! Thanks!

[jsenecal]

NP @hnakamur ! I needed this myself anyways :P