Port get_schema_fields from DRF

[rpkilby]

No description provided.

[carltongibson]

Can you add a Doc string: what's this for? Ta.

[rpkilby]

The original blame points to core-api/schema generation, but I'm not familiar with that so I don't actually understand how this method is being used. @tomchristie?

Side note - I saw @kevin-brown's comment here and simplified.

[lovelydinosaur]

Indeed, this is used by the schema generation to introspect what fields are required by a filter class. It's not formalized in the docs yet, so we should discuss prior to any 1.0 django-filter / 3.5 rest framework releases.

[rpkilby]

@tomchristie - could you take a look at 291717f? Does this seem correct? Thanks for the help.

[lovelydinosaur]

Seems good to me.

[rpkilby]

get_fitler_class()

And this is why we test anyway.

[rpkilby]

I promise I can spell.

[rpkilby]

@carltongibson. Anything else that needs to be done here? I'm considering holding off on a doc string until get_fields is public/final in DRF's API.

[lovelydinosaur]

Okay, these will become public API in 3.5 onwards, as get_schema_fields.
Should return a list of coreapi.Field instances.

(see encode/django-rest-framework@3f3213b )

[carltongibson]

Awesome. Thanks Tom.

[rpkilby]

Hi @carltongibson - this should be ready for review.

btw, there is technically a flaw with the implementation, but I don't think it's worth fixing. Given the following,

class UserFilter(FilterSet):
    username = filters.CharFilter()
    last_login__between = filters.DateTimeFromToRangeFilter(name='last_login', lookup_expr='range')

    class Meta:
        model = User

get_schema_fields will incorrectly return query names of ['username', 'last_login__between'] instead of ['username', 'last_login__between_0', 'last_login__between_1'].

Realistically, this is only an issue for MultiWidget, although it could technically apply to any widget. In general, I'm not inclined to try to make this compatible:

• MultiWidget isn't really API-friendly to begin with (see Add custom MultiWidget for better field names #425).
• There isn't a public API for getting the param names.
• There isn't a trivially reliable way of introspecting this.

My thoughts are to either:

• Not worry about it until it becomes relevant.
• Add a note in the docs that some MultiWidget-based filters aren't compatible with all of DRF's features. Instead of using the *RangeFilters, create a CSV-based filter derived from BaseRangeFilter. Either that or create, two separate lte/gte filters (see this thread).

[carltongibson]

OK. This is great. I'll merge this and push a 0.15.3 this morning. 👍

@tomchristie I think we're good from this side for DRF 3.5.

[lovelydinosaur]

Great stuff!