Filtering array query params

Some clients (e.g. Ember) send requests like ?filter[tags][]=1&filter[tags][]=2 for the membership in a list of values (JSON API).

To process this kind of filter I only changed (https://github.com/django-json-api/django-rest-framework-json-api/blob/master/rest_framework_json_api/django_filters/backends.py#L66) from

^filter(?P<ldelim>\[?)(?P<assoc>[\w\.\-]*)(?P<rdelim>\]?$)

to

^filter(?P<ldelim>\[?)(?P<assoc>[\w\.\-]*)(?P<rdelim>\]?)(\[\])?$

Everything seems to work fine. What do you think?

[puremath]

The fact that Ember Data (specifically the JsonAPIAdapter) serializes arrays in the query parameters by adding empty brackets isn’t very well documented. A hint that this is the case can be found here: https://api.emberjs.com/ember-data/3.13/classes/JSONAPIAdapter/methods?anchor=findMany

The IDs will be passed as a URL-encoded Array of IDs, in this form: ids[]=1&ids[]=2&ids[]=3

The relevant code where the actual serialization takes place can be found here: https://github.com/emberjs/data/blob/v3.13.1/packages/adapter/addon/-private/utils/serialize-query-params.ts#L20

Even though this is not detailed out in the JSON API Specification I’d argue to consider the way Ember does this more or less the de-facto standard as there isn’t any other reference client side implementation of the JSON API specification. If not DJA should at least offer the option to handle query parameter lists the Ember way.

[sliverc]

We only want to implement in DJA what is actually JSON API spec specific; otherwise such implementation need to happen in the respective upstream project (Django Filter, DRF or even Django itself). So a allin lookup is not DJA specific in this regard. And how DJA users use DjangoFilterSet is also up to them as JSON API spec doesn’t define how filter arguments are used. If you are referring to changes suggested in https://github.com/django-json-api/django-rest-framework-json-api/issues/718#issuecomment-605821483 I think that it is a good way forward to make the backend more powerful.