DRF Ecosystem Compatibility Boundaries

VUEDA's server builds on DRF, django-filter, drf-flex-fields2, and drf-writable-nested. Its defaults change some of their behavior. A client written for plain DRF meets different parameter names, stricter validation, and different response bodies. This page lists each departure briefly and links the page that describes it.

Query Parameter Names

DRF's DRF: SearchFilter and DRF: OrderingFilter read search and ordering by default, and drf-flex-fields2 reads expand, fields, and omit. VUEDA sets short names for these and for pagination and column totals: s, o, p, ps, e, f, om, and ct. These are the Wire Query Parameters. The client holds each name as a constant, so a rename on the server needs the same change on the client. Configuration Surface and Defaults lists each name with its server setting and client constant.

Default Filter Backends

DRF configures no filter backend by default. VUEDA's REST_FRAMEWORK defaults run three on every list endpoint, in this order:

1. VuedaOrderingFilter extends OrderingFilter. It applies a view's nulls placement to requested ordering, and it accepts every field in the view's default ordering as an o value.
2. VuedaSearchFilterBackend extends SearchFilter with the search prefixes # (trigram similarity), ~ (word similarity), and V: (ranked search). It runs after ordering so that ordering does not reorder ranked results. A search field that reaches through a many-valued relation matches inside a subquery, built from the model's default manager or the viewset's get_search_queryset(). SearchFilter instead copies the viewset's queryset, filters and aggregates included. Search through a many-valued relation describes the rule.
3. django-filter's DjangoFilterBackend applies the viewset's filterset_class.

A viewset that sets its own filter_backends replaces this list. Filtering and Ordering Semantics describes each backend's rules.

Unknown Input Returns 400

DRF ignores query parameters that a view does not read and request body keys that a serializer does not declare. VUEDA answers both with a 400 validation error that names the valid choices:

• NoExtraFieldsForViewSetMixin, part of VuedaViewSet and VuedaReadOnlyViewSet, rejects any query key that list or retrieve does not accept. It also rejects f and e values that name no field or expand. Filtering and Ordering Semantics describes these validation rules.
• NoExtraFieldsSerializerMixin, part of VuedaSerializer, rejects top-level body keys that the serializer does not declare. It checks only the view's own serializer class, so keys inside a nested payload are not checked. Error and Validation Contract describes the error body.

A typo or a stale client gets an error that names the valid keys. An integration that adds its own query parameters or body keys fails until the viewset or serializer declares them.

Response Bodies and Authentication

VUEDA's defaults change these responses and the accepted credentials:

• List pagination. VUEDAPageNumberPagination returns results, columnTotals, perPage, totalPages, and totalRecords. DRF's DRF: PageNumberPagination returns count, next, previous, and results. Expose Aggregates in list Responses describes columnTotals.
• Error bodies. core.exceptions.debug_stack_exception_handler moves a list of errors under non_field_errors, and returns a JSON 500 for exceptions that DRF does not handle. It adds serverStack to every error body, except the 409 of Warning Confirmation. Error and Validation Contract describes these shapes.
• Durations. When a timedelta reaches VuedaJSONRenderer, the renderer writes it as a number of seconds. DRF's renderer writes a string. This affects values that bypass serializer fields, such as a duration column total. A serializer DurationField still returns its string form.
• Authentication. DRF's DRF: SessionAuthentication is the only authentication class. A client sends the session cookie, and writes also need the CSRF token.

Registration Gates Model Info

In plain DRF, a viewset and a router entry give a model its REST API. VUEDA's Model Info endpoints also require the model's Canonical Registration through info.registration. A model with a viewset but no registration has a REST API but no model info, which the default UI needs to build its views. Canonical Registration and Model Discovery describes registration.

Flex Fields with Nested Writes

VuedaSerializer combines drf-flex-fields2 expansion with drf-writable-nested writes. Field and Expand Semantics describes Expand and Sparse Fields. Nested Write Compatibility describes what changes when the two packages share one serializer.

Composite Primary Keys

VuedaSerializer maps Django's Django: CompositePrimaryKey to CompositePrimaryKeyField without a field declaration. VuedaViewSet.get_object reads the key from the URL as a JSON list. Set Up CRUD for a Composite Primary Key Model gives the URL format and how to pass the key to Django: reverse.