Što su DRF viewsets i routers?

Question

Accepted Answer

In Django REST Framework, **viewsets** group the logic for a set of related API endpoints (the CRUD operations for a resource) into a single class, and **routers** automatically generate the URL routing for them. Together they dramatically reduce boilerplate for building RESTful APIs.

## ModelViewSet — kompletan CRUD u nekoliko redaka

```python
from rest_framework import viewsets

class ArticleViewSet(viewsets.ModelViewSet):
    queryset = Article.objects.all()             # the data
    serializer_class = ArticleSerializer          # how to serialize it
    # That's it! This provides ALL standard CRUD endpoints automatically:
    #   list (GET), create (POST), retrieve (GET /id), update (PUT/PATCH /id), destroy (DELETE /id)
```

A `ModelViewSet` automatically provides the **complete set of RESTful CRUD endpoints** for a model — list, create, retrieve, update, partial update, and delete — from just a queryset and serializer. No need to write each view separately.

## Routers — automatic URL generation

```python
from rest_framework.routers import DefaultRouter

router = DefaultRouter()
router.register(r"articles", ArticleViewSet)     # register the viewset

urlpatterns = router.urls
# automatically creates the RESTful URLs:
#   GET    /articles/        → list
#   POST   /articles/        → create
#   GET    /articles/{id}/   → retrieve
#   PUT    /articles/{id}/   → update
#   PATCH  /articles/{id}/   → partial update
#   DELETE /articles/{id}/   → destroy
```

A **router** maps a viewset to a full set of standard RESTful URLs automatically — registering one viewset generates all the conventional endpoints with correct HTTP methods, eliminating manual URL configuration.

## Customizing viewsets

```python
class ArticleViewSet(viewsets.ModelViewSet):
    serializer_class = ArticleSerializer
    permission_classes = [IsAuthenticated]        # authorization

def get_queryset(self):                        # customize the data per request
        return Article.objects.filter(author=self.request.user)

# add CUSTOM endpoints beyond CRUD with @action
    @action(detail=True, methods=["post"])
    def publish(self, request, pk=None):           # POST /articles/{id}/publish/
        article = self.get_object()
        article.published = True
        article.save()
        return Response({"status": "published"})
```

Viewsets are customized by overriding methods (`get_queryset`, `perform_create`), setting permissions, and adding **custom actions** (`@action`) for endpoints beyond standard CRUD.

## Viewsets vs generic API views

```text
ModelViewSet  → ALL CRUD in one class + router → least code for standard REST resources
Generic views (ListCreateAPIView, etc.) → more explicit, one class per endpoint group
APIView       → full manual control for non-standard/custom endpoints
→ Use viewsets+routers for conventional REST resources; generic/APIView for custom needs.
```

## Zašto je to važno

Viewsets i routers su moćna DRF funkcija za efikasnu izgradnju RESTful API-ja — predstavljaju najvišu razinu apstrakcije za izuzetno čest slučaj izlaganja modela kao potpune REST resurse, i razumijevanje ih je dragocjeno za produktivni razvoj API-ja.

Ključna korist je dramatično **smanjenje boilerplate-a**: `ModelViewSet` plus router vam daje kompletnu, konvencionalnu REST API za resurs (sve CRUD endpoints sa ispravnim HTTP metodama i URL-ima) samo iz queryseta i serializera — zamjenjujući što bi inače bilo mnogo odvojenih view-eva i ručnih URL obrazaca.

Ovo čini izgradnju standardnih REST API-ja izuzetno brzu dok se **RESTful konvencije** (konzistentna URL struktura i HTTP metoda semantika) automatski slijede.

Viewsets ostaju fleksibilni — prilagođavate ih nadjačavanjem metoda (`get_queryset`, `perform_create`), postavljanjem dozvola, i dodavanjem **prilagođenih akcija** (`@action`) za endpoints izvan standardnog CRUD-a.

Razumijevanje viewsets i routers, kako oni generiraju endpoints, kako ih prilagoditi, i **kada ih koristiti** (konvencionalni REST resursi) naspram eksplicitnijih generičkih view-eva ili APIView (prilagođeni/nestandardni endpoints) — važno je praktično znanje za DRF razvoj.

Pošto je izgradnja REST API-ja primarna upotreba Django-a danas, i viewsets+routers su idiomatski, najprodukivniji način da se to uradi za standardne resurse, oni su često korišteni, važan dio DRF alata koji omogućava programerima da kreiraju robusne API-je sa minimalnim kodom dok zadržavaju fleksibilnost za rukovanje prilagođenim zahtjevima.