CODEWITHSUNDEEP
pythondjangodjango-rest-frameworkdrf-nested-routers
Aran Freel
Aran Freel

Reputation: 3215

DRF Django - make routable reverse foreign key relationship data

I have the following models

# filename - stocks.models
class Stock(models.Model):

    ticker = models.CharField(max_length=10, unique=True, primary_key=True)
    exchange = models.CharField(default="", max_length=10)
    name = models.CharField(default="", max_length=255)
    slug = models.SlugField(default="", editable=False)

    def save(self, *args, **kwargs):
        value = self.ticker
        self.slug = slugify(value, allow_unicode=True)
        super().save(*args, **kwargs)

    class Meta:
        verbose_name = "stock"
        verbose_name_plural = "stocks"
        ordering = ["ticker"]

# filename - prices.models

from viewflow.fields import CompositeKey


class StockPrice(models.Model):
    id = CompositeKey(columns=["ticker_id", "date"])
    ticker = models.ForeignKey(
        "stocks.Stock", on_delete=models.CASCADE, related_name="stocks"
    )
    date = models.DateTimeField(default=now)
    open = models.FloatField()
    high = models.FloatField()
    low = models.FloatField()
    close = models.FloatField()
    adj_close = models.FloatField()
    volume = models.FloatField()

the following views

class StockViewSet(viewsets.ModelViewSet):
    queryset = Stock.objects.all()
    queryset = queryset.prefetch_related("stocks")
    serializer_class = StockSerializer
    lookup_url_kwarg = "ticker"
    lookup_field = "ticker__iexact"

    # override create method to include many=True
    def create(self, request, *args, **kwargs):
        serializer = self.get_serializer(
            data=request.data, many=isinstance(request.data, list)
        )
        serializer.is_valid(raise_exception=True)
        self.perform_create(serializer)
        headers = self.get_success_headers(serializer.data)
        return Response(
            serializer.data, status=status.HTTP_201_CREATED, headers=headers
        )

#filename prices.views
class StockPriceViewSet(viewsets.ModelViewSet):
    queryset = StockPrice.objects.all()
    serializer_class = StockPriceSerializer

and the following routers

router = routers.SimpleRouter()
router.register(r"stocks", stock_views.StockViewSet, basename="stocks")

stockprice_router = routers.NestedSimpleRouter(router, r"stocks", lookup="stocks")
stockprice_router.register(r"price", price_views.StockPriceViewSet)

urlpatterns = [
    path("", include(router.urls)),
    path("", include(stockprice_router))
]

the router is from drf-nested-routers. How can I set up a url such as localhost:8000/stocks/appl/price/ that will show the reverse foreign key data ( models.StockPrice ) for specifically that stock aapl.

currently when I access localhost:8000/stocks/appl/price I get a view on all the stock prices together.

Upvotes: 1

Views: 197

Answers (1)

Brian Destura
Brian Destura

Reputation: 12068

In this case override get_queryset to filter out the objects that the nested viewset will work on, based on the selected stock ticker so:

class StockPriceViewSet(viewsets.ModelViewSet):
    queryset = StockPrice.objects.all()
    serializer_class = StockPriceSerializer

    def get_queryset(self):
        queryset = super().get_queryset()
        ticker = self.kwargs.get('stocks_ticker')
        if ticker:
            queryset = queryset.filter(ticker__ticker=ticker)
        return queryset

The above is if StockPriceViewSet can be used as a non-nested viewset. But if StockPriceViewSet is only nested on StockViewSet:

class StockPriceViewSet(viewsets.ModelViewSet):
    serializer_class = StockPriceSerializer
    def get_queryset(self):
        return StockPrice.objects.filter(ticker__ticker=self.kwargs['stocks_ticker'])

Upvotes: 1

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