GraphQL Schema

graphiql

query {
  products {
    id
  }
}

graphiql response

{
  "errors": [
    {
      "message": "Product received a non-compatible instance (QuerySet) when expecting Product",
      "locations": [
        {
          "column": 5,
          "line": 3
        }
      ]
    }
  ],
  "data": {
    "products": null
  }
}

schema.py

import graphene
from graphene import relay, resolve_only_args
from graphene.contrib.django.types import DjangoNode

from . import models


class Product(DjangoNode):
    class Meta:
        model = models.Product

    @classmethod
    def get_node(cls, id, info):
        return Product(models.Product.objects.get(pk=id))


class Query(graphene.ObjectType):
    node = relay.NodeField()
    products = graphene.Field(Product)

    @resolve_only_args
    def resolve_products(self):
        return models.Product.objects.all()


schema = graphene.Schema(name='Luxglove Schema')
schema.query = Query

Try with graphene.List(Product) instead of graphene.Field(Product), as Field only expects one item (or None) instead of a iterator.

class Query(graphene.ObjectType):
    node = relay.NodeField()
    products = graphene.List(Product)

    @resolve_only_args
    def resolve_products(self):
        return models.Product.objects.all()

@syrusakbary that was helpful! Thank you!

Now I'm facing another issue. This query:

{
  products(id: 100) {
    title
  }
}

Gives this error:

{
  "errors": [
    {
      "message": "Unknown argument \"id\" on field \"products\" of type \"Query\".",
      "locations": [
        {
          "column": 12,
          "line": 2
        }
      ]
    }
  ]
}

Any idea why?

For having an argument in a Field (in this case the products field in the Query type), you need to specify when creating the field. Like:

class Query(graphene.ObjectType):
    node = relay.NodeField()
    products = graphene.List(Product, id=graphene.String())

    @resolve_only_args
    def resolve_products(self, id=None):
        return models.Product.objects.filter(id=id)