feat: use a type's get_queryset for Relay connections if it defines o…

…ne (#215)

* Use a type's get_queryset for Relay connections

Why:

- Allow nested queries to be filtered by user and permissions

This change addresses the need by:

- Resolve reverse relationship type in Relay connections
- Use get_queryset filter of the resolved type

* Update strawberry_django_plus/type.py

Co-authored-by: Thiago Bellini Ribeiro <hackedbellini@gmail.com>

* Clean up conn_resolver

* Preventive rename to avoid name collision

* Try fix for Python < 3.10

* Simplify implementation

* Add test for Relay Connection resolving

Why:

- Ensure no regressions when querying related models
  - Caught a case where prefetches were ignored
- Allow tests to use a type's custom get_queryset method

This change addresses the need by:

- Adding a Favorite model and type
- Adding a test to check the new use case
- Documenting how to access custom QuerySets in types
- Warm up lazy user in test client to avoid sync/async collision

* Lint clean up

* Fix typing checks

* Add user warmup middleware

Why:

- get_queryset in types only supports sync context
- Avoids error being called in async context

This change addresses the need by:

- Adding a user warmup middleware to cache user object in async context

* Clean up typing

* Actually warmup user with method call

---------

Co-authored-by: Thiago Bellini Ribeiro <hackedbellini@gmail.com>

.coveragerc

@@ -12,3 +12,5 @@ exclude_lines =
     @abstractmethod
     @abc.abstractmethod
     assert_never
+omit =
+    */tests/*

demo/migrations/0006_favorite.py

@@ -0,0 +1,38 @@
+# Generated by Django 4.2.1 on 2023-05-30 05:00
+
+import django.db.models.deletion
+from django.conf import settings
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+    dependencies = [
+        migrations.swappable_dependency(settings.AUTH_USER_MODEL),
+        ("demo", "0005_remove_issue_milestone_not_null"),
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name="Favorite",
+            fields=[
+                ("id", models.BigAutoField(primary_key=True, serialize=False, verbose_name="ID")),
+                ("name", models.CharField(max_length=32)),
+                (
+                    "issue",
+                    models.ForeignKey(
+                        on_delete=django.db.models.deletion.CASCADE,
+                        related_name="favorite_set",
+                        to="demo.issue",
+                    ),
+                ),
+                (
+                    "user",
+                    models.ForeignKey(
+                        on_delete=django.db.models.deletion.CASCADE,
+                        related_name="favorite_set",
+                        to=settings.AUTH_USER_MODEL,
+                    ),
+                ),
+            ],
+        ),
+    ]

demo/models.py

@@ -2,10 +2,12 @@
 
 from django.contrib.auth import get_user_model
 from django.db import models
+from django.db.models import QuerySet
 from django.utils.translation import gettext_lazy as _
 from django_choices_field.fields import TextChoicesField
 
 from strawberry_django_plus.descriptors import model_property
+from strawberry_django_plus.utils.typing import UserType
 
 if TYPE_CHECKING:
     from django.db.models.manager import RelatedManager
@@ -73,6 +75,31 @@ class Milestone(models.Model):
     )
 
 
+class FavoriteQuerySet(QuerySet):
+    def by_user(self, user: UserType):
+        if user.is_anonymous:
+            return self.none()
+        return self.filter(user__pk=user.pk)
+
+
+class Favorite(models.Model):
+    """A user's favorite issues."""
+
+    class Meta:
+        # Needed to allow type's get_queryset() to access a model's custom QuerySet
+        base_manager_name = "objects"
+
+    id = models.BigAutoField(  # noqa: A003
+        verbose_name="ID",
+        primary_key=True,
+    )
+    name = models.CharField(max_length=32)
+    user = models.ForeignKey(User, related_name="favorite_set", on_delete=models.CASCADE)
+    issue = models.ForeignKey("Issue", related_name="favorite_set", on_delete=models.CASCADE)
+
+    objects = FavoriteQuerySet.as_manager()
+
+
 class Issue(models.Model):
     comments: "RelatedManager[Issue]"
     issue_assignees: "RelatedManager[Assignee]"

demo/schema.py

@@ -24,7 +24,7 @@
     IsSuperuser,
 )
 
-from .models import Assignee, Issue, Milestone, Project, Quiz, Tag
+from .models import Assignee, Favorite, FavoriteQuerySet, Issue, Milestone, Project, Quiz, Tag
 
 UserModel = cast(Type[AbstractUser], get_user_model())
 
@@ -122,6 +122,17 @@ async def async_field(self, value: str) -> str:
         return f"value: {value}"
 
 
+@gql.django.type(Favorite)
+class FavoriteType(relay.Node):
+    name: gql.auto
+    user: UserType
+    issue: "IssueType"
+
+    @classmethod
+    def get_queryset(cls, queryset: FavoriteQuerySet, info: Info) -> QuerySet:
+        return queryset.by_user(info.context.request.user)
+
+
 @gql.django.type(Issue)
 class IssueType(relay.Node):
     name: gql.auto
@@ -132,6 +143,7 @@ class IssueType(relay.Node):
     name_with_kind: str = gql.django.field(only=["kind", "name"])
     tags: List["TagType"]
     issue_assignees: List["AssigneeType"]
+    favorite_set: relay.Connection["FavoriteType"]
 
 
 @gql.django.type(Tag)
@@ -218,6 +230,7 @@ class Query:
 
     node: Optional[gql.Node] = gql.django.node()
 
+    favorite: Optional[FavoriteType] = gql.django.node()
     issue: Optional[IssueType] = gql.django.node(description="Foobar")
     milestone: Optional[Annotated["MilestoneType", gql.lazy("demo.schema")]] = gql.django.node()
     milestone_mandatory: MilestoneType = gql.django.node()
@@ -237,6 +250,7 @@ class Query:
     project_list: List[ProjectType] = gql.django.field()
     tag_list: List[TagType] = gql.django.field()
 
+    favorite_conn: relay.Connection[FavoriteType] = gql.django.connection()
     issue_conn: relay.Connection[
         gql.LazyType["IssueType", "demo.schema"]  # type: ignore  # noqa: F821
     ] = gql.django.connection()

demo/settings.py

@@ -47,6 +47,7 @@
 MIDDLEWARE = [
     "django.contrib.sessions.middleware.SessionMiddleware",
     "django.contrib.auth.middleware.AuthenticationMiddleware",
+    "strawberry_django_plus.middlewares.user_warmup.user_warmup_middleware",
     "strawberry_django_plus.middlewares.debug_toolbar.DebugToolbarMiddleware",
 ]