feat: association_proxy support (#267)

* association_proxy support

* better support for assoc proxy lists (rather than one-to-one)

* scope down

* add support for sqlalchemy 1.1

* fix pytest due to master merge

* fix: throw error when association proxy could not be converted

* fix: adjust association proxy to new relationship handling

---------
Co-authored-by: Erik Wrede <[email protected]>

graphene_sqlalchemy/converter.py

@@ -7,8 +7,14 @@
 
 from sqlalchemy import types as sqa_types
 from sqlalchemy.dialects import postgresql
+from sqlalchemy.orm import (
+    ColumnProperty,
+    RelationshipProperty,
+    class_mapper,
+    interfaces,
+    strategies,
+)
 from sqlalchemy.ext.hybrid import hybrid_property
-from sqlalchemy.orm import interfaces, strategies
 
 import graphene
 from graphene.types.json import JSONString
@@ -101,6 +107,49 @@ def is_column_nullable(column):
     return bool(getattr(column, "nullable", True))
 
 
+def convert_sqlalchemy_association_proxy(
+    parent,
+    assoc_prop,
+    obj_type,
+    registry,
+    connection_field_factory,
+    batching,
+    resolver,
+    **field_kwargs,
+):
+    def dynamic_type():
+        prop = class_mapper(parent).attrs[assoc_prop.target_collection]
+        scalar = not prop.uselist
+        model = prop.mapper.class_
+        attr = class_mapper(model).attrs[assoc_prop.value_attr]
+
+        if isinstance(attr, ColumnProperty):
+            field = convert_sqlalchemy_column(attr, registry, resolver, **field_kwargs)
+            if not scalar:
+                # repackage as List
+                field.__dict__["_type"] = graphene.List(field.type)
+            return field
+        elif isinstance(attr, RelationshipProperty):
+            return convert_sqlalchemy_relationship(
+                attr,
+                obj_type,
+                connection_field_factory,
+                field_kwargs.pop("batching", batching),
+                assoc_prop.value_attr,
+                **field_kwargs,
+            ).get_type()
+        else:
+            raise TypeError(
+                "Unsupported association proxy target type: {} for prop {} on type {}. "
+                "Please disable the conversion of this field using an ORMField.".format(
+                    type(attr), assoc_prop, obj_type
+                )
+            )
+        # else, not supported
+
+    return graphene.Dynamic(dynamic_type)
+
+
 def convert_sqlalchemy_relationship(
     relationship_prop,
     obj_type,

graphene_sqlalchemy/tests/models.py

@@ -17,6 +17,7 @@
     Table,
     func,
 )
+from sqlalchemy.ext.associationproxy import association_proxy
 from sqlalchemy.ext.declarative import declarative_base
 from sqlalchemy.ext.hybrid import hybrid_property
 from sqlalchemy.orm import backref, column_property, composite, mapper, relationship
@@ -78,6 +79,18 @@ def __repr__(self):
         return "{} {}".format(self.first_name, self.last_name)
 
 
+class ProxiedReporter(Base):
+    __tablename__ = "reporters_error"
+    id = Column(Integer(), primary_key=True)
+    first_name = Column(String(30), doc="First name")
+    last_name = Column(String(30), doc="Last name")
+    reporter_id = Column(Integer(), ForeignKey("reporters.id"))
+    reporter = relationship("Reporter", uselist=False)
+
+    # This is a hybrid property, we don't support proxies on hybrids yet
+    composite_prop = association_proxy("reporter", "composite_prop")
+
+
 class Reporter(Base):
     __tablename__ = "reporters"
 
@@ -135,6 +148,8 @@ def hybrid_prop_list(self) -> List[int]:
         CompositeFullName, first_name, last_name, doc="Composite"
     )
 
+    headlines = association_proxy("articles", "headline")
+
 
 class Article(Base):
     __tablename__ = "articles"
@@ -145,6 +160,7 @@ class Article(Base):
     readers = relationship(
         "Reader", secondary="articles_readers", back_populates="articles"
     )
+    recommended_reads = association_proxy("reporter", "articles")
 
 
 class Reader(Base):

graphene_sqlalchemy/tests/test_converter.py

@@ -25,6 +25,7 @@
 )
 from .utils import wrap_select_func
 from ..converter import (
+    convert_sqlalchemy_association_proxy,
     convert_sqlalchemy_column,
     convert_sqlalchemy_composite,
     convert_sqlalchemy_hybrid_method,
@@ -41,6 +42,7 @@
     CompositeFullName,
     CustomColumnModel,
     Pet,
+    ProxiedReporter,
     Reporter,
     ShoppingCart,
     ShoppingCartItem,
@@ -650,6 +652,64 @@ class Meta:
     assert graphene_type.type == A
 
 
+def test_should_convert_association_proxy():
+    class ReporterType(SQLAlchemyObjectType):
+        class Meta:
+            model = Reporter
+
+    class ArticleType(SQLAlchemyObjectType):
+        class Meta:
+            model = Article
+
+    field = convert_sqlalchemy_association_proxy(
+        Reporter,
+        Reporter.headlines,
+        ReporterType,
+        get_global_registry(),
+        default_connection_field_factory,
+        True,
+        mock_resolver,
+    )
+    assert isinstance(field, graphene.Dynamic)
+    assert isinstance(field.get_type().type, graphene.List)
+    assert field.get_type().type.of_type == graphene.String
+
+    dynamic_field = convert_sqlalchemy_association_proxy(
+        Article,
+        Article.recommended_reads,
+        ArticleType,
+        get_global_registry(),
+        default_connection_field_factory,
+        True,
+        mock_resolver,
+    )
+    dynamic_field_type = dynamic_field.get_type().type
+    assert isinstance(dynamic_field, graphene.Dynamic)
+    assert isinstance(dynamic_field_type, graphene.NonNull)
+    assert isinstance(dynamic_field_type.of_type, graphene.List)
+    assert isinstance(dynamic_field_type.of_type.of_type, graphene.NonNull)
+    assert dynamic_field_type.of_type.of_type.of_type == ArticleType
+
+
+def test_should_throw_error_association_proxy_unsupported_target():
+    class ProxiedReporterType(SQLAlchemyObjectType):
+        class Meta:
+            model = ProxiedReporter
+
+    field = convert_sqlalchemy_association_proxy(
+        ProxiedReporter,
+        ProxiedReporter.composite_prop,
+        ProxiedReporterType,
+        get_global_registry(),
+        default_connection_field_factory,
+        True,
+        mock_resolver,
+    )
+
+    with pytest.raises(TypeError):
+        field.get_type()
+
+
 def test_should_postgresql_uuid_convert():
     assert get_field(postgresql.UUID()).type == graphene.UUID
 

graphene_sqlalchemy/tests/test_query.py

@@ -80,6 +80,7 @@ async def resolve_reporters(self, _info):
             columnProp
             hybridProp
             compositeProp
+            headlines
           }
           reporters {
             firstName
@@ -92,6 +93,7 @@ async def resolve_reporters(self, _info):
             "hybridProp": "John",
             "columnProp": 2,
             "compositeProp": "John Doe",
+            "headlines": ["Hi!"],
         },
         "reporters": [{"firstName": "John"}, {"firstName": "Jane"}],
     }

graphene_sqlalchemy/tests/test_types.py

@@ -138,6 +138,8 @@ class Meta:
             "pets",
             "articles",
             "favorite_article",
+            # AssociationProxy
+            "headlines",
         ]
     )
 
@@ -206,6 +208,16 @@ class Meta:
     assert favorite_article_field.type().type == ArticleType
     assert favorite_article_field.type().description is None
 
+    # assocation proxy
+    assoc_field = ReporterType._meta.fields["headlines"]
+    assert isinstance(assoc_field, Dynamic)
+    assert isinstance(assoc_field.type().type, List)
+    assert assoc_field.type().type.of_type == String
+
+    assoc_field = ArticleType._meta.fields["recommended_reads"]
+    assert isinstance(assoc_field, Dynamic)
+    assert assoc_field.type().type == ArticleType.connection
+
 
 def test_sqlalchemy_override_fields():
     @convert_sqlalchemy_composite.register(CompositeFullName)
@@ -275,6 +287,7 @@ class Meta:
             "hybrid_prop_float",
             "hybrid_prop_bool",
             "hybrid_prop_list",
+            "headlines",
         ]
     )
 
@@ -390,6 +403,7 @@ class Meta:
             "pets",
             "articles",
             "favorite_article",
+            "headlines",
         ]
     )
 
@@ -510,7 +524,7 @@ class Meta:
 
     assert issubclass(CustomReporterType, ObjectType)
     assert CustomReporterType._meta.model == Reporter
-    assert len(CustomReporterType._meta.fields) == 17
+    assert len(CustomReporterType._meta.fields) == 18
 
 
 # Test Custom SQLAlchemyObjectType with Custom Options

graphene_sqlalchemy/types.py

@@ -3,6 +3,7 @@
 from typing import Any
 
 import sqlalchemy
+from sqlalchemy.ext.associationproxy import AssociationProxy
 from sqlalchemy.ext.hybrid import hybrid_property
 from sqlalchemy.orm import ColumnProperty, CompositeProperty, RelationshipProperty
 from sqlalchemy.orm.exc import NoResultFound
@@ -16,6 +17,7 @@
 from graphene.utils.orderedtype import OrderedType
 
 from .converter import (
+    convert_sqlalchemy_association_proxy,
     convert_sqlalchemy_column,
     convert_sqlalchemy_composite,
     convert_sqlalchemy_hybrid_method,
@@ -152,7 +154,7 @@ def construct_fields(
         + [
             (name, item)
             for name, item in inspected_model.all_orm_descriptors.items()
-            if isinstance(item, hybrid_property)
+            if isinstance(item, hybrid_property) or isinstance(item, AssociationProxy)
         ]
         + inspected_model.relationships.items()
     )
@@ -230,6 +232,17 @@ def construct_fields(
             field = convert_sqlalchemy_composite(attr, registry, resolver)
         elif isinstance(attr, hybrid_property):
             field = convert_sqlalchemy_hybrid_method(attr, resolver, **orm_field.kwargs)
+        elif isinstance(attr, AssociationProxy):
+            field = convert_sqlalchemy_association_proxy(
+                model,
+                attr,
+                obj_type,
+                registry,
+                connection_field_factory,
+                batching,
+                resolver,
+                **orm_field.kwargs
+            )
         else:
             raise Exception("Property type is not supported")  # Should never happen