Customized sorting for: Graphene SQLAlchemy library
Why do you need it? Graphene SQLAlchemy library has sort mechanism bult-in SQLALchemyConnectionField,
however it enables ordering by using Model columns (Model corresponded to Node). It is not possible
to sort collection using column from joined model / table or exploiting temporary query variable.
This solution is hugly inspired by: graphene-sqlalchemy-filter
class Example(Base):
__tablename__ = "example"
id = Column(Integer, primary_key=True, autoincrement=True)
first_name = Column(String)
second_name = Column(String)
items = relationship("Item", uselist=True, lazy="dynamic")
class Item(Base):
__tablename__ = "item"
id = Column(Integer, primary_key=True, autoincrement=True)
created = Column(DateTime)
example_id = Column(
Integer, ForeignKey("example.id", ondelete="CASCADE"), index=True
)
class ExampleNode(SQLAlchemyObjectType):
class Meta:
model = Example
interfaces = (graphene.relay.Node,)
class ExampleSort(SortSet):
class Meta:
model = Example
fields = ["first_name", "second_name", "name", "item_created"]
@classmethod
def name_sort(cls, query):
return query, case(
[
(Example.second_name.is_(None), Example.first_name),
(Example.first_name.is_(None), Example.second_name),
],
else_=Example.second_name,
)
@classmethod
def item_created_sort(cls, query):
if not is_model_joined(query, Item):
query = query.join("items")
return query, Item.created
class Query(graphene.ObjectType):
examples = SQLAlchemyConnectionField(ExampleNode, sort=ExampleSort())
def resolve_examples(self, info, **kwargs):
query = info.context["session"].query(Example)
if kwargs.get("sort"):
query = ExampleSort().sort(query, kwargs["sort"])
return query
schema = graphene.Schema(query=Query){
examples (sort: {firstName: "ASC"}) {
edges {
node {
firstName
}
}
}
}{
examples (sort: {name: "ASC"}) {
edges {
node {
firstName
}
}
}
}{
examples (sort: {itemCreated: "DESC"}) {
edges {
node {
firstName
}
}
}
}