Add delete mutations

Author: Guido

src/graphql_sqlalchemy/args.py

@@ -19,25 +19,20 @@
 
 
 def make_args(model: DeclarativeMeta, inputs: Inputs) -> GraphQLArgumentMap:
-    args = {}
+    args = {
+        "order": GraphQLArgument(GraphQLList(GraphQLNonNull(get_order_type(model, inputs)))),
+        "where": GraphQLArgument(get_where_type(model, inputs)),
+    }
+
     for name, field in PAGINATION_ARGS.items():
         args[name] = GraphQLArgument(field)
 
-    order_type = get_order_type(model, inputs)
-    args["order"] = GraphQLArgument(GraphQLList(GraphQLNonNull(order_type)))
-
-    where_type = get_where_type(model, inputs)
-    args["where"] = GraphQLArgument(where_type)
-
     return args
 
 
-def make_pk_args(model: DeclarativeMeta) -> Optional[GraphQLArgumentMap]:
+def make_pk_args(model: DeclarativeMeta) -> GraphQLArgumentMap:
     primary_key = get_table(model).primary_key
 
-    if not primary_key:
-        return None
-
     args = {}
     for column in primary_key.columns:
         graphql_type = get_graphql_type_from_column(column)
@@ -58,3 +53,7 @@ def make_insert_one_args(model: DeclarativeMeta, inputs: Inputs) -> GraphQLArgum
         "object": GraphQLArgument(get_insert_type(model, inputs)),
         "on_conflict": GraphQLArgument(get_conflict_type(model, inputs)),
     }
+
+
+def make_delete_args(model: DeclarativeMeta, inputs: Inputs) -> GraphQLArgumentMap:
+    return {"where": GraphQLArgument(get_where_type(model, inputs))}

src/graphql_sqlalchemy/names.py

@@ -58,3 +58,11 @@ def get_model_constraint_key_name(model: DeclarativeMeta, column: Column, is_pri
 
 def get_model_column_update_enum_name(model: DeclarativeMeta) -> str:
     return f"{get_table_name(model)}_update_column"
+
+
+def get_model_delete_name(model: DeclarativeMeta) -> str:
+    return f"delete_{get_table_name(model)}"
+
+
+def get_model_delete_by_pk_name(model: DeclarativeMeta) -> str:
+    return f"delete_{get_table_name(model)}_by_pk"

src/graphql_sqlalchemy/resolvers.py

@@ -182,3 +182,33 @@ def resolver(
         return instance
 
     return resolver
+
+
+def make_delete_resolver(model: DeclarativeMeta) -> Callable:
+    def resolver(
+        _root: DeclarativeMeta, info: Any, where: Optional[Dict[str, Any]] = None
+    ) -> Dict[str, Union[int, List[DeclarativeMeta]]]:
+        session = info.context["session"]
+        query = session.query(model)
+        query = filter_query(model, query, where)
+
+        rows = query.all()
+        affected = query.delete()
+        session.commit()
+
+        return {"affected_rows": affected, "returning": rows}
+
+    return resolver
+
+
+def make_delete_by_pk_resolver(model: DeclarativeMeta) -> Callable:
+    def resolver(_root: DeclarativeMeta, info: Any, **kwargs: Dict[str, Any]) -> List[DeclarativeMeta]:
+        session = info.context["session"]
+
+        row = session.query(model).get(kwargs)
+        session.delete(row)
+        session.commit()
+
+        return row
+
+    return resolver

src/graphql_sqlalchemy/schema.py

@@ -7,16 +7,32 @@
     GraphQLList,
 )
 
-from .resolvers import make_object_resolver, make_pk_resolver, make_insert_resolver, make_insert_one_resolver
-from .args import make_args, make_pk_args, make_insert_args, make_insert_one_args
+from .resolvers import (
+    make_object_resolver,
+    make_pk_resolver,
+    make_insert_resolver,
+    make_insert_one_resolver,
+    make_delete_resolver,
+    make_delete_by_pk_resolver,
+)
+from .args import (
+    make_args,
+    make_pk_args,
+    make_insert_args,
+    make_insert_one_args,
+    make_delete_args,
+)
 from .names import (
     get_model_pk_field_name,
     get_model_insert_object_name,
     get_model_insert_one_object_name,
     get_table_name,
+    get_model_delete_name,
+    get_model_delete_by_pk_name,
 )
 from .objects import build_object_type, build_mutation_response_type
 from .types import Objects, Inputs
+from .helpers import get_table
 
 
 def build_queries(model: DeclarativeMeta, objects: Objects, queries: GraphQLFieldMap, inputs: Inputs) -> None:
@@ -27,24 +43,36 @@ def build_queries(model: DeclarativeMeta, objects: Objects, queries: GraphQLFiel
         GraphQLList(object_type), args=make_args(model, inputs=inputs), resolve=make_object_resolver(model)
     )
 
-    pk_field_name = get_model_pk_field_name(model)
-    queries[pk_field_name] = GraphQLField(object_type, args=make_pk_args(model), resolve=make_pk_resolver(model))
+    if get_table(model).primary_key:
+        pk_field_name = get_model_pk_field_name(model)
+        queries[pk_field_name] = GraphQLField(object_type, args=make_pk_args(model), resolve=make_pk_resolver(model))
 
 
 def build_mutations(model: DeclarativeMeta, objects: Objects, mutations: GraphQLFieldMap, inputs: Inputs) -> None:
-    insert_type_name = get_model_insert_object_name(model)
     mutation_response_type = build_mutation_response_type(model, objects)
+    object_type = objects[get_table_name(model)]
 
+    insert_type_name = get_model_insert_object_name(model)
     mutations[insert_type_name] = GraphQLField(
         mutation_response_type, args=make_insert_args(model, inputs), resolve=make_insert_resolver(model)
     )
 
     insert_one_type_name = get_model_insert_one_object_name(model)
-    object_type = objects[get_table_name(model)]
     mutations[insert_one_type_name] = GraphQLField(
         object_type, args=make_insert_one_args(model, inputs), resolve=make_insert_one_resolver(model)
     )
 
+    delete_type_name = get_model_delete_name(model)
+    mutations[delete_type_name] = GraphQLField(
+        mutation_response_type, args=make_delete_args(model, inputs), resolve=make_delete_resolver(model)
+    )
+
+    if get_table(model).primary_key:
+        delete_by_pk_type_name = get_model_delete_by_pk_name(model)
+        mutations[delete_by_pk_type_name] = GraphQLField(
+            object_type, args=make_pk_args(model), resolve=make_delete_by_pk_resolver(model)
+        )
+
 
 def build_schema(base: DeclarativeMeta) -> GraphQLSchema:
     queries: GraphQLFieldMap = {}