support dict as Schema

flask_smorest/arguments.py

@@ -4,6 +4,7 @@
 from functools import wraps
 import http
 
+import marshmallow as ma
 from webargs.flaskparser import FlaskParser
 
 from .utils import deepupdate
@@ -28,8 +29,8 @@ def arguments(
     ):
         """Decorator specifying the schema used to deserialize parameters
 
-        :param type|Schema schema: Marshmallow ``Schema`` class or instance
-            used to deserialize and validate the argument.
+        :param type|Schema|dict schema: Marshmallow ``Schema`` class or instance
+            or dict used to deserialize and validate the argument.
         :param str location: Location of the argument.
         :param str content_type: Content type of the argument.
             Should only be used in conjunction with ``json``, ``form`` or
@@ -56,6 +57,8 @@ def arguments(
 
         See :doc:`Arguments <arguments>`.
         """
+        if isinstance(schema, dict):
+            schema = ma.Schema.from_dict(schema)
         # At this stage, put schema instance in doc dictionary. Il will be
         # replaced later on by $ref or json.
         parameters = {

flask_smorest/utils.py

@@ -2,6 +2,7 @@
 
 from collections import abc
 
+import marshmallow as ma
 from werkzeug.datastructures import Headers
 from flask import g
 from apispec.utils import trim_docstring, dedent
@@ -31,9 +32,16 @@ def remove_none(mapping):
 def resolve_schema_instance(schema):
     """Return schema instance for given schema (instance or class).
 
-    :param type|Schema schema: marshmallow.Schema instance or class
+    :param type|Schema|dict schema: marshmallow.Schema instance or class or dict
     :return: schema instance of given schema
     """
+
+    # this dict may be used to document a file response, no a schema dict
+    if isinstance(schema, dict) and all(
+        [isinstance(v, (type, ma.fields.Field)) for v in schema.values()]
+    ):
+        schema = ma.Schema.from_dict(schema)
+
     return schema() if isinstance(schema, type) else schema
 
 

tests/conftest.py

@@ -78,6 +78,11 @@ class ClientErrorSchema(ma.Schema):
         error_id = ma.fields.Str()
         text = ma.fields.Str()
 
-    return namedtuple("Model", ("DocSchema", "QueryArgsSchema", "ClientErrorSchema"))(
-        DocSchema, QueryArgsSchema, ClientErrorSchema
-    )
+    DictSchema = {
+        "item_id": ma.fields.Int(dump_only=True),
+        "field": ma.fields.Int(attribute="db_field"),
+    }
+
+    return namedtuple(
+        "Model", ("DocSchema", "QueryArgsSchema", "ClientErrorSchema", "DictSchema")
+    )(DocSchema, QueryArgsSchema, ClientErrorSchema, DictSchema)

tests/test_blueprint.py

@@ -307,6 +307,65 @@ def func(document, query_args):
             "query_args": {"arg1": "test"},
         }
 
+    @pytest.mark.parametrize("openapi_version", ("2.0", "3.0.2"))
+    def test_blueprint_dict_argument_schema(self, app, schemas, openapi_version):
+        app.config["OPENAPI_VERSION"] = openapi_version
+        api = Api(app)
+        blp = Blueprint("test", __name__, url_prefix="/test")
+        client = app.test_client()
+
+        @blp.route("/", methods=("POST",))
+        @blp.arguments(schemas.DictSchema)
+        def func(document):
+            return {"document": document}
+
+        api.register_blueprint(blp)
+        spec = api.spec.to_dict()
+
+        # Check parameters are documented
+        if openapi_version == "2.0":
+            parameters = spec["paths"]["/test/"]["post"]["parameters"]
+            assert len(parameters) == 1
+            assert parameters[0]["in"] == "body"
+            assert "schema" in parameters[0]
+        else:
+            assert (
+                "schema"
+                in spec["paths"]["/test/"]["post"]["requestBody"]["content"][
+                    "application/json"
+                ]
+            )
+
+        # Check parameters are passed as arguments to view function
+        item_data = {"field": 12}
+        response = client.post(
+            "/test/",
+            data=json.dumps(item_data),
+            content_type="application/json",
+        )
+        assert response.status_code == 200
+        assert response.json == {
+            "document": {"db_field": 12},
+        }
+
+    @pytest.mark.parametrize("openapi_version", ["2.0", "3.0.2"])
+    def test_blueprint_dict_response_schema(self, app, schemas, openapi_version):
+        """Check alt_response passes response transparently"""
+        app.config["OPENAPI_VERSION"] = openapi_version
+        api = Api(app)
+        blp = Blueprint("test", "test", url_prefix="/test")
+        client = app.test_client()
+
+        @blp.route("/")
+        @blp.response(200, schema=schemas.DictSchema)
+        def func():
+            return {"item_id": 12}
+
+        api.register_blueprint(blp)
+
+        resp = client.get("/test/")
+        assert resp.json == {"item_id": 12}
+
     @pytest.mark.parametrize("openapi_version", ("2.0", "3.0.2"))
     def test_blueprint_arguments_files_multipart(self, app, schemas, openapi_version):
         app.config["OPENAPI_VERSION"] = openapi_version