add unknown optional keywords to parse and use_args

src/webargs/asyncparser.py

@@ -30,7 +30,8 @@ async def parse(
         location: str = None,
         validate: Validate = None,
         error_status_code: typing.Union[int, None] = None,
-        error_headers: typing.Union[typing.Mapping[str, str], None] = None
+        error_headers: typing.Union[typing.Mapping[str, str], None] = None,
+        unknown=None
     ) -> typing.Union[typing.Mapping, None]:
         """Coroutine variant of `webargs.core.Parser`.
 
@@ -42,7 +43,7 @@ async def parse(
             raise ValueError("Must pass req object")
         data = None
         validators = core._ensure_list_of_callables(validate)
-        schema = self._get_schema(argmap, req)
+        schema = self._get_schema(argmap, req, unknown=unknown)
         try:
             location_data = await self._load_location_data(
                 schema=schema, req=req, location=location
@@ -114,7 +115,8 @@ def use_args(
         as_kwargs: bool = False,
         validate: Validate = None,
         error_status_code: typing.Optional[int] = None,
-        error_headers: typing.Union[typing.Mapping[str, str], None] = None
+        error_headers: typing.Union[typing.Mapping[str, str], None] = None,
+        unknown = None
     ) -> typing.Callable[..., typing.Callable]:
         """Decorator that injects parsed arguments into a view function or method.
 
@@ -125,7 +127,10 @@ def use_args(
         # Optimization: If argmap is passed as a dictionary, we only need
         # to generate a Schema once
         if isinstance(argmap, Mapping):
-            argmap = core.dict2schema(argmap, schema_class=self.schema_class)()
+            if unknown is None:
+                argmap = core.dict2schema(argmap, schema_class=self.schema_class)()
+            else:
+                argmap = core.dict2schema(argmap, schema_class=self.schema_class)(unknown=unknown)
 
         def decorator(func: typing.Callable) -> typing.Callable:
             req_ = request_obj

src/webargs/core.py

@@ -191,7 +191,7 @@ def _validate_arguments(self, data, validators):
                 msg = self.DEFAULT_VALIDATION_MESSAGE
                 raise ValidationError(msg, data=data)
 
-    def _get_schema(self, argmap, req):
+    def _get_schema(self, argmap, req, unknown=None):
         """Return a `marshmallow.Schema` for the given argmap and request.
 
         :param argmap: Either a `marshmallow.Schema`, `dict`
@@ -207,7 +207,14 @@ def _get_schema(self, argmap, req):
         elif callable(argmap):
             schema = argmap(req)
         else:
-            schema = dict2schema(argmap, schema_class=self.schema_class)()
+            if 'unknown' in argmap:
+                unknown = argmap['unknown']
+            else:
+                pass
+            if unknown is None:
+                schema = dict2schema(argmap, schema_class=self.schema_class)()
+            else:
+                schema = dict2schema(argmap, schema_class=self.schema_class)(unknown=unknown)
         if MARSHMALLOW_VERSION_INFO[0] < 3 and not schema.strict:
             warnings.warn(
                 "It is highly recommended that you set strict=True on your schema "
@@ -224,7 +231,8 @@ def parse(
         location=None,
         validate=None,
         error_status_code=None,
-        error_headers=None
+        error_headers=None,
+        unknown=None
     ):
         """Main request parsing method.
 
@@ -252,7 +260,7 @@ def parse(
             raise ValueError("Must pass req object")
         data = None
         validators = _ensure_list_of_callables(validate)
-        schema = self._get_schema(argmap, req)
+        schema = self._get_schema(argmap, req, unknown)
         try:
             location_data = self._load_location_data(
                 schema=schema, req=req, location=location
@@ -310,7 +318,8 @@ def use_args(
         as_kwargs=False,
         validate=None,
         error_status_code=None,
-        error_headers=None
+        error_headers=None,
+        unknown=None
     ):
         """Decorator that injects parsed arguments into a view function or method.
 
@@ -339,7 +348,10 @@ def greet(args):
         # Optimization: If argmap is passed as a dictionary, we only need
         # to generate a Schema once
         if isinstance(argmap, Mapping):
-            argmap = dict2schema(argmap, schema_class=self.schema_class)()
+            if unknown is None:
+                argmap = dict2schema(argmap, schema_class=self.schema_class)()
+            else:
+                argmap = dict2schema(argmap, schema_class=self.schema_class)(unknown = unknown)
 
         def decorator(func):
             req_ = request_obj