Introduce mapping shapes

fastapi/dependencies/utils.py

@@ -41,7 +41,7 @@ from pydantic.fields import (
     SHAPE_TUPLE_ELLIPSIS,
     FieldInfo,
     ModelField,
-    Required,
+    Required, SHAPE_MAPPING,
 )
 from pydantic.schema import get_annotation_from_field_info
 from pydantic.typing import ForwardRef, evaluate_forwardref
@@ -69,6 +69,13 @@ sequence_shape_to_type = {
     SHAPE_TUPLE_ELLIPSIS: list,
 }
 
+mapping_shapes = {
+    SHAPE_MAPPING
+}
+mapping_types = (dict)
+mapping_shapes_to_type = {
+    SHAPE_MAPPING: dict
+}
 
 multipart_not_installed_error = (
     'Form data requires "python-multipart" to be installed. \n'
@@ -240,6 +247,20 @@ def is_scalar_sequence_field(field: ModelField) -> bool:
     return False
 
 
+def is_scalar_mapping_field(field: ModelField) -> bool:
+    if (field.shape in mapping_shapes) and not lenient_issubclass(
+        field.type_, BaseModel
+    ):
+        if field.sub_fields is not None:
+            for sub_field in field.sub_fields:
+                if not is_scalar_field(sub_field):
+                    return False
+        return True
+    if lenient_issubclass(field.type_, mapping_types):
+        return True
+    return False
+
+
 def get_typed_signature(call: Callable) -> inspect.Signature:
     signature = inspect.signature(call)
     globalns = getattr(call, "__globals__", {})
@@ -324,7 +345,8 @@ def get_dependant(
             add_param_to_fields(field=param_field, dependant=dependant)
         elif isinstance(
             param.default, (params.Query, params.Header)
-        ) and is_scalar_sequence_field(param_field):
+        ) and (is_scalar_sequence_field(param_field)
+               or is_scalar_mapping_field(param_field)):
             add_param_to_fields(field=param_field, dependant=dependant)
         else:
             field_info = param_field.field_info
@@ -610,6 +632,10 @@ def request_params_to_args(
             received_params, (QueryParams, Headers)
         ):
             value = received_params.getlist(field.alias) or field.default
+        elif is_scalar_mapping_field(field) and isinstance(
+            received_params, (QueryParams,)
+        ):
+            value = received_params._dict
         else:
             value = received_params.get(field.alias)
         field_info = field.field_info