fix: bugfix/openapi/header_params_model

fastapi/dependencies/utils.py

@@ -713,14 +713,21 @@ def _validate_value_with_model_field(
         return v_, []
 
 
-def _get_multidict_value(
-    field: ModelField, values: Mapping[str, Any], alias: Union[str, None] = None
-) -> Any:
-    alias = alias or field.alias
+def _get_value(field: ModelField, values: Mapping[str, Any], alias: Union[str, None] = None) -> Any:
     if is_sequence_field(field) and isinstance(values, (ImmutableMultiDict, Headers)):
         value = values.getlist(alias)
     else:
         value = values.get(alias, None)
+    return value
+
+
+def _get_multidict_value(
+        field: ModelField, values: Mapping[str, Any], alias: Union[str, None] = None
+) -> Any:
+    alias = alias or field.alias
+    value = _get_value(field, values, alias)
+    if value is None and alias is not None:
+        value = _get_value(field, values, field.alias)
     if (
         value is None
         or (

fastapi/openapi/utils.py

@@ -126,8 +126,11 @@ def _get_openapi_operation_parameters(
                 field_mapping=field_mapping,
                 separate_input_output_schemas=separate_input_output_schemas,
             )
+            param_name = param.alias
+            if param_type == ParamTypes.header and param_name:
+                param_name = param.alias.replace("_", "-")
             parameter = {
-                "name": param.alias,
+                "name": param_name,
                 "in": param_type.value,
                 "required": param.required,
                 "schema": param_schema,