From f507a77a430fbc499533ade438d348308f7c4aa1 Mon Sep 17 00:00:00 2001
From: Yasin Tatar <ytatar9@googlemail.com>
Date: Fri, 10 Nov 2023 12:07:11 +0100
Subject: [PATCH 1/2] add: option to generate api specification by field name
 instead of alias

---
 docs/en/docs/how-to/extending-openapi.md | 1 +
 fastapi/openapi/utils.py                 | 5 ++++-
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/docs/en/docs/how-to/extending-openapi.md b/docs/en/docs/how-to/extending-openapi.md
index a18fd737e..4126cf79b 100644
--- a/docs/en/docs/how-to/extending-openapi.md
+++ b/docs/en/docs/how-to/extending-openapi.md
@@ -26,6 +26,7 @@ And that function `get_openapi()` receives as parameters:
 * `summary`: A short summary of the API.
 * `description`: The description of your API, this can include markdown and will be shown in the docs.
 * `routes`: A list of routes, these are each of the registered *path operations*. They are taken from `app.routes`.
+* `field_names_by_alias`: A boolean indicating whether to use the field names or the alias names for the models.
 
 !!! info
     The parameter `summary` is available in OpenAPI 3.1.0 and above, supported by FastAPI 0.99.0 and above.
diff --git a/fastapi/openapi/utils.py b/fastapi/openapi/utils.py
index 5bfb5acef..58c0b460a 100644
--- a/fastapi/openapi/utils.py
+++ b/fastapi/openapi/utils.py
@@ -450,6 +450,7 @@ def get_openapi(
     contact: Optional[Dict[str, Union[str, Any]]] = None,
     license_info: Optional[Dict[str, Union[str, Any]]] = None,
     separate_input_output_schemas: bool = True,
+    field_names_by_alias: bool = True,
 ) -> Dict[str, Any]:
     info: Dict[str, Any] = {"title": title, "version": version}
     if summary:
@@ -471,7 +472,9 @@ def get_openapi(
     operation_ids: Set[str] = set()
     all_fields = get_fields_from_routes(list(routes or []) + list(webhooks or []))
     model_name_map = get_compat_model_name_map(all_fields)
-    schema_generator = GenerateJsonSchema(ref_template=REF_TEMPLATE)
+    schema_generator = GenerateJsonSchema(
+        ref_template=REF_TEMPLATE, by_alias=field_names_by_alias
+    )
     field_mapping, definitions = get_definitions(
         fields=all_fields,
         schema_generator=schema_generator,

From 217bf8f2b99bc1a07b0e0c2dad98dcb6eab3ad8b Mon Sep 17 00:00:00 2001
From: Yasin Tatar <ytatar9@googlemail.com>
Date: Fri, 10 Nov 2023 12:19:18 +0100
Subject: [PATCH 2/2] update dataclass for backward-compat

---
 fastapi/_compat.py | 1 +
 1 file changed, 1 insertion(+)

diff --git a/fastapi/_compat.py b/fastapi/_compat.py
index fc605d0ec..13f596423 100644
--- a/fastapi/_compat.py
+++ b/fastapi/_compat.py
@@ -347,6 +347,7 @@ else:
     @dataclass
     class GenerateJsonSchema:  # type: ignore[no-redef]
         ref_template: str
+        by_alias: bool = True
 
     class PydanticSchemaGenerationError(Exception):  # type: ignore[no-redef]
         pass