fix(openapi): generate requestBody for body parameter

litestar/_openapi/path_item.py

@@ -62,12 +62,17 @@ def create_operation_for_handler_method(
         signature_fields = route_handler.parsed_fn_signature.parameters
 
         request_body = None
+        request_body_field = None
         if data_field := signature_fields.get("data"):
             request_body = create_request_body(
                 self.context, route_handler.handler_id, route_handler.data_dto, data_field
             )
+            request_body_field = data_field
+        elif body_field := signature_fields.get("body"):
+            request_body = create_request_body(self.context, route_handler.handler_id, None, body_field)
+            request_body_field = body_field
 
-        raises_validation_error = bool(data_field or self._path_item.parameters or parameters)
+        raises_validation_error = bool(request_body_field or self._path_item.parameters or parameters)
         responses = create_responses_for_handler(
             self.context, route_handler, raises_validation_error=raises_validation_error
         )

litestar/_openapi/request_body.py

@@ -34,7 +34,9 @@ def create_request_body(
     Returns:
         A RequestBody instance.
     """
-    media_type: RequestEncodingType | str = RequestEncodingType.JSON
+    media_type: RequestEncodingType | str = (
+        "application/octet-stream" if data_field.is_subclass_of(bytes) else RequestEncodingType.JSON
+    )
     schema_creator = SchemaCreator.from_openapi_context(context, prefer_alias=True)
     if isinstance(data_field.kwarg_definition, BodyKwarg) and data_field.kwarg_definition.media_type:
         media_type = data_field.kwarg_definition.media_type

tests/unit/test_openapi/test_request_body.py

@@ -217,3 +217,69 @@ async def handler(
             }
         }
     }
+
+
+def test_body_parameter_binary_request() -> None:
+    @post("/upload/")
+    async def handle_binary_upload(body: bytes) -> None:
+        return None
+
+    app = Litestar([handle_binary_upload])
+    schema = app.openapi_schema.to_schema()
+
+    assert "requestBody" in schema["paths"]["/upload"]["post"]
+    assert schema["paths"]["/upload"]["post"]["requestBody"] == {
+        "required": True,
+        "content": {"application/octet-stream": {"schema": {"type": "string"}}},
+    }
+
+
+def test_body_parameter_with_body_annotation() -> None:
+    @post("/upload/")
+    async def handle_binary_upload(
+        body: Annotated[bytes, Body(media_type="application/octet-stream", title="Binary Data")],
+    ) -> None:
+        return None
+
+    app = Litestar([handle_binary_upload])
+    schema = app.openapi_schema.to_schema()
+
+    assert "requestBody" in schema["paths"]["/upload"]["post"]
+    assert schema["paths"]["/upload"]["post"]["requestBody"] == {
+        "required": True,
+        "content": {"application/octet-stream": {"schema": {"type": "string", "title": "Binary Data"}}},
+    }
+
+
+def test_body_parameter_with_default_value() -> None:
+    @post("/upload/")
+    async def handle_binary_upload(
+        body: bytes = Body(media_type="application/octet-stream", title="Binary Data"),
+    ) -> None:
+        return None
+
+    app = Litestar([handle_binary_upload])
+    schema = app.openapi_schema.to_schema()
+
+    assert "requestBody" in schema["paths"]["/upload"]["post"]
+    assert schema["paths"]["/upload"]["post"]["requestBody"] == {
+        "required": True,
+        "content": {"application/octet-stream": {"schema": {"type": "string", "title": "Binary Data"}}},
+    }
+
+
+def test_body_parameter_with_custom_media_type() -> None:
+    @post("/upload/")
+    async def handle_binary_upload(
+        body: Annotated[bytes, Body(media_type="application/x-custom-binary")],
+    ) -> None:
+        return None
+
+    app = Litestar([handle_binary_upload])
+    schema = app.openapi_schema.to_schema()
+
+    assert "requestBody" in schema["paths"]["/upload"]["post"]
+    assert schema["paths"]["/upload"]["post"]["requestBody"] == {
+        "required": True,
+        "content": {"application/x-custom-binary": {"schema": {"type": "string"}}},
+    }