Migrate magic numbers for status codes to named constants (#44176)

airflow/api_fastapi/core_api/routes/public/connections.py

@@ -44,7 +44,7 @@
 
 @connections_router.delete(
     "/{connection_id}",
-    status_code=204,
+    status_code=status.HTTP_204_NO_CONTENT,
     responses=create_openapi_http_exception_doc([status.HTTP_404_NOT_FOUND]),
 )
 def delete_connection(
@@ -120,7 +120,7 @@ def get_connections(
 
 @connections_router.post(
     "/",
-    status_code=201,
+    status_code=status.HTTP_201_CREATED,
     responses=create_openapi_http_exception_doc([status.HTTP_409_CONFLICT]),
 )
 def post_connection(
@@ -131,11 +131,14 @@ def post_connection(
     try:
         helpers.validate_key(post_body.connection_id, max_length=200)
     except Exception as e:
-        raise HTTPException(400, f"{e}")
+        raise HTTPException(status.HTTP_400_BAD_REQUEST, f"{e}")
 
     connection = session.scalar(select(Connection).filter_by(conn_id=post_body.connection_id))
     if connection is not None:
-        raise HTTPException(409, f"Connection with connection_id: `{post_body.connection_id}` already exists")
+        raise HTTPException(
+            status.HTTP_409_CONFLICT,
+            f"Connection with connection_id: `{post_body.connection_id}` already exists",
+        )
 
     connection = Connection(**post_body.model_dump(by_alias=True))
     session.add(connection)
@@ -160,7 +163,10 @@ def patch_connection(
 ) -> ConnectionResponse:
     """Update a connection entry."""
     if patch_body.connection_id != connection_id:
-        raise HTTPException(400, "The connection_id in the request body does not match the URL parameter")
+        raise HTTPException(
+            status.HTTP_400_BAD_REQUEST,
+            "The connection_id in the request body does not match the URL parameter",
+        )
 
     non_update_fields = {"connection_id", "conn_id"}
     connection = session.scalar(select(Connection).filter_by(conn_id=connection_id).limit(1))
@@ -195,7 +201,7 @@ def test_connection(
     """
     if conf.get("core", "test_connection", fallback="Disabled").lower().strip() != "enabled":
         raise HTTPException(
-            403,
+            status.HTTP_403_FORBIDDEN,
             "Testing connections is disabled in Airflow configuration. "
             "Contact your deployment admin to enable it.",
         )

airflow/api_fastapi/core_api/routes/public/variables.py

@@ -38,7 +38,7 @@
 
 @variables_router.delete(
     "/{variable_key}",
-    status_code=204,
+    status_code=status.HTTP_204_NO_CONTENT,
     responses=create_openapi_http_exception_doc([status.HTTP_404_NOT_FOUND]),
 )
 def delete_variable(