From 974c2b24d07adf869e1c3298e7186cff57284121 Mon Sep 17 00:00:00 2001
From: Travis Addair <tgaddair@gmail.com>
Date: Wed, 16 Oct 2024 12:48:12 -0700
Subject: [PATCH] Added backwards compatible  field to OpenAI json_object API
 (#648)

---
 router/src/lib.rs    |  4 ++++
 router/src/server.rs | 21 ++++++++++++++++-----
 2 files changed, 20 insertions(+), 5 deletions(-)

diff --git a/router/src/lib.rs b/router/src/lib.rs
index f8bdb8f3f..0a64ec6ce 100644
--- a/router/src/lib.rs
+++ b/router/src/lib.rs
@@ -523,6 +523,10 @@ struct OpenAiResponseFormat {
     #[serde(rename(deserialize = "type"))]
     response_format_type: ResponseFormatType,
     json_schema: Option<JsonSchema>,
+
+    // For backwards compatibility
+    #[serde(default = "default_json_schema")]
+    schema: Option<serde_json::Value>,
 }
 
 #[derive(Clone, Deserialize, ToSchema, Serialize, Debug, PartialEq)]
diff --git a/router/src/server.rs b/router/src/server.rs
index 7a2480c3d..b0f1d7f7d 100644
--- a/router/src/server.rs
+++ b/router/src/server.rs
@@ -272,11 +272,22 @@ async fn chat_completions_v1(
                 // Ignore when type is text
                 ResponseFormatType::Text => None,
 
-                // For json_object, use the fixed schema
-                ResponseFormatType::JsonObject => Some(ResponseFormat {
-                    r#type: response_format_type.clone(),
-                    schema: default_json_schema(),
-                }),
+                // For json_object, use the fixed schema.
+                // For backwards compatibility, also support non-standard `schema` field
+                ResponseFormatType::JsonObject => openai_format.schema.map_or_else(
+                    || {
+                        Some(ResponseFormat {
+                            r#type: response_format_type.clone(),
+                            schema: default_json_schema(),
+                        })
+                    },
+                    |schema_value: serde_json::Value| {
+                        Some(ResponseFormat {
+                            r#type: response_format_type.clone(),
+                            schema: Some(schema_value),
+                        })
+                    },
+                ),
 
                 // For json_schema, use schema_value if available, otherwise fallback to the fixed schema
                 ResponseFormatType::JsonSchema => openai_format