chore: add backward compatible for thread (#1782)

Author: namchuai

engine/common/thread.h

@@ -124,6 +124,21 @@ struct Thread : JsonSerializable {
       json["object"] = object;
       json["created_at"] = created_at;
 
+      // Deprecated: This is for backward compatibility. Please remove it later. (2-3 releases) to be sure
+      try {
+        auto it = metadata.find("title");
+        if (it == metadata.end()) {
+          json["title"] = "";
+        } else {
+          json["title"] = std::get<std::string>(metadata["title"]);
+        }
+
+      } catch (const std::bad_variant_access& ex) {
+        // std::cerr << "Error: value is not a string" << std::endl;
+        CTL_WRN("Error: value of title is not a string: " << ex.what());
+      }
+      // End deprecated
+
       if (tool_resources) {
         auto tool_result = tool_resources->ToJson();
         if (tool_result.has_error()) {

engine/controllers/threads.cc

@@ -26,6 +26,7 @@ void Threads::ListThreads(
   for (auto& msg : res.value()) {
     if (auto it = msg.ToJson(); it.has_value()) {
       it->removeMember("assistants");
+      it->removeMember("title");
       msg_arr.append(it.value());
     } else {
       CTL_WRN("Failed to convert message to json: " + it.error());
@@ -86,8 +87,10 @@ void Threads::CreateThread(
       resp->setStatusCode(k400BadRequest);
       callback(resp);
     } else {
-      auto resp =
-          cortex_utils::CreateCortexHttpJsonResponse(res->ToJson().value());
+      auto json_res = res->ToJson();
+      json_res->removeMember("title");
+      json_res->removeMember("assistants");
+      auto resp = cortex_utils::CreateCortexHttpJsonResponse(json_res.value());
       resp->setStatusCode(k200OK);
       callback(resp);
     }
@@ -116,6 +119,7 @@ void Threads::RetrieveThread(
       callback(resp);
     } else {
       thread_to_json->removeMember("assistants");
+      thread_to_json->removeMember("title");
       auto resp =
           cortex_utils::CreateCortexHttpJsonResponse(thread_to_json.value());
       resp->setStatusCode(k200OK);
@@ -189,6 +193,8 @@ void Threads::ModifyThread(
       resp->setStatusCode(k400BadRequest);
       callback(resp);
     } else {
+      res->ToJson()->removeMember("title");
+      res->ToJson()->removeMember("assistants");
       auto resp =
           cortex_utils::CreateCortexHttpJsonResponse(res->ToJson().value());
       resp->setStatusCode(k200OK);