Feature/sse (#3125)

* Base changes for ServerSide Events (instead of socket.io)

* lint fixes

* adding of interface and separate methods for streaming events

* lint

* first draft, handles both internal and external prediction end points.

* lint fixes

* additional internal end point for streaming and associated changes

* return streamresponse as true to build agent flow

* 1) JSON formatting for internal events
2) other fixes

* 1) convert internal event to metadata to maintain consistency with external response

* fix action and metadata streaming

* fix for error when agent flow is aborted

* prevent subflows from streaming and other code cleanup

* prevent streaming from enclosed tools

* add fix for preventing chaintool streaming

* update lock file

* add open when hidden to sse

* Streaming errors

* Streaming errors

* add fix for showing error message

---------

Co-authored-by: Henry <hzj94@hotmail.com>

packages/server/src/middlewares/errors/index.ts

@@ -12,8 +12,10 @@ async function errorHandlerMiddleware(err: InternalFlowiseError, req: Request, r
         // Provide error stack trace only in development
         stack: process.env.NODE_ENV === 'development' ? err.stack : {}
     }
-    res.setHeader('Content-Type', 'application/json')
-    res.status(displayedError.statusCode).json(displayedError)
+    if (!req.body.streaming || req.body.streaming === 'false') {
+        res.setHeader('Content-Type', 'application/json')
+        res.status(displayedError.statusCode).json(displayedError)
+    }
 }
 
 export default errorHandlerMiddleware