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/components/nodes/engine/SubQuestionQueryEngine/SubQuestionQueryEngine.ts

@@ -1,5 +1,5 @@
 import { flatten } from 'lodash'
-import { ICommonObject, INode, INodeData, INodeOutputsValue, INodeParams } from '../../../src/Interface'
+import { ICommonObject, INode, INodeData, INodeOutputsValue, INodeParams, IServerSideEventStreamer } from '../../../src/Interface'
 import {
     TreeSummarize,
     SimpleResponseBuilder,
@@ -88,24 +88,32 @@ class SubQuestionQueryEngine_LlamaIndex implements INode {
         let sourceDocuments: ICommonObject[] = []
         let sourceNodes: NodeWithScore<Metadata>[] = []
         let isStreamingStarted = false
-        const isStreamingEnabled = options.socketIO && options.socketIOClientId
 
-        if (isStreamingEnabled) {
+        const shouldStreamResponse = options.shouldStreamResponse
+        const sseStreamer: IServerSideEventStreamer = options.sseStreamer as IServerSideEventStreamer
+        const chatId = options.chatId
+
+        if (shouldStreamResponse) {
             const stream = await queryEngine.query({ query: input, stream: true })
             for await (const chunk of stream) {
                 text += chunk.response
                 if (chunk.sourceNodes) sourceNodes = chunk.sourceNodes
                 if (!isStreamingStarted) {
                     isStreamingStarted = true
-                    options.socketIO.to(options.socketIOClientId).emit('start', chunk.response)
+                    if (sseStreamer) {
+                        sseStreamer.streamStartEvent(chatId, chunk.response)
+                    }
+                }
+                if (sseStreamer) {
+                    sseStreamer.streamTokenEvent(chatId, chunk.response)
                 }
-
-                options.socketIO.to(options.socketIOClientId).emit('token', chunk.response)
             }
 
             if (returnSourceDocuments) {
                 sourceDocuments = reformatSourceDocuments(sourceNodes)
-                options.socketIO.to(options.socketIOClientId).emit('sourceDocuments', sourceDocuments)
+                if (sseStreamer) {
+                    sseStreamer.streamSourceDocumentsEvent(chatId, sourceDocuments)
+                }
             }
         } else {
             const response = await queryEngine.query({ query: input })