fix(llm): sending messages no longer throws an error at first

apps/server/src/routes/api/llm.ts

@@ -809,20 +809,26 @@ async function indexNote(req: Request, res: Response) {
 async function streamMessage(req: Request, res: Response) {
     log.info("=== Starting streamMessage ===");
     try {
-        // Set up the response headers for streaming first, before any data is sent
-        res.setHeader('Content-Type', 'text/event-stream');
-        res.setHeader('Cache-Control', 'no-cache');
-        res.setHeader('Connection', 'keep-alive');
-        
         const chatNoteId = req.params.chatNoteId;
         const { content, useAdvancedContext, showThinking, mentions } = req.body;
 
         if (!content || typeof content !== 'string' || content.trim().length === 0) {
-            // Early return with error
-            res.write(`data: ${JSON.stringify({ error: 'Content cannot be empty', done: true })}\n\n`);
-            res.end();
-            return;
+            return res.status(400).json({
+                success: false,
+                error: 'Content cannot be empty'
+            });
         }
+        
+        // IMPORTANT: Immediately send a success response to the initial POST request
+        // The client is waiting for this to confirm streaming has been initiated
+        res.status(200).json({
+            success: true,
+            message: 'Streaming initiated successfully'
+        });
+        log.info(`Sent immediate success response for streaming setup`);
+        
+        // Create a new response object for streaming through WebSocket only
+        // We won't use HTTP streaming since we've already sent the HTTP response
 
         // Get or create chat directly from storage (simplified approach)
         let chat = await chatStorageService.getChat(chatNoteId);
@@ -883,28 +889,70 @@ async function streamMessage(req: Request, res: Response) {
             thinking: showThinking ? 'Initializing streaming LLM response...' : undefined
         });
 
-        // Process the streaming request directly
+        // Instead of trying to reimplement the streaming logic ourselves,
+        // delegate to restChatService but set up the correct protocol:
+        // 1. We've already sent a success response to the initial POST
+        // 2. Now we'll have restChatService process the actual streaming through WebSocket
         try {
-            // Call the streaming handler - it will handle the response streaming
-            // IMPORTANT: We do not await this because we don't want to try sending a response
-            // after the streaming has completed - the stream handler takes care of ending the response
-            restChatService.handleSendMessage({
-                ...req,
-                method: 'GET', // Indicate streaming mode
-                query: {
-                    ...req.query,
-                    stream: 'true' // Add the required stream parameter
-                },
-                body: {
-                    content: enhancedContent,
-                    useAdvancedContext: useAdvancedContext === true,
-                    showThinking: showThinking === true
-                },
-                params: { chatNoteId }
-            } as unknown as Request, res);
+            // Import the WebSocket service for sending messages
+            const wsService = (await import('../../services/ws.js')).default;
             
-            // Don't return or send any additional response here
-            // handleSendMessage handles the full streaming response cycle and will end the response
+            // Create a simple pass-through response object that won't write to the HTTP response
+            // but will allow restChatService to send WebSocket messages
+            const dummyResponse = {
+                writableEnded: false,
+                // Implement methods that would normally be used by restChatService
+                write: (_chunk: string) => {
+                    // Silent no-op - we're only using WebSocket
+                    return true;
+                },
+                end: (_chunk?: string) => {
+                    // Log when streaming is complete via WebSocket
+                    log.info(`[${chatNoteId}] Completed HTTP response handling during WebSocket streaming`);
+                    return dummyResponse;
+                },
+                setHeader: (name: string, _value: string) => {
+                    // Only log for content-type to reduce noise
+                    if (name.toLowerCase() === 'content-type') {
+                        log.info(`[${chatNoteId}] Setting up streaming for WebSocket only`);
+                    }
+                    return dummyResponse;
+                }
+            };
+            
+            // Process the streaming now through WebSocket only
+            try {
+                log.info(`[${chatNoteId}] Processing LLM streaming through WebSocket after successful initiation at ${new Date().toISOString()}`);
+                
+                // Call restChatService with our enhanced request and dummy response
+                // The important part is setting method to GET to indicate streaming mode
+                await restChatService.handleSendMessage({
+                    ...req,
+                    method: 'GET', // Indicate streaming mode
+                    query: {
+                        ...req.query,
+                        stream: 'true' // Add the required stream parameter
+                    },
+                    body: {
+                        content: enhancedContent,
+                        useAdvancedContext: useAdvancedContext === true,
+                        showThinking: showThinking === true
+                    },
+                    params: { chatNoteId }
+                } as unknown as Request, dummyResponse as unknown as Response);
+                
+                log.info(`[${chatNoteId}] WebSocket streaming completed at ${new Date().toISOString()}`);
+            } catch (streamError) {
+                log.error(`[${chatNoteId}] Error during WebSocket streaming: ${streamError}`);
+                
+                // Send error message through WebSocket
+                wsService.sendMessageToAllClients({
+                    type: 'llm-stream',
+                    chatNoteId: chatNoteId,
+                    error: `Error during streaming: ${streamError}`,
+                    done: true
+                });
+            }
         } catch (error) {
             log.error(`Error during streaming: ${error}`);