Dockerfile

@@ -1,4 +1,4 @@
-# Build stage
+# ---------- Build stage (Keep this the same) ----------
 FROM node:20-alpine AS build
 WORKDIR /app
 COPY package.json package-lock.json ./
@@ -6,11 +6,18 @@ RUN npm ci
 COPY . .
 RUN npm run build
 
-# Production stage
-FROM node:20-alpine
-WORKDIR /app
-COPY --from=build /app/dist ./dist
-COPY server.js .
-RUN npm install express@4 google-auth-library
-EXPOSE 8080
-CMD ["node", "server.js"]
+# ---------- Diagnostic Production stage ----------
+FROM python:3.11-slim
+
+# Set the working directory to where the React files live
+WORKDIR /usr/share/nginx/html
+
+# Copy build output from the build stage
+COPY --from=build /app/dist .
+
+# Expose port 80 (Cloud Run expects this)
+EXPOSE 80
+
+# Run Python's built-in simple HTTP server
+# This server is very "dumb" and will ignore/accept large IAP headers
+CMD ["python", "-m", "http.server", "80"]

server.js

@@ -1,60 +0,0 @@
-const express = require('express');
-const path = require('path');
-const { GoogleAuth } = require('google-auth-library');
-
-const app = express();
-app.use(express.json({ limit: '1mb' }));
-
-const BACKEND_URL = process.env.BACKEND_URL;
-if (!BACKEND_URL) {
-  console.error('FATAL: BACKEND_URL env var is required');
-  process.exit(1);
-}
-
-const auth = new GoogleAuth();
-
-app.get('/health', (_req, res) => {
-  res.status(200).json({ status: 'ok' });
-});
-
-app.post('/api/chat', async (req, res) => {
-    console.log('🔥🔥🔥 /api/chat ROUTE HIT 🔥🔥🔥');
-  try {
-    // Create an ID-token authenticated client for the backend (audience = BACKEND_URL)
-    const idTokenClient = await auth.getIdTokenClient(BACKEND_URL);
-
-    // Forward request to backend
-    const backendResp = await idTokenClient.request({
-      url: `${BACKEND_URL}/chat`,
-      method: 'POST',
-      data: req.body,
-    });
-
-    res.status(backendResp.status).json(backendResp.data);
-  } catch (err) {
-    console.error('Proxy error FULL:', {
-    message: err.message,
-    responseStatus: err.response?.status,
-    responseData: err.response?.data,
-    stack: err.stack,
-  });
-    const status = err.response?.status || 500;
-    const message = err.response?.data || { error: err.message };
-    res.status(err.response?.status || 500).json({
-    error: err.response?.data || err.message || 'Unknown proxy error',
-  });
-  }
-});
-
-// Serve static assets
-app.use(express.static(path.join(__dirname, 'dist')));
-
-// SPA fallback
-app.get('*', (_req, res) => {
-  res.sendFile(path.join(__dirname, 'dist', 'index.html'));
-});
-
-const port = parseInt(process.env.PORT || '8080', 10);
-app.listen(port, '0.0.0.0', () => {
-  console.log(`Frontend proxy listening on port ${port}`);
-});

src/hooks/useChat.ts

@@ -24,21 +24,47 @@ export const useChat = (mode: ChatMode) => {
     setIsLoading(true)
 
     try {
-      // Call the chat API and get the response
-      const response = await apiClient.chat(question, mode)
+      // Create placeholder assistant message
+      const assistantMessageId = (Date.now() + 1).toString()
+      let assistantContent = ''
 
-      // Add assistant message with the response
-      const assistantMessage: Message = {
-        id: (Date.now() + 1).toString(),
-        role: 'assistant',
-        content: response.response,
+      setMessages((prev) => [
+        ...prev,
+        {
+          id: assistantMessageId,
+          role: 'assistant',
+          content: '',
+        },
+      ])
+
+      // Process SSE stream
+      const streamGenerator = apiClient.chatStream(question, mode)
+
+      for await (const chunk of streamGenerator) {
+        if (chunk.type === 'chunk') {
+          // Append chunk content
+          assistantContent += chunk.data
+
+          // Update assistant message
+          setMessages((prev) =>
+            prev.map((msg) =>
+              msg.id === assistantMessageId
+                ? { ...msg, content: assistantContent }
+                : msg
+            )
+          )
+        } else if (chunk.type === 'error') {
+          toast.error(chunk.data)
+          console.error('Stream error:', chunk.data)
+        } else if (chunk.type === 'done') {
+          setIsLoading(false)
+        }
       }
 
-      setMessages((prev) => [...prev, assistantMessage])
+      setIsLoading(false)
     } catch (error) {
       console.error('Error sending message:', error)
-      toast.error(error instanceof Error ? error.message : 'Failed to send message. Please try again.')
-    } finally {
+      toast.error('Failed to send message. Please try again.')
       setIsLoading(false)
     }
   }

src/lib/api.ts

@@ -1,8 +1,7 @@
 import type { ChatMode } from '@/types/chat'
 
-// In production, use relative URL to route through the proxy server
-const API_BASE_URL = '/api'
-const USE_MOCK_DATA = false // Set to true to use mock data for testing
+const API_BASE_URL = import.meta.env.VITE_API_URL || 'http://localhost:5000'
+const USE_MOCK_DATA = true // Set to false when backend is ready
 
 // Session management
 export const getChatSessionId = (): string | null => {
@@ -33,34 +32,39 @@ const MOCK_RESPONSES = {
   ],
 }
 
-// Chat response type from backend
-export interface ChatResponse {
-  conversation_id: string
-  response: string
-  mode: string
-  sources: string[]
-}
-
-// Mock chat function
-async function mockChat(
+// Mock streaming function
+async function* mockChatStream(
   _question: string,
   mode: ChatMode
-): Promise<ChatResponse> {
+): AsyncGenerator<StreamEvent> {
+  const sessionId = crypto.randomUUID()
+  yield { type: 'session_id', data: sessionId }
+
   // Select a random response based on mode
   const responses = MOCK_RESPONSES[mode]
   const response = responses[Math.floor(Math.random() * responses.length)]
 
-  // Simulate network delay
-  await new Promise(resolve => setTimeout(resolve, 500))
+  // Simulate streaming by yielding words with delays
+  const words = response.split(' ')
+  for (let i = 0; i < words.length; i++) {
+    // Add space before word (except first word)
+    const chunk = i === 0 ? words[i] : ' ' + words[i]
+    yield { type: 'chunk', data: chunk }
 
-  return {
-    conversation_id: crypto.randomUUID(),
-    response,
-    mode,
-    sources: [],
+    // Random delay between 30-80ms to simulate typing
+    await new Promise(resolve => setTimeout(resolve, Math.random() * 50 + 30))
   }
+
+  yield { type: 'done', data: null }
 }
 
+// SSE stream event types
+export type StreamEvent =
+  | { type: 'chunk'; data: string }
+  | { type: 'done'; data: null }
+  | { type: 'error'; data: string }
+  | { type: 'session_id'; data: string }
+
 class ApiClient {
   private sessionId: string | null = null
 
@@ -78,40 +82,95 @@ class ApiClient {
     clearChatSessionId()
   }
 
-  // Simple JSON chat endpoint
-  async chat(
+  // Streaming chat endpoint (SSE)
+  async *chatStream(
     question: string,
     mode: ChatMode,
     sessionId?: string
-  ): Promise<ChatResponse> {
+  ): AsyncGenerator<StreamEvent> {
     // Use mock data if enabled
     if (USE_MOCK_DATA) {
-      return mockChat(question, mode)
+      yield* mockChatStream(question, mode)
+      return
     }
 
     // Generate or reuse session ID
     const actualSessionId = sessionId || this.getSessionId() || crypto.randomUUID()
     this.setSessionId(actualSessionId)
 
-    const response = await fetch(`${API_BASE_URL}/chat`, {
-      method: 'POST',
-      headers: {
-        'Content-Type': 'application/json',
-      },
-      body: JSON.stringify({
-        message: question,
-        conversation_id: actualSessionId,
-      }),
-    })
+    // Yield session ID first
+    yield { type: 'session_id', data: actualSessionId }
 
-    if (!response.ok) {
-      const errorData = await response.json().catch(() => ({}))
-      throw new Error(errorData.detail || `HTTP error! status: ${response.status}`)
+    try {
+      const response = await fetch(`${API_BASE_URL}/api/chat/stream`, {
+        method: 'POST',
+        headers: {
+          'Content-Type': 'application/json',
+        },
+        body: JSON.stringify({
+          question,
+          mode,
+          sessionId: actualSessionId,
+        }),
+      })
+
+      if (!response.ok) {
+        yield { type: 'error', data: `HTTP error! status: ${response.status}` }
+        return
+      }
+
+      if (!response.body) {
+        yield { type: 'error', data: 'Response body is null' }
+        return
+      }
+
+      const reader = response.body.getReader()
+      const decoder = new TextDecoder()
+      let buffer = ''
+
+      while (true) {
+        const { done, value } = await reader.read()
+
+        if (done) break
+
+        buffer += decoder.decode(value, { stream: true })
+        const lines = buffer.split('\n')
+        buffer = lines.pop() || ''
+
+        for (const line of lines) {
+          if (line.startsWith('data: ')) {
+            const data = line.slice(6)
+
+            if (data === '[DONE]') {
+              yield { type: 'done', data: null }
+              return
+            }
+
+            try {
+              const parsed = JSON.parse(data)
+              if (parsed.type === 'error') {
+                yield { type: 'error', data: parsed.message }
+              } else if (parsed.content) {
+                yield { type: 'chunk', data: parsed.content }
+              } else {
+                // Raw string chunk
+                yield { type: 'chunk', data: data }
+              }
+            } catch {
+              // Raw string chunk (not JSON)
+              yield { type: 'chunk', data: data }
+            }
+          }
+        }
+      }
+
+      yield { type: 'done', data: null }
+    } catch (error) {
+      yield {
+        type: 'error',
+        data: error instanceof Error ? error.message : 'Network error',
+      }
     }
-
-    const data: ChatResponse = await response.json()
-    this.setSessionId(data.conversation_id)
-    return data
   }
 }
 

vite.config.ts

@@ -12,14 +12,7 @@ export default defineConfig({
   },
   server: {
     port: 3000,
-    host: true,
-    proxy: {
-      '/api': {
-        target: 'http://localhost:8000',
-        changeOrigin: true,
-        rewrite: (path) => path.replace(/^\/api/, ''),
-      }
-    }
+    host: true
   },
   build: {
     outDir: 'dist',