balakamatchi/ai_travel_planner

Purpose and entry points

AI Travel Planner is a MERN application for authenticated trip planning, AI itinerary generation, budgeting, maps, and photo journals. The React/Vite client starts at client/src/main.jsx and composes routes/UI in client/src/App.jsx. The Express API starts at server/server.js, connects MongoDB through server/config/db.js, and mounts resource routes.

Client application shell and session boundary

client/src/context/AuthContext.jsx restores the session through /api/auth/me, owns login/logout state, and supplies credentials to protected UI. client/src/services/api.js is the Axios boundary: it attaches the locally stored JWT and handles global 401 logout behavior. client/src/components/ProtectedRoute.jsx guards private routes; client/src/components/DashboardLayout.jsx provides the authenticated navigation shell. Theme state is independently managed and persisted by client/src/context/ThemeContext.jsx.

API security and request pipeline

server/server.js configures Express, CORS scoped to CLIENT_URL, cookie parsing, JSON handling, and centralized errors. Protected resource routes pass through JWT authentication in server/middleware/auth.js, accepting bearer token or cookie and attaching the owning user to req.user. Validation, multipart handling, and normalized API failures form key boundaries in server/middleware/validate.js, server/middleware/upload.js, and server/middleware/errorHandler.js.

Domain persistence and ownership model

MongoDB/Mongoose persists four user-owned collections: server/models/User.js, server/models/Trip.js, server/models/Expense.js, and server/models/Journal.js. Trips are the aggregate center: expenses and journal records reference both trip and user. Controllers scope reads and mutations to req.user._id; permanent trip deletion cascades related expenses and journals. Non-cancelled trip state is computed from travel dates via server/utils/getTripStatus.js, rather than persisted.

Trip planning and AI generation flow

The planner UI invokes client/src/services/aiService.js from client/src/pages/AITripPlannerPage.jsx. API endpoints in server/routes/aiRoutes.js route to server/controllers/aiController.js, which either returns a preview or persists an AI-generated Trip. server/utils/aiService.js calls Google Gemini for structured itinerary JSON, sanitizes model-derived values, and falls back to deterministic mock plans when unavailable or invalid. It separately queries Unsplash for destination cover images. AI endpoints are rate-limited to bound cost and abuse.

Trip lifecycle, budgets, and visualization

Trip CRUD flows through client/src/services/tripService.js and server/controllers/tripController.js; UI pages include trip list/details and dashboard views. Expense CRUD flows through client/src/services/expenseService.js and server/controllers/expenseController.js, producing per-trip totals/category breakdowns for the budget tracker. A Trip’s AI-produced places data crosses into client/src/pages/MapViewPage.jsx, where React Leaflet renders valid coordinates on OpenStreetMap tiles with type filtering.

Media and journal subsystem

Journal UI/service calls (client/src/pages/TravelJournalPage.jsx, client/src/services/journalService.js) reach server/controllers/journalController.js. Multer streams avatar and journal images using Cloudinary storage configured in server/config/cloudinary.js; journal deletion also removes Cloudinary assets. Profile operations are handled by server/controllers/userController.js, including avatar replacement and dashboard aggregation.

Runtime and external dependencies

The frontend is React 18/Vite with React Router, Tailwind, Leaflet, Recharts, and Framer Motion. The backend is Node.js 18+ and Express with MongoDB/Mongoose. Required infrastructure is MongoDB and Cloudinary; Gemini and Unsplash are optional due to graceful AI/mock and cover-image fallbacks. The root project runs client and server concurrently; client production output is independently deployable.