A modern React Native (Expo) mobile application with Node.js/Express backend for movie taste analysis and recommendation system.

• Features
• Tech Stack
• Requirements
• Installation
• Configuration
• Usage
• API Documentation
• Database Schema
• Development
• Troubleshooting
• License

• ✅ User Authentication: Secure registration and login system
• ✅ Movie Taste Quiz: Interactive quiz to analyze user preferences
• ✅ Profile Management: Automatically generated movie taste profile
• ✅ Token-Based Security: JWT-protected API calls
• ✅ Offline Support: Session persistence with AsyncStorage
• ✅ Expo Go Support: Quick testing and development via QR code

• ✅ RESTful API: Modern and scalable API architecture
• ✅ JWT Authentication: Secure token-based authentication
• ✅ PostgreSQL Integration: Robust and reliable database
• ✅ CORS Support: Cross-origin request configuration
• ✅ Transaction Management: Transaction support for data integrity
• ✅ Profile Analysis: Automatic movie taste profile calculation

• React Native 0.74.3
• Expo SDK 51
• TypeScript 5.0.4
• React Navigation 7.x
• AsyncStorage - Local storage
• Expo Constants - Environment variables

• Node.js 18+
• Express 5.1.0
• PostgreSQL - Database
• JWT (jsonwebtoken) - Token-based authentication
• bcryptjs - Password hashing
• CORS - Cross-origin support

• Node.js 18 or higher
• npm 9+ or yarn
• PostgreSQL 12+ (local or remote)
• Expo Go app (for mobile device testing)
• Git (for version control)

git clone https://github.com/emrekurum/MovieRecommendationApp.git
cd MovieRecommendationApp

npm install

cd MovieRecommendationApp-Backend
npm install
cd ..

Create a new database in PostgreSQL:

CREATE DATABASE movierecommendation;

Apply the schema:

psql -U postgres -d movierecommendation -f MovieRecommendationApp-Backend/database/schema.sql

Or run the schema.sql file using your PostgreSQL client.

Create a .env file in the MovieRecommendationApp-Backend directory:

cd MovieRecommendationApp-Backend
cp .env.example .env

Edit the .env file:

# PostgreSQL Database Settings
DB_USER=postgres
DB_PASSWORD=your_password_here
DB_HOST=localhost
DB_PORT=5432
DB_DATABASE=movierecommendation

# Server Port
PORT=3001

# JWT Secret Key (Use a strong key!)
JWT_SECRET=your-super-secret-jwt-key-change-this-in-production

⚠️ Important: Use a strong and random key for JWT_SECRET in production!

By default:

• iOS Simulator: http://localhost:3001
• Android Emulator: http://10.0.2.2:3001

Find the local IP address of the machine running the backend server:

Windows:

ipconfig

macOS/Linux:

ifconfig
# or
ip addr

Then set the environment variable when starting Expo:

EXPO_PUBLIC_API_URL=http://192.168.1.100:3001 npm start

Or create a .env file (in the root directory):

EXPO_PUBLIC_API_URL=http://192.168.1.100:3001

Note: Mobile device and computer must be on the same Wi-Fi network.

cd MovieRecommendationApp-Backend
npm run dev  # Development mode (auto-restart with nodemon)
# or
npm start    # Production mode

If the backend is running successfully, you'll see:

Backend server running at http://localhost:3001
Successfully connected to PostgreSQL database.

npm start

When Expo CLI starts:

1. A QR code will appear in the terminal
2. Open the Expo Go app on your mobile device
3. Scan the QR code
4. The app will load and run

Alternative Methods:

• npm run android - Open in Android emulator
• npm run ios - Open in iOS simulator (macOS only)
• npm run web - Open in web browser

1. Register: Create a new user account
2. Login: Sign in with your created account
3. Take Quiz: Complete the movie taste test
4. View Profile: See your automatically generated profile

Register a new user.

Request Body:

{
  "username": "john_doe",
  "email": "[email protected]",
  "password": "password123"
}

Response (201):

{
  "message": "User successfully registered!",
  "user": {
    "user_id": 1,
    "username": "john_doe",
    "email": "[email protected]",
    "created_at": "2024-01-01T00:00:00.000Z"
  }
}

User login.

Request Body:

{
  "email": "[email protected]",
  "password": "password123"
}

Response (200):

{
  "message": "Login successful!",
  "token": "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9...",
  "user": {
    "user_id": 1,
    "username": "john_doe",
    "email": "[email protected]"
  }
}

Get quiz questions. (Token optional)

Headers:

Authorization: Bearer <token>  (Optional)

Response (200):

[
  {
    "questionId": 1,
    "questionText": "What type of movies do you prefer?",
    "questionOrder": 1,
    "answers": [
      {
        "answerId": 1,
        "answerText": "Action"
      },
      {
        "answerId": 2,
        "answerText": "Drama"
      }
    ]
  }
]

Submit quiz answers and update user profile. (Token required)

Headers:

Authorization: Bearer <token>

Request Body:

{
  "answers": [
    {
      "questionId": 1,
      "chosenAnswerId": 1
    },
    {
      "questionId": 2,
      "chosenAnswerId": 3
    }
  ]
}

Response (200):

{
  "message": "Quiz answers successfully submitted and your profile has been updated!",
  "profile": {
    "summary": "Your movie taste generally includes: action, thriller, adventure.",
    "tags": ["action", "thriller", "adventure", "drama", "emotional"]
  },
  "user": {
    "user_id": 1,
    "username": "john_doe",
    "email": "[email protected]"
  }
}

• user_id (SERIAL PRIMARY KEY)
• username (VARCHAR, UNIQUE)
• email (VARCHAR, UNIQUE)
• password_hash (VARCHAR)
• taste_profile_summary (TEXT)
• taste_profile_tags (TEXT[])
• created_at (TIMESTAMP)

• question_id (SERIAL PRIMARY KEY)
• question_text (TEXT)
• question_order (INTEGER)
• created_at (TIMESTAMP)

• answer_id (SERIAL PRIMARY KEY)
• question_id (INTEGER, FOREIGN KEY)
• answer_text (TEXT)
• answer_tags (TEXT[])
• created_at (TIMESTAMP)

• user_id (INTEGER, FOREIGN KEY)
• question_id (INTEGER, FOREIGN KEY)
• chosen_answer_id (INTEGER, FOREIGN KEY)
• submitted_at (TIMESTAMP)
• PRIMARY KEY (user_id, question_id)

See MovieRecommendationApp-Backend/database/schema.sql for detailed schema.

MovieRecommendationApp/
├── src/
│   ├── components/          # Reusable components
│   ├── config/              # Configuration files
│   │   └── apiConfig.ts     # API URL configuration
│   ├── context/             # React Contexts
│   │   └── AuthContext.tsx  # Authentication context
│   ├── navigation/          # Navigation configuration
│   │   ├── AuthNavigator.tsx
│   │   └── MainAppNavigator.tsx
│   ├── screens/             # Screen components
│   │   ├── Auth/
│   │   │   ├── LoginScreen.tsx
│   │   │   └── RegisterScreen.tsx
│   │   └── Main/
│   │       ├── HomeScreen.tsx
│   │       └── QuizScreen.tsx
│   └── services/            # API services
│       ├── authService.ts
│       ├── quizService.ts
│       └── httpClient.ts
├── MovieRecommendationApp-Backend/
│   ├── src/
│   │   ├── config/
│   │   │   └── db.js        # Database connection
│   │   ├── middleware/
│   │   │   └── authMiddleware.js  # JWT verification
│   │   └── routes/
│   │       ├── authRoutes.js
│   │       └── quizRoutes.js
│   ├── database/
│   │   └── schema.sql       # Database schema
│   └── server.js            # Express server
├── App.tsx                  # Main application component
├── app.json                 # Expo configuration
└── package.json

• TypeScript: All frontend code is written in TypeScript
• ESLint: ESLint is used for code quality
• Async/Await: async/await is preferred for promises
• Error Handling: All API calls are protected with try-catch

1. New Screen: Create a new folder under src/screens/
2. Navigation: Add route in src/navigation/
3. API Endpoint: Create new route in backend
4. Service: Add new service function in frontend

Problem: PostgreSQL connection error

Solution: Check database credentials in .env file. Ensure PostgreSQL service is running.

Problem: Port already in use

Solution: Change PORT value in .env file or terminate the process using the port.

Problem: API requests failing

Solution: 
1. Ensure backend is running
2. Check EXPO_PUBLIC_API_URL environment variable
3. Mobile device and computer must be on same Wi-Fi network
4. Check firewall settings

Problem: App not opening in Expo Go

Solution:
1. Ensure Expo Go app is up to date
2. Run npm start again
3. Rescan QR code
4. Ensure Metro bundler is running

Problem: Table not found error

Solution: Run schema.sql file to create database schema.

This project is licensed under the MIT License - see the LICENSE file for details.

• Emre Kurum - Project owner and developer

• React Native and Expo community
• All open-source library developers

Note: This project is for educational and development purposes. Additional security measures should be taken for production use.