Expense Tracker is a comprehensive expense reporting system designed to simplify the process of recording and tracking purchases.

• Features
• Usage
• Languages and Frameworks Used
• Installation
• Backend Documentation
• License

• Receipt Upload: Users can easily upload receipts, and the system will automatically extract via OCR and record the necessary information.
• Manual Reporting: For those who prefer a hands-on approach, the system also supports manual entry of purchase details.
• Detailed Reporting: Expense Tracker generates detailed, interactive reports based on the recorded data. This allows users to easily visualize and understand their spending habits.
• Secure Login: System also features mordern secure login that no one else can access user's own sensitive data
• Google Login: For added convenience, users can also log in using their Google accounts.
• Real-time Currency Exchange inquiry: Using FreecurrencyAPI, application provides accurate Real-time currency conversion

To use Expense Tracker, simply log in, and choose to either upload a receipt or manually enter your purchase details. The system will take care of the rest, automatically updating your reports to reflect the new data.

• Python: The backend of the application is built with Python.
• Flask: Flask is used as the web framework.
• Flask-login: Flask-login is used to handle user login session.
• Jinja2: Jinja2 is used for templating and generating HTML dynamically.
• JavaScript: JavaScript is used for client-side scripting.
• CSS: CSS is used for styling the web pages.
• SQLAlchemy: SQLAlchemy is used as the ORM for database operations.
• SQLite: SQLite is used as the database.
• OAuth2: OAuth2 is used for Google Login.
• Pillow: Pillow is used to handle the images upload by users
• Tesseract OCR: Tesseract OCR is used for extracting text from uploaded receipt images.
• Werkzeug: werkzeug.security is used to generate secure password hashing to store in server database.
• APIs: FreecurrencyAPI is used for currency conversion data.

1. Clone the repository:

   git clone https://github.com/huajie-zhong/expense-tracker.git
   cd expense-tracker

2. Install dependencies:

   pip install -r requirements.txt

3. Set up the environment variables: Create a .env file in the project root with the following variables:

   SECRET_KEY=your_secret_key
   GOOGLE_CLIENT_ID=your_google_client_id
   GOOGLE_CLIENT_SECRET=your_google_client_secret
   TESSERACT_PATH=your_tesseract_installation_location
   CURRENCY_API_KEY=yoru_currency_api_key

4. Run the Flask application:

   python api/app.py

   The application will be accessible at http://localhost:8000.

• URL: /
• Method: GET
• Description: Renders the main page of the application.

• URL: /currency/
• Methods: GET, POST
• Description: Renders the currency page. If the method is POST, it redirects to the /currency route.

• URL: /header/
• Methods: GET, POST
• Description: Renders the header page. If the method is POST, it redirects to the /header route.

• URL: /report/
• Methods: GET, POST
• Description: Renders the report page. If the method is POST, it redirects to the /report route.

• URL: /login/
• Methods: GET, POST
• Description: Renders the login page. If the method is POST, it redirects to the /login route.

• URL: /api/login/
• Method: POST
• Description:
  • Retrieves username and password from the request body.
  • Verifies user existence in the database and checks the correctness of the password.
  • Generates access and refresh tokens.
  • Sets access and refresh tokens as cookies in the response.

• URL: /api/refresh-token/
• Method: POST
• Description:
  • Refreshes the access token using a provided refresh token.
  • Sets the new access token as a cookie in the response.

• URL: /api/logout/
• Method: POST
• Description:
  • Logs out the user.
  • Clears access and refresh tokens by setting their expiration to the immediate time.

• URL: /api/register/
• Method: POST
• Description:
  • Registers a new user.
  • Hashes the password and stores the user in the database.

• URL: /api/submit_expense/
• Method: POST
• Description:
  • Takes receipt or amount as input and returns the amount and type of expense.
  • Records the expense in the database.

• URL: /api/get_expenses/
• Method: GET
• Description:
  • Returns all expenses for the authenticated user.

• URL: /api/authorize/<provider>
• Method: GET
• Description:
  • Authorizes the user with the specified OAuth2 provider.

• URL: /api/callback/<provider>
• Method: GET
• Description:
  • Handles the OAuth2 callback, exchanging the code for an access token.

• 404 Page Not Found

  • URL: * (catch-all)
  • Method: GET
  • Description: Renders a custom 404 page.

• Unauthorized Handler

  • URL: * (catch-all)
  • Method: GET
  • Description: Handles unauthorized access with a 401 response.

This project is licensed under the GNU General Public License v3.0.

We are constantly working to improve Expense Tracker. Future updates will include more detailed reports, support for multiple currencies, and improved receipt scanning accuracy.