Development

This section describes version control practices and technologies used during development of AggFin.

Version Control (Git & GitHub)

GitHub as remote version control platform. development tracked via Git terminal.

Branching Strategy

  • main branch used for most of work.
  • different branch used for Login and Error Page.
  • Some optional feature testing done in local branches(not pushed).
  • For simplicity, no GitFlow or PR-based branching strategy enforced.

Commit Conventions

  • Commit messages descriptive
  • Messages referred to the section being worked on.

.gitignore Usage

  • A .gitignore file was used to exclude:
    • Python cache files (__pycache__/)
    • Environment files (e.g., .env)
    • SQLite database files
  • prevent unnecessary or sensitive data from entering version control.

Learning Experience: .gitignore Setup

Initially, .gitignore not configured before creating the Python virtual environment. As a result, some unnecessary files (e.g., .pyc ) tracked. This issue was later corrected by updating .gitignore and removing cached files.

Implementation Details

Network Protocols

  • HTTP/HTTPS used for all frontend/backend communication.
    • Browser → Flask server
    • Flask server → External APIs (NewsAPI, Yahoo Finance)
  • TCP served as the transport protocol underneath HTTP.

Why: HTTP standard for web apps. HTTPS for encrypted transmission . TCP for reliable communication for API access.

In-Transit Data Representation

  • HTML: used between server and browser via Jinja2 templates.
  • JSON: used in:
    • AJAX calls for autocomplete (/suggest)
    • Responses from NewsAPI and Yahoo Finance

Why: JSON lightweight for both internal and external API communication. HTML suited for rendering views in web apps.

Database Querying

  • SQLAlchemy ORM utilized to define and query the User model.
  • Under the hood, queries are translated into SQL specific to SQLite.

Why: SQL standard for relational data. SQLAlchemy easy querying while offering protection against SQL injection.

Component Authentication

  • Flask-Login for managing user sessions.
  • Authentication via email/password.
  • Passwords hashed using Flask-Bcrypt before saving.

Why: Flask-Login proper for secure handling user sessions. Hashing protects user credentials even if the database is leaked.

Technological Details

Languages, Frameworks, and Tools

  • Python: backend language for logic
  • Flask: lightweight web framework
  • HTML/CSS/JavaScript: standard frontend stack
  • Jinja2: template engine for rendering views
  • SQLite: simple embedded database
  • Bootstrap: UI framework for responsive design

Libraries and Dependencies

  • Flask: web app routing and middleware
  • Flask-Bcrypt: secure password hashing
  • Flask-Login: user session management
  • Flask-SQLAlchemy: ORM for database interactions
  • requests: HTTP client for external APIs
  • yfinance: fetches stock financial data
  • python-dotenv: environment variable management (if used)
  • NewsAPI: external news integration

External Services

  • NewsAPI: financial news based on stock names
  • Yahoo Finance (via yfinance): real-time financial data

Why: Both APIs reliable, accessible with free keys, easy to integrate in Python.