🏋️‍♂️ FitLog

A backend application built with FastAPI, PostgreSQL, SQLAlchemy, and Alembic. It provides user authentication, exercise and workout management, and personal record tracking.

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🚀 Features

• User Authentication
  • Registration and login using hashed passwords (bcrypt)
  • JWT-based authentication and authorization
• Exercise Management
  • CRUD endpoints to create, read, update, and delete exercises
  • Exercises are linked to individual users
• Workout Management
  • Create and manage workouts
  • Link workouts with multiple exercises (many-to-many relationship)
• Personal Record (PR) Endpoint
  • Query that joins exercises, workouts, and workout-exercises tables to display (exercise_name, weight) for a specific user.

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🧱 Tech Stack

• FastAPI – Web framework for building APIs
• Uvicorn – ASGI server to run FastAPI
• PostgreSQL (Docker) – Database
• SQLAlchemy – ORM for database modeling
• Alembic – Database migrations
• python-jose – JWT encoding and decoding
• bcrypt – Password hashing
• python-dotenv – Environment variable management

⚙️ Environment Setup

Prerequisites

You need Python 3.8+ and a running PostgreSQL instance.

Installation

1. Create and Activate a Virtual Environment:

   python -m venv venv
   # For Linux/Mac
   source venv/bin/activate
   # For Windows
   venv\Scripts\activate

2. Install Dependencies:

   pip install fastapi uvicorn[standard] sqlalchemy alembic psycopg2-binary python-dotenv python-jose[cryptography] bcrypt

   (You should also create a requirements.txt file by running pip freeze > requirements.txt)

Environment Variables

Create a .env file in the project root (and ensure it is added to .gitignore):

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🗄️ Project Structure

fitness-tracker-api/
│
├── app/
│   ├── main.py (or app.py)
│   ├── config.py             # Load environment variables
│   ├── database.py           # DB engine, session, and dependency
│   ├── models/               # SQLAlchemy ORM models
│   │   ├── base.py
│   │   ├── user.py
│   │   ├── exercise.py
│   │   ├── workout.py
│   │   └── workoutexercise.py
│   ├── schemas/              # Pydantic schemas for request/response validation
│   ├── routes/               # FastAPI routers (API endpoints)
│   └── utils/                # Helper functions (e.g., password hashing, JWT)
│
├── alembic/                  # Alembic migration environment
│   ├── versions/
│   └── env.py
│
├── .env
├── .gitignore
├── alembic.ini
├── requirements.txt
└── README.md

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🔧 Database Connection (app/database.py)

The database.py module will handle the SQLAlchemy setup:

• Import DATABASE_URL from app/config.py.
• Create a SQLAlchemy Engine (connection factory).
• Create a SessionLocal (session factory).
• Define a get_db() dependency for FastAPI routes to manage DB sessions safely.

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🧩 Migrations (Alembic)

1. Initialize Alembic:

   alembic init alembic

2. Configuration:

   • In alembic.ini, leave sqlalchemy.url = blank.
   • In alembic/env.py, update to load DATABASE_URL from .env, import Base and models, and set:

     target_metadata = Base.metadata

3. Generate Migration Script:

   alembic revision --autogenerate -m "Create users table"

4. Apply Migrations:

   alembic upgrade head

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🧠 Authentication

Authentication uses secure practices for password management and token generation:

• Password Hashing: bcrypt.hashpw()
• Password Verification: bcrypt.checkpw()
• JWT Encoding/Decoding: via python-jose

JWT Example

def jwt_encode(payload: dict):
    # Uses SECRET_KEY and ALGORITHM from .env
    return jwt.encode(payload, SECRET_KEY, algorithm=ALGORITHM)

def jwt_decode(token: str):
    return jwt.decode(token, SECRET_KEY, algorithms=[ALGORITHM])

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🔒 Routes Overview

Endpoint	Method	Description	Auth Required
/register	POST	Register a new user	❌
/login	POST	Login user and get JWT token	❌
/exercises/	CRUD	Manage exercises (Create, Read, Update, Delete)	✅
/workouts/	CRUD	Manage workouts (Create, Read, Update, Delete)	✅
/pr/	GET	Get user’s personal records	✅

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▶️ Running the Server

Start the FastAPI application:

uvicorn app.main:app --reload

API will be available at:

• Base URL: http://localhost:8000
• Interactive Docs (Swagger UI): http://localhost:8000/docs

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🧾 Notes

• Alembic: Use Alembic only when modifying schema (not for runtime CRUD changes).
• DB Sessions: Always use get_db() dependency to safely handle DB sessions.
• Security: .env should never be committed to version control.

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