Implement simple cart system with FastAPI and SQLite

README.md

@@ -1,3 +1,106 @@
-# FastAPI Application
+# Simple Cart System API
 
-This is a FastAPI application bootstrapped by BackendIM, the AI-powered backend generation platform.
+A simple cart system API built with FastAPI and SQLite for managing products and shopping carts.
+
+## Features
+
+- User registration and authentication with JWT tokens
+- Product management (CRUD operations)
+- Shopping cart functionality (add, update, remove, clear)
+- SQLite database with SQLAlchemy ORM
+- Alembic migrations
+
+## Tech Stack
+
+- **FastAPI:** High-performance web framework for building APIs
+- **SQLAlchemy:** SQL toolkit and ORM 
+- **SQLite:** Lightweight, file-based database
+- **Alembic:** Database migration tool
+- **Pydantic:** Data validation and settings management
+- **Python-Jose:** JWT token handling
+- **Uvicorn:** ASGI server for running the application
+
+## Project Structure
+
+```
+.
+├── alembic.ini                 # Alembic configuration file
+├── app                         # Main application package
+│   ├── api                     # API routes
+│   │   └── routes              # API route modules
+│   ├── core                    # Core functionality
+│   │   ├── config.py           # Configuration settings
+│   │   └── security.py         # Authentication and security utilities
+│   ├── db                      # Database related modules
+│   │   ├── models              # SQLAlchemy models
+│   │   └── session.py          # Database session management
+│   └── schemas                 # Pydantic models for request/response validation
+├── main.py                     # Application entry point
+├── migrations                  # Alembic migrations
+│   └── versions                # Migration script versions
+└── requirements.txt            # Project dependencies
+```
+
+## Getting Started
+
+### Prerequisites
+
+- Python 3.8+
+- pip
+
+### Installation
+
+1. Clone the repository
+
+2. Install dependencies
+   ```bash
+   pip install -r requirements.txt
+   ```
+
+3. Run database migrations
+   ```bash
+   alembic upgrade head
+   ```
+
+4. Start the application
+   ```bash
+   uvicorn main:app --reload
+   ```
+
+5. Access the API documentation
+   - Swagger UI: http://localhost:8000/docs
+   - ReDoc: http://localhost:8000/redoc
+
+## API Endpoints
+
+### Authentication
+- `POST /api/v1/login/access-token` - Get access token
+
+### Users
+- `POST /api/v1/users/` - Create a new user
+- `GET /api/v1/users/` - Get all users
+- `GET /api/v1/users/{user_id}` - Get a specific user
+- `PATCH /api/v1/users/{user_id}` - Update a user
+- `DELETE /api/v1/users/{user_id}` - Delete a user
+
+### Products
+- `POST /api/v1/products/` - Create a new product (admin only)
+- `GET /api/v1/products/` - Get all products
+- `GET /api/v1/products/{product_id}` - Get a specific product
+- `PATCH /api/v1/products/{product_id}` - Update a product (admin only)
+- `DELETE /api/v1/products/{product_id}` - Delete a product (admin only)
+
+### Cart
+- `POST /api/v1/cart/items/` - Add an item to cart
+- `GET /api/v1/cart/` - Get current user's cart
+- `GET /api/v1/cart/summary` - Get cart summary
+- `PATCH /api/v1/cart/items/{item_id}` - Update cart item quantity
+- `DELETE /api/v1/cart/items/{item_id}` - Remove an item from cart
+- `DELETE /api/v1/cart/` - Clear cart
+
+### Health Check
+- `GET /health` - Check application health status
+
+## License
+
+MIT

alembic.ini

@@ -0,0 +1,102 @@
+# A generic, single database configuration.
+
+[alembic]
+# path to migration scripts
+script_location = migrations
+
+# template used to generate migration files
+# file_template = %%(rev)s_%%(slug)s
+
+# sys.path path, will be prepended to sys.path if present.
+# defaults to the current working directory.
+prepend_sys_path = .
+
+# timezone to use when rendering the date within the migration file
+# as well as the filename.
+# If specified, requires the python-dateutil library that can be
+# installed by adding `alembic[tz]` to the pip requirements
+# string value is passed to dateutil.tz.gettz()
+# leave blank for localtime
+# timezone =
+
+# max length of characters to apply to the
+# "slug" field
+# truncate_slug_length = 40
+
+# set to 'true' to run the environment during
+# the 'revision' command, regardless of autogenerate
+# revision_environment = false
+
+# set to 'true' to allow .pyc and .pyo files without
+# a source .py file to be detected as revisions in the
+# versions/ directory
+# sourceless = false
+
+# version location specification; This defaults
+# to migrations/versions.  When using multiple version
+# directories, initial revisions must be specified with --version-path.
+# The path separator used here should be the separator specified by "version_path_separator" below.
+# version_locations = %(here)s/bar:%(here)s/bat:migrations/versions
+
+# version path separator; As mentioned above, this is the character used to split
+# version_locations. The default within new alembic.ini files is "os", which uses os.pathsep.
+# If this key is omitted entirely, it falls back to the legacy behavior of splitting on spaces and/or commas.
+# Valid values for version_path_separator are:
+#
+# version_path_separator = :
+# version_path_separator = ;
+# version_path_separator = space
+version_path_separator = os  # Use os.pathsep. Default configuration used for new projects.
+
+# the output encoding used when revision files
+# are written from script.py.mako
+# output_encoding = utf-8
+
+# SQLite URL example
+sqlalchemy.url = sqlite:////app/storage/db/db.sqlite
+
+[post_write_hooks]
+# post_write_hooks defines scripts or Python functions that are run
+# on newly generated revision scripts.  See the documentation for further
+# detail and examples
+
+# format using "black" - use the console_scripts runner, against the "black" entrypoint
+# hooks = black
+# black.type = console_scripts
+# black.entrypoint = black
+# black.options = -l 79 REVISION_SCRIPT_FILENAME
+
+# Logging configuration
+[loggers]
+keys = root,sqlalchemy,alembic
+
+[handlers]
+keys = console
+
+[formatters]
+keys = generic
+
+[logger_root]
+level = WARN
+handlers = console
+qualname =
+
+[logger_sqlalchemy]
+level = WARN
+handlers =
+qualname = sqlalchemy.engine
+
+[logger_alembic]
+level = INFO
+handlers =
+qualname = alembic
+
+[handler_console]
+class = StreamHandler
+args = (sys.stderr,)
+level = NOTSET
+formatter = generic
+
+[formatter_generic]
+format = %(levelname)-5.5s [%(name)s] %(message)s
+datefmt = %H:%M:%S

app/api/routes/__init__.py

@@ -0,0 +1,9 @@
+from fastapi import APIRouter
+
+from app.api.routes import users, products, cart, login
+
+api_router = APIRouter()
+api_router.include_router(login.router, tags=["authentication"])
+api_router.include_router(users.router, tags=["users"])
+api_router.include_router(products.router, tags=["products"])
+api_router.include_router(cart.router, tags=["cart"])

app/api/routes/cart.py

@@ -0,0 +1,222 @@
+
+from fastapi import APIRouter, Depends, HTTPException, status
+from sqlalchemy.orm import Session
+
+from app.db.session import get_db
+from app.db.models.cart import Cart, CartItem
+from app.db.models.product import Product
+from app.db.models.user import User
+from app.schemas.cart import (
+    CartResponse, CartItemResponse, 
+    AddToCartRequest, CartItemUpdate,
+    CartSummary
+)
+from app.core.security import get_current_active_user
+
+router = APIRouter()
+
+
+@router.post("/cart/items/", response_model=CartItemResponse, status_code=status.HTTP_201_CREATED)
+def add_to_cart(
+    item_in: AddToCartRequest,
+    db: Session = Depends(get_db),
+    current_user: User = Depends(get_current_active_user)
+):
+    """
+    Add an item to the user's cart.
+    """
+    # Check if product exists and has enough stock
+    product = db.query(Product).filter(Product.id == item_in.product_id).first()
+    if not product:
+        raise HTTPException(
+            status_code=status.HTTP_404_NOT_FOUND,
+            detail="Product not found"
+        )
+    
+    if product.stock < item_in.quantity:
+        raise HTTPException(
+            status_code=status.HTTP_400_BAD_REQUEST,
+            detail="Not enough stock available"
+        )
+    
+    # Get user's active cart or create a new one
+    cart = db.query(Cart).filter(Cart.user_id == current_user.id).first()
+    if not cart:
+        cart = Cart(user_id=current_user.id)
+        db.add(cart)
+        db.commit()
+        db.refresh(cart)
+    
+    # Check if the product is already in the cart
+    cart_item = db.query(CartItem).filter(
+        CartItem.cart_id == cart.id,
+        CartItem.product_id == item_in.product_id
+    ).first()
+    
+    if cart_item:
+        # Update existing cart item quantity
+        new_quantity = cart_item.quantity + item_in.quantity
+        
+        # Check if enough stock
+        if product.stock < new_quantity:
+            raise HTTPException(
+                status_code=status.HTTP_400_BAD_REQUEST,
+                detail="Not enough stock available"
+            )
+        
+        cart_item.quantity = new_quantity
+    else:
+        # Add new cart item
+        cart_item = CartItem(
+            cart_id=cart.id,
+            product_id=item_in.product_id,
+            user_id=current_user.id,
+            quantity=item_in.quantity,
+            unit_price=product.price
+        )
+        db.add(cart_item)
+    
+    db.commit()
+    db.refresh(cart_item)
+    
+    return cart_item
+
+
+@router.get("/cart/", response_model=CartResponse)
+def get_cart(
+    db: Session = Depends(get_db),
+    current_user: User = Depends(get_current_active_user)
+):
+    """
+    Get the current user's cart.
+    """
+    cart = db.query(Cart).filter(Cart.user_id == current_user.id).first()
+    if not cart:
+        cart = Cart(user_id=current_user.id)
+        db.add(cart)
+        db.commit()
+        db.refresh(cart)
+    
+    return cart
+
+
+@router.get("/cart/summary", response_model=CartSummary)
+def get_cart_summary(
+    db: Session = Depends(get_db),
+    current_user: User = Depends(get_current_active_user)
+):
+    """
+    Get a summary of the current user's cart.
+    """
+    cart = db.query(Cart).filter(Cart.user_id == current_user.id).first()
+    if not cart:
+        cart = Cart(user_id=current_user.id)
+        db.add(cart)
+        db.commit()
+        db.refresh(cart)
+    
+    items_count = db.query(CartItem).filter(CartItem.cart_id == cart.id).count()
+    
+    return {
+        "id": cart.id,
+        "total": cart.total,
+        "items_count": items_count
+    }
+
+
+@router.patch("/cart/items/{item_id}", response_model=CartItemResponse)
+def update_cart_item(
+    item_id: int,
+    item_in: CartItemUpdate,
+    db: Session = Depends(get_db),
+    current_user: User = Depends(get_current_active_user)
+):
+    """
+    Update quantity of an item in the cart.
+    """
+    cart_item = db.query(CartItem).filter(
+        CartItem.id == item_id,
+        CartItem.user_id == current_user.id
+    ).first()
+    
+    if not cart_item:
+        raise HTTPException(
+            status_code=status.HTTP_404_NOT_FOUND,
+            detail="Cart item not found"
+        )
+    
+    if item_in.quantity:
+        if item_in.quantity < 1:
+            # Remove item if quantity is zero or negative
+            db.delete(cart_item)
+            db.commit()
+            raise HTTPException(
+                status_code=status.HTTP_204_NO_CONTENT,
+                detail="Item removed from cart"
+            )
+        
+        # Check if product has enough stock
+        product = db.query(Product).filter(Product.id == cart_item.product_id).first()
+        if not product:
+            raise HTTPException(
+                status_code=status.HTTP_404_NOT_FOUND,
+                detail="Product not found"
+            )
+        
+        if product.stock < item_in.quantity:
+            raise HTTPException(
+                status_code=status.HTTP_400_BAD_REQUEST,
+                detail="Not enough stock available"
+            )
+        
+        cart_item.quantity = item_in.quantity
+        db.add(cart_item)
+        db.commit()
+        db.refresh(cart_item)
+    
+    return cart_item
+
+
+@router.delete("/cart/items/{item_id}", status_code=status.HTTP_204_NO_CONTENT, response_model=None)
+def remove_from_cart(
+    item_id: int,
+    db: Session = Depends(get_db),
+    current_user: User = Depends(get_current_active_user)
+):
+    """
+    Remove an item from the cart.
+    """
+    cart_item = db.query(CartItem).filter(
+        CartItem.id == item_id,
+        CartItem.user_id == current_user.id
+    ).first()
+    
+    if not cart_item:
+        raise HTTPException(
+            status_code=status.HTTP_404_NOT_FOUND,
+            detail="Cart item not found"
+        )
+    
+    db.delete(cart_item)
+    db.commit()
+    
+    return None
+
+
+@router.delete("/cart/", status_code=status.HTTP_204_NO_CONTENT, response_model=None)
+def clear_cart(
+    db: Session = Depends(get_db),
+    current_user: User = Depends(get_current_active_user)
+):
+    """
+    Clear the user's cart (remove all items).
+    """
+    cart = db.query(Cart).filter(Cart.user_id == current_user.id).first()
+    if not cart:
+        return None
+    
+    # Delete all cart items
+    db.query(CartItem).filter(CartItem.cart_id == cart.id).delete()
+    db.commit()
+    
+    return None

app/api/routes/health.py

@@ -0,0 +1,11 @@
+from fastapi import APIRouter
+
+router = APIRouter()
+
+
+@router.get("/health", tags=["health"])
+async def health_check():
+    """
+    Health check endpoint.
+    """
+    return {"status": "ok"}

app/api/routes/login.py

@@ -0,0 +1,51 @@
+from datetime import timedelta
+from typing import Any
+
+from fastapi import APIRouter, Depends, HTTPException, status
+from fastapi.security import OAuth2PasswordRequestForm
+from sqlalchemy.orm import Session
+
+from app.core.config import settings
+from app.core.security import create_access_token, verify_password
+from app.db.session import get_db
+from app.db.models.user import User
+from app.schemas.token import Token
+
+router = APIRouter()
+
+
+@router.post("/login/access-token", response_model=Token)
+def login_access_token(
+    db: Session = Depends(get_db),
+    form_data: OAuth2PasswordRequestForm = Depends()
+) -> Any:
+    """
+    OAuth2 compatible token login, get an access token for future requests.
+    """
+    # Try to authenticate with username/password
+    user = db.query(User).filter(User.email == form_data.username).first()
+    if not user:
+        # If email doesn't match, try username
+        user = db.query(User).filter(User.username == form_data.username).first()
+    
+    if not user or not verify_password(form_data.password, user.hashed_password):
+        raise HTTPException(
+            status_code=status.HTTP_401_UNAUTHORIZED,
+            detail="Incorrect username or password",
+            headers={"WWW-Authenticate": "Bearer"},
+        )
+    
+    if not user.is_active:
+        raise HTTPException(
+            status_code=status.HTTP_400_BAD_REQUEST,
+            detail="Inactive user"
+        )
+    
+    # Create access token
+    access_token_expires = timedelta(minutes=settings.ACCESS_TOKEN_EXPIRE_MINUTES)
+    return {
+        "access_token": create_access_token(
+            user.id, expires_delta=access_token_expires
+        ),
+        "token_type": "bearer",
+    }

app/api/routes/products.py

@@ -0,0 +1,117 @@
+from typing import List
+
+from fastapi import APIRouter, Depends, HTTPException, status
+from sqlalchemy.orm import Session
+
+from app.db.session import get_db
+from app.db.models.product import Product
+from app.db.models.user import User
+from app.schemas.product import ProductCreate, ProductResponse, ProductUpdate
+from app.core.security import get_current_active_superuser
+
+router = APIRouter()
+
+
+@router.post("/products/", response_model=ProductResponse, status_code=status.HTTP_201_CREATED)
+def create_product(
+    product_in: ProductCreate,
+    db: Session = Depends(get_db),
+    current_user: User = Depends(get_current_active_superuser)
+):
+    """
+    Create a new product (superuser only).
+    """
+    product = Product(
+        name=product_in.name,
+        description=product_in.description,
+        price=product_in.price,
+        stock=product_in.stock,
+        image_url=product_in.image_url
+    )
+    db.add(product)
+    db.commit()
+    db.refresh(product)
+    
+    return product
+
+
+@router.get("/products/", response_model=List[ProductResponse])
+def get_products(
+    skip: int = 0,
+    limit: int = 100,
+    db: Session = Depends(get_db)
+):
+    """
+    Get all products.
+    """
+    products = db.query(Product).offset(skip).limit(limit).all()
+    return products
+
+
+@router.get("/products/{product_id}", response_model=ProductResponse)
+def get_product(
+    product_id: int,
+    db: Session = Depends(get_db)
+):
+    """
+    Get a specific product by ID.
+    """
+    product = db.query(Product).filter(Product.id == product_id).first()
+    if not product:
+        raise HTTPException(
+            status_code=status.HTTP_404_NOT_FOUND,
+            detail="Product not found"
+        )
+    return product
+
+
+@router.patch("/products/{product_id}", response_model=ProductResponse)
+def update_product(
+    product_id: int,
+    product_in: ProductUpdate,
+    db: Session = Depends(get_db),
+    current_user: User = Depends(get_current_active_superuser)
+):
+    """
+    Update a product (superuser only).
+    """
+    product = db.query(Product).filter(Product.id == product_id).first()
+    if not product:
+        raise HTTPException(
+            status_code=status.HTTP_404_NOT_FOUND,
+            detail="Product not found"
+        )
+    
+    # Update product fields if provided
+    update_data = product_in.dict(exclude_unset=True)
+    
+    for field, value in update_data.items():
+        setattr(product, field, value)
+    
+    db.add(product)
+    db.commit()
+    db.refresh(product)
+    
+    return product
+
+
+@router.delete("/products/{product_id}", status_code=status.HTTP_204_NO_CONTENT, response_model=None)
+def delete_product(
+    product_id: int,
+    db: Session = Depends(get_db),
+    current_user: User = Depends(get_current_active_superuser)
+):
+    """
+    Delete a product (superuser only).
+    """
+    product = db.query(Product).filter(Product.id == product_id).first()
+    if not product:
+        raise HTTPException(
+            status_code=status.HTTP_404_NOT_FOUND,
+            detail="Product not found"
+        )
+    
+    db.delete(product)
+    db.commit()
+    
+    return None

app/api/routes/users.py

@@ -0,0 +1,135 @@
+from typing import List
+
+from fastapi import APIRouter, Depends, HTTPException, status
+from sqlalchemy.orm import Session
+
+from app.db.session import get_db
+from app.db.models.user import User
+from app.schemas.user import UserCreate, UserResponse, UserUpdate
+from app.core.security import get_password_hash
+
+router = APIRouter()
+
+
+@router.post("/users/", response_model=UserResponse, status_code=status.HTTP_201_CREATED)
+def create_user(
+    user_in: UserCreate,
+    db: Session = Depends(get_db)
+):
+    """
+    Create a new user.
+    """
+    # Check if user with given email exists
+    user = db.query(User).filter(User.email == user_in.email).first()
+    if user:
+        raise HTTPException(
+            status_code=status.HTTP_400_BAD_REQUEST,
+            detail="Email already registered"
+        )
+    
+    # Check if username is taken
+    user = db.query(User).filter(User.username == user_in.username).first()
+    if user:
+        raise HTTPException(
+            status_code=status.HTTP_400_BAD_REQUEST,
+            detail="Username already taken"
+        )
+    
+    # Create new user
+    hashed_password = get_password_hash(user_in.password)
+    user = User(
+        email=user_in.email,
+        username=user_in.username,
+        hashed_password=hashed_password,
+        is_active=user_in.is_active,
+        is_superuser=user_in.is_superuser
+    )
+    db.add(user)
+    db.commit()
+    db.refresh(user)
+    
+    return user
+
+
+@router.get("/users/", response_model=List[UserResponse])
+def get_users(
+    skip: int = 0,
+    limit: int = 100,
+    db: Session = Depends(get_db)
+):
+    """
+    Get all users.
+    """
+    users = db.query(User).offset(skip).limit(limit).all()
+    return users
+
+
+@router.get("/users/{user_id}", response_model=UserResponse)
+def get_user(
+    user_id: int,
+    db: Session = Depends(get_db)
+):
+    """
+    Get a specific user by ID.
+    """
+    user = db.query(User).filter(User.id == user_id).first()
+    if not user:
+        raise HTTPException(
+            status_code=status.HTTP_404_NOT_FOUND,
+            detail="User not found"
+        )
+    return user
+
+
+@router.patch("/users/{user_id}", response_model=UserResponse)
+def update_user(
+    user_id: int,
+    user_in: UserUpdate,
+    db: Session = Depends(get_db)
+):
+    """
+    Update a user.
+    """
+    user = db.query(User).filter(User.id == user_id).first()
+    if not user:
+        raise HTTPException(
+            status_code=status.HTTP_404_NOT_FOUND,
+            detail="User not found"
+        )
+    
+    # Update user fields if provided
+    update_data = user_in.dict(exclude_unset=True)
+    
+    # Hash the password if it's being updated
+    if "password" in update_data:
+        update_data["hashed_password"] = get_password_hash(update_data.pop("password"))
+    
+    for field, value in update_data.items():
+        setattr(user, field, value)
+    
+    db.add(user)
+    db.commit()
+    db.refresh(user)
+    
+    return user
+
+
+@router.delete("/users/{user_id}", status_code=status.HTTP_204_NO_CONTENT, response_model=None)
+def delete_user(
+    user_id: int,
+    db: Session = Depends(get_db)
+):
+    """
+    Delete a user.
+    """
+    user = db.query(User).filter(User.id == user_id).first()
+    if not user:
+        raise HTTPException(
+            status_code=status.HTTP_404_NOT_FOUND,
+            detail="User not found"
+        )
+    
+    db.delete(user)
+    db.commit()
+    
+    return None

app/core/config.py

@@ -0,0 +1,30 @@
+from pathlib import Path
+from typing import List
+
+from pydantic_settings import BaseSettings
+
+class Settings(BaseSettings):
+    API_V1_STR: str = "/api/v1"
+    PROJECT_NAME: str = "Simple Cart System"
+    PROJECT_DESCRIPTION: str = "A simple cart system API using FastAPI and SQLite"
+    PROJECT_VERSION: str = "0.1.0"
+    CORS_ORIGINS: List[str] = ["*"]
+
+    # Database settings
+    DB_DIR = Path("/app") / "storage" / "db"
+    DB_DIR.mkdir(parents=True, exist_ok=True)
+    DATABASE_URL: str = f"sqlite:///{DB_DIR}/db.sqlite"
+    
+    # Security settings
+    SECRET_KEY: str = "supersecretkey"  # You should change this in production
+    ALGORITHM: str = "HS256"
+    ACCESS_TOKEN_EXPIRE_MINUTES: int = 30
+    
+    # CORS configuration
+    BACKEND_CORS_ORIGINS: List[str] = ["*"]
+
+    class Config:
+        case_sensitive = True
+        env_file = ".env"
+
+settings = Settings()

app/core/security.py

@@ -0,0 +1,114 @@
+from datetime import datetime, timedelta
+from typing import Any, Optional
+
+from jose import jwt
+from passlib.context import CryptContext
+from fastapi import Depends, HTTPException, status
+from fastapi.security import OAuth2PasswordBearer
+from sqlalchemy.orm import Session
+
+from app.core.config import settings
+from app.db.session import get_db
+from app.db.models.user import User
+
+# Password hashing context
+pwd_context = CryptContext(schemes=["bcrypt"], deprecated="auto")
+
+# OAuth2 scheme
+oauth2_scheme = OAuth2PasswordBearer(tokenUrl=f"{settings.API_V1_STR}/login/access-token")
+
+
+def verify_password(plain_password: str, hashed_password: str) -> bool:
+    """
+    Verify if the password matches the hash.
+    """
+    return pwd_context.verify(plain_password, hashed_password)
+
+
+def get_password_hash(password: str) -> str:
+    """
+    Generate a password hash.
+    """
+    return pwd_context.hash(password)
+
+
+def create_access_token(subject: Any, expires_delta: Optional[timedelta] = None) -> str:
+    """
+    Create a new JWT access token.
+    """
+    if expires_delta:
+        expire = datetime.utcnow() + expires_delta
+    else:
+        expire = datetime.utcnow() + timedelta(
+            minutes=settings.ACCESS_TOKEN_EXPIRE_MINUTES
+        )
+    
+    to_encode = {"exp": expire, "sub": str(subject)}
+    encoded_jwt = jwt.encode(to_encode, settings.SECRET_KEY, algorithm=settings.ALGORITHM)
+    
+    return encoded_jwt
+
+
+def get_current_user(
+    db: Session = Depends(get_db),
+    token: str = Depends(oauth2_scheme)
+) -> User:
+    """
+    Decode JWT token and get current user.
+    """
+    try:
+        payload = jwt.decode(
+            token, settings.SECRET_KEY, algorithms=[settings.ALGORITHM]
+        )
+        user_id: str = payload.get("sub")
+        if user_id is None:
+            raise HTTPException(
+                status_code=status.HTTP_401_UNAUTHORIZED,
+                detail="Could not validate credentials",
+                headers={"WWW-Authenticate": "Bearer"},
+            )
+    except jwt.JWTError:
+        raise HTTPException(
+            status_code=status.HTTP_401_UNAUTHORIZED,
+            detail="Could not validate credentials",
+            headers={"WWW-Authenticate": "Bearer"},
+        )
+    
+    user = db.query(User).filter(User.id == user_id).first()
+    if user is None:
+        raise HTTPException(
+            status_code=status.HTTP_404_NOT_FOUND,
+            detail="User not found"
+        )
+    
+    return user
+
+
+def get_current_active_user(
+    current_user: User = Depends(get_current_user),
+) -> User:
+    """
+    Check if the current user is active.
+    """
+    if not current_user.is_active:
+        raise HTTPException(
+            status_code=status.HTTP_400_BAD_REQUEST,
+            detail="Inactive user"
+        )
+    
+    return current_user
+
+
+def get_current_active_superuser(
+    current_user: User = Depends(get_current_user),
+) -> User:
+    """
+    Check if the current user is a superuser.
+    """
+    if not current_user.is_superuser:
+        raise HTTPException(
+            status_code=status.HTTP_403_FORBIDDEN,
+            detail="Not enough permissions"
+        )
+    
+    return current_user

app/db/models/base.py

@@ -0,0 +1,20 @@
+from datetime import datetime
+from typing import Any
+
+from sqlalchemy import Column, DateTime
+from sqlalchemy.ext.declarative import as_declarative, declared_attr
+
+
+@as_declarative()
+class Base:
+    id: Any
+    __name__: str
+    
+    # Generate tablename automatically based on class name
+    @declared_attr
+    def __tablename__(cls) -> str:
+        return cls.__name__.lower()
+    
+    # Add created_at and updated_at columns to all models
+    created_at = Column(DateTime, default=datetime.utcnow, nullable=False)
+    updated_at = Column(DateTime, default=datetime.utcnow, onupdate=datetime.utcnow, nullable=False)

app/db/models/cart.py

@@ -0,0 +1,35 @@
+from sqlalchemy import Column, Integer, ForeignKey, Float
+from sqlalchemy.orm import relationship
+
+from app.db.models.base import Base
+
+
+class Cart(Base):
+    id = Column(Integer, primary_key=True, index=True)
+    user_id = Column(Integer, ForeignKey("user.id"), nullable=False)
+    
+    # Relationships
+    user = relationship("User", back_populates="carts")
+    items = relationship("CartItem", back_populates="cart", cascade="all, delete-orphan")
+    
+    @property
+    def total(self) -> float:
+        return sum(item.subtotal for item in self.items)
+
+
+class CartItem(Base):
+    id = Column(Integer, primary_key=True, index=True)
+    cart_id = Column(Integer, ForeignKey("cart.id"), nullable=False)
+    product_id = Column(Integer, ForeignKey("product.id"), nullable=False)
+    user_id = Column(Integer, ForeignKey("user.id"), nullable=False)
+    quantity = Column(Integer, nullable=False, default=1)
+    unit_price = Column(Float, nullable=False)
+    
+    # Relationships
+    cart = relationship("Cart", back_populates="items")
+    product = relationship("Product")
+    user = relationship("User", back_populates="cart_items")
+    
+    @property
+    def subtotal(self) -> float:
+        return self.quantity * self.unit_price

app/db/models/product.py

@@ -0,0 +1,12 @@
+from sqlalchemy import Column, Integer, String, Float, Text
+
+from app.db.models.base import Base
+
+
+class Product(Base):
+    id = Column(Integer, primary_key=True, index=True)
+    name = Column(String, index=True, nullable=False)
+    description = Column(Text, nullable=True)
+    price = Column(Float, nullable=False)
+    stock = Column(Integer, nullable=False, default=0)
+    image_url = Column(String, nullable=True)

app/db/models/user.py

@@ -0,0 +1,17 @@
+from sqlalchemy import Column, Integer, String, Boolean
+from sqlalchemy.orm import relationship
+
+from app.db.models.base import Base
+
+
+class User(Base):
+    id = Column(Integer, primary_key=True, index=True)
+    email = Column(String, unique=True, index=True, nullable=False)
+    username = Column(String, unique=True, index=True, nullable=False)
+    hashed_password = Column(String, nullable=False)
+    is_active = Column(Boolean, default=True)
+    is_superuser = Column(Boolean, default=False)
+    
+    # Relationships
+    carts = relationship("Cart", back_populates="user", cascade="all, delete-orphan")
+    cart_items = relationship("CartItem", back_populates="user", cascade="all, delete-orphan")

app/db/session.py

@@ -0,0 +1,25 @@
+from sqlalchemy import create_engine
+from sqlalchemy.ext.declarative import declarative_base
+from sqlalchemy.orm import sessionmaker
+
+from app.core.config import settings
+
+# Create the SQLAlchemy engine with SQLite
+engine = create_engine(
+    settings.DATABASE_URL,
+    connect_args={"check_same_thread": False}  # Needed for SQLite
+)
+
+# Create SessionLocal class for creating database sessions
+SessionLocal = sessionmaker(autocommit=False, autoflush=False, bind=engine)
+
+# Create Base class for declarative models
+Base = declarative_base()
+
+# Dependency to get a database session
+def get_db():
+    db = SessionLocal()
+    try:
+        yield db
+    finally:
+        db.close()

app/schemas/__init__.py

@@ -0,0 +1,3 @@
+# Import schemas for easier access
+# This file is intentionally left empty
+# Import from the specific schema files directly when needed

app/schemas/cart.py

@@ -0,0 +1,59 @@
+from typing import List, Optional
+
+from pydantic import BaseModel, Field
+
+
+# Cart Item schemas
+class CartItemBase(BaseModel):
+    product_id: int
+    quantity: int = Field(..., gt=0)
+
+
+class CartItemCreate(CartItemBase):
+    pass
+
+
+class CartItemUpdate(BaseModel):
+    quantity: Optional[int] = Field(None, gt=0)
+
+
+class CartItemResponse(CartItemBase):
+    id: int
+    unit_price: float
+    subtotal: float
+    
+    class Config:
+        from_attributes = True
+
+
+# Cart schemas
+class CartBase(BaseModel):
+    user_id: int
+
+
+class CartCreate(CartBase):
+    pass
+
+
+class CartResponse(CartBase):
+    id: int
+    items: List[CartItemResponse] = []
+    total: float
+    
+    class Config:
+        from_attributes = True
+
+
+# Schema for adding items to cart
+class AddToCartRequest(CartItemBase):
+    pass
+
+
+# Schema for cart summary
+class CartSummary(BaseModel):
+    id: int
+    total: float
+    items_count: int
+    
+    class Config:
+        from_attributes = True

app/schemas/product.py

@@ -0,0 +1,34 @@
+from typing import Optional
+
+from pydantic import BaseModel, Field
+
+
+# Base Product Schema
+class ProductBase(BaseModel):
+    name: str
+    description: Optional[str] = None
+    price: float = Field(..., gt=0)
+    stock: int = Field(..., ge=0)
+    image_url: Optional[str] = None
+
+
+# Schema for creating a new product
+class ProductCreate(ProductBase):
+    pass
+
+
+# Schema for updating an existing product
+class ProductUpdate(BaseModel):
+    name: Optional[str] = None
+    description: Optional[str] = None
+    price: Optional[float] = Field(None, gt=0)
+    stock: Optional[int] = Field(None, ge=0)
+    image_url: Optional[str] = None
+
+
+# Schema for returning product data
+class ProductResponse(ProductBase):
+    id: int
+    
+    class Config:
+        from_attributes = True

app/schemas/token.py

@@ -0,0 +1,12 @@
+from typing import Optional
+
+from pydantic import BaseModel
+
+
+class Token(BaseModel):
+    access_token: str
+    token_type: str
+
+
+class TokenPayload(BaseModel):
+    sub: Optional[int] = None

app/schemas/user.py

@@ -0,0 +1,33 @@
+from typing import Optional
+
+from pydantic import BaseModel, EmailStr, Field
+
+
+# Base User Schema
+class UserBase(BaseModel):
+    email: EmailStr
+    username: str
+    is_active: Optional[bool] = True
+    is_superuser: Optional[bool] = False
+
+
+# Schema for creating a new user
+class UserCreate(UserBase):
+    password: str = Field(..., min_length=8)
+
+
+# Schema for updating an existing user
+class UserUpdate(BaseModel):
+    email: Optional[EmailStr] = None
+    username: Optional[str] = None
+    password: Optional[str] = Field(None, min_length=8)
+    is_active: Optional[bool] = None
+    is_superuser: Optional[bool] = None
+
+
+# Schema for returning user data
+class UserResponse(UserBase):
+    id: int
+
+    class Config:
+        from_attributes = True

main.py

@@ -0,0 +1,32 @@
+import uvicorn
+from fastapi import FastAPI
+from fastapi.middleware.cors import CORSMiddleware
+
+from app.api.routes import products, cart, health
+from app.core.config import settings
+
+app = FastAPI(
+    title=settings.PROJECT_NAME,
+    description=settings.PROJECT_DESCRIPTION,
+    version=settings.PROJECT_VERSION,
+    openapi_url=f"{settings.API_V1_STR}/openapi.json",
+    docs_url="/docs",
+    redoc_url="/redoc",
+)
+
+# Set up CORS middleware
+app.add_middleware(
+    CORSMiddleware,
+    allow_origins=settings.CORS_ORIGINS,
+    allow_credentials=True,
+    allow_methods=["*"],
+    allow_headers=["*"],
+)
+
+# Include routers
+app.include_router(health.router, tags=["health"])
+app.include_router(products.router, prefix=settings.API_V1_STR, tags=["products"])
+app.include_router(cart.router, prefix=settings.API_V1_STR, tags=["cart"])
+
+if __name__ == "__main__":
+    uvicorn.run("main:app", host="0.0.0.0", port=8000, reload=True)

migrations/env.py

@@ -0,0 +1,84 @@
+from logging.config import fileConfig
+
+from sqlalchemy import engine_from_config
+from sqlalchemy import pool
+
+from alembic import context
+
+# Import database models
+from app.db.models.base import Base
+from app.db.models import user, product, cart  # noqa
+
+# this is the Alembic Config object, which provides
+# access to the values within the .ini file in use.
+config = context.config
+
+# Interpret the config file for Python logging.
+# This line sets up loggers basically.
+if config.config_file_name is not None:
+    fileConfig(config.config_file_name)
+
+# add your model's MetaData object here
+# for 'autogenerate' support
+target_metadata = Base.metadata
+
+# other values from the config, defined by the needs of env.py,
+# can be acquired:
+# my_important_option = config.get_main_option("my_important_option")
+# ... etc.
+
+
+def run_migrations_offline() -> None:
+    """Run migrations in 'offline' mode.
+
+    This configures the context with just a URL
+    and not an Engine, though an Engine is acceptable
+    here as well.  By skipping the Engine creation
+    we don't even need a DBAPI to be available.
+
+    Calls to context.execute() here emit the given string to the
+    script output.
+
+    """
+    url = config.get_main_option("sqlalchemy.url")
+    context.configure(
+        url=url,
+        target_metadata=target_metadata,
+        literal_binds=True,
+        dialect_opts={"paramstyle": "named"},
+        render_as_batch=True,  # Added for SQLite
+    )
+
+    with context.begin_transaction():
+        context.run_migrations()
+
+
+def run_migrations_online() -> None:
+    """Run migrations in 'online' mode.
+
+    In this scenario we need to create an Engine
+    and associate a connection with the context.
+
+    """
+    connectable = engine_from_config(
+        config.get_section(config.config_ini_section),
+        prefix="sqlalchemy.",
+        poolclass=pool.NullPool,
+    )
+
+    with connectable.connect() as connection:
+        is_sqlite = connection.dialect.name == "sqlite"
+        context.configure(
+            connection=connection,
+            target_metadata=target_metadata,
+            render_as_batch=is_sqlite,  # Added for SQLite
+        )
+
+        with context.begin_transaction():
+            context.run_migrations()
+
+
+if context.is_offline_mode():
+    run_migrations_offline()
+else:
+    run_migrations_online()

migrations/script.py.mako

@@ -0,0 +1,24 @@
+"""${message}
+
+Revision ID: ${up_revision}
+Revises: ${down_revision | comma,n}
+Create Date: ${create_date}
+
+"""
+from alembic import op
+import sqlalchemy as sa
+${imports if imports else ""}
+
+# revision identifiers, used by Alembic.
+revision = ${repr(up_revision)}
+down_revision = ${repr(down_revision)}
+branch_labels = ${repr(branch_labels)}
+depends_on = ${repr(depends_on)}
+
+
+def upgrade() -> None:
+    ${upgrades if upgrades else "pass"}
+
+
+def downgrade() -> None:
+    ${downgrades if downgrades else "pass"}

migrations/versions/1_initial_migration.py

@@ -0,0 +1,95 @@
+"""Initial database migration
+
+Revision ID: 1_initial_migration
+Revises: 
+Create Date: 2023-05-18 00:00:00.000000
+
+"""
+from alembic import op
+import sqlalchemy as sa
+
+
+# revision identifiers, used by Alembic.
+revision = '1_initial_migration'
+down_revision = None
+branch_labels = None
+depends_on = None
+
+
+def upgrade() -> None:
+    # Create user table
+    op.create_table(
+        'user',
+        sa.Column('id', sa.Integer(), nullable=False),
+        sa.Column('email', sa.String(), nullable=False),
+        sa.Column('username', sa.String(), nullable=False),
+        sa.Column('hashed_password', sa.String(), nullable=False),
+        sa.Column('is_active', sa.Boolean(), nullable=True),
+        sa.Column('is_superuser', sa.Boolean(), nullable=True),
+        sa.Column('created_at', sa.DateTime(), nullable=False),
+        sa.Column('updated_at', sa.DateTime(), nullable=False),
+        sa.PrimaryKeyConstraint('id')
+    )
+    op.create_index(op.f('ix_user_email'), 'user', ['email'], unique=True)
+    op.create_index(op.f('ix_user_id'), 'user', ['id'], unique=False)
+    op.create_index(op.f('ix_user_username'), 'user', ['username'], unique=True)
+    
+    # Create product table
+    op.create_table(
+        'product',
+        sa.Column('id', sa.Integer(), nullable=False),
+        sa.Column('name', sa.String(), nullable=False),
+        sa.Column('description', sa.Text(), nullable=True),
+        sa.Column('price', sa.Float(), nullable=False),
+        sa.Column('stock', sa.Integer(), nullable=False),
+        sa.Column('image_url', sa.String(), nullable=True),
+        sa.Column('created_at', sa.DateTime(), nullable=False),
+        sa.Column('updated_at', sa.DateTime(), nullable=False),
+        sa.PrimaryKeyConstraint('id')
+    )
+    op.create_index(op.f('ix_product_id'), 'product', ['id'], unique=False)
+    op.create_index(op.f('ix_product_name'), 'product', ['name'], unique=False)
+    
+    # Create cart table
+    op.create_table(
+        'cart',
+        sa.Column('id', sa.Integer(), nullable=False),
+        sa.Column('user_id', sa.Integer(), nullable=False),
+        sa.Column('created_at', sa.DateTime(), nullable=False),
+        sa.Column('updated_at', sa.DateTime(), nullable=False),
+        sa.ForeignKeyConstraint(['user_id'], ['user.id'], ),
+        sa.PrimaryKeyConstraint('id')
+    )
+    op.create_index(op.f('ix_cart_id'), 'cart', ['id'], unique=False)
+    
+    # Create cart_item table
+    op.create_table(
+        'cartitem',
+        sa.Column('id', sa.Integer(), nullable=False),
+        sa.Column('cart_id', sa.Integer(), nullable=False),
+        sa.Column('product_id', sa.Integer(), nullable=False),
+        sa.Column('user_id', sa.Integer(), nullable=False),
+        sa.Column('quantity', sa.Integer(), nullable=False),
+        sa.Column('unit_price', sa.Float(), nullable=False),
+        sa.Column('created_at', sa.DateTime(), nullable=False),
+        sa.Column('updated_at', sa.DateTime(), nullable=False),
+        sa.ForeignKeyConstraint(['cart_id'], ['cart.id'], ),
+        sa.ForeignKeyConstraint(['product_id'], ['product.id'], ),
+        sa.ForeignKeyConstraint(['user_id'], ['user.id'], ),
+        sa.PrimaryKeyConstraint('id')
+    )
+    op.create_index(op.f('ix_cartitem_id'), 'cartitem', ['id'], unique=False)
+
+
+def downgrade() -> None:
+    op.drop_index(op.f('ix_cartitem_id'), table_name='cartitem')
+    op.drop_table('cartitem')
+    op.drop_index(op.f('ix_cart_id'), table_name='cart')
+    op.drop_table('cart')
+    op.drop_index(op.f('ix_product_name'), table_name='product')
+    op.drop_index(op.f('ix_product_id'), table_name='product')
+    op.drop_table('product')
+    op.drop_index(op.f('ix_user_username'), table_name='user')
+    op.drop_index(op.f('ix_user_id'), table_name='user')
+    op.drop_index(op.f('ix_user_email'), table_name='user')
+    op.drop_table('user')

requirements.txt

@@ -0,0 +1,11 @@
+fastapi>=0.103.1
+uvicorn>=0.23.2
+sqlalchemy>=2.0.21
+alembic>=1.12.0
+pydantic>=2.4.2
+pydantic-settings>=2.0.3
+python-dotenv>=1.0.0
+python-jose>=3.3.0
+python-multipart>=0.0.6
+email-validator>=2.0.0
+ruff>=0.0.292