Create FastAPI Todo App with SQLite and CRUD functionality

README.md

@@ -1,3 +1,108 @@
-# FastAPI Application
+# FastAPI Todo App
 
-This is a FastAPI application bootstrapped by BackendIM, the AI-powered backend generation platform.
+A simple Todo API built with FastAPI and SQLite.
+
+## Features
+
+- Create, read, update, and delete Todo items
+- RESTful API endpoints
+- SQLite database with SQLAlchemy ORM
+- Alembic migrations
+- API documentation with Swagger UI and ReDoc
+
+## Project Structure
+
+```
+simpletodoapp/
+├── alembic/                    # Database migrations
+│   ├── versions/               # Migration scripts
+│   ├── env.py                  # Migration environment
+│   └── script.py.mako          # Migration script template
+├── app/                        # Application package
+│   ├── api/                    # API endpoints
+│   │   └── routers/            # API routers
+│   │       ├── health.py       # Health check endpoints
+│   │       └── todos.py        # Todo endpoints
+│   ├── core/                   # Core functionality
+│   │   └── database.py         # Database configuration
+│   ├── models/                 # SQLAlchemy models
+│   │   └── todo.py             # Todo model
+│   ├── schemas/                # Pydantic schemas
+│   │   └── todo.py             # Todo schemas
+│   └── services/               # Business logic
+│       └── todo.py             # Todo services
+├── storage/                    # Data storage directory
+│   └── db/                     # Database files
+├── alembic.ini                 # Alembic configuration
+├── main.py                     # Application entry point
+├── pyproject.toml              # Project configuration (Ruff)
+└── requirements.txt            # Python dependencies
+```
+
+## Getting Started
+
+### Prerequisites
+
+- Python 3.8 or higher
+
+### Installation
+
+1. Clone the repository
+2. Install dependencies:
+
+```bash
+pip install -r requirements.txt
+```
+
+3. Run the application:
+
+```bash
+uvicorn main:app --reload
+```
+
+The API will be available at http://localhost:8000
+
+### API Documentation
+
+- Swagger UI: http://localhost:8000/docs
+- ReDoc: http://localhost:8000/redoc
+
+## API Endpoints
+
+### Health Check
+
+- `GET /health` - Check API health
+
+### Todo Operations
+
+- `GET /api/todos` - List all todos
+- `GET /api/todos/{todo_id}` - Get a single todo
+- `POST /api/todos` - Create a new todo
+- `PUT /api/todos/{todo_id}` - Update a todo
+- `DELETE /api/todos/{todo_id}` - Delete a todo
+
+## Database Migrations
+
+The application uses Alembic for database migrations. The initial migration is included to create the `todos` table.
+
+To apply migrations:
+
+```bash
+alembic upgrade head
+```
+
+## Development
+
+### Linting
+
+The project uses Ruff for linting:
+
+```bash
+ruff check .
+```
+
+To automatically fix linting issues:
+
+```bash
+ruff check --fix .
+```

alembic.ini

@@ -0,0 +1,86 @@
+# A generic, single database configuration.
+
+[alembic]
+# path to migration scripts
+script_location = alembic
+
+# template used to generate migration files
+# file_template = %%(rev)s_%%(slug)s
+
+# timezone to use when rendering the date
+# within the migration file as well as the filename.
+# 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 alembic/versions.  When using multiple version
+# directories, initial revisions must be specified with --version-path
+# version_locations = %(here)s/bar %(here)s/bat alembic/versions
+
+# 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
+
+# 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

alembic/env.py

@@ -0,0 +1,78 @@
+"""
+Alembic environment script for database migrations
+"""
+from logging.config import fileConfig
+
+from alembic import context
+from sqlalchemy import engine_from_config, pool
+
+# 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
+from app.models import Todo  # noqa
+from app.core.database import Base  # noqa
+
+target_metadata = Base.metadata
+
+
+def run_migrations_offline():
+    """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"},
+    )
+
+    with context.begin_transaction():
+        context.run_migrations()
+
+
+def run_migrations_online():
+    """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,  # Key configuration for SQLite
+        )
+
+        with context.begin_transaction():
+            context.run_migrations()
+
+
+if context.is_offline_mode():
+    run_migrations_offline()
+else:
+    run_migrations_online()

alembic/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():
+    ${upgrades if upgrades else "pass"}
+
+
+def downgrade():
+    ${downgrades if downgrades else "pass"}

alembic/versions/initial_migration.py

@@ -0,0 +1,39 @@
+"""Create todos table
+
+Revision ID: e6d3d15b6c3c
+Revises:
+Create Date: 2023-08-01 12:00:00.000000
+
+"""
+import sqlalchemy as sa
+from alembic import op
+
+# revision identifiers, used by Alembic.
+revision = 'e6d3d15b6c3c'
+down_revision = None
+branch_labels = None
+depends_on = None
+
+
+def upgrade():
+    op.create_table(
+        'todos',
+        sa.Column('id', sa.Integer(), nullable=False),
+        sa.Column('title', sa.String(length=255), nullable=False),
+        sa.Column('description', sa.Text(), nullable=True),
+        sa.Column('completed', sa.Boolean(), default=False),
+        sa.Column('created_at', sa.DateTime(), default=sa.func.current_timestamp()),
+        sa.Column(
+            'updated_at',
+            sa.DateTime(),
+            default=sa.func.current_timestamp(),
+            onupdate=sa.func.current_timestamp(),
+        ),
+        sa.PrimaryKeyConstraint('id')
+    )
+    op.create_index(op.f('ix_todos_id'), 'todos', ['id'], unique=False)
+
+
+def downgrade():
+    op.drop_index(op.f('ix_todos_id'), table_name='todos')
+    op.drop_table('todos')

app/api/routers/health.py

@@ -0,0 +1,14 @@
+"""
+Health check endpoints
+"""
+from fastapi import APIRouter
+
+router = APIRouter()
+
+
+@router.get("/health")
+def health_check():
+    """
+    Health check endpoint to verify the application is running
+    """
+    return {"status": "ok"}

app/api/routers/todos.py

@@ -0,0 +1,75 @@
+"""
+Router for Todo CRUD operations
+"""
+
+from fastapi import APIRouter, Depends, HTTPException, Response, status
+from sqlalchemy.orm import Session
+
+from app.core.database import get_db
+from app.schemas.todo import Todo, TodoCreate, TodoUpdate
+from app.services import todo as todo_service
+
+router = APIRouter()
+
+
+@router.get("/todos", response_model=list[Todo])
+def get_todos(
+    skip: int = 0, limit: int = 100, db: Session = Depends(get_db)
+):
+    """
+    Get all todos with pagination
+    """
+    todos = todo_service.get_todos(db, skip=skip, limit=limit)
+    return todos
+
+
+@router.get("/todos/{todo_id}", response_model=Todo)
+def get_todo(todo_id: int, db: Session = Depends(get_db)):
+    """
+    Get a single todo by ID
+    """
+    db_todo = todo_service.get_todo(db, todo_id=todo_id)
+    if db_todo is None:
+        raise HTTPException(
+            status_code=404,
+            detail=f"Todo with ID {todo_id} not found"
+        )
+    return db_todo
+
+
+@router.post("/todos", response_model=Todo, status_code=status.HTTP_201_CREATED)
+def create_todo(todo: TodoCreate, db: Session = Depends(get_db)):
+    """
+    Create a new todo
+    """
+    return todo_service.create_todo(db=db, todo=todo)
+
+
+@router.put("/todos/{todo_id}", response_model=Todo)
+def update_todo(
+    todo_id: int, todo_update: TodoUpdate, db: Session = Depends(get_db)
+):
+    """
+    Update an existing todo
+    """
+    db_todo = todo_service.update_todo(db, todo_id, todo_update)
+    if db_todo is None:
+        raise HTTPException(
+            status_code=404,
+            detail=f"Todo with ID {todo_id} not found"
+        )
+    return db_todo
+
+
+@router.delete("/todos/{todo_id}", status_code=status.HTTP_204_NO_CONTENT, response_model=None)
+def delete_todo(todo_id: int, db: Session = Depends(get_db)):
+    """
+    Delete a todo
+    """
+    success = todo_service.delete_todo(db, todo_id)
+    if not success:
+        raise HTTPException(
+            status_code=404,
+            detail=f"Todo with ID {todo_id} not found"
+        )
+    return Response(status_code=status.HTTP_204_NO_CONTENT)

app/core/database.py

@@ -0,0 +1,41 @@
+"""
+Database configuration module
+"""
+from pathlib import Path
+
+from sqlalchemy import create_engine
+from sqlalchemy.ext.declarative import declarative_base
+from sqlalchemy.orm import sessionmaker
+
+# Create database directory if it doesn't exist
+DB_DIR = Path("/app") / "storage" / "db"
+DB_DIR.mkdir(parents=True, exist_ok=True)
+
+SQLALCHEMY_DATABASE_URL = f"sqlite:///{DB_DIR}/db.sqlite"
+
+engine = create_engine(
+    SQLALCHEMY_DATABASE_URL,
+    connect_args={"check_same_thread": False}
+)
+
+SessionLocal = sessionmaker(autocommit=False, autoflush=False, bind=engine)
+
+Base = declarative_base()
+
+
+def get_db():
+    """
+    Dependency for getting a database session
+    """
+    db = SessionLocal()
+    try:
+        yield db
+    finally:
+        db.close()
+
+
+def create_db_and_tables():
+    """
+    Create database tables from SQLAlchemy models
+    """
+    Base.metadata.create_all(bind=engine)

app/models/__init__.py

@@ -0,0 +1,6 @@
+"""
+Models package for SQLAlchemy database models
+"""
+from app.models.todo import Todo  # noqa
+
+__all__ = ["Todo"]

app/models/todo.py

@@ -0,0 +1,22 @@
+"""
+SQLAlchemy model for Todo items
+"""
+from datetime import datetime
+
+from sqlalchemy import Boolean, Column, DateTime, Integer, String, Text
+
+from app.core.database import Base
+
+
+class Todo(Base):
+    """
+    Todo model for storing task information
+    """
+    __tablename__ = "todos"
+
+    id = Column(Integer, primary_key=True, index=True)
+    title = Column(String(255), nullable=False)
+    description = Column(Text, nullable=True)
+    completed = Column(Boolean, default=False)
+    created_at = Column(DateTime, default=datetime.utcnow)
+    updated_at = Column(DateTime, default=datetime.utcnow, onupdate=datetime.utcnow)

app/schemas/__init__.py

@@ -0,0 +1,6 @@
+"""
+Schemas package for Pydantic models
+"""
+from app.schemas.todo import Todo, TodoCreate, TodoInDB, TodoUpdate  # noqa
+
+__all__ = ["Todo", "TodoCreate", "TodoUpdate", "TodoInDB"]

app/schemas/todo.py

@@ -0,0 +1,56 @@
+"""
+Pydantic schemas for Todo
+"""
+from datetime import datetime
+
+from pydantic import BaseModel, Field
+
+
+class TodoBase(BaseModel):
+    """
+    Base Todo schema with shared attributes
+    """
+    title: str = Field(..., min_length=1, max_length=255, description="The title of the todo item")
+    description: str | None = Field(None, description="Optional detailed description of the todo item")
+    completed: bool = Field(False, description="Whether the todo item is completed")
+
+
+class TodoCreate(TodoBase):
+    """
+    Schema for creating a new Todo
+    """
+    pass
+
+
+class TodoUpdate(BaseModel):
+    """
+    Schema for updating an existing Todo
+    """
+    title: str | None = Field(None, min_length=1, max_length=255, description="The title of the todo item")
+    description: str | None = Field(None, description="Optional detailed description of the todo item")
+    completed: bool | None = Field(None, description="Whether the todo item is completed")
+
+
+class TodoInDB(TodoBase):
+    """
+    Schema for Todo as stored in the database
+    """
+    id: int
+    created_at: datetime
+    updated_at: datetime
+
+    class Config:
+        """
+        Pydantic configuration
+        """
+        from_attributes = True
+        json_encoders = {
+            datetime: lambda v: v.isoformat()
+        }
+
+
+class Todo(TodoInDB):
+    """
+    Schema for Todo response
+    """
+    pass

app/services/__init__.py

@@ -0,0 +1,4 @@
+"""
+Services package for business logic and database operations
+"""
+# Import services here when needed

app/services/todo.py

@@ -0,0 +1,66 @@
+"""
+Service functions for Todo CRUD operations
+"""
+
+from sqlalchemy.orm import Session
+
+from app.models.todo import Todo
+from app.schemas.todo import TodoCreate, TodoUpdate
+
+
+def get_todos(db: Session, skip: int = 0, limit: int = 100) -> list[Todo]:
+    """
+    Get all todos with pagination
+    """
+    return db.query(Todo).offset(skip).limit(limit).all()
+
+
+def get_todo(db: Session, todo_id: int) -> Todo | None:
+    """
+    Get a single todo by ID
+    """
+    return db.query(Todo).filter(Todo.id == todo_id).first()
+
+
+def create_todo(db: Session, todo: TodoCreate) -> Todo:
+    """
+    Create a new todo
+    """
+    db_todo = Todo(**todo.model_dump())
+    db.add(db_todo)
+    db.commit()
+    db.refresh(db_todo)
+    return db_todo
+
+
+def update_todo(
+    db: Session, todo_id: int, todo_update: TodoUpdate
+) -> Todo | None:
+    """
+    Update an existing todo
+    """
+    db_todo = get_todo(db, todo_id)
+    if db_todo is None:
+        return None
+
+    update_data = todo_update.model_dump(exclude_unset=True)
+    for key, value in update_data.items():
+        setattr(db_todo, key, value)
+
+    db.add(db_todo)
+    db.commit()
+    db.refresh(db_todo)
+    return db_todo
+
+
+def delete_todo(db: Session, todo_id: int) -> bool:
+    """
+    Delete a todo by ID
+    """
+    db_todo = get_todo(db, todo_id)
+    if db_todo is None:
+        return False
+
+    db.delete(db_todo)
+    db.commit()
+    return True

main.py

@@ -0,0 +1,39 @@
+"""
+FastAPI Todo Application Entry Point
+"""
+from fastapi import FastAPI
+from fastapi.middleware.cors import CORSMiddleware
+
+from app.api.routers import health, todos
+from app.core.database import create_db_and_tables
+
+app = FastAPI(
+    title="Todo API",
+    description="A simple Todo API built with FastAPI and SQLite",
+    version="0.1.0",
+)
+
+# Configure CORS
+app.add_middleware(
+    CORSMiddleware,
+    allow_origins=["*"],  # Allows all origins
+    allow_credentials=True,
+    allow_methods=["*"],  # Allows all methods
+    allow_headers=["*"],  # Allows all headers
+)
+
+# Include routers
+app.include_router(todos.router, prefix="/api", tags=["todos"])
+app.include_router(health.router, tags=["health"])
+
+
+@app.on_event("startup")
+def on_startup():
+    """Create database tables on application startup"""
+    create_db_and_tables()
+
+
+if __name__ == "__main__":
+    import uvicorn
+
+    uvicorn.run("main:app", host="0.0.0.0", port=8000, reload=True)

pyproject.toml

@@ -0,0 +1,30 @@
+[tool.ruff]
+line-length = 110
+target-version = "py310"
+
+[tool.ruff.lint]
+# Enable Pyflakes, pycodestyle, isort, and more
+select = ["E", "F", "I", "W", "N", "UP"]
+
+ignore = []
+
+# Allow autofix for all enabled rules (when `--fix`) is provided.
+fixable = ["ALL"]
+unfixable = []
+
+# Exclude a variety of commonly ignored directories.
+exclude = [
+    ".git",
+    ".ruff_cache",
+    ".venv",
+    "__pypackages__",
+    "dist",
+    "node_modules",
+    "venv",
+]
+
+[tool.ruff.lint.isort]
+known-third-party = ["fastapi", "pydantic", "sqlalchemy", "alembic", "uvicorn"]
+
+[tool.ruff.lint.mccabe]
+max-complexity = 10

requirements.txt

@@ -0,0 +1,8 @@
+fastapi>=0.95.1
+uvicorn>=0.22.0
+pydantic>=2.0.0
+sqlalchemy>=2.0.0
+alembic>=1.11.0
+python-dotenv>=1.0.0
+ruff>=0.0.284
+pathlib>=1.0.1