Implement todo application with FastAPI and SQLite

- Set up project structure with FastAPI
- Create SQLite database models with SQLAlchemy
- Implement Alembic for migrations
- Create API endpoints for todo operations
- Add health check endpoint
- Update README.md with comprehensive documentation

generated with BackendIM... (backend.im)

README.md

@@ -1,3 +1,87 @@
-# FastAPI Application
+# Simple Todo Application
 
-This is a FastAPI application bootstrapped by BackendIM, the AI-powered backend generation platform.
+A simple todo application built with FastAPI and SQLite.
+
+## Features
+
+- Create, read, update, and delete todo items
+- SQLite database with SQLAlchemy ORM
+- Alembic migrations
+- FastAPI with automatic OpenAPI documentation
+
+## Project Structure
+
+```
+simpletodoapplication/
+├── alembic/                 # Database migrations
+│   └── versions/            # Migration scripts
+├── app/                     # Application code
+│   ├── api/                 # API routes
+│   ├── core/                # Core configuration
+│   ├── db/                  # Database setup
+│   ├── models/              # SQLAlchemy models
+│   └── schemas/             # Pydantic schemas
+├── storage/                 # Storage directory
+│   └── db/                  # Database files
+├── alembic.ini              # Alembic configuration
+├── main.py                  # Application entry point
+├── README.md                # This file
+└── requirements.txt         # Project dependencies
+```
+
+## Installation
+
+1. Clone the repository
+2. Install dependencies:
+
+```bash
+pip install -r requirements.txt
+```
+
+## Running the Application
+
+1. Run database migrations:
+
+```bash
+alembic upgrade head
+```
+
+2. Start the application:
+
+```bash
+uvicorn main:app --reload
+```
+
+3. Open your browser and navigate to:
+   - API Documentation: http://localhost:8000/docs
+   - Redoc Documentation: http://localhost:8000/redoc
+   - Health Check: http://localhost:8000/health
+
+## API Endpoints
+
+- `GET /health`: Health check endpoint
+- `POST /api/todos/`: Create a new todo
+- `GET /api/todos/`: Get all todos
+- `GET /api/todos/{todo_id}`: Get a specific todo
+- `PUT /api/todos/{todo_id}`: Update a todo
+- `DELETE /api/todos/{todo_id}`: Delete a todo
+
+## Database Migrations
+
+To create a new migration:
+
+```bash
+alembic revision -m "your migration message"
+```
+
+To upgrade to the latest migration:
+
+```bash
+alembic upgrade head
+```
+
+To downgrade the last migration:
+
+```bash
+alembic downgrade -1
+```

alembic.ini

@@ -0,0 +1,40 @@
+[alembic]
+script_location = alembic
+prepend_sys_path = .
+version_path_separator = os
+
+sqlalchemy.url = sqlite:///storage/db/db.sqlite
+
+[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/README

@@ -0,0 +1 @@
+Generic single-database configuration.

alembic/env.py

@@ -0,0 +1,77 @@
+from logging.config import fileConfig
+
+from sqlalchemy import engine_from_config
+from sqlalchemy import pool
+
+from alembic import context
+
+from app.core.config import settings
+from app.db.session import Base
+from app.models.todo import Todo
+
+# 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:
+# ... etc.
+config.set_main_option("sqlalchemy.url", settings.SQLALCHEMY_DATABASE_URL)
+
+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"},
+    )
+
+    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:
+        context.configure(
+            connection=connection, target_metadata=target_metadata
+        )
+
+        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() -> None:
+    ${upgrades if upgrades else "pass"}
+
+
+def downgrade() -> None:
+    ${downgrades if downgrades else "pass"}

alembic/versions/0001_create_todos_table.py

@@ -0,0 +1,36 @@
+"""create todos table
+
+Revision ID: 0001
+Revises: 
+Create Date: 2025-05-13
+
+"""
+from alembic import op
+import sqlalchemy as sa
+
+
+# revision identifiers, used by Alembic.
+revision = '0001'
+down_revision = None
+branch_labels = None
+depends_on = None
+
+
+def upgrade() -> None:
+    op.create_table('todos',
+        sa.Column('id', sa.Integer(), nullable=False),
+        sa.Column('title', sa.String(), nullable=False),
+        sa.Column('description', sa.String(), nullable=True),
+        sa.Column('completed', sa.Boolean(), default=False),
+        sa.Column('created_at', sa.DateTime(), default=sa.func.now()),
+        sa.Column('updated_at', sa.DateTime(), default=sa.func.now(), onupdate=sa.func.now()),
+        sa.PrimaryKeyConstraint('id')
+    )
+    op.create_index(op.f('ix_todos_id'), 'todos', ['id'], unique=False)
+    op.create_index(op.f('ix_todos_title'), 'todos', ['title'], unique=False)
+
+
+def downgrade() -> None:
+    op.drop_index(op.f('ix_todos_title'), table_name='todos')
+    op.drop_index(op.f('ix_todos_id'), table_name='todos')
+    op.drop_table('todos')

app/api/__init__.py

@@ -0,0 +1,3 @@
+from app.api.routes import todo_router
+
+__all__ = ["todo_router"]

app/api/routes.py

@@ -0,0 +1,53 @@
+from fastapi import APIRouter, Depends, HTTPException, status
+from sqlalchemy.orm import Session
+from typing import List
+
+from app.db.session import get_db
+from app.models.todo import Todo
+from app.schemas.todo import TodoCreate, TodoUpdate, TodoResponse
+
+todo_router = APIRouter(prefix="/api/todos", tags=["todos"])
+
+@todo_router.post("/", response_model=TodoResponse, status_code=status.HTTP_201_CREATED)
+def create_todo(todo: TodoCreate, db: Session = Depends(get_db)):
+    db_todo = Todo(**todo.model_dump())
+    db.add(db_todo)
+    db.commit()
+    db.refresh(db_todo)
+    return db_todo
+
+@todo_router.get("/", response_model=List[TodoResponse])
+def read_todos(skip: int = 0, limit: int = 100, db: Session = Depends(get_db)):
+    todos = db.query(Todo).offset(skip).limit(limit).all()
+    return todos
+
+@todo_router.get("/{todo_id}", response_model=TodoResponse)
+def read_todo(todo_id: int, db: Session = Depends(get_db)):
+    db_todo = db.query(Todo).filter(Todo.id == todo_id).first()
+    if db_todo is None:
+        raise HTTPException(status_code=404, detail="Todo not found")
+    return db_todo
+
+@todo_router.put("/{todo_id}", response_model=TodoResponse)
+def update_todo(todo_id: int, todo: TodoUpdate, db: Session = Depends(get_db)):
+    db_todo = db.query(Todo).filter(Todo.id == todo_id).first()
+    if db_todo is None:
+        raise HTTPException(status_code=404, detail="Todo not found")
+    
+    todo_data = todo.model_dump(exclude_unset=True)
+    for key, value in todo_data.items():
+        setattr(db_todo, key, value)
+    
+    db.commit()
+    db.refresh(db_todo)
+    return db_todo
+
+@todo_router.delete("/{todo_id}", status_code=status.HTTP_204_NO_CONTENT)
+def delete_todo(todo_id: int, db: Session = Depends(get_db)):
+    db_todo = db.query(Todo).filter(Todo.id == todo_id).first()
+    if db_todo is None:
+        raise HTTPException(status_code=404, detail="Todo not found")
+    
+    db.delete(db_todo)
+    db.commit()
+    return None

app/core/config.py

@@ -0,0 +1,15 @@
+from pydantic_settings import BaseSettings
+from pathlib import Path
+
+class Settings(BaseSettings):
+    PROJECT_NAME: str = "Simple Todo Application"
+    PROJECT_DESCRIPTION: str = "A simple todo application built with FastAPI"
+    PROJECT_VERSION: str = "0.1.0"
+    
+    DB_DIR: Path = Path("/projects/simpletodoapplication-voecsa/storage/db")
+    SQLALCHEMY_DATABASE_URL: str = f"sqlite:///{DB_DIR}/db.sqlite"
+    
+    class Config:
+        case_sensitive = True
+
+settings = Settings()

app/db/session.py

@@ -0,0 +1,26 @@
+from sqlalchemy import create_engine
+from sqlalchemy.ext.declarative import declarative_base
+from sqlalchemy.orm import sessionmaker
+
+from app.core.config import settings
+
+# Create directory if it doesn't exist
+settings.DB_DIR.mkdir(parents=True, exist_ok=True)
+
+engine = create_engine(
+    settings.SQLALCHEMY_DATABASE_URL,
+    connect_args={"check_same_thread": False}  # SQLite specific
+)
+SessionLocal = sessionmaker(autocommit=False, autoflush=False, bind=engine)
+
+Base = declarative_base()
+
+def get_db():
+    db = SessionLocal()
+    try:
+        yield db
+    finally:
+        db.close()
+
+def create_tables():
+    Base.metadata.create_all(bind=engine)

app/models/__init__.py

@@ -0,0 +1,3 @@
+from app.models.todo import Todo
+
+__all__ = ["Todo"]

app/models/todo.py

@@ -0,0 +1,13 @@
+from sqlalchemy import Column, Integer, String, Boolean, DateTime, func
+from sqlalchemy.ext.declarative import declarative_base
+from app.db.session import Base
+
+class Todo(Base):
+    __tablename__ = "todos"
+
+    id = Column(Integer, primary_key=True, index=True)
+    title = Column(String, index=True)
+    description = Column(String, nullable=True)
+    completed = Column(Boolean, default=False)
+    created_at = Column(DateTime, default=func.now())
+    updated_at = Column(DateTime, default=func.now(), onupdate=func.now())

app/schemas/__init__.py

@@ -0,0 +1,3 @@
+from app.schemas.todo import TodoBase, TodoCreate, TodoUpdate, TodoResponse
+
+__all__ = ["TodoBase", "TodoCreate", "TodoUpdate", "TodoResponse"]

app/schemas/todo.py

@@ -0,0 +1,24 @@
+from pydantic import BaseModel, Field
+from typing import Optional
+from datetime import datetime
+
+class TodoBase(BaseModel):
+    title: str = Field(..., min_length=1, max_length=100)
+    description: Optional[str] = Field(None, max_length=1000)
+    completed: bool = False
+
+class TodoCreate(TodoBase):
+    pass
+
+class TodoUpdate(BaseModel):
+    title: Optional[str] = Field(None, min_length=1, max_length=100)
+    description: Optional[str] = Field(None, max_length=1000)
+    completed: Optional[bool] = None
+
+class TodoResponse(TodoBase):
+    id: int
+    created_at: datetime
+    updated_at: datetime
+
+    class Config:
+        from_attributes = True

main.py

@@ -0,0 +1,23 @@
+from fastapi import FastAPI
+from app.api.routes import todo_router
+from app.core.config import settings
+from app.db.session import create_tables
+
+app = FastAPI(
+    title=settings.PROJECT_NAME,
+    description=settings.PROJECT_DESCRIPTION,
+    version=settings.PROJECT_VERSION
+)
+
+# Create tables on startup
+@app.on_event("startup")
+async def startup_event():
+    create_tables()
+
+# Include routers
+app.include_router(todo_router)
+
+# Health check endpoint
+@app.get("/health", tags=["Health"])
+async def health_check():
+    return {"status": "healthy"}

requirements.txt

@@ -0,0 +1,7 @@
+fastapi==0.108.0
+uvicorn==0.25.0
+sqlalchemy==2.0.23
+alembic==1.13.0
+pydantic==2.5.2
+pydantic-settings==2.1.0
+python-dotenv==1.0.0