Create simple todo application with FastAPI and SQLite

- Set up project structure with FastAPI and SQLite
- Created Todo model with SQLAlchemy ORM
- Added CRUD operations for todos
- Implemented API endpoints for Todo operations
- Added health check endpoint
- Added Alembic for database migrations
- Updated README with documentation

generated with BackendIM... (backend.im)

README.md

@@ -1,3 +1,95 @@
-# FastAPI Application
+# Simple Todo Application
 
-This is a FastAPI application bootstrapped by BackendIM, the AI-powered backend generation platform.
+A simple RESTful Todo application API built with FastAPI and SQLite.
+
+## Features
+
+- Create, read, update, and delete todo items
+- SQLite database with SQLAlchemy ORM
+- Alembic for database migrations
+- Health check endpoint
+- API documentation with Swagger UI
+
+## Installation
+
+1. Clone the repository:
+
+```bash
+git clone [repository-url]
+cd simpletodoapplication
+```
+
+2. Install dependencies:
+
+```bash
+pip install -r requirements.txt
+```
+
+3. Apply database migrations:
+
+```bash
+alembic upgrade head
+```
+
+## Running the Application
+
+Start the application with Uvicorn:
+
+```bash
+uvicorn main:app --reload
+```
+
+The API will be available at `http://localhost:8000`.
+
+API documentation is available at:
+- Swagger UI: `http://localhost:8000/docs`
+- ReDoc: `http://localhost:8000/redoc`
+
+## API Endpoints
+
+### Todos
+
+- `GET /api/todos/` - List all todos
+- `POST /api/todos/` - Create a new todo
+- `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
+
+### Health Check
+
+- `GET /health` - Health check endpoint
+
+## Project Structure
+
+```
+.
+├── alembic/              # Database migration scripts
+├── app/
+│   ├── api/              # API routes
+│   │   ├── health.py     # Health check endpoint
+│   │   └── todos.py      # Todo API endpoints
+│   ├── database/         # Database related code
+│   │   ├── base.py       # Database connection setup
+│   │   └── crud.py       # CRUD operations
+│   ├── models/           # Data models
+│   │   ├── schemas.py    # Pydantic schemas
+│   │   └── todo.py       # SQLAlchemy Todo model
+│   └── storage/
+│       └── db/           # SQLite database files
+├── main.py               # FastAPI application entry point
+├── requirements.txt      # Project dependencies
+└── README.md             # Project documentation
+```
+
+## Database Schema
+
+### Todo
+
+| Column      | Type      | Description                   |
+|-------------|-----------|-------------------------------|
+| id          | Integer   | Primary key                   |
+| title       | String    | Todo title                    |
+| description | String    | Todo description (optional)   |
+| completed   | Boolean   | Todo completion status        |
+| created_at  | DateTime  | Creation timestamp            |
+| updated_at  | DateTime  | Last update timestamp         |

alembic.ini

@@ -0,0 +1,40 @@
+[alembic]
+script_location = alembic
+prepend_sys_path = .
+
+# SQLite URL example
+sqlalchemy.url = sqlite:///app/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 +1,9 @@
+Generic single-database configuration for the Todo application.
+
+This directory contains Alembic migration scripts for database schema changes.
+
+To apply migrations:
+alembic upgrade head
+
+To create a new migration:
+alembic revision -m "description"

alembic/env.py

@@ -0,0 +1,79 @@
+from logging.config import fileConfig
+
+from sqlalchemy import engine_from_config
+from sqlalchemy import pool
+
+from alembic import context
+
+# Import Base from app
+from app.database.base 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.
+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():
+    """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:
+        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():
+    ${upgrades if upgrades else "pass"}
+
+
+def downgrade():
+    ${downgrades if downgrades else "pass"}

alembic/versions/001_create_todos_table.py

@@ -0,0 +1,36 @@
+"""create todos table
+
+Revision ID: 001
+Revises: 
+Create Date: 2023-05-13
+
+"""
+from alembic import op
+import sqlalchemy as sa
+
+
+# revision identifiers, used by Alembic.
+revision = '001'
+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(), nullable=False),
+        sa.Column('description', sa.String(), nullable=True),
+        sa.Column('completed', sa.Boolean(), default=False),
+        sa.Column('created_at', sa.DateTime(timezone=True), server_default=sa.text('(CURRENT_TIMESTAMP)')),
+        sa.Column('updated_at', sa.DateTime(timezone=True), nullable=True),
+        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():
+    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/__init__.py

@@ -0,0 +1 @@
+# This file is intentionally left empty to make the directory a Python package

app/api/__init__.py

@@ -0,0 +1 @@
+# This file is intentionally left empty to make the directory a Python package

app/api/health.py

@@ -0,0 +1,25 @@
+from fastapi import APIRouter, Depends, status
+from sqlalchemy.orm import Session
+from sqlalchemy import text
+
+from app.database.base import get_db
+
+router = APIRouter()
+
+@router.get("/health", status_code=status.HTTP_200_OK)
+def health_check(db: Session = Depends(get_db)):
+    """
+    Health check endpoint to verify the API and database are operational.
+    """
+    # Check database connection
+    try:
+        db.execute(text("SELECT 1"))
+        db_status = "healthy"
+    except Exception as e:
+        db_status = f"unhealthy: {str(e)}"
+    
+    return {
+        "status": "healthy",
+        "database": db_status,
+        "version": "0.1.0"
+    }

app/api/todos.py

@@ -0,0 +1,58 @@
+from fastapi import APIRouter, Depends, HTTPException, status
+from sqlalchemy.orm import Session
+from typing import List, Optional
+
+from app.database.base import get_db
+from app.database import crud
+from app.models.schemas import TodoCreate, TodoResponse, TodoUpdate
+
+router = APIRouter()
+
+@router.get("/todos/", response_model=List[TodoResponse])
+def read_todos(
+    skip: int = 0, 
+    limit: int = 100, 
+    db: Session = Depends(get_db)
+):
+    """
+    Retrieve all todos with pagination support.
+    """
+    todos = crud.get_todos(db, skip=skip, limit=limit)
+    return todos
+
+@router.get("/todos/{todo_id}", response_model=TodoResponse)
+def read_todo(todo_id: int, db: Session = Depends(get_db)):
+    """
+    Retrieve a specific todo by its ID.
+    """
+    db_todo = crud.get_todo(db, todo_id=todo_id)
+    if db_todo is None:
+        raise HTTPException(status_code=404, detail="Todo not found")
+    return db_todo
+
+@router.post("/todos/", response_model=TodoResponse, status_code=status.HTTP_201_CREATED)
+def create_todo(todo: TodoCreate, db: Session = Depends(get_db)):
+    """
+    Create a new todo.
+    """
+    return crud.create_todo(db=db, todo=todo)
+
+@router.put("/todos/{todo_id}", response_model=TodoResponse)
+def update_todo(todo_id: int, todo: TodoUpdate, db: Session = Depends(get_db)):
+    """
+    Update a todo by its ID.
+    """
+    db_todo = crud.update_todo(db, todo_id=todo_id, todo=todo)
+    if db_todo is None:
+        raise HTTPException(status_code=404, detail="Todo not found")
+    return db_todo
+
+@router.delete("/todos/{todo_id}", response_model=TodoResponse)
+def delete_todo(todo_id: int, db: Session = Depends(get_db)):
+    """
+    Delete a todo by its ID.
+    """
+    db_todo = crud.delete_todo(db, todo_id=todo_id)
+    if db_todo is None:
+        raise HTTPException(status_code=404, detail="Todo not found")
+    return db_todo

app/database/__init__.py

@@ -0,0 +1 @@
+# This file is intentionally left empty to make the directory a Python package

app/database/base.py

@@ -0,0 +1,27 @@
+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()
+
+# Dependency
+def get_db():
+    db = SessionLocal()
+    try:
+        yield db
+    finally:
+        db.close()

app/database/crud.py

@@ -0,0 +1,34 @@
+from sqlalchemy.orm import Session
+from app.models.todo import Todo
+from app.models.schemas import TodoCreate, TodoUpdate
+
+# Todo CRUD operations
+def get_todos(db: Session, skip: int = 0, limit: int = 100):
+    return db.query(Todo).offset(skip).limit(limit).all()
+
+def get_todo(db: Session, todo_id: int):
+    return db.query(Todo).filter(Todo.id == todo_id).first()
+
+def create_todo(db: Session, todo: TodoCreate):
+    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: TodoUpdate):
+    db_todo = get_todo(db, todo_id)
+    if db_todo:
+        update_data = todo.model_dump(exclude_unset=True)
+        for key, value in update_data.items():
+            setattr(db_todo, key, value)
+        db.commit()
+        db.refresh(db_todo)
+    return db_todo
+
+def delete_todo(db: Session, todo_id: int):
+    db_todo = get_todo(db, todo_id)
+    if db_todo:
+        db.delete(db_todo)
+        db.commit()
+    return db_todo

app/models/__init__.py

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+# Import models for easy access
+from app.models.todo import Todo

app/models/schemas.py

@@ -0,0 +1,25 @@
+from datetime import datetime
+from typing import Optional
+from pydantic import BaseModel
+
+# Todo schemas
+class TodoBase(BaseModel):
+    title: str
+    description: Optional[str] = None
+    completed: bool = False
+
+class TodoCreate(TodoBase):
+    pass
+
+class TodoUpdate(BaseModel):
+    title: Optional[str] = None
+    description: Optional[str] = None
+    completed: Optional[bool] = None
+
+class TodoResponse(TodoBase):
+    id: int
+    created_at: datetime
+    updated_at: Optional[datetime] = None
+
+    class Config:
+        from_attributes = True

app/models/todo.py

@@ -0,0 +1,13 @@
+from sqlalchemy import Column, Integer, String, Boolean, DateTime
+from sqlalchemy.sql import func
+from app.database.base import Base
+
+class Todo(Base):
+    __tablename__ = "todos"
+
+    id = Column(Integer, primary_key=True, index=True)
+    title = Column(String, index=True)
+    description = Column(String)
+    completed = Column(Boolean, default=False)
+    created_at = Column(DateTime(timezone=True), server_default=func.now())
+    updated_at = Column(DateTime(timezone=True), onupdate=func.now())

main.py

@@ -0,0 +1,31 @@
+from fastapi import FastAPI
+from fastapi.middleware.cors import CORSMiddleware
+
+from app.api import todos, health
+from app.database.base import engine, Base
+
+# Create tables
+Base.metadata.create_all(bind=engine)
+
+app = FastAPI(
+    title="Todo Application API",
+    description="A simple Todo application API built with FastAPI and SQLite",
+    version="0.1.0",
+)
+
+# Add CORS middleware
+app.add_middleware(
+    CORSMiddleware,
+    allow_origins=["*"],
+    allow_credentials=True,
+    allow_methods=["*"],
+    allow_headers=["*"],
+)
+
+# Include routers
+app.include_router(todos.router, prefix="/api", tags=["todos"])
+app.include_router(health.router, tags=["health"])
+
+if __name__ == "__main__":
+    import uvicorn
+    uvicorn.run("main:app", host="0.0.0.0", port=8000, reload=True)

requirements.txt

@@ -0,0 +1,6 @@
+fastapi==0.109.2
+uvicorn==0.27.1
+sqlalchemy==2.0.25
+pydantic==2.5.3
+alembic==1.12.1
+python-dotenv==1.0.0