Implement ToDo application with FastAPI and SQLite

- Create project structure and configuration files
- Set up database models and schemas for ToDo items
- Implement CRUD operations for ToDo management
- Create API endpoints for ToDo operations
- Add health check endpoint
- Set up Alembic for database migrations
- Add comprehensive README documentation

README.md

@@ -1,3 +1,128 @@
-# FastAPI Application
+# ToDo Application API
 
-This is a FastAPI application bootstrapped by BackendIM, the AI-powered backend generation platform.
+A simple ToDo Application API built with FastAPI and SQLite.
+
+## Features
+
+- Create, read, update, and delete ToDo items
+- Filter ToDo items by completion status
+- Pagination support
+- Health check endpoint
+- SQLite database for data persistence
+- Alembic for database migrations
+
+## Project Structure
+
+```
+.
+├── alembic.ini
+├── app
+│   ├── api
+│   │   ├── routes
+│   │   │   ├── health.py
+│   │   │   └── todo.py
+│   ├── core
+│   ├── crud
+│   │   └── todo.py
+│   ├── db
+│   │   ├── base.py
+│   │   └── session.py
+│   ├── models
+│   │   └── todo.py
+│   └── schemas
+│       └── todo.py
+├── main.py
+├── migrations
+│   ├── env.py
+│   ├── script.py.mako
+│   └── versions
+│       └── 001_create_todos_table.py
+└── requirements.txt
+```
+
+## Installation
+
+1. Clone the repository
+
+2. Install dependencies:
+```bash
+pip install -r requirements.txt
+```
+
+3. Run database migrations:
+```bash
+alembic upgrade head
+```
+
+## Running the application
+
+Start the application:
+```bash
+uvicorn main:app --reload
+```
+
+The API will be available at http://localhost:8000. You can access the API documentation at http://localhost:8000/docs.
+
+## API Endpoints
+
+### ToDo Operations
+
+- `GET /api/todos`: List all todos
+  - Query Parameters:
+    - `skip`: Number of items to skip (default: 0)
+    - `limit`: Maximum number of items to return (default: 100)
+    - `completed`: Filter by completion status (Boolean, optional)
+
+- `POST /api/todos`: Create a new todo
+  - Request Body: 
+    ```json
+    {
+      "title": "string", 
+      "description": "string", 
+      "completed": false
+    }
+    ```
+
+- `GET /api/todos/{todo_id}`: Get a specific todo
+
+- `PUT /api/todos/{todo_id}`: Update a todo
+  - Request Body:
+    ```json
+    {
+      "title": "string", 
+      "description": "string", 
+      "completed": true
+    }
+    ```
+
+- `DELETE /api/todos/{todo_id}`: Delete a todo
+
+### Health Check
+
+- `GET /health`: Check application health
+  - Response:
+    ```json
+    {
+      "status": "OK", 
+      "database_connected": true
+    }
+    ```
+
+## Development
+
+### Database Migrations
+
+Create a new migration:
+```bash
+alembic revision -m "description"
+```
+
+Apply migrations:
+```bash
+alembic upgrade head
+```
+
+Rollback migration:
+```bash
+alembic downgrade -1
+```

alembic.ini

@@ -0,0 +1,85 @@
+# 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
+
+# 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 migrations/versions.  When using multiple version
+# directories, initial revisions must be specified with --version-path
+# version_locations = %(here)s/bar %(here)s/bat migrations/versions
+
+# the output encoding used when revision files
+# are written from script.py.mako
+# output_encoding = utf-8
+
+# SQLite database
+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/health.py

@@ -0,0 +1,33 @@
+from fastapi import APIRouter, Depends
+from pydantic import BaseModel
+from sqlalchemy.orm import Session
+from sqlalchemy import text
+
+from app.db.session import get_db
+
+
+class HealthResponse(BaseModel):
+    status: str
+    database_connected: bool
+
+
+router = APIRouter()
+
+
+@router.get("/health", response_model=HealthResponse)
+def health_check(db: Session = Depends(get_db)):
+    """
+    Health check endpoint to verify API and database status.
+    """
+    # Check database connection
+    try:
+        # Execute a simple query to verify database connection
+        db.execute(text("SELECT 1"))
+        database_connected = True
+    except Exception:
+        database_connected = False
+
+    return HealthResponse(
+        status="OK" if database_connected else "ERROR",
+        database_connected=database_connected,
+    )

app/api/routes/todo.py

@@ -0,0 +1,77 @@
+from typing import List, Optional
+from fastapi import APIRouter, Depends, HTTPException, status
+from sqlalchemy.orm import Session
+
+from app.crud import todo as todo_crud
+from app.db.session import get_db
+from app.schemas.todo import Todo, TodoCreate, TodoUpdate
+
+router = APIRouter()
+
+
+@router.get("/", response_model=List[Todo])
+def read_todos(
+    skip: int = 0,
+    limit: int = 100,
+    completed: Optional[bool] = None,
+    db: Session = Depends(get_db),
+):
+    """
+    Retrieve todos with optional filtering.
+    
+    - **skip**: Number of todos to skip (pagination)
+    - **limit**: Maximum number of todos to return (pagination)
+    - **completed**: Filter by completion status (None for all todos)
+    """
+    todos = todo_crud.get_todos(db, skip=skip, limit=limit, completed=completed)
+    return todos
+
+
+@router.post("/", response_model=Todo, status_code=status.HTTP_201_CREATED)
+def create_todo(todo: TodoCreate, db: Session = Depends(get_db)):
+    """
+    Create a new todo item.
+    
+    - **todo**: Todo item to create
+    """
+    return todo_crud.create_todo(db=db, todo=todo)
+
+
+@router.get("/{todo_id}", response_model=Todo)
+def read_todo(todo_id: int, db: Session = Depends(get_db)):
+    """
+    Get a specific todo by ID.
+    
+    - **todo_id**: ID of the todo to retrieve
+    """
+    db_todo = 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.put("/{todo_id}", response_model=Todo)
+def update_todo(todo_id: int, todo: TodoUpdate, db: Session = Depends(get_db)):
+    """
+    Update a todo item.
+    
+    - **todo_id**: ID of the todo to update
+    - **todo**: Updated todo data
+    """
+    db_todo = 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("/{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 item.
+    
+    - **todo_id**: ID of the todo to delete
+    """
+    success = todo_crud.delete_todo(db, todo_id=todo_id)
+    if not success:
+        raise HTTPException(status_code=404, detail="Todo not found")
+    return None

app/crud/todo.py

@@ -0,0 +1,60 @@
+from typing import List, Optional
+from sqlalchemy.orm import Session
+from app.models.todo import Todo
+from app.schemas.todo import TodoCreate, TodoUpdate
+
+
+def get_todo(db: Session, todo_id: int) -> Optional[Todo]:
+    """Get a todo item by ID."""
+    return db.query(Todo).filter(Todo.id == todo_id).first()
+
+
+def get_todos(
+    db: Session, skip: int = 0, limit: int = 100, completed: Optional[bool] = None
+) -> List[Todo]:
+    """Get a list of todo items with optional filtering by completion status."""
+    query = db.query(Todo)
+    
+    if completed is not None:
+        query = query.filter(Todo.completed == completed)
+    
+    return query.offset(skip).limit(limit).all()
+
+
+def create_todo(db: Session, todo: TodoCreate) -> Todo:
+    """Create a new todo item."""
+    db_todo = Todo(
+        title=todo.title,
+        description=todo.description,
+        completed=todo.completed
+    )
+    db.add(db_todo)
+    db.commit()
+    db.refresh(db_todo)
+    return db_todo
+
+
+def update_todo(db: Session, todo_id: int, todo: TodoUpdate) -> Optional[Todo]:
+    """Update a todo item."""
+    db_todo = get_todo(db, todo_id)
+    if db_todo is None:
+        return None
+    
+    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) -> bool:
+    """Delete a todo item."""
+    db_todo = get_todo(db, todo_id)
+    if db_todo is None:
+        return False
+    
+    db.delete(db_todo)
+    db.commit()
+    return True

app/db/base.py

@@ -0,0 +1,2 @@
+# Import all the models, so that Base has them before being
+# imported by Alembic

app/db/session.py

@@ -0,0 +1,28 @@
+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():
+    db = SessionLocal()
+    try:
+        yield db
+    finally:
+        db.close()
+
+def create_tables():
+    Base.metadata.create_all(bind=engine)

app/models/todo.py

@@ -0,0 +1,17 @@
+from sqlalchemy import Column, Integer, String, Boolean, DateTime
+from sqlalchemy.sql import func
+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(timezone=True), server_default=func.now())
+    updated_at = Column(DateTime(timezone=True), onupdate=func.now())
+
+    def __repr__(self):
+        return f"<Todo(id={self.id}, title='{self.title}', completed={self.completed})>"

app/schemas/todo.py

@@ -0,0 +1,32 @@
+from datetime import datetime
+from typing import Optional
+from pydantic import BaseModel, Field
+
+
+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 TodoInDB(TodoBase):
+    id: int
+    created_at: datetime
+    updated_at: Optional[datetime] = None
+
+    class Config:
+        from_attributes = True
+
+
+class Todo(TodoInDB):
+    pass

main.py

@@ -0,0 +1,20 @@
+import uvicorn
+from fastapi import FastAPI
+from app.api.routes import todo, health
+from app.db.session import create_tables
+
+app = FastAPI(
+    title="ToDo Application API",
+    description="A simple ToDo Application API built with FastAPI and SQLite",
+    version="1.0.0",
+)
+
+# Create tables
+create_tables()
+
+# Include routers
+app.include_router(todo.router, prefix="/api/todos", tags=["todos"])
+app.include_router(health.router, tags=["health"])
+
+if __name__ == "__main__":
+    uvicorn.run("main:app", host="0.0.0.0", port=8000, reload=True)

migrations/env.py

@@ -0,0 +1,82 @@
+from logging.config import fileConfig
+
+from sqlalchemy import engine_from_config
+from sqlalchemy import pool
+
+from alembic import context
+from app.db.base import Base
+
+# 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
+# from myapp import mymodel
+# target_metadata = mymodel.Base.metadata
+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:
+        is_sqlite = connection.dialect.name == 'sqlite'
+        context.configure(
+            connection=connection,
+            target_metadata=target_metadata,
+            render_as_batch=is_sqlite,  # Key configuration for SQLite
+            compare_type=True,
+        )
+
+        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():
+    ${upgrades if upgrades else "pass"}
+
+
+def downgrade():
+    ${downgrades if downgrades else "pass"}

migrations/versions/001_create_todos_table.py

@@ -0,0 +1,38 @@
+"""create todos table
+
+Revision ID: 001
+Revises: 
+Create Date: 2023-10-25
+
+"""
+from alembic import op
+import sqlalchemy as sa
+from sqlalchemy.sql import func
+
+
+# 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(), nullable=False, default=False),
+        sa.Column('created_at', sa.DateTime(timezone=True), server_default=func.now(), nullable=False),
+        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')

requirements.txt

@@ -0,0 +1,10 @@
+fastapi>=0.104.0
+uvicorn>=0.23.2
+sqlalchemy>=2.0.0
+pydantic>=2.4.0
+alembic>=1.12.0
+python-multipart>=0.0.6
+python-jose[cryptography]>=3.3.0
+passlib[bcrypt]>=1.7.4
+python-dotenv>=1.0.0
+ruff>=0.1.3