Complete FastAPI Todo application with full CRUD functionality

- Add SQLAlchemy models for Todo with timestamps
- Create Pydantic schemas for request/response validation
- Implement CRUD operations for Todo management
- Add REST API endpoints for todo operations (GET, POST, PUT, DELETE)
- Configure SQLite database with proper connection settings
- Set up Alembic migrations for database schema management
- Add comprehensive API documentation and health check endpoint
- Enable CORS for all origins
- Include proper error handling and HTTP status codes
- Update README with complete setup and usage instructions

README.md

@@ -1,3 +1,125 @@
-# FastAPI Application
+# Todo App 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 todos
+- ✅ SQLite database with SQLAlchemy ORM
+- ✅ Database migrations with Alembic
+- ✅ API documentation with Swagger UI
+- ✅ Health check endpoint
+- ✅ CORS enabled for all origins
+- ✅ Input validation with Pydantic
+
+## Quick Start
+
+### Prerequisites
+
+- Python 3.8+
+
+### Installation
+
+1. Install dependencies:
+   ```bash
+   pip install -r requirements.txt
+   ```
+
+2. Run database migrations:
+   ```bash
+   alembic upgrade head
+   ```
+
+3. Start the development server:
+   ```bash
+   uvicorn main:app --host 0.0.0.0 --port 8000 --reload
+   ```
+
+   Or alternatively:
+   ```bash
+   python main.py
+   ```
+
+## API Endpoints
+
+The API is available at `http://localhost:8000`
+
+### Documentation
+- **Swagger UI**: http://localhost:8000/docs
+- **ReDoc**: http://localhost:8000/redoc
+- **OpenAPI JSON**: http://localhost:8000/openapi.json
+
+### Core Endpoints
+- **GET** `/` - Root endpoint with project information
+- **GET** `/health` - Health check endpoint
+
+### Todo Endpoints
+- **GET** `/api/v1/todos/` - List all todos (with pagination)
+- **POST** `/api/v1/todos/` - Create a new todo
+- **GET** `/api/v1/todos/{todo_id}` - Get a specific todo
+- **PUT** `/api/v1/todos/{todo_id}` - Update a specific todo
+- **DELETE** `/api/v1/todos/{todo_id}` - Delete a specific todo
+
+## Database
+
+The application uses SQLite database stored at `/app/storage/db/db.sqlite`.
+
+### Schema
+
+**todos** table:
+- `id` (Integer, Primary Key)
+- `title` (String, Required)
+- `description` (String, Optional)
+- `completed` (Boolean, Default: False)
+- `created_at` (DateTime with timezone)
+- `updated_at` (DateTime with timezone)
+
+## Development
+
+### Linting and Formatting
+
+```bash
+# Check and fix linting issues
+ruff check . --fix
+
+# Format code
+ruff format .
+```
+
+### Database Migrations
+
+```bash
+# Create a new migration
+alembic revision --autogenerate -m "Description of changes"
+
+# Apply migrations
+alembic upgrade head
+
+# Downgrade
+alembic downgrade -1
+```
+
+## Project Structure
+
+```
+├── app/
+│   ├── api/
+│   │   └── v1/
+│   │       ├── api.py          # API router
+│   │       └── todos.py        # Todo endpoints
+│   ├── core/
+│   │   └── config.py           # Configuration settings
+│   ├── crud/
+│   │   └── todo.py             # CRUD operations
+│   ├── db/
+│   │   ├── base.py             # SQLAlchemy base
+│   │   ├── base_model.py       # Model imports
+│   │   └── session.py          # Database session
+│   ├── models/
+│   │   └── todo.py             # SQLAlchemy models
+│   └── schemas/
+│       └── todo.py             # Pydantic schemas
+├── migrations/                 # Alembic migrations
+├── main.py                     # FastAPI application
+└── requirements.txt            # Python dependencies
+```

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 URL
+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

app/api/v1/api.py

@@ -0,0 +1,7 @@
+from fastapi import APIRouter
+
+from app.api.v1 import todos
+
+api_router = APIRouter()
+
+api_router.include_router(todos.router, prefix="/todos", tags=["todos"])

app/api/v1/todos.py

@@ -0,0 +1,87 @@
+from typing import List
+
+from fastapi import APIRouter, Depends, HTTPException, status
+from sqlalchemy.orm import Session
+
+from app.crud import todo
+from app.db.session import get_db
+from app.schemas.todo import TodoCreate, TodoResponse, TodoUpdate
+
+router = APIRouter()
+
+
+@router.get("/", response_model=List[TodoResponse])
+def read_todos(
+    skip: int = 0,
+    limit: int = 100,
+    db: Session = Depends(get_db),
+):
+    """
+    Retrieve todos with pagination.
+    """
+    todos = todo.get_multi(db, skip=skip, limit=limit)
+    return todos
+
+
+@router.post("/", response_model=TodoResponse, status_code=status.HTTP_201_CREATED)
+def create_todo(
+    *,
+    db: Session = Depends(get_db),
+    todo_in: TodoCreate,
+):
+    """
+    Create new todo.
+    """
+    return todo.create(db=db, obj_in=todo_in)
+
+
+@router.get("/{todo_id}", response_model=TodoResponse)
+def read_todo(
+    *,
+    db: Session = Depends(get_db),
+    todo_id: int,
+):
+    """
+    Get todo by ID.
+    """
+    todo_obj = todo.get(db=db, todo_id=todo_id)
+    if not todo_obj:
+        raise HTTPException(
+            status_code=status.HTTP_404_NOT_FOUND, detail="Todo not found"
+        )
+    return todo_obj
+
+
+@router.put("/{todo_id}", response_model=TodoResponse)
+def update_todo(
+    *,
+    db: Session = Depends(get_db),
+    todo_id: int,
+    todo_in: TodoUpdate,
+):
+    """
+    Update a todo.
+    """
+    todo_obj = todo.get(db=db, todo_id=todo_id)
+    if not todo_obj:
+        raise HTTPException(
+            status_code=status.HTTP_404_NOT_FOUND, detail="Todo not found"
+        )
+    return todo.update(db=db, db_obj=todo_obj, obj_in=todo_in)
+
+
+@router.delete("/{todo_id}", response_model=TodoResponse)
+def delete_todo(
+    *,
+    db: Session = Depends(get_db),
+    todo_id: int,
+):
+    """
+    Delete a todo.
+    """
+    todo_obj = todo.remove(db=db, todo_id=todo_id)
+    if not todo_obj:
+        raise HTTPException(
+            status_code=status.HTTP_404_NOT_FOUND, detail="Todo not found"
+        )
+    return todo_obj

app/core/config.py

@@ -0,0 +1,30 @@
+import os
+from pathlib import Path
+
+from pydantic_settings import BaseSettings
+
+# Build paths inside the project
+BASE_DIR = Path(__file__).resolve().parent.parent.parent
+
+
+class Settings(BaseSettings):
+    API_V1_STR: str = "/api/v1"
+    PROJECT_NAME: str = "Todo App API"
+    PROJECT_DESCRIPTION: str = (
+        "A simple Todo application API built with FastAPI and SQLite"
+    )
+    VERSION: str = "0.1.0"
+
+    # SQLite Database settings
+    DB_DIR = Path("/app") / "storage" / "db"
+    SQLALCHEMY_DATABASE_URL: str = f"sqlite:///{DB_DIR}/db.sqlite"
+
+    class Config:
+        case_sensitive = True
+        env_file = os.path.join(BASE_DIR, ".env")
+
+
+settings = Settings()
+
+# Ensure database directory exists
+settings.DB_DIR.mkdir(parents=True, exist_ok=True)

app/crud/__init__.py

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

app/crud/todo.py

@@ -0,0 +1,51 @@
+from typing import List, Optional
+
+from sqlalchemy.orm import Session
+
+from app.models.todo import Todo
+from app.schemas.todo import TodoCreate, TodoUpdate
+
+
+class CRUDTodo:
+    """CRUD operations for Todo model."""
+
+    def get(self, db: Session, todo_id: int) -> Optional[Todo]:
+        """Get a single todo by ID."""
+        return db.query(Todo).filter(Todo.id == todo_id).first()
+
+    def get_multi(self, db: Session, *, skip: int = 0, limit: int = 100) -> List[Todo]:
+        """Get multiple todos with pagination."""
+        return db.query(Todo).offset(skip).limit(limit).all()
+
+    def create(self, db: Session, *, obj_in: TodoCreate) -> Todo:
+        """Create a new todo."""
+        db_obj = Todo(
+            title=obj_in.title,
+            description=obj_in.description,
+            completed=obj_in.completed,
+        )
+        db.add(db_obj)
+        db.commit()
+        db.refresh(db_obj)
+        return db_obj
+
+    def update(self, db: Session, *, db_obj: Todo, obj_in: TodoUpdate) -> Todo:
+        """Update a todo."""
+        update_data = obj_in.model_dump(exclude_unset=True)
+        for field, value in update_data.items():
+            setattr(db_obj, field, value)
+        db.add(db_obj)
+        db.commit()
+        db.refresh(db_obj)
+        return db_obj
+
+    def remove(self, db: Session, *, todo_id: int) -> Optional[Todo]:
+        """Delete a todo."""
+        obj = db.query(Todo).get(todo_id)
+        if obj:
+            db.delete(obj)
+            db.commit()
+        return obj
+
+
+todo = CRUDTodo()

app/db/base.py

@@ -0,0 +1,4 @@
+from sqlalchemy.ext.declarative import declarative_base
+
+# Create a Base class for SQLAlchemy models
+Base = declarative_base()

app/db/base_model.py

@@ -0,0 +1,4 @@
+"""Import all models here to ensure they are registered with SQLAlchemy."""
+
+from app.db.base import Base  # noqa
+from app.models.todo import Todo  # noqa

app/db/session.py

@@ -0,0 +1,22 @@
+from sqlalchemy import create_engine
+from sqlalchemy.orm import sessionmaker
+
+from app.core.config import settings
+
+# Create SQLAlchemy engine
+engine = create_engine(
+    settings.SQLALCHEMY_DATABASE_URL,
+    connect_args={"check_same_thread": False},  # Needed for SQLite
+)
+
+# Create a session factory
+SessionLocal = sessionmaker(autocommit=False, autoflush=False, bind=engine)
+
+
+def get_db():
+    """Dependency for getting DB session."""
+    db = SessionLocal()
+    try:
+        yield db
+    finally:
+        db.close()

app/models/__init__.py

@@ -0,0 +1,4 @@
+from app.models.todo import Todo  # noqa
+
+# Add all models here for easy importing
+__all__ = ["Todo"]

app/models/todo.py

@@ -0,0 +1,17 @@
+from sqlalchemy import Boolean, Column, Integer, String, DateTime
+from sqlalchemy.sql import func
+
+from app.db.base import Base
+
+
+class Todo(Base):
+    """SQLAlchemy model for a Todo item."""
+
+    __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())

app/schemas/__init__.py

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

app/schemas/todo.py

@@ -0,0 +1,37 @@
+from datetime import datetime
+from typing import Optional
+
+from pydantic import BaseModel
+
+
+class TodoBase(BaseModel):
+    """Base schema for Todo."""
+
+    title: str
+    description: Optional[str] = None
+    completed: bool = False
+
+
+class TodoCreate(TodoBase):
+    """Schema for creating a Todo."""
+
+    pass
+
+
+class TodoUpdate(BaseModel):
+    """Schema for updating a Todo."""
+
+    title: Optional[str] = None
+    description: Optional[str] = None
+    completed: Optional[bool] = None
+
+
+class TodoResponse(TodoBase):
+    """Schema for Todo response."""
+
+    id: int
+    created_at: datetime
+    updated_at: Optional[datetime] = None
+
+    class Config:
+        from_attributes = True

main.py

@@ -0,0 +1,49 @@
+import uvicorn
+from fastapi import FastAPI
+from fastapi.middleware.cors import CORSMiddleware
+
+from app.api.v1.api import api_router
+from app.core.config import settings
+
+app = FastAPI(
+    title=settings.PROJECT_NAME,
+    description=settings.PROJECT_DESCRIPTION,
+    version=settings.VERSION,
+    openapi_url="/openapi.json",
+    docs_url="/docs",
+    redoc_url="/redoc",
+)
+
+# Add CORS middleware
+app.add_middleware(
+    CORSMiddleware,
+    allow_origins=["*"],
+    allow_credentials=True,
+    allow_methods=["*"],
+    allow_headers=["*"],
+)
+
+# Include API router
+app.include_router(api_router, prefix=settings.API_V1_STR)
+
+
+@app.get("/")
+async def root():
+    """Root endpoint returning project info and links."""
+    return {
+        "title": settings.PROJECT_NAME,
+        "version": settings.VERSION,
+        "description": settings.PROJECT_DESCRIPTION,
+        "docs": "/docs",
+        "health": "/health",
+    }
+
+
+@app.get("/health", status_code=200)
+async def health_check():
+    """Health check endpoint."""
+    return {"status": "healthy"}
+
+
+if __name__ == "__main__":
+    uvicorn.run("main:app", host="0.0.0.0", port=8000, reload=True)

migrations/env.py

@@ -0,0 +1,90 @@
+import sys
+from logging.config import fileConfig
+from pathlib import Path
+
+from sqlalchemy import engine_from_config, pool
+
+from alembic import context
+
+# Add the project root directory to the Python path
+sys.path.append(str(Path(__file__).resolve().parent.parent))
+
+# Import Base from app.db.base
+from app.db.base_model import Base  # noqa
+from app.core.config import settings  # 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.
+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.
+
+    """
+    configuration = config.get_section(config.config_ini_section)
+
+    # Ensure SQLite uses batch mode for migrations
+    connectable = engine_from_config(
+        configuration,
+        prefix="sqlalchemy.",
+        poolclass=pool.NullPool,
+    )
+
+    with connectable.connect() as connection:
+        # Ensure SQLite uses batch mode for migrations
+        is_sqlite = connection.dialect.name == "sqlite"
+        context.configure(
+            connection=connection,
+            target_metadata=target_metadata,
+            render_as_batch=is_sqlite,  # Critical 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():
+    ${upgrades if upgrades else "pass"}
+
+
+def downgrade():
+    ${downgrades if downgrades else "pass"}

migrations/versions/001_create_todos_table.py

@@ -0,0 +1,46 @@
+"""Create todos table
+
+Revision ID: 001
+Revises:
+Create Date: 2023-10-30
+
+"""
+
+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(), nullable=False, default=False),
+        sa.Column(
+            "created_at",
+            sa.DateTime(timezone=True),
+            server_default=sa.text("(CURRENT_TIMESTAMP)"),
+        ),
+        sa.Column(
+            "updated_at",
+            sa.DateTime(timezone=True),
+            onupdate=sa.text("(CURRENT_TIMESTAMP)"),
+        ),
+        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 +1,8 @@
+fastapi>=0.104.0
+uvicorn>=0.23.2
+sqlalchemy>=2.0.0
+pydantic>=2.4.2
+pydantic[email]>=2.4.2
+alembic>=1.12.0
+python-dotenv>=1.0.0
+ruff>=0.1.3