Implement Todo app with FastAPI and SQLite

README.md

@@ -1,3 +1,95 @@
-# FastAPI Application
+# Todo App API
 
-This is a FastAPI application bootstrapped by BackendIM, the AI-powered backend generation platform.
+A simple Todo app API built with FastAPI and SQLite.
+
+## Features
+
+- CRUD operations for todo items
+- SQLAlchemy ORM for database interactions
+- Alembic for database migrations
+- Pydantic for data validation
+- Health check endpoint
+- FastAPI automatic documentation with Swagger UI and ReDoc
+
+## Project Structure
+
+```
+/
+├── app/                  # Application package
+│   ├── api/              # API endpoints
+│   │   ├── deps.py       # Dependencies
+│   │   └── endpoints/    # API routes
+│   ├── core/             # Core modules
+│   │   └── config.py     # Configuration
+│   ├── crud/             # CRUD operations
+│   ├── db/               # Database setup
+│   ├── models/           # SQLAlchemy models
+│   └── schemas/          # Pydantic schemas
+├── migrations/           # Alembic migrations
+├── alembic.ini           # Alembic config
+├── main.py               # Application entry point
+└── requirements.txt      # Dependencies
+```
+
+## Getting Started
+
+### Prerequisites
+
+- Python 3.8 or higher
+
+### Installation
+
+1. Clone the repository:
+
+```bash
+git clone <repository-url>
+cd todoapp
+```
+
+2. Install dependencies:
+
+```bash
+pip install -r requirements.txt
+```
+
+3. Run database migrations:
+
+```bash
+alembic upgrade head
+```
+
+4. Start the application:
+
+```bash
+uvicorn main:app --reload
+```
+
+The API will be available at http://localhost:8000
+
+## API Documentation
+
+Once the application is running, you can access:
+
+- Swagger UI documentation: http://localhost:8000/docs
+- ReDoc documentation: http://localhost:8000/redoc
+
+## API Endpoints
+
+- `GET /health` - Health check endpoint
+- `GET /api/v1/todos` - List all todos
+- `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 todo
+- `DELETE /api/v1/todos/{todo_id}` - Delete a todo
+
+## Data Models
+
+### Todo
+
+- `id`: Integer (auto-generated)
+- `title`: String (required)
+- `description`: String (optional)
+- `completed`: Boolean (default: false)
+- `priority`: Integer (0=low, 1=medium, 2=high)
+- `created_at`: DateTime (auto-generated)
+- `updated_at`: DateTime (auto-updated)

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/deps.py

@@ -0,0 +1,12 @@
+from typing import Generator
+
+from sqlalchemy.orm import Session
+
+from app.db.session import get_db
+
+
+def get_db_session() -> Generator[Session, None, None]:
+    """
+    Dependency to get a SQLAlchemy database session.
+    """
+    return get_db()

app/api/endpoints/__init__.py

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

app/api/endpoints/todos.py

@@ -0,0 +1,92 @@
+from typing import List
+
+from fastapi import APIRouter, Depends, HTTPException, status
+from sqlalchemy.orm import Session
+
+from app import crud, schemas
+from app.api import deps
+
+router = APIRouter()
+
+
+@router.get("/", response_model=List[schemas.todo.Todo])
+def read_todos(
+    skip: int = 0,
+    limit: int = 100,
+    db: Session = Depends(deps.get_db_session),
+) -> List[schemas.todo.Todo]:
+    """
+    Retrieve todos.
+    """
+    todos = crud.todo.get_todos(db, skip=skip, limit=limit)
+    return todos
+
+
+@router.post("/", response_model=schemas.todo.Todo, status_code=status.HTTP_201_CREATED)
+def create_todo(
+    *,
+    todo_in: schemas.todo.TodoCreate,
+    db: Session = Depends(deps.get_db_session),
+) -> schemas.todo.Todo:
+    """
+    Create new todo.
+    """
+    todo = crud.todo.create_todo(db=db, todo=todo_in)
+    return todo
+
+
+@router.get("/{todo_id}", response_model=schemas.todo.Todo)
+def read_todo(
+    *,
+    todo_id: int,
+    db: Session = Depends(deps.get_db_session),
+) -> schemas.todo.Todo:
+    """
+    Get todo by ID.
+    """
+    todo = crud.todo.get_todo(db=db, todo_id=todo_id)
+    if not todo:
+        raise HTTPException(
+            status_code=status.HTTP_404_NOT_FOUND,
+            detail="Todo not found",
+        )
+    return todo
+
+
+@router.put("/{todo_id}", response_model=schemas.todo.Todo)
+def update_todo(
+    *,
+    todo_id: int,
+    todo_in: schemas.todo.TodoUpdate,
+    db: Session = Depends(deps.get_db_session),
+) -> schemas.todo.Todo:
+    """
+    Update a todo.
+    """
+    todo = crud.todo.get_todo(db=db, todo_id=todo_id)
+    if not todo:
+        raise HTTPException(
+            status_code=status.HTTP_404_NOT_FOUND,
+            detail="Todo not found",
+        )
+    todo = crud.todo.update_todo(db=db, todo_id=todo_id, todo=todo_in)
+    return todo
+
+
+@router.delete("/{todo_id}", status_code=status.HTTP_204_NO_CONTENT, response_model=None)
+def delete_todo(
+    *,
+    todo_id: int,
+    db: Session = Depends(deps.get_db_session),
+) -> None:
+    """
+    Delete a todo.
+    """
+    todo = crud.todo.get_todo(db=db, todo_id=todo_id)
+    if not todo:
+        raise HTTPException(
+            status_code=status.HTTP_404_NOT_FOUND,
+            detail="Todo not found",
+        )
+    crud.todo.delete_todo(db=db, todo_id=todo_id)
+    return None

app/core/config.py

@@ -0,0 +1,27 @@
+from pathlib import Path
+from typing import List
+
+from pydantic_settings import BaseSettings
+
+
+class Settings(BaseSettings):
+    # API
+    API_V1_STR: str = "/api/v1"
+    PROJECT_NAME: str = "Todo App API"
+    PROJECT_DESCRIPTION: str = "A simple Todo App API built with FastAPI"
+    VERSION: str = "0.1.0"
+    
+    # CORS
+    ALLOWED_ORIGINS: List[str] = ["*"]
+    
+    # Database
+    DB_DIR: Path = Path("/app") / "storage" / "db"
+    SQLALCHEMY_DATABASE_URL: str = f"sqlite:///{DB_DIR}/db.sqlite"
+    
+    class Config:
+        env_file = ".env"
+        env_file_encoding = "utf-8"
+        case_sensitive = True
+
+# Create settings instance
+settings = Settings()

app/crud/__init__.py

@@ -0,0 +1 @@
+from app.crud.todo import delete_todo, get_todo, get_todos, create_todo, update_todo  # noqa

app/crud/todo.py

@@ -0,0 +1,52 @@
+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 single todo by ID."""
+    return db.query(Todo).filter(Todo.id == todo_id).first()
+
+
+def get_todos(db: Session, skip: int = 0, limit: int = 100) -> List[Todo]:
+    """Get all todos with pagination."""
+    return db.query(Todo).order_by(Todo.created_at.desc()).offset(skip).limit(limit).all()
+
+
+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: TodoUpdate) -> Optional[Todo]:
+    """Update a todo."""
+    db_todo = get_todo(db, todo_id)
+    if not db_todo:
+        return None
+    
+    update_data = todo.model_dump(exclude_unset=True)
+    for field, value in update_data.items():
+        setattr(db_todo, field, 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."""
+    db_todo = get_todo(db, todo_id)
+    if not db_todo:
+        return False
+    
+    db.delete(db_todo)
+    db.commit()
+    return True

app/db/base.py

@@ -0,0 +1,4 @@
+# Import all the models, so that Base has them before being
+# imported by Alembic
+from app.db.base_class import Base  # noqa
+from app.models.todo import Todo  # noqa

app/db/base_class.py

@@ -0,0 +1,14 @@
+from typing import Any
+
+from sqlalchemy.ext.declarative import as_declarative, declared_attr
+
+
+@as_declarative()
+class Base:
+    id: Any
+    __name__: str
+    
+    # Generate __tablename__ automatically
+    @declared_attr
+    def __tablename__(cls) -> str:
+        return cls.__name__.lower()

app/db/session.py

@@ -0,0 +1,22 @@
+from sqlalchemy import create_engine
+from sqlalchemy.orm import sessionmaker
+
+from app.core.config import settings
+
+# Ensure the DB directory exists
+settings.DB_DIR.mkdir(parents=True, exist_ok=True)
+
+engine = create_engine(
+    settings.SQLALCHEMY_DATABASE_URL,
+    connect_args={"check_same_thread": False}
+)
+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/todo.py

@@ -0,0 +1,17 @@
+from datetime import datetime
+
+from sqlalchemy import Boolean, Column, DateTime, Integer, String, Text
+
+from app.db.base_class import Base
+
+
+class Todo(Base):
+    """SQLAlchemy model for todo items."""
+    
+    id = Column(Integer, primary_key=True, index=True)
+    title = Column(String(255), nullable=False, index=True)
+    description = Column(Text, nullable=True)
+    completed = Column(Boolean, default=False)
+    priority = Column(Integer, default=0)  # 0=low, 1=medium, 2=high
+    created_at = Column(DateTime, default=datetime.utcnow)
+    updated_at = Column(DateTime, default=datetime.utcnow, onupdate=datetime.utcnow)

app/schemas/__init__.py

@@ -0,0 +1 @@
+from app.schemas.todo import Todo, TodoCreate, TodoUpdate  # noqa

app/schemas/todo.py

@@ -0,0 +1,40 @@
+from datetime import datetime
+from typing import Optional
+
+from pydantic import BaseModel, Field
+
+
+# Shared properties
+class TodoBase(BaseModel):
+    title: str = Field(..., min_length=1, max_length=255)
+    description: Optional[str] = None
+    completed: bool = False
+    priority: int = Field(0, ge=0, le=2)  # 0=low, 1=medium, 2=high
+
+
+# Properties to receive on item creation
+class TodoCreate(TodoBase):
+    pass
+
+
+# Properties to receive on item update
+class TodoUpdate(BaseModel):
+    title: Optional[str] = Field(None, min_length=1, max_length=255)
+    description: Optional[str] = None
+    completed: Optional[bool] = None
+    priority: Optional[int] = Field(None, ge=0, le=2)
+
+
+# Properties shared by models stored in DB
+class TodoInDBBase(TodoBase):
+    id: int
+    created_at: datetime
+    updated_at: datetime
+    
+    class Config:
+        from_attributes = True
+
+
+# Properties to return to client
+class Todo(TodoInDBBase):
+    pass

main.py

@@ -0,0 +1,35 @@
+from fastapi import FastAPI
+from fastapi.middleware.cors import CORSMiddleware
+
+from app.api.endpoints import router as api_router
+from app.core.config import settings
+
+app = FastAPI(
+    title=settings.PROJECT_NAME,
+    description=settings.PROJECT_DESCRIPTION,
+    version=settings.VERSION,
+    openapi_url=f"{settings.API_V1_STR}/openapi.json",
+    docs_url="/docs",
+    redoc_url="/redoc",
+)
+
+# Set up CORS middleware
+app.add_middleware(
+    CORSMiddleware,
+    allow_origins=settings.ALLOWED_ORIGINS,
+    allow_credentials=True,
+    allow_methods=["*"],
+    allow_headers=["*"],
+)
+
+# Include routers
+app.include_router(api_router, prefix=settings.API_V1_STR)
+
+# Health check endpoint
+@app.get("/health", tags=["health"])
+async def health_check():
+    return {"status": "ok"}
+
+if __name__ == "__main__":
+    import uvicorn
+    uvicorn.run("main:app", host="0.0.0.0", port=8000, reload=True)

migrations/README

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

migrations/env.py

@@ -0,0 +1,88 @@
+import os
+import sys
+from logging.config import fileConfig
+
+from sqlalchemy import engine_from_config
+from sqlalchemy import pool
+
+from alembic import context
+
+# Add the app directory to the Python path
+BASE_DIR = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
+sys.path.append(BASE_DIR)
+
+# Import the SQLAlchemy Base and metadata
+from app.db.base 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.
+
+    """
+    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()

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_todo_table.py

@@ -0,0 +1,36 @@
+"""Create todo table
+
+Revision ID: 001
+Revises: 
+Create Date: 2023-09-15
+
+"""
+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(
+        'todo',
+        sa.Column('id', sa.Integer(), nullable=False),
+        sa.Column('title', sa.String(255), nullable=False, index=True),
+        sa.Column('description', sa.Text(), nullable=True),
+        sa.Column('completed', sa.Boolean(), default=False),
+        sa.Column('priority', sa.Integer(), default=0),
+        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_todo_id'), 'todo', ['id'], unique=False)
+
+
+def downgrade():
+    op.drop_index(op.f('ix_todo_id'), table_name='todo')
+    op.drop_table('todo')

pyproject.toml

@@ -0,0 +1,32 @@
+[tool.ruff]
+# Exclude a variety of commonly ignored directories.
+exclude = [
+    ".git",
+    ".ruff_cache",
+    ".venv",
+    "venv",
+    "__pypackages__",
+    "migrations",
+]
+
+# Assume Python 3.10
+target-version = "py310"
+
+[tool.ruff.lint]
+# Enable flake8-bugbear (B) rules.
+select = ["E", "F", "B", "I"]
+
+# Ignore line length violations and B008 (function calls in defaults)
+ignore = ["E501", "B008"]
+
+# Allow autofix for all enabled rules (when `--fix`) is provided.
+fixable = ["ALL"]
+
+# Allow unused variables when underscore-prefixed.
+dummy-variable-rgx = "^(_+|(_+[a-zA-Z0-9_]*[a-zA-Z0-9]+?))$"
+
+[tool.ruff.lint.per-file-ignores]
+"__init__.py" = ["F401"] # Ignore unused imports in __init__.py files
+
+[tool.ruff.lint.isort]
+known-first-party = ["app"]

requirements.txt

@@ -0,0 +1,9 @@
+fastapi>=0.103.1
+uvicorn>=0.23.2
+sqlalchemy>=2.0.20
+alembic>=1.12.0
+pydantic>=2.3.0
+pydantic-settings>=2.0.3
+python-dotenv>=1.0.0
+ruff>=0.0.291
+pytest>=7.4.2