Implement Todo API application with FastAPI and SQLite

- Created project structure with FastAPI setup
- Added SQLite database connection with SQLAlchemy ORM
- Implemented Todo model and schemas
- Added CRUD operations for Todo items
- Created API endpoints for Todo management
- Added health check endpoint
- Configured Alembic for database migrations
- Updated project documentation in README.md

README.md

@@ -1,3 +1,103 @@
-# FastAPI Application
+# Todo 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
+
+- RESTful API using FastAPI
+- SQLite database with SQLAlchemy ORM
+- Database migrations using Alembic
+- CRUD operations for Todo items
+- Health check endpoint
+- OpenAPI documentation
+
+## Project Structure
+
+```
+/
+├── app/
+│   ├── api/
+│   │   ├── v1/
+│   │   │   ├── health.py
+│   │   │   └── todos.py
+│   │   ├── deps.py
+│   │   └── routers.py
+│   ├── core/
+│   │   └── config.py
+│   ├── crud/
+│   │   ├── base.py
+│   │   └── todo.py
+│   ├── db/
+│   │   ├── base.py
+│   │   ├── base_class.py
+│   │   └── session.py
+│   ├── models/
+│   │   └── todo.py
+│   └── schemas/
+│       └── todo.py
+├── migrations/
+│   ├── versions/
+│   │   └── 01_initial_todo_table.py
+│   ├── env.py
+│   └── script.py.mako
+├── alembic.ini
+├── main.py
+└── requirements.txt
+```
+
+## Installation
+
+1. Clone the repository
+2. Install dependencies:
+
+```bash
+pip install -r requirements.txt
+```
+
+## Database Setup
+
+The application uses SQLite as its database. The database will be created at `/app/storage/db/db.sqlite` when the application starts.
+
+To run the migrations:
+
+```bash
+alembic upgrade head
+```
+
+## Running the Application
+
+To run the application locally:
+
+```bash
+uvicorn main:app --reload
+```
+
+The API will be available at http://localhost:8000
+
+## API Documentation
+
+API documentation is available at:
+- Swagger UI: http://localhost:8000/docs
+- ReDoc: http://localhost:8000/redoc
+
+## API Endpoints
+
+### Health Check
+
+- `GET /api/v1/health` - Check API health
+
+### Todo Endpoints
+
+- `GET /api/v1/todos` - List all todos
+- `POST /api/v1/todos` - Create a new todo
+- `GET /api/v1/todos/{id}` - Get a specific todo
+- `PUT /api/v1/todos/{id}` - Update a todo
+- `DELETE /api/v1/todos/{id}` - Delete a todo
+
+## Query Parameters
+
+### List todos
+
+- `skip` - Number of records to skip (default: 0)
+- `limit` - Maximum number of records to return (default: 100)
+- `completed` - Filter by completion status (optional, boolean)

alembic.ini

@@ -0,0 +1,73 @@
+# 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
+
+sqlalchemy.url = sqlite:////app/storage/db/db.sqlite
+
+# 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 +1,2 @@
+
+

app/api/routers.py

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

app/api/v1/health.py

@@ -0,0 +1,28 @@
+from fastapi import APIRouter, Depends, status
+from sqlalchemy.orm import Session
+
+from app.db.session import get_db
+
+router = APIRouter()
+
+
+@router.get("/", status_code=status.HTTP_200_OK)
+def health_check(db: Session = Depends(get_db)):
+    """
+    Check the health of the API.
+    """
+    try:
+        # Validate database connection
+        db.execute("SELECT 1")
+        return {
+            "status": "ok",
+            "message": "API is healthy",
+            "database": "connected"
+        }
+    except Exception as e:
+        return {
+            "status": "error",
+            "message": "API health check failed",
+            "database": "disconnected",
+            "error": str(e)
+        }

app/api/v1/todos.py

@@ -0,0 +1,99 @@
+from typing import Any, List
+
+from fastapi import APIRouter, Depends, HTTPException, status
+from sqlalchemy.orm import Session
+
+from app import crud, schemas
+from app.db.session import get_db
+
+router = APIRouter()
+
+
+@router.get("/", response_model=List[schemas.todo.Todo])
+def read_todos(
+    db: Session = Depends(get_db),
+    skip: int = 0,
+    limit: int = 100,
+    completed: bool = None,
+) -> Any:
+    """
+    Retrieve todos.
+    """
+    if completed is not None:
+        if completed:
+            todos = crud.todo.get_completed(db, skip=skip, limit=limit)
+        else:
+            todos = crud.todo.get_incomplete(db, skip=skip, limit=limit)
+    else:
+        todos = crud.todo.get_multi(db, skip=skip, limit=limit)
+    return todos
+
+
+@router.post("/", response_model=schemas.todo.Todo, status_code=status.HTTP_201_CREATED)
+def create_todo(
+    *,
+    db: Session = Depends(get_db),
+    todo_in: schemas.todo.TodoCreate,
+) -> Any:
+    """
+    Create new todo.
+    """
+    todo = crud.todo.create(db=db, obj_in=todo_in)
+    return todo
+
+
+@router.get("/{id}", response_model=schemas.todo.Todo)
+def read_todo(
+    *,
+    db: Session = Depends(get_db),
+    id: int,
+) -> Any:
+    """
+    Get todo by ID.
+    """
+    todo = crud.todo.get(db=db, id=id)
+    if not todo:
+        raise HTTPException(
+            status_code=status.HTTP_404_NOT_FOUND,
+            detail="Todo not found",
+        )
+    return todo
+
+
+@router.put("/{id}", response_model=schemas.todo.Todo)
+def update_todo(
+    *,
+    db: Session = Depends(get_db),
+    id: int,
+    todo_in: schemas.todo.TodoUpdate,
+) -> Any:
+    """
+    Update a todo.
+    """
+    todo = crud.todo.get(db=db, id=id)
+    if not todo:
+        raise HTTPException(
+            status_code=status.HTTP_404_NOT_FOUND,
+            detail="Todo not found",
+        )
+    todo = crud.todo.update(db=db, db_obj=todo, obj_in=todo_in)
+    return todo
+
+
+@router.delete("/{id}", status_code=status.HTTP_204_NO_CONTENT, response_model=None)
+def delete_todo(
+    *,
+    db: Session = Depends(get_db),
+    id: int,
+) -> Any:
+    """
+    Delete a todo.
+    """
+    todo = crud.todo.get(db=db, id=id)
+    if not todo:
+        raise HTTPException(
+            status_code=status.HTTP_404_NOT_FOUND,
+            detail="Todo not found",
+        )
+    crud.todo.remove(db=db, id=id)
+    return None

app/core/config.py

@@ -0,0 +1,30 @@
+from pathlib import Path
+from typing import List
+
+from pydantic_settings import BaseSettings
+
+
+class Settings(BaseSettings):
+    # API Configuration
+    API_V1_STR: str = "/api/v1"
+    PROJECT_NAME: str = "Todo API"
+    PROJECT_DESCRIPTION: str = "A simple TODO application API"
+    PROJECT_VERSION: str = "0.1.0"
+    
+    # CORS Configuration
+    CORS_ORIGINS: List[str] = ["*"]
+    
+    # Database Configuration
+    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
+
+
+settings = Settings()
+
+# Create DB directory if it doesn't exist
+settings.DB_DIR.mkdir(parents=True, exist_ok=True)

app/crud/base.py

@@ -0,0 +1,65 @@
+from typing import Any, Dict, Generic, List, Optional, Type, TypeVar, Union
+
+from fastapi.encoders import jsonable_encoder
+from pydantic import BaseModel
+from sqlalchemy.orm import Session
+
+from app.db.base_class import Base
+
+ModelType = TypeVar("ModelType", bound=Base)
+CreateSchemaType = TypeVar("CreateSchemaType", bound=BaseModel)
+UpdateSchemaType = TypeVar("UpdateSchemaType", bound=BaseModel)
+
+
+class CRUDBase(Generic[ModelType, CreateSchemaType, UpdateSchemaType]):
+    def __init__(self, model: Type[ModelType]):
+        """
+        CRUD base class with default methods to Create, Read, Update, Delete (CRUD).
+        
+        **Parameters**
+        
+        * `model`: A SQLAlchemy model class
+        """
+        self.model = model
+
+    def get(self, db: Session, id: Any) -> Optional[ModelType]:
+        return db.query(self.model).filter(self.model.id == id).first()
+
+    def get_multi(
+        self, db: Session, *, skip: int = 0, limit: int = 100
+    ) -> List[ModelType]:
+        return db.query(self.model).offset(skip).limit(limit).all()
+
+    def create(self, db: Session, *, obj_in: CreateSchemaType) -> ModelType:
+        obj_in_data = jsonable_encoder(obj_in)
+        db_obj = self.model(**obj_in_data)
+        db.add(db_obj)
+        db.commit()
+        db.refresh(db_obj)
+        return db_obj
+
+    def update(
+        self,
+        db: Session,
+        *,
+        db_obj: ModelType,
+        obj_in: Union[UpdateSchemaType, Dict[str, Any]]
+    ) -> ModelType:
+        obj_data = jsonable_encoder(db_obj)
+        if isinstance(obj_in, dict):
+            update_data = obj_in
+        else:
+            update_data = obj_in.dict(exclude_unset=True)
+        for field in obj_data:
+            if field in update_data:
+                setattr(db_obj, field, update_data[field])
+        db.add(db_obj)
+        db.commit()
+        db.refresh(db_obj)
+        return db_obj
+
+    def remove(self, db: Session, *, id: int) -> ModelType:
+        obj = db.query(self.model).get(id)
+        db.delete(obj)
+        db.commit()
+        return obj

app/crud/todo.py

@@ -0,0 +1,24 @@
+from typing import List, Optional
+
+from sqlalchemy.orm import Session
+
+from app.crud.base import CRUDBase
+from app.models.todo import Todo
+from app.schemas.todo import TodoCreate, TodoUpdate
+
+
+class CRUDTodo(CRUDBase[Todo, TodoCreate, TodoUpdate]):
+    def get_by_title(self, db: Session, *, title: str) -> Optional[Todo]:
+        """Get a todo by title"""
+        return db.query(Todo).filter(Todo.title == title).first()
+    
+    def get_completed(self, db: Session, *, skip: int = 0, limit: int = 100) -> List[Todo]:
+        """Get all completed todos"""
+        return db.query(Todo).filter(Todo.completed.is_(True)).offset(skip).limit(limit).all()
+    
+    def get_incomplete(self, db: Session, *, skip: int = 0, limit: int = 100) -> List[Todo]:
+        """Get all incomplete todos"""
+        return db.query(Todo).filter(Todo.completed.is_(False)).offset(skip).limit(limit).all()
+
+
+todo = CRUDTodo(Todo)

app/db/base.py

@@ -0,0 +1 @@
+# Import all models for Alembic to detect

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 +1,25 @@
+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 SessionLocal class
+SessionLocal = sessionmaker(autocommit=False, autoflush=False, bind=engine)
+
+
+def get_db():
+    """
+    Dependency function that creates a new SQLAlchemy SessionLocal
+    that will be used in a single request, and then closed.
+    """
+    db = SessionLocal()
+    try:
+        yield db
+    finally:
+        db.close()

app/models/todo.py

@@ -0,0 +1,14 @@
+from datetime import datetime
+
+from sqlalchemy import Boolean, Column, DateTime, Integer, String, Text
+
+from app.db.base_class import Base
+
+
+class Todo(Base):
+    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)
+    created_at = Column(DateTime, default=datetime.utcnow)
+    updated_at = Column(DateTime, default=datetime.utcnow, onupdate=datetime.utcnow)

app/schemas/todo.py

@@ -0,0 +1,37 @@
+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: Optional[bool] = False
+
+
+# Properties to receive via API on creation
+class TodoCreate(TodoBase):
+    pass
+
+
+# Properties to receive via API on update
+class TodoUpdate(BaseModel):
+    title: Optional[str] = Field(None, min_length=1, max_length=255)
+    description: Optional[str] = None
+    completed: Optional[bool] = None
+
+
+class TodoInDBBase(TodoBase):
+    id: int
+    created_at: datetime
+    updated_at: datetime
+
+    class Config:
+        orm_mode = True
+
+
+# Additional properties to return via API
+class Todo(TodoInDBBase):
+    pass

main.py

@@ -0,0 +1,37 @@
+from pathlib import Path
+
+from fastapi import FastAPI
+from fastapi.middleware.cors import CORSMiddleware
+
+from app.api.routers import router as api_router
+from app.core.config import settings
+
+app = FastAPI(
+    title=settings.PROJECT_NAME,
+    description=settings.PROJECT_DESCRIPTION,
+    version=settings.PROJECT_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.CORS_ORIGINS,
+    allow_credentials=True,
+    allow_methods=["*"],
+    allow_headers=["*"],
+)
+
+# Include API router
+app.include_router(api_router, prefix=settings.API_V1_STR)
+
+# Ensure storage directory exists
+storage_dir = Path("/app/storage")
+storage_dir.mkdir(parents=True, exist_ok=True)
+
+if __name__ == "__main__":
+    import uvicorn
+
+    uvicorn.run("main:app", host="0.0.0.0", port=8000, reload=True)

migrations/env.py

@@ -0,0 +1,62 @@
+import sys
+from pathlib import Path
+
+from alembic import context
+from sqlalchemy import engine_from_config, pool
+
+# Add app directory to path
+sys.path.insert(0, str(Path(__file__).parent.parent))
+
+# Import models
+from app.db.base import Base
+from app.core.config import settings
+
+# Alembic Config object
+config = context.config
+
+# Set SQLAlchemy URL in Alembic config
+config.set_main_option("sqlalchemy.url", settings.SQLALCHEMY_DATABASE_URL)
+
+# Metadata for autogenerate support
+target_metadata = Base.metadata
+
+
+def run_migrations_offline():
+    """Run migrations in 'offline' mode."""
+    url = config.get_main_option("sqlalchemy.url")
+    context.configure(
+        url=url,
+        target_metadata=target_metadata,
+        literal_binds=True,
+        compare_type=True,
+    )
+
+    with context.begin_transaction():
+        context.run_migrations()
+
+
+def run_migrations_online():
+    """Run migrations in 'online' mode."""
+    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,
+            compare_type=True,
+            render_as_batch=is_sqlite,  # Enable batch mode 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/01_initial_todo_table.py

@@ -0,0 +1,35 @@
+"""Initial todo table
+
+Revision ID: 01_initial_todo_table
+Revises: 
+Create Date: 2023-09-15
+
+"""
+from alembic import op
+import sqlalchemy as sa
+
+
+# revision identifiers, used by Alembic.
+revision = '01_initial_todo_table'
+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('created_at', sa.DateTime(), default=sa.func.current_timestamp()),
+        sa.Column('updated_at', sa.DateTime(), default=sa.func.current_timestamp(), onupdate=sa.func.current_timestamp()),
+        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')

requirements.txt

@@ -0,0 +1,7 @@
+fastapi>=0.103.1
+uvicorn>=0.23.2
+sqlalchemy>=2.0.20
+alembic>=1.12.0
+pydantic>=2.3.0
+python-dotenv>=1.0.0
+ruff>=0.0.287