Create Todo application with FastAPI and SQLite

- Implemented project structure
- Added SQLAlchemy models and database connection
- Created Alembic migrations
- Implemented CRUD API endpoints
- Added health endpoint
- Updated README.md

generated with BackendIM... (backend.im)

README.md

@@ -1,3 +1,83 @@
-# FastAPI Application
+# Todo Application
 
-This is a FastAPI application bootstrapped by BackendIM, the AI-powered backend generation platform.
+A simple Todo application built with FastAPI and SQLite.
+
+## Features
+
+- Create, read, update, and delete todo items
+- SQLite database with SQLAlchemy ORM
+- Database migrations with Alembic
+- Health check endpoint
+- OpenAPI documentation
+
+## Project Structure
+
+```
+todoapplication/
+├── alembic/                  # Database migrations
+├── app/                      # Application code
+│   ├── api/                  # API routes and endpoints
+│   │   ├── crud/             # CRUD operations
+│   │   ├── endpoints/        # API endpoint implementations
+│   ├── core/                 # Core functionality
+│   │   ├── config.py         # Application configuration
+│   ├── db/                   # Database related code
+│   │   ├── session.py        # Database session management
+│   ├── models/               # SQLAlchemy models
+│   │   ├── todo.py           # Todo model
+│   ├── schemas/              # Pydantic schemas
+│   │   ├── todo.py           # Todo schemas
+├── storage/                  # Storage directory
+│   ├── db/                   # Database files location
+├── alembic.ini               # Alembic configuration
+├── main.py                   # Application entry point
+├── requirements.txt          # Python dependencies
+```
+
+## API Endpoints
+
+- `GET /api/v1/todos`: Get 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 specific todo
+- `DELETE /api/v1/todos/{todo_id}`: Delete a specific todo
+- `GET /health`: Health check endpoint
+- `GET /docs`: API documentation (Swagger UI)
+- `GET /redoc`: API documentation (ReDoc)
+
+## Getting Started
+
+### Prerequisites
+
+- Python 3.8+
+
+### Installation
+
+1. Clone the repository
+2. Install dependencies:
+
+```bash
+pip install -r requirements.txt
+```
+
+3. Run the application:
+
+```bash
+uvicorn main:app --reload
+```
+
+The application will be available at http://localhost:8000.
+
+### Database Migrations
+
+Run migrations:
+
+```bash
+alembic upgrade head
+```
+
+Create a new migration:
+
+```bash
+alembic revision -m "your migration message"
+```

alembic.ini

@@ -0,0 +1,38 @@
+[alembic]
+script_location = alembic
+prepend_sys_path = .
+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/env.py

@@ -0,0 +1,47 @@
+from logging.config import fileConfig
+from sqlalchemy import engine_from_config
+from sqlalchemy import pool
+from alembic import context
+
+from app.models import Base
+from app.core.config import settings
+
+config = context.config
+fileConfig(config.config_file_name)
+target_metadata = Base.metadata
+
+# Set the SQLAlchemy URL from our settings
+config.set_main_option("sqlalchemy.url", settings.SQLALCHEMY_DATABASE_URL)
+
+def run_migrations_offline():
+    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():
+    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/initial_migration.py

@@ -0,0 +1,38 @@
+"""Initial migration
+
+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():
+    # Create todos table
+    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.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')

app/api/crud/todo.py

@@ -0,0 +1,43 @@
+from sqlalchemy.orm import Session
+from typing import List, Optional
+from app.models.todo import Todo
+from app.schemas.todo import TodoCreate, TodoUpdate
+
+def get_todo(db: Session, todo_id: int) -> Optional[Todo]:
+    return db.query(Todo).filter(Todo.id == todo_id).first()
+
+def get_todos(db: Session, skip: int = 0, limit: int = 100) -> List[Todo]:
+    return db.query(Todo).offset(skip).limit(limit).all()
+
+def create_todo(db: Session, todo: TodoCreate) -> Todo:
+    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]:
+    db_todo = get_todo(db, todo_id)
+    if not db_todo:
+        return None
+    
+    update_data = todo.dict(exclude_unset=True)
+    for field, value in update_data.items():
+        setattr(db_todo, field, value)
+    
+    db.commit()
+    db.refresh(db_todo)
+    return db_todo
+
+def delete_todo(db: Session, todo_id: int) -> bool:
+    db_todo = get_todo(db, todo_id)
+    if not db_todo:
+        return False
+    
+    db.delete(db_todo)
+    db.commit()
+    return True

app/api/endpoints/todos.py

@@ -0,0 +1,85 @@
+from fastapi import APIRouter, Depends, HTTPException, status
+from sqlalchemy.orm import Session
+from typing import List, Any
+
+from app.api.crud import todo as crud
+from app.schemas.todo import Todo, TodoCreate, TodoUpdate
+from app.db.session import get_db
+
+router = APIRouter()
+
+@router.get("/", response_model=List[Todo])
+def read_todos(
+    db: Session = Depends(get_db),
+    skip: int = 0,
+    limit: int = 100,
+) -> Any:
+    """
+    Retrieve all todos.
+    """
+    todos = crud.get_todos(db, skip=skip, limit=limit)
+    return todos
+
+@router.post("/", response_model=Todo, status_code=status.HTTP_201_CREATED)
+def create_todo(
+    *,
+    db: Session = Depends(get_db),
+    todo_in: TodoCreate,
+) -> Any:
+    """
+    Create new todo.
+    """
+    todo = crud.create_todo(db, todo_in)
+    return todo
+
+@router.get("/{todo_id}", response_model=Todo)
+def read_todo(
+    *,
+    db: Session = Depends(get_db),
+    todo_id: int,
+) -> Any:
+    """
+    Get todo by ID.
+    """
+    todo = crud.get_todo(db, 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=Todo)
+def update_todo(
+    *,
+    db: Session = Depends(get_db),
+    todo_id: int,
+    todo_in: TodoUpdate,
+) -> Any:
+    """
+    Update a todo.
+    """
+    todo = crud.update_todo(db, todo_id, todo_in)
+    if not todo:
+        raise HTTPException(
+            status_code=status.HTTP_404_NOT_FOUND,
+            detail="Todo not found"
+        )
+    return todo
+
+@router.delete("/{todo_id}", status_code=status.HTTP_204_NO_CONTENT)
+def delete_todo(
+    *,
+    db: Session = Depends(get_db),
+    todo_id: int,
+) -> Any:
+    """
+    Delete a todo.
+    """
+    success = crud.delete_todo(db, todo_id)
+    if not success:
+        raise HTTPException(
+            status_code=status.HTTP_404_NOT_FOUND,
+            detail="Todo not found"
+        )
+    return None

app/api/routes.py

@@ -0,0 +1,6 @@
+from fastapi import APIRouter
+from app.api.endpoints import todos
+
+router = APIRouter()
+
+router.include_router(todos.router, prefix="/todos", tags=["todos"])

app/core/config.py

@@ -0,0 +1,24 @@
+from pydantic import BaseModel
+from typing import Optional
+from pathlib import Path
+
+class Settings(BaseModel):
+    API_V1_STR: str = "/api/v1"
+    PROJECT_NAME: str = "Todo API"
+    PROJECT_DESCRIPTION: str = "A simple Todo API built with FastAPI and SQLite"
+    VERSION: str = "0.1.0"
+    
+    # Database settings
+    DB_DIR: Path = Path("/app") / "storage" / "db"
+    SQLALCHEMY_DATABASE_URL: Optional[str] = None
+
+    class Config:
+        case_sensitive = True
+
+settings = Settings()
+
+# Ensure DB directory exists
+settings.DB_DIR.mkdir(parents=True, exist_ok=True)
+
+# Set the database URL
+settings.SQLALCHEMY_DATABASE_URL = f"sqlite:///{settings.DB_DIR}/db.sqlite"

app/db/session.py

@@ -0,0 +1,24 @@
+from sqlalchemy import create_engine
+from sqlalchemy.ext.declarative import declarative_base
+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}  # Only needed for SQLite
+)
+
+# Create a SessionLocal class
+SessionLocal = sessionmaker(autocommit=False, autoflush=False, bind=engine)
+
+# Create a Base class
+Base = declarative_base()
+
+# Dependency to get DB session
+def get_db():
+    db = SessionLocal()
+    try:
+        yield db
+    finally:
+        db.close()

app/models/__init__.py

@@ -0,0 +1 @@
+from app.models.todo import Todo

app/models/todo.py

@@ -0,0 +1,13 @@
+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())

app/schemas/__init__.py

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

app/schemas/todo.py

@@ -0,0 +1,27 @@
+from pydantic import BaseModel
+from datetime import datetime
+from typing import Optional
+
+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 TodoInDBBase(TodoBase):
+    id: int
+    created_at: datetime
+    updated_at: Optional[datetime] = None
+
+    class Config:
+        orm_mode = True
+
+class Todo(TodoInDBBase):
+    pass

main.py

@@ -0,0 +1,25 @@
+from fastapi import FastAPI
+from app.api.routes 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",
+)
+
+app.include_router(api_router, prefix=settings.API_V1_STR)
+
+@app.get("/health", status_code=200)
+def health_check():
+    """
+    Health check endpoint to verify the application is running
+    """
+    return {"status": "healthy", "version": settings.VERSION}
+
+if __name__ == "__main__":
+    import uvicorn
+    uvicorn.run("main:app", host="0.0.0.0", port=8000, reload=True)

requirements.txt

@@ -0,0 +1,7 @@
+fastapi==0.110.0
+uvicorn==0.28.0
+sqlalchemy==2.0.27
+pydantic==2.5.3
+alembic==1.12.1
+python-dotenv==1.0.0
+pathlib==1.0.1