Create simple Todo application with FastAPI and SQLite

README.md

@@ -1,3 +1,116 @@
-# FastAPI Application
+# Simple 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
+- Filter TODO items by completion status
+- Health check endpoint
+
+## Tech Stack
+
+- FastAPI: Web framework for building APIs
+- SQLAlchemy: ORM for database interactions
+- Pydantic: Data validation and settings management
+- Alembic: Database migration tool
+- SQLite: Lightweight relational database
+- Uvicorn: ASGI server for running the application
+
+## Project Structure
+
+```
+.
+├── alembic.ini                   # Alembic configuration
+├── main.py                       # FastAPI application entry point
+├── migrations/                   # Database migrations
+│   ├── env.py
+│   ├── script.py.mako
+│   └── versions/
+│       └── 001_create_todos_table.py
+├── app/
+│   ├── api/                      # API endpoints
+│   │   └── routes/
+│   │       ├── health.py         # Health check endpoint
+│   │       └── todos.py          # Todo endpoints
+│   ├── core/                     # Core application code
+│   │   └── config.py             # Application configuration
+│   ├── db/                       # Database setup
+│   │   ├── base.py
+│   │   ├── deps.py               # Database dependencies
+│   │   └── session.py            # Database session setup
+│   ├── models/                   # SQLAlchemy models
+│   │   └── todo.py               # Todo model
+│   └── schemas/                  # Pydantic schemas
+│       └── todo.py               # Todo schemas
+└── requirements.txt              # Project dependencies
+```
+
+## Running the Application
+
+1. Install dependencies:
+```bash
+pip install -r requirements.txt
+```
+
+2. Run database migrations:
+```bash
+alembic upgrade head
+```
+
+3. Start the application:
+```bash
+uvicorn main:app --host 0.0.0.0 --port 8000 --reload
+```
+
+4. Visit the API documentation:
+   - Swagger UI: http://localhost:8000/docs
+   - ReDoc: http://localhost:8000/redoc
+
+## API Endpoints
+
+### Health Check
+- `GET /health` - Check API and database status
+
+### Todo Operations
+- `GET /api/todos` - List all todos (can filter by completion status)
+- `POST /api/todos` - Create a new todo
+- `GET /api/todos/{todo_id}` - Get a specific todo
+- `PUT /api/todos/{todo_id}` - Update a todo
+- `DELETE /api/todos/{todo_id}` - Delete a todo
+
+## Example Usage
+
+### Create a Todo
+
+```bash
+curl -X POST http://localhost:8000/api/todos \
+  -H "Content-Type: application/json" \
+  -d '{"title": "Learn FastAPI", "description": "Complete FastAPI tutorial", "completed": false}'
+```
+
+### Get All Todos
+
+```bash
+curl http://localhost:8000/api/todos
+```
+
+### Get Completed Todos
+
+```bash
+curl http://localhost:8000/api/todos?completed=true
+```
+
+### Update a Todo
+
+```bash
+curl -X PUT http://localhost:8000/api/todos/1 \
+  -H "Content-Type: application/json" \
+  -d '{"completed": true}'
+```
+
+### Delete a Todo
+
+```bash
+curl -X DELETE http://localhost:8000/api/todos/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 URL with absolute path
+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/routes/health.py

@@ -0,0 +1,21 @@
+from fastapi import APIRouter, Depends
+from sqlalchemy.orm import Session
+
+from app.db.deps import get_db
+
+router = APIRouter()
+
+
+@router.get("/health")
+def health_check(db: Session = Depends(get_db)):
+    """
+    Health check endpoint to verify API is working and database is connected.
+    """
+    try:
+        # Try to execute a simple query to verify database connection
+        db.execute("SELECT 1")
+        db_status = "connected"
+    except Exception:
+        db_status = "disconnected"
+
+    return {"status": "ok", "database": db_status}

app/api/routes/todos.py

@@ -0,0 +1,89 @@
+from typing import List, Optional
+
+from fastapi import APIRouter, Depends, HTTPException, status
+from sqlalchemy.orm import Session
+
+from app.db.deps import get_db
+from app.models.todo import Todo
+from app.schemas.todo import TodoCreate, TodoResponse, TodoUpdate
+
+router = APIRouter()
+
+
+@router.post("/", response_model=TodoResponse, status_code=status.HTTP_201_CREATED)
+def create_todo(todo: TodoCreate, db: Session = Depends(get_db)):
+    """
+    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
+
+
+@router.get("/", response_model=List[TodoResponse])
+def read_todos(
+    skip: int = 0,
+    limit: int = 100,
+    completed: Optional[bool] = None,
+    db: Session = Depends(get_db),
+):
+    """
+    Retrieve todos with optional filtering by completion status.
+    """
+    query = db.query(Todo)
+
+    if completed is not None:
+        query = query.filter(Todo.completed == completed)
+
+    todos = query.offset(skip).limit(limit).all()
+    return todos
+
+
+@router.get("/{todo_id}", response_model=TodoResponse)
+def read_todo(todo_id: int, db: Session = Depends(get_db)):
+    """
+    Get a specific todo by ID.
+    """
+    todo = db.query(Todo).filter(Todo.id == todo_id).first()
+    if todo is None:
+        raise HTTPException(status_code=404, detail="Todo not found")
+    return todo
+
+
+@router.put("/{todo_id}", response_model=TodoResponse)
+def update_todo(todo_id: int, todo_update: TodoUpdate, db: Session = Depends(get_db)):
+    """
+    Update a todo item.
+    """
+    db_todo = db.query(Todo).filter(Todo.id == todo_id).first()
+    if db_todo is None:
+        raise HTTPException(status_code=404, detail="Todo not found")
+
+    update_data = todo_update.model_dump(exclude_unset=True)
+    for key, value in update_data.items():
+        setattr(db_todo, key, value)
+
+    db.add(db_todo)
+    db.commit()
+    db.refresh(db_todo)
+    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.
+    """
+    db_todo = db.query(Todo).filter(Todo.id == todo_id).first()
+    if db_todo is None:
+        raise HTTPException(status_code=404, detail="Todo not found")
+
+    db.delete(db_todo)
+    db.commit()
+    return None

app/core/config.py

@@ -0,0 +1,28 @@
+from pathlib import Path
+from typing import List
+
+from pydantic_settings import BaseSettings
+
+
+class Settings(BaseSettings):
+    # Project settings
+    PROJECT_NAME: str = "Simple TODO Application"
+    PROJECT_DESCRIPTION: str = "A simple TODO application built with FastAPI and SQLite"
+    PROJECT_VERSION: str = "0.1.0"
+
+    # API settings
+    API_PREFIX: str = "/api"
+    CORS_ORIGINS: List[str] = ["*"]
+
+    # Database settings
+    DB_DIR: Path = Path("/app") / "storage" / "db"
+
+    class Config:
+        env_file = ".env"
+        case_sensitive = True
+
+
+settings = Settings()
+
+# Ensure database directory exists
+settings.DB_DIR.mkdir(parents=True, exist_ok=True)

app/db/base.py

@@ -0,0 +1,2 @@
+# Import all models here for Alembic autogenerate to work
+from app.models.todo import Todo  # noqa

app/db/deps.py

@@ -0,0 +1,16 @@
+from typing import Generator
+
+from sqlalchemy.orm import Session
+
+from app.db.session import SessionLocal
+
+
+def get_db() -> Generator[Session, None, None]:
+    """
+    Dependency to get a database session.
+    """
+    db = SessionLocal()
+    try:
+        yield db
+    finally:
+        db.close()

app/db/session.py

@@ -0,0 +1,20 @@
+from sqlalchemy import create_engine
+from sqlalchemy.ext.declarative import declarative_base
+from sqlalchemy.orm import sessionmaker
+
+from app.core.config import settings
+
+# SQLite database URL
+SQLALCHEMY_DATABASE_URL = f"sqlite:///{settings.DB_DIR}/db.sqlite"
+
+# Create SQLAlchemy engine
+engine = create_engine(
+    SQLALCHEMY_DATABASE_URL,
+    connect_args={"check_same_thread": False},  # Only needed for SQLite
+)
+
+# Create session factory
+SessionLocal = sessionmaker(autocommit=False, autoflush=False, bind=engine)
+
+# Create base class for models
+Base = declarative_base()

app/models/todo.py

@@ -0,0 +1,15 @@
+from datetime import datetime
+from sqlalchemy import Boolean, Column, DateTime, Integer, String
+
+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, 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
+
+
+# Base schema for Todo
+class TodoBase(BaseModel):
+    title: str = Field(
+        ..., title="The title of the todo item", min_length=1, max_length=100
+    )
+    description: Optional[str] = Field(None, title="The description of the todo item")
+    completed: bool = Field(False, title="Whether the todo item is completed")
+
+
+# Schema for creating a new Todo
+class TodoCreate(TodoBase):
+    pass
+
+
+# Schema for updating a Todo
+class TodoUpdate(BaseModel):
+    title: Optional[str] = Field(
+        None, title="The title of the todo item", min_length=1, max_length=100
+    )
+    description: Optional[str] = Field(None, title="The description of the todo item")
+    completed: Optional[bool] = Field(None, title="Whether the todo item is completed")
+
+
+# Schema for reading Todo information
+class TodoResponse(TodoBase):
+    id: int
+    created_at: datetime
+    updated_at: datetime
+
+    class Config:
+        from_attributes = True

main.py

@@ -0,0 +1,29 @@
+from fastapi import FastAPI
+from fastapi.middleware.cors import CORSMiddleware
+
+from app.api.routes import todos, health
+from app.core.config import settings
+
+app = FastAPI(
+    title=settings.PROJECT_NAME,
+    description=settings.PROJECT_DESCRIPTION,
+    version=settings.PROJECT_VERSION,
+)
+
+# CORS Middleware
+app.add_middleware(
+    CORSMiddleware,
+    allow_origins=settings.CORS_ORIGINS,
+    allow_credentials=True,
+    allow_methods=["*"],
+    allow_headers=["*"],
+)
+
+# Include routers
+app.include_router(health.router, tags=["health"])
+app.include_router(todos.router, prefix="/api/todos", tags=["todos"])
+
+if __name__ == "__main__":
+    import uvicorn
+
+    uvicorn.run("main:app", host="0.0.0.0", port=8000, reload=True)

migrations/env.py

@@ -0,0 +1,81 @@
+from logging.config import fileConfig
+
+from alembic import context
+from sqlalchemy import engine_from_config, pool
+
+# Import models for Alembic to detect
+from app.db.session import Base
+from app.models.todo import Todo  # noqa: F401
+
+# 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:
+        # Configure using SQLite "batch mode" for migrations
+        is_sqlite = connection.dialect.name == "sqlite"
+        context.configure(
+            connection=connection,
+            target_metadata=target_metadata,
+            render_as_batch=is_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 +1,38 @@
+"""create todos table
+
+Revision ID: 001
+Revises:
+Create Date: 2023-07-15 00:00:00.000000
+
+"""
+
+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(), nullable=False),
+        sa.Column("updated_at", sa.DateTime(), nullable=False),
+        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==0.100.0
+uvicorn==0.22.0
+sqlalchemy==2.0.19
+pydantic==2.0.3
+pydantic-settings==2.0.3
+alembic==1.11.1
+python-dotenv==1.0.0
+ruff==0.0.277