Create simple todo app with FastAPI and SQLite

- Set up project structure
- Create database models with SQLAlchemy
- Add Alembic migrations
- Implement CRUD API endpoints
- Update README with documentation

generated with BackendIM... (backend.im)

README.md

@@ -1,3 +1,113 @@
-# FastAPI Application
+# SimpleTodoApp
 
-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 todo items
+- SQLite database with SQLAlchemy ORM
+- Alembic migrations for database versioning
+- RESTful API with proper HTTP methods and status codes
+- Health check endpoint
+- Documentation with Swagger UI and ReDoc
+
+## Project Structure
+
+```
+simpletodoapp/
+├── alembic.ini
+├── app/
+│   ├── __init__.py
+│   ├── api/
+│   │   ├── __init__.py
+│   │   └── todos.py
+│   ├── crud/
+│   │   ├── __init__.py
+│   │   └── todo.py
+│   ├── db/
+│   │   ├── __init__.py
+│   │   └── database.py
+│   ├── models/
+│   │   ├── __init__.py
+│   │   └── todo.py
+│   └── schemas/
+│       ├── __init__.py
+│       └── todo.py
+├── main.py
+├── migrations/
+│   ├── README
+│   ├── env.py
+│   ├── script.py.mako
+│   └── versions/
+│       └── a7d956f83192_create_todos_table.py
+└── requirements.txt
+```
+
+## Installation
+
+1. Clone the repository
+2. Install dependencies:
+
+```bash
+pip install -r requirements.txt
+```
+
+## Running the application
+
+```bash
+uvicorn main:app --reload
+```
+
+The API will be available at http://localhost:8000
+
+## API Documentation
+
+- Swagger UI: http://localhost:8000/docs
+- ReDoc: http://localhost:8000/redoc
+
+## API Endpoints
+
+- `GET /health` - Health check endpoint
+- `GET /api/todos` - Get all todos (with pagination)
+- `GET /api/todos/{todo_id}` - Get a specific todo
+- `POST /api/todos` - Create a new todo
+- `PUT /api/todos/{todo_id}` - Update a todo
+- `DELETE /api/todos/{todo_id}` - Delete a todo
+
+## Example Requests
+
+### Create a Todo
+
+```bash
+curl -X 'POST' \
+  'http://localhost:8000/api/todos/' \
+  -H 'Content-Type: application/json' \
+  -d '{
+  "title": "Buy groceries",
+  "description": "Milk, eggs, bread",
+  "completed": false
+}'
+```
+
+### Get All Todos
+
+```bash
+curl -X 'GET' 'http://localhost:8000/api/todos/'
+```
+
+### 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 +1,105 @@
+# A generic, single database configuration.
+
+[alembic]
+# path to migration scripts
+script_location = migrations
+
+# template used to generate migration file names; The default value is %%(rev)s_%%(slug)s
+# Uncomment the line below if you want the files to be prepended with date and time
+# see https://alembic.sqlalchemy.org/en/latest/tutorial.html#editing-the-ini-file
+# for all available tokens
+# file_template = %%(year)d_%%(month).2d_%%(day).2d_%%(hour).2d%%(minute).2d-%%(rev)s_%%(slug)s
+
+# sys.path path, will be prepended to sys.path if present.
+# defaults to the current working directory.
+prepend_sys_path = .
+
+# timezone to use when rendering the date within the migration file
+# as well as the filename.
+# If specified, requires the python-dateutil library that can be
+# installed by adding `alembic[tz]` to the pip requirements
+# 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.
+# The path separator used here should be the separator specified by "version_path_separator" below.
+# version_locations = %(here)s/bar:%(here)s/bat:migrations/versions
+
+# version path separator; As mentioned above, this is the character used to split
+# version_locations. The default within new alembic.ini files is "os", which uses os.pathsep.
+# If this key is omitted entirely, it falls back to the legacy behavior of splitting on spaces and/or commas.
+# Valid values for version_path_separator are:
+#
+# version_path_separator = :
+# version_path_separator = ;
+# version_path_separator = space
+version_path_separator = os  # Use os.pathsep. Default configuration used for new projects.
+
+# 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
+
+
+[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 REVISION_SCRIPT_FILENAME
+
+# 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/todos.py

@@ -0,0 +1,74 @@
+from fastapi import APIRouter, Depends, HTTPException, status
+from sqlalchemy.orm import Session
+from app.db.database import get_db
+from app.crud import todo as todo_crud
+from app.schemas.todo import Todo, TodoCreate, TodoUpdate
+from typing import List
+
+router = APIRouter(
+    prefix="/todos",
+    tags=["todos"],
+    responses={404: {"description": "Not found"}}
+)
+
+@router.get("/", response_model=List[Todo])
+def read_todos(
+    skip: int = 0, 
+    limit: int = 100, 
+    db: Session = Depends(get_db)
+):
+    """
+    Get all todos with pagination.
+    """
+    todos = todo_crud.get_todos(db, skip=skip, limit=limit)
+    return todos
+
+@router.get("/{todo_id}", response_model=Todo)
+def read_todo(
+    todo_id: int, 
+    db: Session = Depends(get_db)
+):
+    """
+    Get a todo by ID.
+    """
+    db_todo = todo_crud.get_todo_by_id(db, todo_id=todo_id)
+    if db_todo is None:
+        raise HTTPException(status_code=404, detail="Todo not found")
+    return db_todo
+
+@router.post("/", response_model=Todo, status_code=status.HTTP_201_CREATED)
+def create_todo(
+    todo: TodoCreate, 
+    db: Session = Depends(get_db)
+):
+    """
+    Create a new todo.
+    """
+    return todo_crud.create_todo(db=db, todo=todo)
+
+@router.put("/{todo_id}", response_model=Todo)
+def update_todo(
+    todo_id: int, 
+    todo: TodoUpdate, 
+    db: Session = Depends(get_db)
+):
+    """
+    Update a todo by ID.
+    """
+    db_todo = todo_crud.update_todo(db=db, todo_id=todo_id, todo=todo)
+    if db_todo is None:
+        raise HTTPException(status_code=404, detail="Todo not found")
+    return db_todo
+
+@router.delete("/{todo_id}", response_model=Todo)
+def delete_todo(
+    todo_id: int, 
+    db: Session = Depends(get_db)
+):
+    """
+    Delete a todo by ID.
+    """
+    db_todo = todo_crud.delete_todo(db=db, todo_id=todo_id)
+    if db_todo is None:
+        raise HTTPException(status_code=404, detail="Todo not found")
+    return db_todo

app/crud/__init__.py

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

app/crud/todo.py

@@ -0,0 +1,34 @@
+from sqlalchemy.orm import Session
+from app.models.todo import Todo
+from app.schemas.todo import TodoCreate, TodoUpdate
+from typing import List, Optional
+
+def get_todos(db: Session, skip: int = 0, limit: int = 100) -> List[Todo]:
+    return db.query(Todo).offset(skip).limit(limit).all()
+
+def get_todo_by_id(db: Session, todo_id: int) -> Optional[Todo]:
+    return db.query(Todo).filter(Todo.id == todo_id).first()
+
+def create_todo(db: Session, todo: TodoCreate) -> Todo:
+    db_todo = Todo(**todo.dict())
+    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_by_id(db, todo_id)
+    if db_todo:
+        update_data = todo.dict(exclude_unset=True)
+        for key, value in update_data.items():
+            setattr(db_todo, key, value)
+        db.commit()
+        db.refresh(db_todo)
+    return db_todo
+
+def delete_todo(db: Session, todo_id: int) -> Optional[Todo]:
+    db_todo = get_todo_by_id(db, todo_id)
+    if db_todo:
+        db.delete(db_todo)
+        db.commit()
+    return db_todo

app/db/database.py

@@ -0,0 +1,27 @@
+from pathlib import Path
+from sqlalchemy import create_engine
+from sqlalchemy.ext.declarative import declarative_base
+from sqlalchemy.orm import sessionmaker
+
+DB_DIR = Path("/app") / "storage" / "db"
+DB_DIR.mkdir(parents=True, exist_ok=True)
+
+SQLALCHEMY_DATABASE_URL = f"sqlite:///{DB_DIR}/db.sqlite"
+
+engine = create_engine(
+    SQLALCHEMY_DATABASE_URL,
+    connect_args={"check_same_thread": False}
+)
+SessionLocal = sessionmaker(autocommit=False, autoflush=False, bind=engine)
+
+Base = declarative_base()
+
+def get_db():
+    db = SessionLocal()
+    try:
+        yield db
+    finally:
+        db.close()
+
+def create_db_and_tables():
+    Base.metadata.create_all(bind=engine)

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.database 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 +1,25 @@
+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 Todo(TodoBase):
+    id: int
+    created_at: datetime
+    updated_at: Optional[datetime] = None
+
+    class Config:
+        orm_mode = True
+        from_attributes = True

main.py

@@ -0,0 +1,23 @@
+from fastapi import FastAPI
+from app.api.todos import router as todos_router
+from app.db.database import create_db_and_tables
+
+app = FastAPI(
+    title="SimpleTodoApp",
+    description="A simple todo application API",
+    version="0.1.0",
+)
+
+@app.on_event("startup")
+def on_startup():
+    create_db_and_tables()
+
+@app.get("/health", tags=["Health"])
+def health_check():
+    return {"status": "healthy"}
+
+app.include_router(todos_router, prefix="/api")
+
+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 for Alembic.

migrations/env.py

@@ -0,0 +1,78 @@
+from logging.config import fileConfig
+
+from sqlalchemy import engine_from_config
+from sqlalchemy import pool
+
+from alembic import context
+
+# 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.
+if config.config_file_name is not None:
+    fileConfig(config.config_file_name)
+
+# add your model's MetaData object here
+# for 'autogenerate' support
+from app.models import Todo
+from app.db.database import Base
+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() -> None:
+    """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() -> None:
+    """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:
+        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()

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() -> None:
+    ${upgrades if upgrades else "pass"}
+
+
+def downgrade() -> None:
+    ${downgrades if downgrades else "pass"}

migrations/versions/a7d956f83192_create_todos_table.py

@@ -0,0 +1,37 @@
+"""create todos table
+
+Revision ID: a7d956f83192
+Revises: 
+Create Date: 2025-05-14 12:00:00
+
+"""
+from alembic import op
+import sqlalchemy as sa
+
+
+# revision identifiers, used by Alembic.
+revision = 'a7d956f83192'
+down_revision = None
+branch_labels = None
+depends_on = None
+
+
+def upgrade() -> None:
+    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(), default=False),
+        sa.Column('created_at', sa.DateTime(timezone=True), server_default=sa.func.now()),
+        sa.Column('updated_at', sa.DateTime(timezone=True), onupdate=sa.func.now()),
+        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() -> None:
+    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 +1,7 @@
+fastapi==0.104.1
+uvicorn==0.23.2
+sqlalchemy==2.0.22
+alembic==1.12.1
+pydantic==2.4.2
+ruff==0.1.3
+python-dotenv==1.0.0