Create a simple Todo API with FastAPI and SQLite

README.md

@@ -1,3 +1,135 @@
-# FastAPI Application
+# Todo API
 
-This is a FastAPI application bootstrapped by BackendIM, the AI-powered backend generation platform.
+A simple Todo API built with FastAPI and SQLite.
+
+## Features
+
+- Create, read, update, and delete todo items
+- Filter todos by completion status
+- Pagination support
+- SQLite database with SQLAlchemy ORM
+- Database migrations with Alembic
+- API documentation with Swagger UI and ReDoc
+- Health check endpoint
+
+## Project Structure
+
+```
+todoapp/
+├── alembic.ini                  # Alembic configuration
+├── app/                         # Application package
+│   ├── api/                     # API endpoints
+│   │   ├── endpoints/           # API endpoint modules
+│   │   │   ├── health.py        # Health check endpoint
+│   │   │   └── todos.py         # Todo endpoints
+│   │   └── api.py               # API router
+│   ├── core/                    # Core modules
+│   │   └── config.py            # Application configuration
+│   ├── crud/                    # CRUD operations
+│   │   └── todo.py              # Todo CRUD operations
+│   ├── db/                      # Database modules
+│   │   └── session.py           # Database session setup
+│   ├── models/                  # SQLAlchemy models
+│   │   └── todo.py              # Todo model
+│   └── schemas/                 # Pydantic schemas
+│       └── todo.py              # Todo schemas
+├── main.py                      # Application entry point
+├── migrations/                  # Alembic migrations
+│   ├── versions/                # Migration versions
+│   └── env.py                   # Alembic environment
+└── requirements.txt             # Python dependencies
+```
+
+## Getting Started
+
+### Prerequisites
+
+- Python 3.8 or higher
+
+### Installation
+
+1. Clone the repository:
+   ```bash
+   git clone <repository-url>
+   cd todoapp
+   ```
+
+2. Install the required packages:
+   ```bash
+   pip install -r requirements.txt
+   ```
+
+3. Run the database migrations:
+   ```bash
+   alembic upgrade head
+   ```
+
+4. Start the application:
+   ```bash
+   uvicorn main:app --reload
+   ```
+
+5. The API will be available at http://localhost:8000
+   - API documentation: http://localhost:8000/docs
+   - Alternative documentation: http://localhost:8000/redoc
+
+## API Endpoints
+
+### Health Check
+
+- `GET /api/v1/health`: Check the API status
+
+### Todo Endpoints
+
+- `GET /api/v1/todos`: List all todos (with optional filtering and pagination)
+  - Query parameters:
+    - `skip`: Number of records to skip (default: 0)
+    - `limit`: Maximum number of records to return (default: 100)
+    - `completed`: Filter by completion status (optional)
+
+- `POST /api/v1/todos`: Create a new todo
+  - Request body:
+    ```json
+    {
+      "title": "string",
+      "description": "string (optional)",
+      "completed": false
+    }
+    ```
+
+- `GET /api/v1/todos/{todo_id}`: Get a specific todo by ID
+
+- `PATCH /api/v1/todos/{todo_id}`: Update a specific todo
+  - Request body (all fields optional):
+    ```json
+    {
+      "title": "string",
+      "description": "string",
+      "completed": true
+    }
+    ```
+
+- `DELETE /api/v1/todos/{todo_id}`: Delete a specific todo
+
+## Development
+
+### Database Migrations
+
+To create a new migration after modifying the models:
+
+```bash
+alembic revision --autogenerate -m "description of changes"
+alembic upgrade head
+```
+
+### Running Tests
+
+Tests can be run using pytest:
+
+```bash
+pytest
+```
+
+## License
+
+This project is licensed under the MIT License.

alembic.ini

@@ -0,0 +1,106 @@
+# 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
+
+# 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 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/__init__.py

@@ -0,0 +1 @@
+# app package initialization

app/api/api.py

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

app/api/endpoints/health.py

@@ -0,0 +1,15 @@
+from fastapi import APIRouter, Depends
+from sqlalchemy.orm import Session
+
+from app.db.session import get_db
+
+router = APIRouter()
+
+
+@router.get("", summary="Health check endpoint")
+def health_check(db: Session = Depends(get_db)):
+    """
+    Health check endpoint that verifies the application is running
+    and database connection is working
+    """
+    return {"status": "ok", "message": "Todo API is running"}

app/api/endpoints/todos.py

@@ -0,0 +1,120 @@
+from typing import List, Optional
+
+from fastapi import APIRouter, Depends, HTTPException, status
+from sqlalchemy.orm import Session
+
+from app.crud import todo as todo_crud
+from app.db.session import get_db
+from app.schemas.todo import TodoCreate, TodoResponse, TodoUpdate
+
+router = APIRouter()
+
+
+@router.get("", response_model=List[TodoResponse])
+def get_todos(
+    skip: int = 0,
+    limit: int = 100,
+    completed: Optional[bool] = None,
+    db: Session = Depends(get_db),
+):
+    """
+    Retrieve a list of todo items with optional filtering and pagination.
+    
+    Args:
+        skip: Number of records to skip (for pagination)
+        limit: Maximum number of records to return
+        completed: Filter by completion status if provided
+        db: Database session
+    
+    Returns:
+        List of todo items
+    """
+    todos = todo_crud.get_todos(
+        db=db, skip=skip, limit=limit, completed=completed
+    )
+    return todos
+
+
+@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.
+    
+    Args:
+        todo: Todo data for creation
+        db: Database session
+    
+    Returns:
+        The created todo item
+    """
+    return todo_crud.create_todo(db=db, todo=todo)
+
+
+@router.get("/{todo_id}", response_model=TodoResponse)
+def get_todo(todo_id: int, db: Session = Depends(get_db)):
+    """
+    Retrieve a specific todo item by ID.
+    
+    Args:
+        todo_id: ID of the todo to retrieve
+        db: Database session
+    
+    Returns:
+        The requested todo item
+    
+    Raises:
+        HTTPException: If todo item is not found
+    """
+    db_todo = todo_crud.get_todo(db=db, todo_id=todo_id)
+    if db_todo is None:
+        raise HTTPException(
+            status_code=status.HTTP_404_NOT_FOUND,
+            detail=f"Todo with ID {todo_id} not found",
+        )
+    return db_todo
+
+
+@router.patch("/{todo_id}", response_model=TodoResponse)
+def update_todo(todo_id: int, todo_update: TodoUpdate, db: Session = Depends(get_db)):
+    """
+    Update a specific todo item.
+    
+    Args:
+        todo_id: ID of the todo to update
+        todo_update: Todo data for update
+        db: Database session
+    
+    Returns:
+        The updated todo item
+    
+    Raises:
+        HTTPException: If todo item is not found
+    """
+    db_todo = todo_crud.update_todo(db=db, todo_id=todo_id, todo_update=todo_update)
+    if db_todo is None:
+        raise HTTPException(
+            status_code=status.HTTP_404_NOT_FOUND,
+            detail=f"Todo with ID {todo_id} not found",
+        )
+    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 specific todo item.
+    
+    Args:
+        todo_id: ID of the todo to delete
+        db: Database session
+    
+    Raises:
+        HTTPException: If todo item is not found
+    """
+    success = todo_crud.delete_todo(db=db, todo_id=todo_id)
+    if not success:
+        raise HTTPException(
+            status_code=status.HTTP_404_NOT_FOUND,
+            detail=f"Todo with ID {todo_id} not found",
+        )
+    return None

app/core/config.py

@@ -0,0 +1,23 @@
+from typing import List, Union
+
+from pydantic import AnyHttpUrl, field_validator
+from pydantic_settings import BaseSettings
+
+
+class Settings(BaseSettings):
+    API_V1_STR: str = "/api/v1"
+    PROJECT_NAME: str = "Todo API"
+    
+    # CORS settings
+    BACKEND_CORS_ORIGINS: List[AnyHttpUrl] = []
+
+    @field_validator("BACKEND_CORS_ORIGINS", mode="before")
+    def assemble_cors_origins(cls, v: Union[str, List[str]]) -> Union[List[str], str]:
+        if isinstance(v, str) and not v.startswith("["):
+            return [i.strip() for i in v.split(",")]
+        elif isinstance(v, (list, str)):
+            return v
+        raise ValueError(v)
+
+
+settings = Settings()

app/crud/__init__.py

@@ -0,0 +1 @@
+# Import CRUD operations for direct imports from crud module

app/crud/todo.py

@@ -0,0 +1,112 @@
+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 Todo item by its ID.
+    
+    Args:
+        db: Database session
+        todo_id: ID of the Todo item to retrieve
+    
+    Returns:
+        Todo item if found, None otherwise
+    """
+    return db.query(Todo).filter(Todo.id == todo_id).first()
+
+
+def get_todos(
+    db: Session, skip: int = 0, limit: int = 100, completed: Optional[bool] = None
+) -> List[Todo]:
+    """
+    Get a list of Todo items with optional filtering and pagination.
+    
+    Args:
+        db: Database session
+        skip: Number of items to skip (offset)
+        limit: Maximum number of items to return
+        completed: Filter by completion status if provided
+    
+    Returns:
+        List of Todo items
+    """
+    query = db.query(Todo)
+    
+    if completed is not None:
+        query = query.filter(Todo.completed == completed)
+    
+    return query.offset(skip).limit(limit).all()
+
+
+def create_todo(db: Session, todo: TodoCreate) -> Todo:
+    """
+    Create a new Todo item.
+    
+    Args:
+        db: Database session
+        todo: Todo data for creation
+    
+    Returns:
+        The created 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
+
+
+def update_todo(db: Session, todo_id: int, todo_update: TodoUpdate) -> Optional[Todo]:
+    """
+    Update an existing Todo item.
+    
+    Args:
+        db: Database session
+        todo_id: ID of the Todo item to update
+        todo_update: Todo data for update
+    
+    Returns:
+        Updated Todo item if found, None otherwise
+    """
+    db_todo = get_todo(db, todo_id)
+    if not db_todo:
+        return None
+    
+    # Update model with provided values, skipping None values
+    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
+
+
+def delete_todo(db: Session, todo_id: int) -> bool:
+    """
+    Delete a Todo item.
+    
+    Args:
+        db: Database session
+        todo_id: ID of the Todo item to delete
+    
+    Returns:
+        True if deleted successfully, False if item not found
+    """
+    db_todo = get_todo(db, todo_id)
+    if not db_todo:
+        return False
+    
+    db.delete(db_todo)
+    db.commit()
+    return True

app/db/session.py

@@ -0,0 +1,31 @@
+from pathlib import Path
+from sqlalchemy import create_engine
+from sqlalchemy.ext.declarative import declarative_base
+from sqlalchemy.orm import sessionmaker
+
+# Create the database directory if it doesn't exist
+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():
+    """
+    Dependency function to get a database session.
+    Yields the session and ensures it is closed after use.
+    """
+    db = SessionLocal()
+    try:
+        yield db
+    finally:
+        db.close()

app/models/__init__.py

@@ -0,0 +1,3 @@
+from app.models.todo import Todo  # noqa
+
+# Import all models here so that Alembic can discover them

app/models/todo.py

@@ -0,0 +1,18 @@
+from sqlalchemy import Boolean, Column, Integer, String, Text
+from sqlalchemy.sql import func
+from sqlalchemy.types import DateTime
+
+from app.db.session import Base
+
+
+class Todo(Base):
+    """SQLAlchemy model for Todo items."""
+    
+    __tablename__ = "todos"
+
+    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(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 TodoCreate, TodoResponse, TodoUpdate  # noqa

app/schemas/todo.py

@@ -0,0 +1,38 @@
+from datetime import datetime
+from typing import Optional
+
+from pydantic import BaseModel, Field
+
+
+class TodoBase(BaseModel):
+    """Base schema for Todo items with common attributes."""
+    
+    title: str = Field(..., min_length=1, max_length=255, description="Title of the todo item")
+    description: Optional[str] = Field(None, description="Detailed description of the todo item")
+    completed: bool = Field(False, description="Whether the todo item is completed")
+
+
+class TodoCreate(TodoBase):
+    """Schema for creating a new Todo item."""
+    pass
+
+
+class TodoUpdate(BaseModel):
+    """Schema for updating an existing Todo item. All fields are optional."""
+    
+    title: Optional[str] = Field(None, min_length=1, max_length=255, description="Title of the todo item")
+    description: Optional[str] = Field(None, description="Detailed description of the todo item")
+    completed: Optional[bool] = Field(None, description="Whether the todo item is completed")
+
+
+class TodoResponse(TodoBase):
+    """Schema for Todo item responses, including database fields."""
+    
+    id: int
+    created_at: datetime
+    updated_at: Optional[datetime] = None
+
+    class Config:
+        """Configure Pydantic model to work with SQLAlchemy models."""
+        
+        from_attributes = True

main.py

@@ -0,0 +1,31 @@
+from fastapi import FastAPI
+from fastapi.middleware.cors import CORSMiddleware
+
+from app.api.api import api_router
+from app.core.config import settings
+
+app = FastAPI(
+    title=settings.PROJECT_NAME,
+    description="Simple Todo API using FastAPI and SQLite",
+    version="1.0.0",
+    openapi_url=f"{settings.API_V1_STR}/openapi.json",
+    docs_url="/docs",
+    redoc_url="/redoc",
+)
+
+# Set all CORS enabled origins
+if settings.BACKEND_CORS_ORIGINS:
+    app.add_middleware(
+        CORSMiddleware,
+        allow_origins=[str(origin) for origin in settings.BACKEND_CORS_ORIGINS],
+        allow_credentials=True,
+        allow_methods=["*"],
+        allow_headers=["*"],
+    )
+
+app.include_router(api_router, prefix=settings.API_V1_STR)
+
+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 SQLite.

migrations/env.py

@@ -0,0 +1,82 @@
+from logging.config import fileConfig
+
+from sqlalchemy import engine_from_config
+from sqlalchemy import pool
+
+from alembic import context
+from app.db.session import Base
+from app.models import Todo  # noqa: F401 - Import to register model with Base.metadata
+
+# 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
+# from myapp import mymodel
+# target_metadata = mymodel.Base.metadata
+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/b1a0f9d3e6a2_create_todos_table.py

@@ -0,0 +1,38 @@
+"""create todos table
+
+Revision ID: b1a0f9d3e6a2
+Revises: 
+Create Date: 2023-10-24 12:00:00.000000
+
+"""
+from alembic import op
+import sqlalchemy as sa
+from sqlalchemy.sql import func
+
+
+# revision identifiers, used by Alembic.
+revision = 'b1a0f9d3e6a2'
+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(255), nullable=False),
+        sa.Column('description', sa.Text(), nullable=True),
+        sa.Column('completed', sa.Boolean(), default=False),
+        sa.Column('created_at', sa.DateTime(timezone=True), server_default=func.now()),
+        sa.Column('updated_at', sa.DateTime(timezone=True), onupdate=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():
+    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>=0.103.1
+uvicorn>=0.23.2
+sqlalchemy>=2.0.0
+alembic>=1.12.0
+pydantic>=2.4.0
+pydantic-settings>=2.0.3
+python-dotenv>=1.0.0
+ruff>=0.0.290