Create simple Todo app with FastAPI and SQLite

README.md

@@ -1,3 +1,128 @@
-# FastAPI Application
+# FastAPI Todo App
 
-This is a FastAPI application bootstrapped by BackendIM, the AI-powered backend generation platform.
+This is a simple Todo API application built with FastAPI and SQLite. The application allows you to create, read, update, and delete Todo items.
+
+## Features
+
+- Create new todo items
+- Retrieve all todo items
+- Retrieve a specific todo item by ID
+- Update todo items
+- Delete todo items
+- Health check endpoint
+
+## Tech Stack
+
+- **FastAPI**: High-performance web framework
+- **SQLAlchemy**: SQL toolkit and ORM
+- **Alembic**: Database migration tool
+- **SQLite**: Lightweight disk-based database
+- **Pydantic**: Data validation and settings management
+- **Uvicorn**: ASGI server
+
+## Project Structure
+
+```
+.
+├── alembic.ini                  # Alembic configuration
+├── main.py                      # FastAPI application entry point
+├── migrations/                  # Database migrations
+│   ├── env.py                   # Alembic environment
+│   ├── README                   # Alembic readme
+│   ├── script.py.mako           # Alembic script template
+│   └── versions/                # Migration scripts
+│       └── 001_create_todo_table.py  # Initial migration
+├── app/                         # Application package
+│   ├── api/                     # API endpoints
+│   │   ├── api.py               # API router
+│   │   ├── deps.py              # Dependencies
+│   │   └── endpoints/           # Endpoint modules
+│   │       └── todos.py         # Todo endpoints
+│   ├── core/                    # Core modules
+│   │   ├── config.py            # Configuration
+│   │   └── exceptions.py        # Custom exceptions
+│   ├── crud/                    # CRUD operations
+│   │   └── crud_todo.py         # Todo CRUD operations
+│   ├── db/                      # Database
+│   │   ├── base.py              # Base class
+│   │   ├── base_class.py        # Import all models
+│   │   └── session.py           # Database session
+│   ├── models/                  # SQLAlchemy models
+│   │   └── todo.py              # Todo model
+│   └── schemas/                 # Pydantic schemas
+│       └── todo.py              # Todo schemas
+└── requirements.txt             # Project dependencies
+```
+
+## Installation
+
+1. Clone the repository
+2. Install dependencies:
+
+```bash
+pip install -r requirements.txt
+```
+
+3. Run the application:
+
+```bash
+uvicorn main:app --reload
+```
+
+## API Documentation
+
+Once the application is running, you can access the API documentation at:
+
+- Swagger UI: http://localhost:8000/docs
+- ReDoc: http://localhost:8000/redoc
+
+## 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 todo
+- `DELETE /api/v1/todos/{todo_id}`: Delete a todo
+- `GET /health`: Health check endpoint
+
+## Example Usage
+
+### Create a Todo
+
+```bash
+curl -X POST "http://localhost:8000/api/v1/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/v1/todos/"
+```
+
+### Get a Specific Todo
+
+```bash
+curl -X GET "http://localhost:8000/api/v1/todos/1"
+```
+
+### Update a Todo
+
+```bash
+curl -X PUT "http://localhost:8000/api/v1/todos/1" \
+     -H "Content-Type: application/json" \
+     -d '{"title": "Buy groceries", "description": "Milk, eggs, bread, cheese", "completed": true}'
+```
+
+### Delete a Todo
+
+```bash
+curl -X DELETE "http://localhost:8000/api/v1/todos/1"
+```
+
+### Health Check
+
+```bash
+curl -X GET "http://localhost:8000/health"
+```

alembic.ini

@@ -0,0 +1,103 @@
+# 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
+
+# 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 example
+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/api.py

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

app/api/deps.py

@@ -0,0 +1,10 @@
+from typing import Generator
+from app.db.session import SessionLocal
+
+
+def get_db() -> Generator:
+    db = SessionLocal()
+    try:
+        yield db
+    finally:
+        db.close()

app/api/endpoints/todos.py

@@ -0,0 +1,91 @@
+from typing import List, Any
+from fastapi import APIRouter, Depends, status, Response
+from sqlalchemy.orm import Session
+
+from app import crud
+from app.api.deps import get_db
+from app.schemas.todo import Todo, TodoCreate, TodoUpdate
+from app.core.exceptions import TodoNotFoundException, BadRequestException
+
+router = APIRouter()
+
+
+@router.get("/", response_model=List[Todo])
+def read_todos(
+    skip: int = 0,
+    limit: int = 100,
+    db: Session = Depends(get_db)
+) -> Any:
+    """
+    Retrieve 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(
+    *,
+    todo_in: TodoCreate,
+    db: Session = Depends(get_db)
+) -> Any:
+    """
+    Create new todo.
+    """
+    todo = crud.create_todo(db=db, todo=todo_in)
+    return todo
+
+
+@router.get("/{todo_id}", response_model=Todo)
+def read_todo(
+    *,
+    todo_id: int,
+    db: Session = Depends(get_db)
+) -> Any:
+    """
+    Get todo by ID.
+    """
+    todo = crud.get_todo(db=db, todo_id=todo_id)
+    if not todo:
+        raise TodoNotFoundException(todo_id=todo_id)
+    return todo
+
+
+@router.put("/{todo_id}", response_model=Todo)
+def update_todo(
+    *,
+    todo_id: int,
+    todo_in: TodoUpdate,
+    db: Session = Depends(get_db)
+) -> Any:
+    """
+    Update a todo.
+    """
+    todo = crud.get_todo(db=db, todo_id=todo_id)
+    if not todo:
+        raise TodoNotFoundException(todo_id=todo_id)
+    
+    # Validate that at least one field is provided for update
+    update_data = todo_in.model_dump(exclude_unset=True)
+    if not update_data:
+        raise BadRequestException(detail="No fields provided for update")
+        
+    todo = crud.update_todo(db=db, todo_id=todo_id, todo=todo_in)
+    return 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)
+) -> Any:
+    """
+    Delete a todo.
+    """
+    todo = crud.get_todo(db=db, todo_id=todo_id)
+    if not todo:
+        raise TodoNotFoundException(todo_id=todo_id)
+        
+    crud.delete_todo(db=db, todo_id=todo_id)
+    return Response(status_code=status.HTTP_204_NO_CONTENT)

app/core/config.py

@@ -0,0 +1,21 @@
+from typing import List
+from pydantic_settings import BaseSettings
+from pathlib import Path
+
+
+class Settings(BaseSettings):
+    API_V1_STR: str = "/api/v1"
+    PROJECT_NAME: str = "Todo App"
+    ALLOWED_ORIGINS: List[str] = ["*"]
+    
+    # Database settings
+    DB_DIR = Path("/app") / "storage" / "db"
+    DB_DIR.mkdir(parents=True, exist_ok=True)
+    DATABASE_URL: str = f"sqlite:///{DB_DIR}/db.sqlite"
+
+    class Config:
+        env_file = ".env"
+        case_sensitive = True
+
+
+settings = Settings()

app/core/exceptions.py

@@ -0,0 +1,17 @@
+from fastapi import HTTPException, status
+
+
+class TodoNotFoundException(HTTPException):
+    def __init__(self, todo_id: int):
+        super().__init__(
+            status_code=status.HTTP_404_NOT_FOUND,
+            detail=f"Todo with ID {todo_id} not found"
+        )
+
+
+class BadRequestException(HTTPException):
+    def __init__(self, detail: str = "Bad request"):
+        super().__init__(
+            status_code=status.HTTP_400_BAD_REQUEST,
+            detail=detail
+        )

app/crud/__init__.py

@@ -0,0 +1 @@
+from app.crud.crud_todo import get_todo, get_todos, create_todo, update_todo, delete_todo  # noqa

app/crud/crud_todo.py

@@ -0,0 +1,50 @@
+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]:
+    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.model_dump(exclude_unset=True)
+    for field, value in update_data.items():
+        setattr(db_todo, field, value)
+    
+    db.add(db_todo)
+    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/db/base.py

@@ -0,0 +1,3 @@
+from sqlalchemy.ext.declarative import declarative_base
+
+Base = declarative_base()

app/db/base_class.py

@@ -0,0 +1,2 @@
+from app.db.base import Base  # noqa
+from app.models.todo import Todo  # noqa

app/db/session.py

@@ -0,0 +1,25 @@
+from sqlalchemy import create_engine
+from sqlalchemy.orm import sessionmaker
+from pathlib import Path
+
+
+# Create db 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)
+
+# 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  # noqa

app/models/todo.py

@@ -0,0 +1,14 @@
+from sqlalchemy import Column, Integer, String, Boolean, DateTime
+from sqlalchemy.sql import func
+from app.db.base 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), server_default=func.now(), onupdate=func.now())

app/schemas/__init__.py

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

app/schemas/todo.py

@@ -0,0 +1,42 @@
+from datetime import datetime
+from typing import Optional
+from pydantic import BaseModel, Field, validator
+
+
+# Shared properties
+class TodoBase(BaseModel):
+    title: str
+    description: Optional[str] = None
+    completed: bool = False
+
+
+# Properties to receive via API on creation
+class TodoCreate(TodoBase):
+    title: str = Field(..., min_length=1, max_length=100)
+    
+    @validator("title")
+    def title_must_not_be_empty(cls, v):
+        if not v.strip():
+            raise ValueError("Title must not be empty or whitespace only")
+        return v
+
+
+# Properties to receive via API on update
+class TodoUpdate(TodoBase):
+    title: Optional[str] = None
+    completed: Optional[bool] = None
+
+
+# Properties shared by models stored in DB
+class TodoInDBBase(TodoBase):
+    id: int
+    created_at: datetime
+    updated_at: datetime
+
+    class Config:
+        from_attributes = True
+
+
+# Properties to return to client
+class Todo(TodoInDBBase):
+    pass

main.py

@@ -0,0 +1,40 @@
+import uvicorn
+from fastapi import FastAPI
+from fastapi.middleware.cors import CORSMiddleware
+
+from app.api.api import api_router
+from app.core.config import settings
+from app.db.session import engine
+from app.db.base import Base
+
+# Create tables if they don't exist
+Base.metadata.create_all(bind=engine)
+
+app = FastAPI(
+    title=settings.PROJECT_NAME,
+    description="A simple Todo app API",
+    version="0.1.0",
+    openapi_url=f"{settings.API_V1_STR}/openapi.json",
+    docs_url="/docs",
+    redoc_url="/redoc",
+)
+
+# Set CORS middleware
+app.add_middleware(
+    CORSMiddleware,
+    allow_origins=settings.ALLOWED_ORIGINS,
+    allow_credentials=True,
+    allow_methods=["*"],
+    allow_headers=["*"],
+)
+
+# Include API router
+app.include_router(api_router, prefix=settings.API_V1_STR)
+
+# Add health check endpoint
+@app.get("/health", tags=["Health"])
+async def health():
+    return {"status": "ok"}
+
+if __name__ == "__main__":
+    uvicorn.run("main:app", host="0.0.0.0", port=8000, reload=True)

migrations/README

@@ -0,0 +1 @@
+Generic single-database configuration with Alembic.

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
+
+# Import models here to support 'autogenerate'
+from app.db.base import Base  # noqa
+from app.models.todo import Todo  # noqa
+
+# 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)
+
+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:
+        is_sqlite = connection.dialect.name == 'sqlite'
+        context.configure(
+            connection=connection,
+            target_metadata=target_metadata,
+            render_as_batch=is_sqlite,
+            compare_type=True,
+        )
+
+        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/001_create_todo_table.py

@@ -0,0 +1,38 @@
+"""Create Todo table
+
+Revision ID: 001
+Revises: 
+Create Date: 2023-11-10
+
+"""
+from alembic import op
+import sqlalchemy as sa
+from sqlalchemy.sql import func
+
+
+# revision identifiers, used by Alembic.
+revision = '001'
+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(), nullable=False, default=False),
+        sa.Column('created_at', sa.DateTime(timezone=True), server_default=func.now(), nullable=False),
+        sa.Column('updated_at', sa.DateTime(timezone=True), server_default=func.now(), 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() -> 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 +1,8 @@
+fastapi>=0.104.0
+uvicorn>=0.23.2
+sqlalchemy>=2.0.0
+alembic>=1.12.0
+pydantic>=2.4.2
+pydantic-settings>=2.0.3
+python-dotenv>=1.0.0
+ruff>=0.1.5