Create simple Todo API with FastAPI and SQLite

README.md

@@ -1,3 +1,78 @@
-# FastAPI Application
+# Simple Todo App
 
-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
+- Health check endpoint to verify API and database status
+- API documentation with Swagger UI and ReDoc
+
+## Requirements
+
+- Python 3.8+
+- FastAPI
+- SQLAlchemy
+- Alembic (for database migrations)
+- Uvicorn (ASGI server)
+- SQLite
+
+## Project Structure
+
+```
+.
+├── alembic.ini             # Alembic configuration file
+├── app/                    # Application package
+│   ├── api/                # API endpoints
+│   │   ├── deps.py         # API dependencies
+│   │   ├── health.py       # Health check endpoint
+│   │   └── v1/             # API version 1
+│   │       ├── api.py      # API router
+│   │       └── endpoints/  # API endpoints by resource
+│   │           └── todos.py # Todo CRUD operations
+│   ├── core/               # Core modules
+│   │   └── config.py       # Application configuration
+│   ├── db/                 # Database related code
+│   │   └── session.py      # Database session
+│   ├── models/             # SQLAlchemy models
+│   │   └── todo.py         # Todo model
+│   ├── schemas/            # Pydantic schemas
+│   │   └── todo.py         # Todo schemas
+│   └── storage/            # Storage directory
+│       └── db/             # Database files
+├── main.py                 # Application entry point
+├── migrations/             # Alembic migrations
+│   ├── env.py              # Migration environment
+│   ├── script.py.mako      # Migration script template
+│   └── versions/           # Migration versions
+│       └── initial_migration.py # Initial migration
+├── pyproject.toml          # Project configuration for tools
+└── requirements.txt        # Python dependencies
+```
+
+## Quick Start
+
+1. Clone the repository
+2. Create a virtual environment: `python -m venv venv`
+3. Activate the virtual environment: `source venv/bin/activate` (Linux/Mac) or `venv\Scripts\activate` (Windows)
+4. Install dependencies: `pip install -r requirements.txt`
+5. Run the application: `uvicorn main:app --reload`
+
+The API will be available at http://localhost:8000
+
+## API Documentation
+
+Once the application is running, you can access:
+- Swagger UI: http://localhost:8000/docs
+- ReDoc: http://localhost:8000/redoc
+
+## API Endpoints
+
+- **GET /api/v1/todos**: List all todos
+- **POST /api/v1/todos**: Create a new todo
+- **GET /api/v1/todos/{todo_id}**: Get a specific todo
+- **PATCH /api/v1/todos/{todo_id}**: Update a todo
+- **DELETE /api/v1/todos/{todo_id}**: Delete a todo
+- **GET /health**: Health check endpoint
+- **GET /**: Root endpoint with welcome message

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
+
+# 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/deps.py

@@ -0,0 +1,4 @@
+from app.db.session import get_db
+
+# Re-export the get_db dependency
+db_dependency = get_db

app/api/health.py

@@ -0,0 +1,26 @@
+from fastapi import APIRouter, Depends
+from sqlalchemy import text
+from sqlalchemy.orm import Session
+
+from app.api.deps import db_dependency
+
+router = APIRouter()
+
+
+@router.get("/health")
+def health_check(db: Session = Depends(db_dependency)):
+    """
+    Health check endpoint to verify the API and database are working properly.
+    """
+    try:
+        # Test database connection
+        db.execute(text("SELECT 1"))
+        db_status = "healthy"
+    except Exception:
+        db_status = "unhealthy"
+
+    return {
+        "status": "ok" if db_status == "healthy" else "error",
+        "api": "healthy",
+        "database": db_status
+    }

app/api/v1/api.py

@@ -0,0 +1,6 @@
+from fastapi import APIRouter
+
+from app.api.v1.endpoints import todos
+
+api_router = APIRouter()
+api_router.include_router(todos.router, prefix="/todos", tags=["todos"])

app/api/v1/endpoints/todos.py

@@ -0,0 +1,105 @@
+from typing import List, Optional
+
+from fastapi import APIRouter, Depends, HTTPException, status
+from sqlalchemy.orm import Session
+
+from app.api.deps import db_dependency
+from app.models.todo import Todo
+from app.schemas.todo import Todo as TodoSchema
+from app.schemas.todo import TodoCreate, TodoUpdate
+
+router = APIRouter()
+
+
+@router.get("/", response_model=List[TodoSchema])
+def read_todos(
+    skip: int = 0,
+    limit: int = 100,
+    completed: Optional[bool] = None,
+    db: Session = Depends(db_dependency),
+):
+    """
+    Retrieve todos.
+    - **skip**: Number of records to skip for pagination
+    - **limit**: Maximum number of records to return
+    - **completed**: Filter by completion status (optional)
+    """
+    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.post("/", response_model=TodoSchema, status_code=status.HTTP_201_CREATED)
+def create_todo(
+    todo: TodoCreate,
+    db: Session = Depends(db_dependency),
+):
+    """
+    Create new todo.
+    """
+    db_todo = Todo(**todo.model_dump())
+    db.add(db_todo)
+    db.commit()
+    db.refresh(db_todo)
+    return db_todo
+
+
+@router.get("/{todo_id}", response_model=TodoSchema)
+def read_todo(
+    todo_id: int,
+    db: Session = Depends(db_dependency),
+):
+    """
+    Get a specific todo by ID.
+    """
+    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")
+    return db_todo
+
+
+@router.patch("/{todo_id}", response_model=TodoSchema)
+def update_todo(
+    todo_id: int,
+    todo: TodoUpdate,
+    db: Session = Depends(db_dependency),
+):
+    """
+    Update a todo.
+    """
+    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.model_dump(exclude_unset=True)
+    for field, value in update_data.items():
+        setattr(db_todo, field, value)
+    
+    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(db_dependency),
+):
+    """
+    Delete a todo.
+    """
+    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 +1,15 @@
+from pathlib import Path
+
+# Project directories
+BASE_DIR = Path("/projects/simpletodoapp-3hunrv")
+APP_DIR = BASE_DIR / "app"
+
+# Database
+DB_DIR = Path("/app") / "storage" / "db"
+DB_DIR.mkdir(parents=True, exist_ok=True)
+
+SQLALCHEMY_DATABASE_URL = f"sqlite:///{DB_DIR}/db.sqlite"
+
+# API settings
+API_V1_STR = "/api/v1"
+PROJECT_NAME = "Simple Todo App"

app/db/session.py

@@ -0,0 +1,23 @@
+from sqlalchemy import create_engine
+from sqlalchemy.ext.declarative import declarative_base
+from sqlalchemy.orm import sessionmaker
+
+from app.core.config import SQLALCHEMY_DATABASE_URL
+
+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 for getting DB session"""
+    db = SessionLocal()
+    try:
+        yield db
+    finally:
+        db.close()

app/models/todo.py

@@ -0,0 +1,20 @@
+from sqlalchemy import Boolean, Column, DateTime, Integer, String, Text
+from sqlalchemy.sql import func
+
+from app.db.session import Base
+
+
+class Todo(Base):
+    """Todo model"""
+    __tablename__ = "todos"
+
+    id = Column(Integer, primary_key=True, index=True)
+    title = Column(String(100), nullable=False)
+    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),
+        server_default=func.now(),
+        onupdate=func.now()
+    )

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 Todo schema with common attributes"""
+    title: str = Field(..., min_length=1, max_length=100)
+    description: Optional[str] = None
+    completed: bool = False
+
+
+class TodoCreate(TodoBase):
+    """Schema for creating a new Todo"""
+    pass
+
+
+class TodoUpdate(BaseModel):
+    """Schema for updating a Todo - all fields are optional"""
+    title: Optional[str] = Field(None, min_length=1, max_length=100)
+    description: Optional[str] = None
+    completed: Optional[bool] = None
+
+
+class TodoInDB(TodoBase):
+    """Schema for Todo as stored in the database"""
+    id: int
+    created_at: datetime
+    updated_at: datetime
+
+    class Config:
+        from_attributes = True
+
+
+class Todo(TodoInDB):
+    """Schema for Todo responses"""
+    pass

main.py

@@ -0,0 +1,41 @@
+from fastapi import FastAPI
+from fastapi.middleware.cors import CORSMiddleware
+
+from app.api.health import router as health_router
+from app.api.v1.api import api_router
+from app.core.config import API_V1_STR, PROJECT_NAME
+from app.db.session import Base, engine
+
+# Create tables if they don't exist
+Base.metadata.create_all(bind=engine)
+
+app = FastAPI(
+    title=PROJECT_NAME,
+    description="A simple Todo API built with FastAPI and SQLite",
+    version="0.1.0",
+    docs_url="/docs",
+    redoc_url="/redoc",
+)
+
+# Set all CORS enabled origins
+app.add_middleware(
+    CORSMiddleware,
+    allow_origins=["*"],  # Allow all origins in development
+    allow_credentials=True,
+    allow_methods=["*"],  # Allow all methods
+    allow_headers=["*"],  # Allow all headers
+)
+
+# Include routers
+app.include_router(api_router, prefix=API_V1_STR)
+app.include_router(health_router)
+
+
+@app.get("/")
+def root():
+    """
+    Root endpoint that redirects to the API documentation.
+    """
+    return {
+        "message": "Welcome to the Todo API! Visit /docs for the API documentation."
+    }

migrations/env.py

@@ -0,0 +1,83 @@
+from logging.config import fileConfig
+
+from alembic import context
+from sqlalchemy import engine_from_config, pool
+
+from app.db.session import Base
+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)
+
+# 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() -> 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"},
+        render_as_batch=True,
+    )
+
+    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,
+        )
+
+        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/initial_migration.py

@@ -0,0 +1,47 @@
+"""Initial migration
+
+Revision ID: initial
+Revises: 
+Create Date: 2023-10-31
+
+"""
+import sqlalchemy as sa
+from alembic import op
+
+# revision identifiers, used by Alembic.
+revision = 'initial'
+down_revision = None
+branch_labels = None
+depends_on = None
+
+
+def upgrade() -> None:
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.create_table('todos',
+        sa.Column('id', sa.Integer(), nullable=False),
+        sa.Column('title', sa.String(length=100), nullable=False),
+        sa.Column('description', sa.Text(), nullable=True),
+        sa.Column('completed', sa.Boolean(), nullable=True),
+        sa.Column(
+            'created_at',
+            sa.DateTime(timezone=True),
+            server_default=sa.text('(CURRENT_TIMESTAMP)'),
+            nullable=True
+        ),
+        sa.Column(
+            'updated_at',
+            sa.DateTime(timezone=True),
+            server_default=sa.text('(CURRENT_TIMESTAMP)'),
+            nullable=True
+        ),
+        sa.PrimaryKeyConstraint('id')
+    )
+    op.create_index(op.f('ix_todos_id'), 'todos', ['id'], unique=False)
+    # ### end Alembic commands ###
+
+
+def downgrade() -> None:
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.drop_index(op.f('ix_todos_id'), table_name='todos')
+    op.drop_table('todos')
+    # ### end Alembic commands ###

pyproject.toml

@@ -0,0 +1,11 @@
+[tool.ruff]
+line-length = 88
+target-version = "py310"
+
+[tool.ruff.lint]
+select = ["E", "F", "I"]
+
+[tool.ruff.format]
+quote-style = "double"
+indent-style = "space"
+line-ending = "auto"

requirements.txt

@@ -0,0 +1,7 @@
+fastapi>=0.104.0
+uvicorn>=0.23.2
+sqlalchemy>=2.0.0
+pydantic>=2.4.2
+alembic>=1.12.0
+python-dotenv>=1.0.0
+ruff>=0.1.6

test_app.py

@@ -0,0 +1,87 @@
+#!/usr/bin/env python3
+"""
+Test script for the Todo API.
+This script tests the basic functionality of the Todo API.
+"""
+
+import sys
+from pprint import pprint
+
+import requests
+
+
+def main():
+    """Main function to test the Todo API."""
+    base_url = "http://localhost:8000"
+    api_base = f"{base_url}/api/v1"
+    todos_url = f"{api_base}/todos"
+    
+    # Test health endpoint
+    print("\n=== Testing health endpoint ===")
+    health_response = requests.get(f"{base_url}/health")
+    pprint(health_response.json())
+    
+    # Test create todo
+    print("\n=== Testing create todo ===")
+    new_todo = {
+        "title": "Test Todo",
+        "description": "This is a test todo item",
+        "completed": False
+    }
+    create_response = requests.post(todos_url, json=new_todo)
+    if create_response.status_code != 201:
+        print(f"Error creating todo: {create_response.status_code}")
+        sys.exit(1)
+    
+    created_todo = create_response.json()
+    todo_id = created_todo["id"]
+    pprint(created_todo)
+    
+    # Test get all todos
+    print("\n=== Testing get all todos ===")
+    get_all_response = requests.get(todos_url)
+    pprint(get_all_response.json())
+    
+    # Test get single todo
+    print(f"\n=== Testing get todo with id {todo_id} ===")
+    get_single_response = requests.get(f"{todos_url}/{todo_id}")
+    pprint(get_single_response.json())
+    
+    # Test update todo
+    print(f"\n=== Testing update todo with id {todo_id} ===")
+    update_data = {
+        "title": "Updated Test Todo",
+        "completed": True
+    }
+    update_response = requests.patch(f"{todos_url}/{todo_id}", json=update_data)
+    pprint(update_response.json())
+    
+    # Test filter by completed
+    print("\n=== Testing filter by completed status ===")
+    filter_response = requests.get(f"{todos_url}?completed=true")
+    pprint(filter_response.json())
+    
+    # Test delete todo
+    print(f"\n=== Testing delete todo with id {todo_id} ===")
+    delete_response = requests.delete(f"{todos_url}/{todo_id}")
+    if delete_response.status_code != 204:
+        print(f"Error deleting todo: {delete_response.status_code}")
+        sys.exit(1)
+    print(f"Todo with id {todo_id} deleted successfully")
+    
+    # Verify todo is deleted
+    print("\n=== Verifying todo was deleted ===")
+    verify_response = requests.get(f"{todos_url}/{todo_id}")
+    if verify_response.status_code == 404:
+        print(f"Todo with id {todo_id} no longer exists (as expected)")
+    else:
+        print(
+            f"Error: Todo with id {todo_id} still exists "
+            f"with status code {verify_response.status_code}"
+        )
+    
+    print("\nAll tests completed successfully!")
+
+
+if __name__ == "__main__":
+    main()