Create REST API with FastAPI and SQLite

- Implemented project structure with FastAPI framework
- Set up SQLite database with SQLAlchemy ORM
- Created Alembic for database migrations
- Implemented Item model and CRUD operations
- Added health check endpoint
- Added error handling
- Configured API documentation with Swagger UI

generated with BackendIM... (backend.im)

README.md

@@ -1,3 +1,84 @@
-# FastAPI Application
+# Generic REST API Service
 
-This is a FastAPI application bootstrapped by BackendIM, the AI-powered backend generation platform.
+A RESTful API service built with FastAPI and SQLite, providing standard CRUD operations with a clean architecture.
+
+## Features
+
+- FastAPI framework for high performance
+- SQLite database with SQLAlchemy ORM
+- Alembic for database migrations
+- RESTful API endpoints
+- Input validation with Pydantic
+- Error handling
+- Health check endpoint
+- Interactive API documentation with Swagger
+
+## Project Structure
+
+```
+├── alembic/              # Database migrations
+│   └── versions/         # Migration scripts
+├── app/                  # Application code
+│   ├── api/              # API endpoints
+│   │   ├── endpoints/    # Individual API route handlers
+│   │   └── routes.py     # API router setup
+│   ├── database.py       # Database connection setup
+│   ├── errors.py         # Error handling
+│   ├── models.py         # SQLAlchemy models
+│   └── schemas.py        # Pydantic schemas
+├── main.py               # Application entry point
+├── alembic.ini           # Alembic configuration
+└── requirements.txt      # Project dependencies
+```
+
+## Installation
+
+1. Clone the repository
+2. Install dependencies:
+
+```bash
+pip install -r requirements.txt
+```
+
+## Usage
+
+Run 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
+
+### Health Check
+
+- `GET /health` - Check API health status
+
+### Items
+
+- `GET /items` - List all items (with optional filtering)
+- `POST /items` - Create a new item
+- `GET /items/{item_id}` - Get a specific item
+- `PUT /items/{item_id}` - Update an item
+- `DELETE /items/{item_id}` - Delete an item
+
+## Database Management
+
+This project uses Alembic for database migrations:
+
+```bash
+# Apply migrations
+alembic upgrade head
+
+# Create a new migration
+alembic revision -m "description"
+```
+
+The SQLite database is stored at `/app/storage/db/db.sqlite`.

alembic.ini

@@ -0,0 +1,85 @@
+# A generic, single database configuration.
+
+[alembic]
+# path to migration scripts
+script_location = alembic
+
+# 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 alembic/versions.  When using multiple version
+# directories, initial revisions must be specified with --version-path
+# version_locations = %(here)s/bar %(here)s/bat alembic/versions
+
+# 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
+
+# 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

alembic/README

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

alembic/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.
+fileConfig(config.config_file_name)
+
+# add your model's MetaData object here
+# for 'autogenerate' support
+# from myapp import mymodel
+# target_metadata = mymodel.Base.metadata
+from app.models 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():
+    """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:
+        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()

alembic/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"}

alembic/versions/01_initial.py

@@ -0,0 +1,39 @@
+"""initial
+
+Revision ID: 01_initial
+Revises: 
+Create Date: 2025-05-13
+
+"""
+from alembic import op
+import sqlalchemy as sa
+
+
+# revision identifiers, used by Alembic.
+revision = '01_initial'
+down_revision = None
+branch_labels = None
+depends_on = None
+
+
+def upgrade():
+    # Create items table
+    op.create_table(
+        'items',
+        sa.Column('id', sa.Integer(), nullable=False),
+        sa.Column('name', sa.String(100), nullable=False),
+        sa.Column('description', sa.Text(), nullable=True),
+        sa.Column('price', sa.Integer(), nullable=False),
+        sa.Column('is_active', sa.Boolean(), default=True),
+        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_items_id'), 'items', ['id'], unique=False)
+    op.create_index(op.f('ix_items_name'), 'items', ['name'], unique=False)
+
+
+def downgrade():
+    op.drop_index(op.f('ix_items_name'), table_name='items')
+    op.drop_index(op.f('ix_items_id'), table_name='items')
+    op.drop_table('items')

app/__init__.py

@@ -0,0 +1 @@
+# This file is intentionally left empty to make the directory a Python package.

app/api/__init__.py

@@ -0,0 +1 @@
+# This file is intentionally left empty to make the directory a Python package.

app/api/endpoints/__init__.py

@@ -0,0 +1 @@
+# This file is intentionally left empty to make the directory a Python package.

app/api/endpoints/health.py

@@ -0,0 +1,26 @@
+from datetime import datetime
+from fastapi import APIRouter, Depends, status
+from sqlalchemy.orm import Session
+
+from app.database import get_db
+from app import schemas
+
+router = APIRouter()
+
+
+@router.get("/", response_model=schemas.HealthCheck)
+def health_check(db: Session = Depends(get_db)):
+    """
+    Health check endpoint
+    """
+    # Verify database connection is working
+    try:
+        db.execute("SELECT 1")
+        db_status = "healthy"
+    except Exception:
+        db_status = "unhealthy"
+        
+    return {
+        "status": db_status,
+        "timestamp": datetime.now()
+    }

app/api/endpoints/items.py

@@ -0,0 +1,70 @@
+from typing import List, Optional
+from fastapi import APIRouter, Depends, HTTPException, Query, status
+from sqlalchemy.orm import Session
+
+from app.database import get_db
+from app import models, schemas
+
+router = APIRouter()
+
+
+@router.post("/", response_model=schemas.Item, status_code=status.HTTP_201_CREATED)
+def create_item(item: schemas.ItemCreate, db: Session = Depends(get_db)):
+    db_item = models.Item(**item.model_dump())
+    db.add(db_item)
+    db.commit()
+    db.refresh(db_item)
+    return db_item
+
+
+@router.get("/", response_model=List[schemas.Item])
+def read_items(
+    skip: int = 0,
+    limit: int = 100,
+    name: Optional[str] = None,
+    is_active: Optional[bool] = None,
+    db: Session = Depends(get_db),
+):
+    query = db.query(models.Item)
+    
+    if name:
+        query = query.filter(models.Item.name.contains(name))
+    if is_active is not None:
+        query = query.filter(models.Item.is_active == is_active)
+        
+    items = query.offset(skip).limit(limit).all()
+    return items
+
+
+@router.get("/{item_id}", response_model=schemas.Item)
+def read_item(item_id: int, db: Session = Depends(get_db)):
+    db_item = db.query(models.Item).filter(models.Item.id == item_id).first()
+    if db_item is None:
+        raise HTTPException(status_code=404, detail="Item not found")
+    return db_item
+
+
+@router.put("/{item_id}", response_model=schemas.Item)
+def update_item(item_id: int, item: schemas.ItemUpdate, db: Session = Depends(get_db)):
+    db_item = db.query(models.Item).filter(models.Item.id == item_id).first()
+    if db_item is None:
+        raise HTTPException(status_code=404, detail="Item not found")
+    
+    update_data = item.model_dump(exclude_unset=True)
+    for key, value in update_data.items():
+        setattr(db_item, key, value)
+            
+    db.commit()
+    db.refresh(db_item)
+    return db_item
+
+
+@router.delete("/{item_id}", status_code=status.HTTP_204_NO_CONTENT)
+def delete_item(item_id: int, db: Session = Depends(get_db)):
+    db_item = db.query(models.Item).filter(models.Item.id == item_id).first()
+    if db_item is None:
+        raise HTTPException(status_code=404, detail="Item not found")
+    
+    db.delete(db_item)
+    db.commit()
+    return None

app/api/routes.py

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

app/database.py

@@ -0,0 +1,31 @@
+from sqlalchemy import create_engine
+from sqlalchemy.ext.declarative import declarative_base
+from sqlalchemy.orm import sessionmaker
+from pathlib import Path
+
+# Create the database directory if it doesn't exist
+DB_DIR = Path("/app") / "storage" / "db"
+DB_DIR.mkdir(parents=True, exist_ok=True)
+
+# Define the SQLite URL
+SQLALCHEMY_DATABASE_URL = f"sqlite:///{DB_DIR}/db.sqlite"
+
+# Create the SQLAlchemy engine
+engine = create_engine(
+    SQLALCHEMY_DATABASE_URL,
+    connect_args={"check_same_thread": False}
+)
+
+# Create a SessionLocal class
+SessionLocal = sessionmaker(autocommit=False, autoflush=False, bind=engine)
+
+# Create a Base class for declarative models
+Base = declarative_base()
+
+# Dependency to get the database session
+def get_db():
+    db = SessionLocal()
+    try:
+        yield db
+    finally:
+        db.close()

app/errors.py

@@ -0,0 +1,53 @@
+from fastapi import FastAPI, Request, status
+from fastapi.responses import JSONResponse
+
+
+class AppError(Exception):
+    """Base error class for the application"""
+    def __init__(self, message: str, status_code: int):
+        self.message = message
+        self.status_code = status_code
+        super().__init__(self.message)
+
+
+class NotFoundError(AppError):
+    """Resource not found error"""
+    def __init__(self, message: str):
+        super().__init__(message, status_code=status.HTTP_404_NOT_FOUND)
+
+
+class ValidationError(AppError):
+    """Data validation error"""
+    def __init__(self, message: str):
+        super().__init__(message, status_code=status.HTTP_400_BAD_REQUEST)
+
+
+class DatabaseError(AppError):
+    """Database-related error"""
+    def __init__(self, message: str):
+        super().__init__(message, status_code=status.HTTP_500_INTERNAL_SERVER_ERROR)
+
+
+def add_error_handlers(app: FastAPI) -> None:
+    """Configure exception handlers for the app"""
+    
+    @app.exception_handler(AppError)
+    async def app_error_handler(request: Request, exc: AppError) -> JSONResponse:
+        return JSONResponse(
+            status_code=exc.status_code,
+            content={"detail": exc.message}
+        )
+        
+    @app.exception_handler(status.HTTP_404_NOT_FOUND)
+    async def not_found_handler(request: Request, exc: Exception) -> JSONResponse:
+        return JSONResponse(
+            status_code=status.HTTP_404_NOT_FOUND,
+            content={"detail": "Resource not found"}
+        )
+        
+    @app.exception_handler(status.HTTP_500_INTERNAL_SERVER_ERROR)
+    async def server_error_handler(request: Request, exc: Exception) -> JSONResponse:
+        return JSONResponse(
+            status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
+            content={"detail": "Internal server error"}
+        )

app/models.py

@@ -0,0 +1,15 @@
+from sqlalchemy import Column, Integer, String, Boolean, DateTime, Text
+from sqlalchemy.sql import func
+from .database import Base
+
+
+class Item(Base):
+    __tablename__ = "items"
+
+    id = Column(Integer, primary_key=True, index=True)
+    name = Column(String(100), nullable=False, index=True)
+    description = Column(Text, nullable=True)
+    price = Column(Integer, nullable=False)  # Price in cents
+    is_active = Column(Boolean, default=True)
+    created_at = Column(DateTime(timezone=True), server_default=func.now())
+    updated_at = Column(DateTime(timezone=True), onupdate=func.now())

app/schemas.py

@@ -0,0 +1,36 @@
+from typing import Optional
+from datetime import datetime
+from pydantic import BaseModel, Field
+
+
+class ItemBase(BaseModel):
+    name: str = Field(..., min_length=1, max_length=100)
+    description: Optional[str] = None
+    price: int = Field(..., gt=0)  # Price in cents
+    is_active: bool = True
+
+
+class ItemCreate(ItemBase):
+    pass
+
+
+class ItemUpdate(BaseModel):
+    name: Optional[str] = Field(None, min_length=1, max_length=100)
+    description: Optional[str] = None
+    price: Optional[int] = Field(None, gt=0)
+    is_active: Optional[bool] = None
+
+
+class Item(ItemBase):
+    id: int
+    created_at: datetime
+    updated_at: Optional[datetime] = None
+
+    class Config:
+        orm_mode = True
+        from_attributes = True
+
+
+class HealthCheck(BaseModel):
+    status: str
+    timestamp: datetime

main.py

@@ -0,0 +1,34 @@
+import uvicorn
+from fastapi import FastAPI
+from fastapi.middleware.cors import CORSMiddleware
+
+from app.api.routes import api_router
+from app.database import Base, engine
+from app.errors import add_error_handlers
+
+# Create database tables
+Base.metadata.create_all(bind=engine)
+
+app = FastAPI(
+    title="Generic REST API Service",
+    description="A simple REST API service built with FastAPI and SQLite",
+    version="0.1.0",
+)
+
+# Set up CORS
+app.add_middleware(
+    CORSMiddleware,
+    allow_origins=["*"],
+    allow_credentials=True,
+    allow_methods=["*"],
+    allow_headers=["*"],
+)
+
+# Add error handlers
+add_error_handlers(app)
+
+# Include API router
+app.include_router(api_router)
+
+if __name__ == "__main__":
+    uvicorn.run("main:app", host="0.0.0.0", port=8000, reload=True)

requirements.txt

@@ -0,0 +1,8 @@
+fastapi==0.104.1
+uvicorn==0.23.2
+sqlalchemy==2.0.22
+alembic==1.12.1
+pydantic==2.4.2
+pydantic-settings==2.0.3
+python-dotenv==1.0.0
+pathlib==1.0.1