Create a simple generic REST API with FastAPI and SQLite

Implemented a complete FastAPI backend with:
- Project structure with FastAPI and SQLAlchemy
- SQLite database with proper configuration
- Alembic for database migrations
- Generic Item resource with CRUD operations
- REST API endpoints with proper validation
- Health check endpoint
- Documentation and setup instructions

README.md

@@ -1,3 +1,120 @@
-# FastAPI Application
+# Generic REST API Service
 
-This is a FastAPI application bootstrapped by BackendIM, the AI-powered backend generation platform.
+This is a FastAPI application that provides a simple generic REST API service with CRUD operations for an "Item" resource.
+
+## Features
+
+- FastAPI-based RESTful API
+- SQLite database with SQLAlchemy ORM
+- Alembic for database migrations
+- Pydantic for data validation
+- Comprehensive CRUD operations
+- Health check endpoint
+- Automatic OpenAPI documentation
+
+## Project Structure
+
+```
+├── alembic/                  # Database migration files
+│   ├── versions/             # Migration version scripts
+│   ├── env.py                # Alembic environment configuration
+│   └── script.py.mako        # Migration script template
+├── app/                      # Application package
+│   ├── api/                  # API routes
+│   │   ├── endpoints/        # API endpoint modules
+│   │   ├── api.py            # API router setup
+│   │   └── deps.py           # Dependency injection functions
+│   ├── core/                 # Core application modules
+│   │   └── config.py         # Application configuration
+│   ├── crud/                 # CRUD operation modules
+│   │   ├── base.py           # Base CRUD operations
+│   │   └── crud_item.py      # Item-specific CRUD operations
+│   ├── db/                   # Database modules
+│   │   ├── base.py           # Import all models
+│   │   ├── base_class.py     # Base model class
+│   │   ├── init_db.py        # Database initialization
+│   │   └── session.py        # DB session setup
+│   ├── models/               # SQLAlchemy models
+│   │   └── item.py           # Item model
+│   └── schemas/              # Pydantic schemas
+│       └── item.py           # Item schema
+├── alembic.ini               # Alembic configuration
+├── main.py                   # Application entry point
+└── requirements.txt          # Project dependencies
+```
+
+## Setup and Installation
+
+1. Clone the repository:
+
+```bash
+git clone <repository-url>
+cd generic-rest-api-service
+```
+
+2. Create and activate a virtual environment (optional, but recommended):
+
+```bash
+python -m venv venv
+source venv/bin/activate  # On Windows: venv\\Scripts\\activate
+```
+
+3. Install dependencies:
+
+```bash
+pip install -r requirements.txt
+```
+
+4. Run database migrations:
+
+```bash
+alembic upgrade head
+```
+
+5. Start the application:
+
+```bash
+uvicorn main:app --reload
+```
+
+The application will be available at http://127.0.0.1:8000.
+
+## API Documentation
+
+Once the application is running, you can access the automatically generated API documentation:
+
+- Swagger UI: http://127.0.0.1:8000/docs
+- ReDoc: http://127.0.0.1:8000/redoc
+
+## API Endpoints
+
+### Health Check
+
+- GET `/api/v1/health`: Check if the service is healthy
+
+### Items
+
+- GET `/api/v1/items`: List all items
+  - Query parameters:
+    - `skip`: Number of items to skip (default: 0)
+    - `limit`: Maximum number of items to return (default: 100)
+    - `active_only`: If true, return only active items (default: false)
+- POST `/api/v1/items`: Create a new item
+- GET `/api/v1/items/{id}`: Get a specific item by ID
+- PUT `/api/v1/items/{id}`: Update a specific item
+- DELETE `/api/v1/items/{id}`: Delete a specific item (returns 204 No Content)
+
+## Development
+
+### Running Tests
+
+```bash
+# Add test command here
+```
+
+### Linting with Ruff
+
+```bash
+ruff check .
+ruff format .
+```

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 - using absolute path for reliability
+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/env.py

@@ -0,0 +1,81 @@
+from logging.config import fileConfig
+
+from sqlalchemy import engine_from_config
+from sqlalchemy import pool
+
+from alembic import context
+from app.db.base import Base
+
+# 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()

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_create_item_table.py

@@ -0,0 +1,45 @@
+"""create item table
+
+Revision ID: 01_create_item_table
+Revises:
+Create Date: 2023-10-01
+
+"""
+
+from alembic import op
+import sqlalchemy as sa
+
+
+# revision identifiers, used by Alembic.
+revision = "01_create_item_table"
+down_revision = None
+branch_labels = None
+depends_on = None
+
+
+def upgrade():
+    op.create_table(
+        "item",
+        sa.Column("id", sa.Integer(), nullable=False),
+        sa.Column("title", sa.String(), nullable=True),
+        sa.Column("description", sa.String(), nullable=True),
+        sa.Column("is_active", sa.Boolean(), nullable=True, default=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), nullable=True),
+        sa.PrimaryKeyConstraint("id"),
+    )
+    op.create_index(op.f("ix_item_id"), "item", ["id"], unique=False)
+    op.create_index(op.f("ix_item_title"), "item", ["title"], unique=False)
+    op.create_index(op.f("ix_item_description"), "item", ["description"], unique=False)
+
+
+def downgrade():
+    op.drop_index(op.f("ix_item_description"), table_name="item")
+    op.drop_index(op.f("ix_item_title"), table_name="item")
+    op.drop_index(op.f("ix_item_id"), table_name="item")
+    op.drop_table("item")

app/__init__.py

@@ -0,0 +1 @@
+# Required for package discovery

app/api/api.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, tags=["health"])
+api_router.include_router(items.router, prefix="/items", tags=["items"])

app/api/deps.py

@@ -0,0 +1,12 @@
+from typing import Generator
+
+
+from app.db.session import SessionLocal
+
+
+def get_db() -> Generator:
+    try:
+        db = SessionLocal()
+        yield db
+    finally:
+        db.close()

app/api/endpoints/__init__.py

@@ -0,0 +1 @@
+# Required for package discovery

app/api/endpoints/health.py

@@ -0,0 +1,19 @@
+from fastapi import APIRouter, Depends
+from sqlalchemy.orm import Session
+
+from app.api import deps
+
+router = APIRouter()
+
+
+@router.get("/health", summary="Check service health")
+def health_check(db: Session = Depends(deps.get_db)):
+    """
+    Check service health:
+    - Database connection is active
+    - API is responding
+    """
+    # Try to execute a simple query to check DB connection
+    db.execute("SELECT 1")
+
+    return {"status": "ok", "message": "Service is healthy"}

app/api/endpoints/items.py

@@ -0,0 +1,87 @@
+from typing import Any, List
+
+from fastapi import APIRouter, Depends, HTTPException, status
+from sqlalchemy.orm import Session
+
+from app import crud, schemas
+from app.api import deps
+
+router = APIRouter()
+
+
+@router.get("/", response_model=List[schemas.Item])
+def read_items(
+    db: Session = Depends(deps.get_db),
+    skip: int = 0,
+    limit: int = 100,
+    active_only: bool = False,
+) -> Any:
+    """
+    Retrieve items.
+    """
+    if active_only:
+        items = crud.item.get_active_items(db, skip=skip, limit=limit)
+    else:
+        items = crud.item.get_multi(db, skip=skip, limit=limit)
+    return items
+
+
+@router.post("/", response_model=schemas.Item, status_code=status.HTTP_201_CREATED)
+def create_item(
+    *,
+    db: Session = Depends(deps.get_db),
+    item_in: schemas.ItemCreate,
+) -> Any:
+    """
+    Create new item.
+    """
+    item = crud.item.create(db=db, obj_in=item_in)
+    return item
+
+
+@router.get("/{id}", response_model=schemas.Item)
+def read_item(
+    *,
+    db: Session = Depends(deps.get_db),
+    id: int,
+) -> Any:
+    """
+    Get item by ID.
+    """
+    item = crud.item.get(db=db, id=id)
+    if not item:
+        raise HTTPException(status_code=404, detail="Item not found")
+    return item
+
+
+@router.put("/{id}", response_model=schemas.Item)
+def update_item(
+    *,
+    db: Session = Depends(deps.get_db),
+    id: int,
+    item_in: schemas.ItemUpdate,
+) -> Any:
+    """
+    Update an item.
+    """
+    item = crud.item.get(db=db, id=id)
+    if not item:
+        raise HTTPException(status_code=404, detail="Item not found")
+    item = crud.item.update(db=db, db_obj=item, obj_in=item_in)
+    return item
+
+
+@router.delete("/{id}", status_code=status.HTTP_204_NO_CONTENT, response_model=None)
+def delete_item(
+    *,
+    db: Session = Depends(deps.get_db),
+    id: int,
+) -> Any:
+    """
+    Delete an item.
+    """
+    item = crud.item.get(db=db, id=id)
+    if not item:
+        raise HTTPException(status_code=404, detail="Item not found")
+    item = crud.item.remove(db=db, id=id)
+    return None

app/core/__init__.py

@@ -0,0 +1 @@
+# Required for package discovery

app/core/config.py

@@ -0,0 +1,30 @@
+import secrets
+
+from pydantic import AnyHttpUrl, BaseSettings, validator
+
+
+class Settings(BaseSettings):
+    API_V1_STR: str = "/api/v1"
+    SECRET_KEY: str = secrets.token_urlsafe(32)
+    # 60 minutes * 24 hours * 8 days = 8 days
+    ACCESS_TOKEN_EXPIRE_MINUTES: int = 60 * 24 * 8
+    # BACKEND_CORS_ORIGINS is a JSON-formatted list of origins
+    # e.g: '["http://localhost", "http://localhost:4200", "http://localhost:3000", \
+    # "http://localhost:8080", "http://local.dockertoolbox.tiangolo.com"]'
+    BACKEND_CORS_ORIGINS: list[AnyHttpUrl] = []
+
+    @validator("BACKEND_CORS_ORIGINS", pre=True)
+    def assemble_cors_origins(cls, v: str | list[str]) -> 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)
+
+    PROJECT_NAME: str = "Generic REST API Service"
+
+    class Config:
+        case_sensitive = True
+
+
+settings = Settings()

app/crud/__init__.py

@@ -0,0 +1,5 @@
+from app.crud.crud_item import item as item
+
+# For easy import in API routes
+# Import all CRUD operations here
+# Example: from app.crud import item

app/crud/base.py

@@ -0,0 +1,66 @@
+from typing import Any, Dict, Generic, List, Optional, Type, TypeVar, Union
+
+from fastapi.encoders import jsonable_encoder
+from pydantic import BaseModel
+from sqlalchemy.orm import Session
+
+from app.db.base_class import Base
+
+ModelType = TypeVar("ModelType", bound=Base)
+CreateSchemaType = TypeVar("CreateSchemaType", bound=BaseModel)
+UpdateSchemaType = TypeVar("UpdateSchemaType", bound=BaseModel)
+
+
+class CRUDBase(Generic[ModelType, CreateSchemaType, UpdateSchemaType]):
+    def __init__(self, model: Type[ModelType]):
+        """
+        CRUD object with default methods to Create, Read, Update, Delete (CRUD).
+
+        **Parameters**
+
+        * `model`: A SQLAlchemy model class
+        * `schema`: A Pydantic model (schema) class
+        """
+        self.model = model
+
+    def get(self, db: Session, id: Any) -> Optional[ModelType]:
+        return db.query(self.model).filter(self.model.id == id).first()
+
+    def get_multi(
+        self, db: Session, *, skip: int = 0, limit: int = 100
+    ) -> List[ModelType]:
+        return db.query(self.model).offset(skip).limit(limit).all()
+
+    def create(self, db: Session, *, obj_in: CreateSchemaType) -> ModelType:
+        obj_in_data = jsonable_encoder(obj_in)
+        db_obj = self.model(**obj_in_data)  # type: ignore
+        db.add(db_obj)
+        db.commit()
+        db.refresh(db_obj)
+        return db_obj
+
+    def update(
+        self,
+        db: Session,
+        *,
+        db_obj: ModelType,
+        obj_in: Union[UpdateSchemaType, Dict[str, Any]],
+    ) -> ModelType:
+        obj_data = jsonable_encoder(db_obj)
+        if isinstance(obj_in, dict):
+            update_data = obj_in
+        else:
+            update_data = obj_in.dict(exclude_unset=True)
+        for field in obj_data:
+            if field in update_data:
+                setattr(db_obj, field, update_data[field])
+        db.add(db_obj)
+        db.commit()
+        db.refresh(db_obj)
+        return db_obj
+
+    def remove(self, db: Session, *, id: int) -> ModelType:
+        obj = db.query(self.model).get(id)
+        db.delete(obj)
+        db.commit()
+        return obj

app/crud/crud_item.py

@@ -0,0 +1,20 @@
+from typing import List, Optional
+
+from sqlalchemy.orm import Session
+
+from app.crud.base import CRUDBase
+from app.models.item import Item
+from app.schemas.item import ItemCreate, ItemUpdate
+
+
+class CRUDItem(CRUDBase[Item, ItemCreate, ItemUpdate]):
+    def get_by_title(self, db: Session, *, title: str) -> Optional[Item]:
+        return db.query(Item).filter(Item.title == title).first()
+
+    def get_active_items(
+        self, db: Session, *, skip: int = 0, limit: int = 100
+    ) -> List[Item]:
+        return db.query(Item).filter(Item.is_active).offset(skip).limit(limit).all()
+
+
+item = CRUDItem(Item)

app/db/base.py

@@ -0,0 +1,4 @@
+# Import all the models, so that Base has them before being
+# imported by Alembic
+from app.db.base_class import Base  # noqa
+from app.models.item import Item  # noqa

app/db/base_class.py

@@ -0,0 +1,14 @@
+from typing import Any
+
+from sqlalchemy.ext.declarative import as_declarative, declared_attr
+
+
+@as_declarative()
+class Base:
+    id: Any
+    __name__: str
+
+    # Generate __tablename__ automatically
+    @declared_attr
+    def __tablename__(cls) -> str:
+        return cls.__name__.lower()

app/db/init_db.py

@@ -0,0 +1,7 @@
+from app.db.base import Base
+from app.db.session import engine
+
+
+# Create tables if they don't exist
+def init_db() -> None:
+    Base.metadata.create_all(bind=engine)

app/db/session.py

@@ -0,0 +1,13 @@
+from pathlib import Path
+from sqlalchemy import create_engine
+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)

app/models/__init__.py

@@ -0,0 +1 @@
+from app.models.item import Item as Item

app/models/item.py

@@ -0,0 +1,13 @@
+from sqlalchemy import Column, Integer, String, Boolean, DateTime
+from sqlalchemy.sql import func
+
+from app.db.base_class import Base
+
+
+class Item(Base):
+    id = Column(Integer, primary_key=True, index=True)
+    title = Column(String, index=True)
+    description = Column(String, index=True)
+    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/__init__.py

@@ -0,0 +1,5 @@
+# Import all schemas here to expose them
+from app.schemas.item import Item as Item
+from app.schemas.item import ItemCreate as ItemCreate
+from app.schemas.item import ItemInDB as ItemInDB
+from app.schemas.item import ItemUpdate as ItemUpdate

app/schemas/item.py

@@ -0,0 +1,44 @@
+from datetime import datetime
+from typing import Optional
+
+from pydantic import BaseModel, Field
+
+
+# Shared properties
+class ItemBase(BaseModel):
+    title: Optional[str] = None
+    description: Optional[str] = None
+    is_active: Optional[bool] = True
+
+
+# Properties to receive on item creation
+class ItemCreate(ItemBase):
+    title: str = Field(..., min_length=1, max_length=100)
+
+
+# Properties to receive on item update
+class ItemUpdate(ItemBase):
+    pass
+
+
+# Properties shared by models stored in DB
+class ItemInDBBase(ItemBase):
+    id: int
+    title: str
+    description: Optional[str] = None
+    is_active: bool
+    created_at: datetime
+    updated_at: Optional[datetime] = None
+
+    class Config:
+        orm_mode = True
+
+
+# Properties to return to client
+class Item(ItemInDBBase):
+    pass
+
+
+# Properties stored in DB
+class ItemInDB(ItemInDBBase):
+    pass

main.py

@@ -0,0 +1,16 @@
+import uvicorn
+from fastapi import FastAPI
+from app.api.api import api_router
+from app.core.config import settings
+
+app = FastAPI(
+    title=settings.PROJECT_NAME,
+    openapi_url=f"{settings.API_V1_STR}/openapi.json",
+    description="A simple generic REST API service",
+    version="0.1.0",
+)
+
+app.include_router(api_router, prefix=settings.API_V1_STR)
+
+if __name__ == "__main__":
+    uvicorn.run("main:app", host="0.0.0.0", port=8000, reload=True)

requirements.txt

@@ -0,0 +1,10 @@
+fastapi>=0.103.1,<0.104.0
+uvicorn>=0.23.2,<0.24.0
+sqlalchemy>=2.0.20,<2.1.0
+alembic>=1.12.0,<1.13.0
+pydantic>=2.3.0,<2.4.0
+python-dotenv>=1.0.0,<1.1.0
+python-multipart>=0.0.6,<0.0.7
+email-validator>=2.0.0,<2.1.0
+ruff>=0.0.291
+pathlib>=1.0.1,<1.1.0