Create REST API with FastAPI and SQLAlchemy

- Set up project structure with FastAPI
- Create SQLite database with SQLAlchemy
- Implement Alembic for database migrations
- Add CRUD operations for items resource
- Create health endpoint
- Update documentation

generated with BackendIM... (backend.im)

README.md

@@ -1,3 +1,71 @@
-# FastAPI Application
+# Generic REST API
 
-This is a FastAPI application bootstrapped by BackendIM, the AI-powered backend generation platform.
+A RESTful API built with FastAPI and SQLAlchemy.
+
+## Features
+
+- FastAPI for high-performance API with automatic OpenAPI documentation
+- SQLAlchemy ORM for database operations
+- SQLite database for storage
+- Alembic for database migrations
+- Pydantic models for request/response validation
+- CRUD operations for the 'items' resource
+- Health check endpoint
+
+## Project Structure
+
+```
+├── alembic/               # Database migration scripts
+├── app/                   # Application source code
+│   ├── api/               # API endpoints
+│   │   ├── endpoints/     # API routes
+│   ├── crud/              # CRUD operations
+│   ├── db/                # Database configurations
+│   ├── models/            # SQLAlchemy models
+│   └── schemas/           # Pydantic schemas
+├── storage/               # Storage directory
+│   └── db/                # Database files
+├── alembic.ini            # Alembic configuration
+├── main.py                # Application entry point
+└── requirements.txt       # Project dependencies
+```
+
+## Installation and Setup
+
+1. Clone the repository
+
+2. Install the dependencies:
+   ```bash
+   pip install -r requirements.txt
+   ```
+
+3. Apply the database migrations:
+   ```bash
+   alembic upgrade head
+   ```
+
+4. 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](http://localhost:8000/docs)
+- ReDoc: [http://localhost:8000/redoc](http://localhost:8000/redoc)
+
+## API Endpoints
+
+### Items Resource
+
+- `GET /items`: Get all items (paginated)
+- `POST /items`: Create a new item
+- `GET /items/{item_id}`: Get a specific item by ID
+- `PUT /items/{item_id}`: Update an item
+- `DELETE /items/{item_id}`: Delete an item
+
+### Health Check
+
+- `GET /health`: Check API health status

alembic.ini

@@ -0,0 +1,41 @@
+[alembic]
+script_location = alembic
+prepend_sys_path = .
+version_path_separator = os
+
+# SQLite URL example
+sqlalchemy.url = sqlite:////app/storage/db/db.sqlite
+
+[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 for SQLAlchemy.

alembic/env.py

@@ -0,0 +1,80 @@
+import os
+import sys
+from logging.config import fileConfig
+
+from sqlalchemy import engine_from_config
+from sqlalchemy import pool
+
+from alembic import context
+
+sys.path.insert(0, os.path.dirname(os.path.dirname(__file__)))
+
+# 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 app.db.base import Base  # noqa
+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/001_create_items_table.py

@@ -0,0 +1,36 @@
+"""create items table
+
+Revision ID: 001
+Revises: 
+Create Date: 2025-05-14
+
+"""
+from alembic import op
+import sqlalchemy as sa
+
+
+# revision identifiers, used by Alembic.
+revision = '001'
+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(length=100), nullable=False),
+        sa.Column('description', sa.Text(), nullable=True),
+        sa.Column('created_at', sa.DateTime(timezone=True), server_default=sa.text('(CURRENT_TIMESTAMP)'), nullable=False),
+        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)
+
+
+def downgrade():
+    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/api/endpoints/__init__.py

@@ -0,0 +1,5 @@
+from fastapi import APIRouter
+from app.api.endpoints import items
+
+router = APIRouter()
+router.include_router(items.router, prefix="/items", tags=["items"])

app/api/endpoints/items.py

@@ -0,0 +1,53 @@
+from typing import List, Optional
+from fastapi import APIRouter, Depends, HTTPException, status
+from sqlalchemy.orm import Session
+from app.crud import item as crud
+from app.schemas.item import Item, ItemCreate, ItemUpdate
+from app.db.session import get_db
+
+router = APIRouter()
+
+
+@router.get("/", response_model=List[Item])
+def read_items(
+    skip: int = 0, limit: int = 100, db: Session = Depends(get_db)
+):
+    items = crud.get_items(db, skip=skip, limit=limit)
+    return items
+
+
+@router.post("/", response_model=Item, status_code=status.HTTP_201_CREATED)
+def create_item(
+    item: ItemCreate, db: Session = Depends(get_db)
+):
+    return crud.create_item(db=db, item=item)
+
+
+@router.get("/{item_id}", response_model=Item)
+def read_item(
+    item_id: int, db: Session = Depends(get_db)
+):
+    db_item = crud.get_item(db, item_id=item_id)
+    if db_item is None:
+        raise HTTPException(status_code=404, detail="Item not found")
+    return db_item
+
+
+@router.put("/{item_id}", response_model=Item)
+def update_item(
+    item_id: int, item: ItemUpdate, db: Session = Depends(get_db)
+):
+    db_item = crud.update_item(db, item_id=item_id, item=item)
+    if db_item is None:
+        raise HTTPException(status_code=404, detail="Item not found")
+    return db_item
+
+
+@router.delete("/{item_id}", response_model=Item)
+def delete_item(
+    item_id: int, db: Session = Depends(get_db)
+):
+    db_item = crud.delete_item(db, item_id=item_id)
+    if db_item is None:
+        raise HTTPException(status_code=404, detail="Item not found")
+    return db_item

app/api/health.py

@@ -0,0 +1,8 @@
+from fastapi import APIRouter
+
+router = APIRouter()
+
+
+@router.get("/health", tags=["health"])
+def health_check():
+    return {"status": "ok", "message": "API is running"}

app/crud/item.py

@@ -0,0 +1,39 @@
+from sqlalchemy.orm import Session
+from typing import List, Optional
+from app.models.item import Item
+from app.schemas.item import ItemCreate, ItemUpdate
+
+
+def get_item(db: Session, item_id: int) -> Optional[Item]:
+    return db.query(Item).filter(Item.id == item_id).first()
+
+
+def get_items(db: Session, skip: int = 0, limit: int = 100) -> List[Item]:
+    return db.query(Item).offset(skip).limit(limit).all()
+
+
+def create_item(db: Session, item: ItemCreate) -> Item:
+    db_item = Item(**item.dict())
+    db.add(db_item)
+    db.commit()
+    db.refresh(db_item)
+    return db_item
+
+
+def update_item(db: Session, item_id: int, item: ItemUpdate) -> Optional[Item]:
+    db_item = get_item(db, item_id)
+    if db_item:
+        update_data = item.dict(exclude_unset=True)
+        for key, value in update_data.items():
+            setattr(db_item, key, value)
+        db.commit()
+        db.refresh(db_item)
+    return db_item
+
+
+def delete_item(db: Session, item_id: int) -> Optional[Item]:
+    db_item = get_item(db, item_id)
+    if db_item:
+        db.delete(db_item)
+        db.commit()
+    return db_item

app/db/base.py

@@ -0,0 +1,3 @@
+# Import all the models, so that alembic can detect them
+from app.db.base_class import Base
+from app.models.item import Item

app/db/base_class.py

@@ -0,0 +1,12 @@
+from typing import Any
+from sqlalchemy.ext.declarative import as_declarative, declared_attr
+
+
+@as_declarative()
+class Base:
+    id: Any
+    __name__: str
+
+    @declared_attr
+    def __tablename__(cls) -> str:
+        return cls.__name__.lower()

app/db/session.py

@@ -0,0 +1,23 @@
+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)
+
+
+def get_db():
+    db = SessionLocal()
+    try:
+        yield db
+    finally:
+        db.close()

app/models/item.py

@@ -0,0 +1,11 @@
+from sqlalchemy import Column, Integer, String, Text, 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(100), index=True)
+    description = Column(Text, nullable=True)
+    created_at = Column(DateTime(timezone=True), server_default=func.now())
+    updated_at = Column(DateTime(timezone=True), onupdate=func.now())

app/schemas/item.py

@@ -0,0 +1,25 @@
+from pydantic import BaseModel
+from datetime import datetime
+from typing import Optional
+
+
+class ItemBase(BaseModel):
+    title: str
+    description: Optional[str] = None
+
+
+class ItemCreate(ItemBase):
+    pass
+
+
+class ItemUpdate(ItemBase):
+    title: Optional[str] = None
+
+
+class Item(ItemBase):
+    id: int
+    created_at: datetime
+    updated_at: Optional[datetime] = None
+
+    class Config:
+        orm_mode = True

main.py

@@ -0,0 +1,16 @@
+from fastapi import FastAPI
+from app.api.endpoints import router as api_router
+from app.api.health import router as health_router
+
+app = FastAPI(
+    title="Generic REST API",
+    description="A generic REST API built with FastAPI and SQLAlchemy",
+    version="0.1.0",
+)
+
+app.include_router(api_router)
+app.include_router(health_router)
+
+if __name__ == "__main__":
+    import uvicorn
+    uvicorn.run("main:app", host="0.0.0.0", port=8000, reload=True)

requirements.txt

@@ -0,0 +1,6 @@
+fastapi==0.103.1
+uvicorn==0.23.2
+sqlalchemy==2.0.21
+pydantic==2.4.2
+alembic==1.12.0
+ruff==0.0.292