FastAPI Programming Notes

Dependency Injection

In FastAPI you need a reference to a Session and/or an Engine. Create them using SqlAlchemy.

DATABASE_URL = "sqlite:///./example.db"

engine = create_engine(DATABASE_URL, connect_args={"check_same_thread": True})  # False?
# a factory method for Sessions
SessionLocal = sessionmaker(autocommit=False, autoflush=False, bind=engine)

def get_session() -> Session:
    session = SessionLocal()
    try:
        yield session
    finally:
        session.close()

Dependency injection:

fastapi = FastAPI()

@fastapi.post("/users/", response_model=User)
def create_user(user: User, session: Session = Depends(get_session)):
    session.add(**user)
    session.commit()
    session.refresh(user)