Python FastAPI

# app.py
from http import HTTPStatus

from fastapi import FastAPI, HTTPException
from sqlalchemy import create_engine, select
from sqlalchemy.orm import Session

from fast_zero.models import User
from fast_zero.schemas import Message, UserDB, UserList, UserPublic, UserSchema
from fast_zero.settings import Settings

app = FastAPI()

database = []  # Lista provisória para fins de estudo


@app.get('/', status_code=HTTPStatus.OK, response_model=Message)
def read_root():
    return {'message': 'Olá Mundo!'}


@app.post('/users/', response_model=UserPublic, status_code=HTTPStatus.CREATED)
def create_user(user: UserSchema):
    # user_with_id = UserDB(**user.model_dump(), id=len(database) + 1)
    # database.append(user_with_id)
    # return user_with_id
    engine = create_engine(Settings().DATABASE_URL)
    with Session(engine) as session:
        db_user = session.scalar(
            select(User).where(
                (User.username == user.username) | (User.email == user.email)
            )
        )
        if db_user:
            if db_user.username == user.username:
                raise HTTPException(
                    status_code=HTTPStatus.BAD_REQUEST,
                    detail='Username already exists!',
                )
            elif db_user.email == user.email:
                raise HTTPException(
                    status_code=HTTPStatus.BAD_REQUEST,
                    detail='Email already exists!',
                )
        db_user = User(
            username=user.username, email=user.email, password=user.password
        )
        session.add(db_user)
        session.commit()
        session.refresh(db_user)

    return db_user


@app.get('/users/', response_model=UserList)
def read_users():
    return {'users': database}


@app.get('/users/{user_id}', response_model=UserPublic)
def read_user_exercicio(user_id: int):
    if user_id > len(database) or user_id < 1:
        raise HTTPException(
            status_code=HTTPStatus.NOT_FOUND, detail='User not found!'
        )

    return database[user_id - 1]


@app.put('/users/{user_id}', response_model=UserPublic)
def update_user(user_id: int, user: UserSchema):
    if user_id < 1 or user_id > len(database):
        raise HTTPException(
            status_code=HTTPStatus.NOT_FOUND, detail='User not found!'
        )
    user_with_id = UserDB(id=user_id, **user.model_dump())
    database[user_id - 1] = user_with_id
    return user_with_id


@app.delete('/users/{user_id}', response_model=Message)
def delete_user(user_id: int):
    if user_id < 1 or user_id > len(database):
        raise HTTPException(
            status_code=HTTPStatus.NOT_FOUND, detail='User not found!'
        )
    del database[user_id - 1]
    return {'message': 'User deleted!'}











#####################################################################################
# errors
      INFO   127.0.0.1:55195 - "POST /users/ HTTP/1.1" 500
     ERROR   Exception in ASGI application
Traceback (most recent call last):
  File "E:\python\projetos\fast_zero\.venv\Lib\site-packages\uvicorn\protocols\http\httptools_impl.py", line 409, in run_asgi
    result = await app(  # type: ignore[func-returns-value]
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
        self.scope, self.receive, self.send
        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    )
    ^
  File "E:\python\projetos\fast_zero\.venv\Lib\site-packages\uvicorn\middleware\proxy_headers.py", line 60, in __call__
    return await self.app(scope, receive, send)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "E:\python\projetos\fast_zero\.venv\Lib\site-packages\fastapi\applications.py", line 1054, in __call__
    await super().__call__(scope, receive, send)
  File "E:\python\projetos\fast_zero\.venv\Lib\site-packages\starlette\applications.py", line 112, in __call__
    await self.middleware_stack(scope, receive, send)
  File "E:\python\projetos\fast_zero\.venv\Lib\site-packages\starlette\middleware\errors.py", line 187, in __call__
    raise exc
  File "E:\python\projetos\fast_zero\.venv\Lib\site-packages\starlette\middleware\errors.py", line 165, in __call__
    await self.app(scope, receive, _send)
  File "E:\python\projetos\fast_zero\.venv\Lib\site-packages\starlette\middleware\exceptions.py", line 62, in __call__
    await wrap_app_handling_exceptions(self.app, conn)(scope, receive, send)
  File "E:\python\projetos\fast_zero\.venv\Lib\site-packages\starlette\_exception_handler.py", line 53, in wrapped_app
    raise exc
  File "E:\python\projetos\fast_zero\.venv\Lib\site-packages\starlette\_exception_handler.py", line 42, in wrapped_app
    await app(scope, receive, sender)
  File "E:\python\projetos\fast_zero\.venv\Lib\site-packages\starlette\routing.py", line 715, in __call__
    await self.middleware_stack(scope, receive, send)
  File "E:\python\projetos\fast_zero\.venv\Lib\site-packages\starlette\routing.py", line 735, in app
    await route.handle(scope, receive, send)
  File "E:\python\projetos\fast_zero\.venv\Lib\site-packages\starlette\routing.py", line 288, in handle
    await self.app(scope, receive, send)
  File "E:\python\projetos\fast_zero\.venv\Lib\site-packages\starlette\routing.py", line 76, in app
    await wrap_app_handling_exceptions(app, request)(scope, receive, send)
  File "E:\python\projetos\fast_zero\.venv\Lib\site-packages\starlette\_exception_handler.py", line 53, in wrapped_app
    raise exc
  File "E:\python\projetos\fast_zero\.venv\Lib\site-packages\starlette\_exception_handler.py", line 42, in wrapped_app
    await app(scope, receive, sender)
  File "E:\python\projetos\fast_zero\.venv\Lib\site-packages\starlette\routing.py", line 73, in app
    response = await f(request)
               ^^^^^^^^^^^^^^^^
  File "E:\python\projetos\fast_zero\.venv\Lib\site-packages\fastapi\routing.py", line 301, in app
    raw_response = await run_endpoint_function(
                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    ...<3 lines>...
    )
    ^
  File "E:\python\projetos\fast_zero\.venv\Lib\site-packages\fastapi\routing.py", line 214, in run_endpoint_function
    return await run_in_threadpool(dependant.call, **values)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "E:\python\projetos\fast_zero\.venv\Lib\site-packages\starlette\concurrency.py", line 37, in run_in_threadpool
    return await anyio.to_thread.run_sync(func)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "E:\python\projetos\fast_zero\.venv\Lib\site-packages\anyio\to_thread.py", line 56, in run_sync
    return await get_async_backend().run_sync_in_worker_thread(
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
        func, args, abandon_on_cancel=abandon_on_cancel, limiter=limiter
        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    )
    ^
  File "E:\python\projetos\fast_zero\.venv\Lib\site-packages\anyio\_backends\_asyncio.py", line 2461, in run_sync_in_worker_thread
    return await future
           ^^^^^^^^^^^^
  File "E:\python\projetos\fast_zero\.venv\Lib\site-packages\anyio\_backends\_asyncio.py", line 962, in run
    result = context.run(func, *args)
  File "E:\python\projetos\fast_zero\fast_zero\app.py", line 23, in create_user
    def create_user(user: UserSchema):
                 ^^^^
NameError: name 'crea' is not defined