Simple OAuth2 con Password y Bearer¶
Ahora vamos a construir a partir del capítulo anterior y agregar las partes faltantes para tener un flujo de seguridad completo.
Obtener el username
y password
¶
Vamos a usar las utilidades de seguridad de FastAPI para obtener el username
y password
.
OAuth2 especifica que cuando se utiliza el "password flow" (que estamos usando), el cliente/usuario debe enviar campos username
y password
como form data.
Y la especificación dice que los campos deben llamarse así. Por lo que user-name
o email
no funcionarían.
Pero no te preocupes, puedes mostrarlo como quieras a tus usuarios finales en el frontend.
Y tus modelos de base de datos pueden usar cualquier otro nombre que desees.
Pero para la path operation de inicio de sesión, necesitamos usar estos nombres para ser compatibles con la especificación (y poder, por ejemplo, utilizar el sistema de documentación integrada de la API).
La especificación también establece que el username
y password
deben enviarse como form data (por lo que no hay JSON aquí).
scope
¶
La especificación también indica que el cliente puede enviar otro campo del formulario llamado "scope
".
El nombre del campo del formulario es scope
(en singular), pero en realidad es un string largo con "scopes" separados por espacios.
Cada "scope" es simplemente un string (sin espacios).
Normalmente se utilizan para declarar permisos de seguridad específicos, por ejemplo:
users:read
ousers:write
son ejemplos comunes.instagram_basic
es usado por Facebook / Instagram.https://www.googleapis.com/auth/drive
es usado por Google.
Información
En OAuth2 un "scope" es solo un string que declara un permiso específico requerido.
No importa si tiene otros caracteres como :
o si es una URL.
Esos detalles son específicos de la implementación.
Para OAuth2 son solo strings.
Código para obtener el username
y password
¶
Ahora vamos a usar las utilidades proporcionadas por FastAPI para manejar esto.
OAuth2PasswordRequestForm
¶
Primero, importa OAuth2PasswordRequestForm
, y úsalo como una dependencia con Depends
en la path operation para /token
:
from typing import Annotated
from fastapi import Depends, FastAPI, HTTPException, status
from fastapi.security import OAuth2PasswordBearer, OAuth2PasswordRequestForm
from pydantic import BaseModel
fake_users_db = {
"johndoe": {
"username": "johndoe",
"full_name": "John Doe",
"email": "johndoe@example.com",
"hashed_password": "fakehashedsecret",
"disabled": False,
},
"alice": {
"username": "alice",
"full_name": "Alice Wonderson",
"email": "alice@example.com",
"hashed_password": "fakehashedsecret2",
"disabled": True,
},
}
app = FastAPI()
def fake_hash_password(password: str):
return "fakehashed" + password
oauth2_scheme = OAuth2PasswordBearer(tokenUrl="token")
class User(BaseModel):
username: str
email: str | None = None
full_name: str | None = None
disabled: bool | None = None
class UserInDB(User):
hashed_password: str
def get_user(db, username: str):
if username in db:
user_dict = db[username]
return UserInDB(**user_dict)
def fake_decode_token(token):
# This doesn't provide any security at all
# Check the next version
user = get_user(fake_users_db, token)
return user
async def get_current_user(token: Annotated[str, Depends(oauth2_scheme)]):
user = fake_decode_token(token)
if not user:
raise HTTPException(
status_code=status.HTTP_401_UNAUTHORIZED,
detail="Invalid authentication credentials",
headers={"WWW-Authenticate": "Bearer"},
)
return user
async def get_current_active_user(
current_user: Annotated[User, Depends(get_current_user)],
):
if current_user.disabled:
raise HTTPException(status_code=400, detail="Inactive user")
return current_user
@app.post("/token")
async def login(form_data: Annotated[OAuth2PasswordRequestForm, Depends()]):
user_dict = fake_users_db.get(form_data.username)
if not user_dict:
raise HTTPException(status_code=400, detail="Incorrect username or password")
user = UserInDB(**user_dict)
hashed_password = fake_hash_password(form_data.password)
if not hashed_password == user.hashed_password:
raise HTTPException(status_code=400, detail="Incorrect username or password")
return {"access_token": user.username, "token_type": "bearer"}
@app.get("/users/me")
async def read_users_me(
current_user: Annotated[User, Depends(get_current_active_user)],
):
return current_user
🤓 Other versions and variants
from typing import Annotated, Union
from fastapi import Depends, FastAPI, HTTPException, status
from fastapi.security import OAuth2PasswordBearer, OAuth2PasswordRequestForm
from pydantic import BaseModel
fake_users_db = {
"johndoe": {
"username": "johndoe",
"full_name": "John Doe",
"email": "johndoe@example.com",
"hashed_password": "fakehashedsecret",
"disabled": False,
},
"alice": {
"username": "alice",
"full_name": "Alice Wonderson",
"email": "alice@example.com",
"hashed_password": "fakehashedsecret2",
"disabled": True,
},
}
app = FastAPI()
def fake_hash_password(password: str):
return "fakehashed" + password
oauth2_scheme = OAuth2PasswordBearer(tokenUrl="token")
class User(BaseModel):
username: str
email: Union[str, None] = None
full_name: Union[str, None] = None
disabled: Union[bool, None] = None
class UserInDB(User):
hashed_password: str
def get_user(db, username: str):
if username in db:
user_dict = db[username]
return UserInDB(**user_dict)
def fake_decode_token(token):
# This doesn't provide any security at all
# Check the next version
user = get_user(fake_users_db, token)
return user
async def get_current_user(token: Annotated[str, Depends(oauth2_scheme)]):
user = fake_decode_token(token)
if not user:
raise HTTPException(
status_code=status.HTTP_401_UNAUTHORIZED,
detail="Invalid authentication credentials",
headers={"WWW-Authenticate": "Bearer"},
)
return user
async def get_current_active_user(
current_user: Annotated[User, Depends(get_current_user)],
):
if current_user.disabled:
raise HTTPException(status_code=400, detail="Inactive user")
return current_user
@app.post("/token")
async def login(form_data: Annotated[OAuth2PasswordRequestForm, Depends()]):
user_dict = fake_users_db.get(form_data.username)
if not user_dict:
raise HTTPException(status_code=400, detail="Incorrect username or password")
user = UserInDB(**user_dict)
hashed_password = fake_hash_password(form_data.password)
if not hashed_password == user.hashed_password:
raise HTTPException(status_code=400, detail="Incorrect username or password")
return {"access_token": user.username, "token_type": "bearer"}
@app.get("/users/me")
async def read_users_me(
current_user: Annotated[User, Depends(get_current_active_user)],
):
return current_user
from typing import Union
from fastapi import Depends, FastAPI, HTTPException, status
from fastapi.security import OAuth2PasswordBearer, OAuth2PasswordRequestForm
from pydantic import BaseModel
from typing_extensions import Annotated
fake_users_db = {
"johndoe": {
"username": "johndoe",
"full_name": "John Doe",
"email": "johndoe@example.com",
"hashed_password": "fakehashedsecret",
"disabled": False,
},
"alice": {
"username": "alice",
"full_name": "Alice Wonderson",
"email": "alice@example.com",
"hashed_password": "fakehashedsecret2",
"disabled": True,
},
}
app = FastAPI()
def fake_hash_password(password: str):
return "fakehashed" + password
oauth2_scheme = OAuth2PasswordBearer(tokenUrl="token")
class User(BaseModel):
username: str
email: Union[str, None] = None
full_name: Union[str, None] = None
disabled: Union[bool, None] = None
class UserInDB(User):
hashed_password: str
def get_user(db, username: str):
if username in db:
user_dict = db[username]
return UserInDB(**user_dict)
def fake_decode_token(token):
# This doesn't provide any security at all
# Check the next version
user = get_user(fake_users_db, token)
return user
async def get_current_user(token: Annotated[str, Depends(oauth2_scheme)]):
user = fake_decode_token(token)
if not user:
raise HTTPException(
status_code=status.HTTP_401_UNAUTHORIZED,
detail="Invalid authentication credentials",
headers={"WWW-Authenticate": "Bearer"},
)
return user
async def get_current_active_user(
current_user: Annotated[User, Depends(get_current_user)],
):
if current_user.disabled:
raise HTTPException(status_code=400, detail="Inactive user")
return current_user
@app.post("/token")
async def login(form_data: Annotated[OAuth2PasswordRequestForm, Depends()]):
user_dict = fake_users_db.get(form_data.username)
if not user_dict:
raise HTTPException(status_code=400, detail="Incorrect username or password")
user = UserInDB(**user_dict)
hashed_password = fake_hash_password(form_data.password)
if not hashed_password == user.hashed_password:
raise HTTPException(status_code=400, detail="Incorrect username or password")
return {"access_token": user.username, "token_type": "bearer"}
@app.get("/users/me")
async def read_users_me(
current_user: Annotated[User, Depends(get_current_active_user)],
):
return current_user
Tip
Prefer to use the Annotated
version if possible.
from fastapi import Depends, FastAPI, HTTPException, status
from fastapi.security import OAuth2PasswordBearer, OAuth2PasswordRequestForm
from pydantic import BaseModel
fake_users_db = {
"johndoe": {
"username": "johndoe",
"full_name": "John Doe",
"email": "johndoe@example.com",
"hashed_password": "fakehashedsecret",
"disabled": False,
},
"alice": {
"username": "alice",
"full_name": "Alice Wonderson",
"email": "alice@example.com",
"hashed_password": "fakehashedsecret2",
"disabled": True,
},
}
app = FastAPI()
def fake_hash_password(password: str):
return "fakehashed" + password
oauth2_scheme = OAuth2PasswordBearer(tokenUrl="token")
class User(BaseModel):
username: str
email: str | None = None
full_name: str | None = None
disabled: bool | None = None
class UserInDB(User):
hashed_password: str
def get_user(db, username: str):
if username in db:
user_dict = db[username]
return UserInDB(**user_dict)
def fake_decode_token(token):
# This doesn't provide any security at all
# Check the next version
user = get_user(fake_users_db, token)
return user
async def get_current_user(token: str = Depends(oauth2_scheme)):
user = fake_decode_token(token)
if not user:
raise HTTPException(
status_code=status.HTTP_401_UNAUTHORIZED,
detail="Invalid authentication credentials",
headers={"WWW-Authenticate": "Bearer"},
)
return user
async def get_current_active_user(current_user: User = Depends(get_current_user)):
if current_user.disabled:
raise HTTPException(status_code=400, detail="Inactive user")
return current_user
@app.post("/token")
async def login(form_data: OAuth2PasswordRequestForm = Depends()):
user_dict = fake_users_db.get(form_data.username)
if not user_dict:
raise HTTPException(status_code=400, detail="Incorrect username or password")
user = UserInDB(**user_dict)
hashed_password = fake_hash_password(form_data.password)
if not hashed_password == user.hashed_password:
raise HTTPException(status_code=400, detail="Incorrect username or password")
return {"access_token": user.username, "token_type": "bearer"}
@app.get("/users/me")
async def read_users_me(current_user: User = Depends(get_current_active_user)):
return current_user
Tip
Prefer to use the Annotated
version if possible.
from typing import Union
from fastapi import Depends, FastAPI, HTTPException, status
from fastapi.security import OAuth2PasswordBearer, OAuth2PasswordRequestForm
from pydantic import BaseModel
fake_users_db = {
"johndoe": {
"username": "johndoe",
"full_name": "John Doe",
"email": "johndoe@example.com",
"hashed_password": "fakehashedsecret",
"disabled": False,
},
"alice": {
"username": "alice",
"full_name": "Alice Wonderson",
"email": "alice@example.com",
"hashed_password": "fakehashedsecret2",
"disabled": True,
},
}
app = FastAPI()
def fake_hash_password(password: str):
return "fakehashed" + password
oauth2_scheme = OAuth2PasswordBearer(tokenUrl="token")
class User(BaseModel):
username: str
email: Union[str, None] = None
full_name: Union[str, None] = None
disabled: Union[bool, None] = None
class UserInDB(User):
hashed_password: str
def get_user(db, username: str):
if username in db:
user_dict = db[username]
return UserInDB(**user_dict)
def fake_decode_token(token):
# This doesn't provide any security at all
# Check the next version
user = get_user(fake_users_db, token)
return user
async def get_current_user(token: str = Depends(oauth2_scheme)):
user = fake_decode_token(token)
if not user:
raise HTTPException(
status_code=status.HTTP_401_UNAUTHORIZED,
detail="Invalid authentication credentials",
headers={"WWW-Authenticate": "Bearer"},
)
return user
async def get_current_active_user(current_user: User = Depends(get_current_user)):
if current_user.disabled:
raise HTTPException(status_code=400, detail="Inactive user")
return current_user
@app.post("/token")
async def login(form_data: OAuth2PasswordRequestForm = Depends()):
user_dict = fake_users_db.get(form_data.username)
if not user_dict:
raise HTTPException(status_code=400, detail="Incorrect username or password")
user = UserInDB(**user_dict)
hashed_password = fake_hash_password(form_data.password)
if not hashed_password == user.hashed_password:
raise HTTPException(status_code=400, detail="Incorrect username or password")
return {"access_token": user.username, "token_type": "bearer"}
@app.get("/users/me")
async def read_users_me(current_user: User = Depends(get_current_active_user)):
return current_user
OAuth2PasswordRequestForm
es una dependencia de clase que declara un body de formulario con:
- El
username
. - El
password
. - Un campo opcional
scope
como un string grande, compuesto por strings separados por espacios. - Un
grant_type
opcional.
Consejo
La especificación de OAuth2 en realidad requiere un campo grant_type
con un valor fijo de password
, pero OAuth2PasswordRequestForm
no lo obliga.
Si necesitas imponerlo, utiliza OAuth2PasswordRequestFormStrict
en lugar de OAuth2PasswordRequestForm
.
- Un
client_id
opcional (no lo necesitamos para nuestro ejemplo). - Un
client_secret
opcional (no lo necesitamos para nuestro ejemplo).
Información
OAuth2PasswordRequestForm
no es una clase especial para FastAPI como lo es OAuth2PasswordBearer
.
OAuth2PasswordBearer
hace que FastAPI sepa que es un esquema de seguridad. Así que se añade de esa manera a OpenAPI.
Pero OAuth2PasswordRequestForm
es solo una dependencia de clase que podrías haber escrito tú mismo, o podrías haber declarado parámetros de Form
directamente.
Pero como es un caso de uso común, se proporciona directamente por FastAPI, solo para facilitarlo.
Usa el form data¶
Consejo
La instance de la clase de dependencia OAuth2PasswordRequestForm
no tendrá un atributo scope
con el string largo separado por espacios, en su lugar, tendrá un atributo scopes
con la lista real de strings para cada scope enviado.
No estamos usando scopes
en este ejemplo, pero la funcionalidad está ahí si la necesitas.
Ahora, obtén los datos del usuario desde la base de datos (falsa), usando el username
del campo del form.
Si no existe tal usuario, devolvemos un error diciendo "Incorrect username or password".
Para el error, usamos la excepción HTTPException
:
from typing import Annotated
from fastapi import Depends, FastAPI, HTTPException, status
from fastapi.security import OAuth2PasswordBearer, OAuth2PasswordRequestForm
from pydantic import BaseModel
fake_users_db = {
"johndoe": {
"username": "johndoe",
"full_name": "John Doe",
"email": "johndoe@example.com",
"hashed_password": "fakehashedsecret",
"disabled": False,
},
"alice": {
"username": "alice",
"full_name": "Alice Wonderson",
"email": "alice@example.com",
"hashed_password": "fakehashedsecret2",
"disabled": True,
},
}
app = FastAPI()
def fake_hash_password(password: str):
return "fakehashed" + password
oauth2_scheme = OAuth2PasswordBearer(tokenUrl="token")
class User(BaseModel):
username: str
email: str | None = None
full_name: str | None = None
disabled: bool | None = None
class UserInDB(User):
hashed_password: str
def get_user(db, username: str):
if username in db:
user_dict = db[username]
return UserInDB(**user_dict)
def fake_decode_token(token):
# This doesn't provide any security at all
# Check the next version
user = get_user(fake_users_db, token)
return user
async def get_current_user(token: Annotated[str, Depends(oauth2_scheme)]):
user = fake_decode_token(token)
if not user:
raise HTTPException(
status_code=status.HTTP_401_UNAUTHORIZED,
detail="Invalid authentication credentials",
headers={"WWW-Authenticate": "Bearer"},
)
return user
async def get_current_active_user(
current_user: Annotated[User, Depends(get_current_user)],
):
if current_user.disabled:
raise HTTPException(status_code=400, detail="Inactive user")
return current_user
@app.post("/token")
async def login(form_data: Annotated[OAuth2PasswordRequestForm, Depends()]):
user_dict = fake_users_db.get(form_data.username)
if not user_dict:
raise HTTPException(status_code=400, detail="Incorrect username or password")
user = UserInDB(**user_dict)
hashed_password = fake_hash_password(form_data.password)
if not hashed_password == user.hashed_password:
raise HTTPException(status_code=400, detail="Incorrect username or password")
return {"access_token": user.username, "token_type": "bearer"}
@app.get("/users/me")
async def read_users_me(
current_user: Annotated[User, Depends(get_current_active_user)],
):
return current_user
🤓 Other versions and variants
from typing import Annotated, Union
from fastapi import Depends, FastAPI, HTTPException, status
from fastapi.security import OAuth2PasswordBearer, OAuth2PasswordRequestForm
from pydantic import BaseModel
fake_users_db = {
"johndoe": {
"username": "johndoe",
"full_name": "John Doe",
"email": "johndoe@example.com",
"hashed_password": "fakehashedsecret",
"disabled": False,
},
"alice": {
"username": "alice",
"full_name": "Alice Wonderson",
"email": "alice@example.com",
"hashed_password": "fakehashedsecret2",
"disabled": True,
},
}
app = FastAPI()
def fake_hash_password(password: str):
return "fakehashed" + password
oauth2_scheme = OAuth2PasswordBearer(tokenUrl="token")
class User(BaseModel):
username: str
email: Union[str, None] = None
full_name: Union[str, None] = None
disabled: Union[bool, None] = None
class UserInDB(User):
hashed_password: str
def get_user(db, username: str):
if username in db:
user_dict = db[username]
return UserInDB(**user_dict)
def fake_decode_token(token):
# This doesn't provide any security at all
# Check the next version
user = get_user(fake_users_db, token)
return user
async def get_current_user(token: Annotated[str, Depends(oauth2_scheme)]):
user = fake_decode_token(token)
if not user:
raise HTTPException(
status_code=status.HTTP_401_UNAUTHORIZED,
detail="Invalid authentication credentials",
headers={"WWW-Authenticate": "Bearer"},
)
return user
async def get_current_active_user(
current_user: Annotated[User, Depends(get_current_user)],
):
if current_user.disabled:
raise HTTPException(status_code=400, detail="Inactive user")
return current_user
@app.post("/token")
async def login(form_data: Annotated[OAuth2PasswordRequestForm, Depends()]):
user_dict = fake_users_db.get(form_data.username)
if not user_dict:
raise HTTPException(status_code=400, detail="Incorrect username or password")
user = UserInDB(**user_dict)
hashed_password = fake_hash_password(form_data.password)
if not hashed_password == user.hashed_password:
raise HTTPException(status_code=400, detail="Incorrect username or password")
return {"access_token": user.username, "token_type": "bearer"}
@app.get("/users/me")
async def read_users_me(
current_user: Annotated[User, Depends(get_current_active_user)],
):
return current_user
from typing import Union
from fastapi import Depends, FastAPI, HTTPException, status
from fastapi.security import OAuth2PasswordBearer, OAuth2PasswordRequestForm
from pydantic import BaseModel
from typing_extensions import Annotated
fake_users_db = {
"johndoe": {
"username": "johndoe",
"full_name": "John Doe",
"email": "johndoe@example.com",
"hashed_password": "fakehashedsecret",
"disabled": False,
},
"alice": {
"username": "alice",
"full_name": "Alice Wonderson",
"email": "alice@example.com",
"hashed_password": "fakehashedsecret2",
"disabled": True,
},
}
app = FastAPI()
def fake_hash_password(password: str):
return "fakehashed" + password
oauth2_scheme = OAuth2PasswordBearer(tokenUrl="token")
class User(BaseModel):
username: str
email: Union[str, None] = None
full_name: Union[str, None] = None
disabled: Union[bool, None] = None
class UserInDB(User):
hashed_password: str
def get_user(db, username: str):
if username in db:
user_dict = db[username]
return UserInDB(**user_dict)
def fake_decode_token(token):
# This doesn't provide any security at all
# Check the next version
user = get_user(fake_users_db, token)
return user
async def get_current_user(token: Annotated[str, Depends(oauth2_scheme)]):
user = fake_decode_token(token)
if not user:
raise HTTPException(
status_code=status.HTTP_401_UNAUTHORIZED,
detail="Invalid authentication credentials",
headers={"WWW-Authenticate": "Bearer"},
)
return user
async def get_current_active_user(
current_user: Annotated[User, Depends(get_current_user)],
):
if current_user.disabled:
raise HTTPException(status_code=400, detail="Inactive user")
return current_user
@app.post("/token")
async def login(form_data: Annotated[OAuth2PasswordRequestForm, Depends()]):
user_dict = fake_users_db.get(form_data.username)
if not user_dict:
raise HTTPException(status_code=400, detail="Incorrect username or password")
user = UserInDB(**user_dict)
hashed_password = fake_hash_password(form_data.password)
if not hashed_password == user.hashed_password:
raise HTTPException(status_code=400, detail="Incorrect username or password")
return {"access_token": user.username, "token_type": "bearer"}
@app.get("/users/me")
async def read_users_me(
current_user: Annotated[User, Depends(get_current_active_user)],
):
return current_user
Tip
Prefer to use the Annotated
version if possible.
from fastapi import Depends, FastAPI, HTTPException, status
from fastapi.security import OAuth2PasswordBearer, OAuth2PasswordRequestForm
from pydantic import BaseModel
fake_users_db = {
"johndoe": {
"username": "johndoe",
"full_name": "John Doe",
"email": "johndoe@example.com",
"hashed_password": "fakehashedsecret",
"disabled": False,
},
"alice": {
"username": "alice",
"full_name": "Alice Wonderson",
"email": "alice@example.com",
"hashed_password": "fakehashedsecret2",
"disabled": True,
},
}
app = FastAPI()
def fake_hash_password(password: str):
return "fakehashed" + password
oauth2_scheme = OAuth2PasswordBearer(tokenUrl="token")
class User(BaseModel):
username: str
email: str | None = None
full_name: str | None = None
disabled: bool | None = None
class UserInDB(User):
hashed_password: str
def get_user(db, username: str):
if username in db:
user_dict = db[username]
return UserInDB(**user_dict)
def fake_decode_token(token):
# This doesn't provide any security at all
# Check the next version
user = get_user(fake_users_db, token)
return user
async def get_current_user(token: str = Depends(oauth2_scheme)):
user = fake_decode_token(token)
if not user:
raise HTTPException(
status_code=status.HTTP_401_UNAUTHORIZED,
detail="Invalid authentication credentials",
headers={"WWW-Authenticate": "Bearer"},
)
return user
async def get_current_active_user(current_user: User = Depends(get_current_user)):
if current_user.disabled:
raise HTTPException(status_code=400, detail="Inactive user")
return current_user
@app.post("/token")
async def login(form_data: OAuth2PasswordRequestForm = Depends()):
user_dict = fake_users_db.get(form_data.username)
if not user_dict:
raise HTTPException(status_code=400, detail="Incorrect username or password")
user = UserInDB(**user_dict)
hashed_password = fake_hash_password(form_data.password)
if not hashed_password == user.hashed_password:
raise HTTPException(status_code=400, detail="Incorrect username or password")
return {"access_token": user.username, "token_type": "bearer"}
@app.get("/users/me")
async def read_users_me(current_user: User = Depends(get_current_active_user)):
return current_user
Tip
Prefer to use the Annotated
version if possible.
from typing import Union
from fastapi import Depends, FastAPI, HTTPException, status
from fastapi.security import OAuth2PasswordBearer, OAuth2PasswordRequestForm
from pydantic import BaseModel
fake_users_db = {
"johndoe": {
"username": "johndoe",
"full_name": "John Doe",
"email": "johndoe@example.com",
"hashed_password": "fakehashedsecret",
"disabled": False,
},
"alice": {
"username": "alice",
"full_name": "Alice Wonderson",
"email": "alice@example.com",
"hashed_password": "fakehashedsecret2",
"disabled": True,
},
}
app = FastAPI()
def fake_hash_password(password: str):
return "fakehashed" + password
oauth2_scheme = OAuth2PasswordBearer(tokenUrl="token")
class User(BaseModel):
username: str
email: Union[str, None] = None
full_name: Union[str, None] = None
disabled: Union[bool, None] = None
class UserInDB(User):
hashed_password: str
def get_user(db, username: str):
if username in db:
user_dict = db[username]
return UserInDB(**user_dict)
def fake_decode_token(token):
# This doesn't provide any security at all
# Check the next version
user = get_user(fake_users_db, token)
return user
async def get_current_user(token: str = Depends(oauth2_scheme)):
user = fake_decode_token(token)
if not user:
raise HTTPException(
status_code=status.HTTP_401_UNAUTHORIZED,
detail="Invalid authentication credentials",
headers={"WWW-Authenticate": "Bearer"},
)
return user
async def get_current_active_user(current_user: User = Depends(get_current_user)):
if current_user.disabled:
raise HTTPException(status_code=400, detail="Inactive user")
return current_user
@app.post("/token")
async def login(form_data: OAuth2PasswordRequestForm = Depends()):
user_dict = fake_users_db.get(form_data.username)
if not user_dict:
raise HTTPException(status_code=400, detail="Incorrect username or password")
user = UserInDB(**user_dict)
hashed_password = fake_hash_password(form_data.password)
if not hashed_password == user.hashed_password:
raise HTTPException(status_code=400, detail="Incorrect username or password")
return {"access_token": user.username, "token_type": "bearer"}
@app.get("/users/me")
async def read_users_me(current_user: User = Depends(get_current_active_user)):
return current_user
Revisa el password¶
En este punto tenemos los datos del usuario de nuestra base de datos, pero no hemos revisado el password.
Primero pongamos esos datos en el modelo UserInDB
de Pydantic.
Nunca deberías guardar passwords en texto plano, así que, usaremos el sistema de hash de passwords (falso).
Si los passwords no coinciden, devolvemos el mismo error.
Hashing de passwords¶
"Hacer hash" significa: convertir algún contenido (un password en este caso) en una secuencia de bytes (solo un string) que parece un galimatías.
Siempre que pases exactamente el mismo contenido (exactamente el mismo password) obtienes exactamente el mismo galimatías.
Pero no puedes convertir del galimatías al password.
Por qué usar hashing de passwords¶
Si tu base de datos es robada, el ladrón no tendrá los passwords en texto plano de tus usuarios, solo los hashes.
Entonces, el ladrón no podrá intentar usar esos mismos passwords en otro sistema (como muchos usuarios usan el mismo password en todas partes, esto sería peligroso).
from typing import Annotated
from fastapi import Depends, FastAPI, HTTPException, status
from fastapi.security import OAuth2PasswordBearer, OAuth2PasswordRequestForm
from pydantic import BaseModel
fake_users_db = {
"johndoe": {
"username": "johndoe",
"full_name": "John Doe",
"email": "johndoe@example.com",
"hashed_password": "fakehashedsecret",
"disabled": False,
},
"alice": {
"username": "alice",
"full_name": "Alice Wonderson",
"email": "alice@example.com",
"hashed_password": "fakehashedsecret2",
"disabled": True,
},
}
app = FastAPI()
def fake_hash_password(password: str):
return "fakehashed" + password
oauth2_scheme = OAuth2PasswordBearer(tokenUrl="token")
class User(BaseModel):
username: str
email: str | None = None
full_name: str | None = None
disabled: bool | None = None
class UserInDB(User):
hashed_password: str
def get_user(db, username: str):
if username in db:
user_dict = db[username]
return UserInDB(**user_dict)
def fake_decode_token(token):
# This doesn't provide any security at all
# Check the next version
user = get_user(fake_users_db, token)
return user
async def get_current_user(token: Annotated[str, Depends(oauth2_scheme)]):
user = fake_decode_token(token)
if not user:
raise HTTPException(
status_code=status.HTTP_401_UNAUTHORIZED,
detail="Invalid authentication credentials",
headers={"WWW-Authenticate": "Bearer"},
)
return user
async def get_current_active_user(
current_user: Annotated[User, Depends(get_current_user)],
):
if current_user.disabled:
raise HTTPException(status_code=400, detail="Inactive user")
return current_user
@app.post("/token")
async def login(form_data: Annotated[OAuth2PasswordRequestForm, Depends()]):
user_dict = fake_users_db.get(form_data.username)
if not user_dict:
raise HTTPException(status_code=400, detail="Incorrect username or password")
user = UserInDB(**user_dict)
hashed_password = fake_hash_password(form_data.password)
if not hashed_password == user.hashed_password:
raise HTTPException(status_code=400, detail="Incorrect username or password")
return {"access_token": user.username, "token_type": "bearer"}
@app.get("/users/me")
async def read_users_me(
current_user: Annotated[User, Depends(get_current_active_user)],
):
return current_user
🤓 Other versions and variants
from typing import Annotated, Union
from fastapi import Depends, FastAPI, HTTPException, status
from fastapi.security import OAuth2PasswordBearer, OAuth2PasswordRequestForm
from pydantic import BaseModel
fake_users_db = {
"johndoe": {
"username": "johndoe",
"full_name": "John Doe",
"email": "johndoe@example.com",
"hashed_password": "fakehashedsecret",
"disabled": False,
},
"alice": {
"username": "alice",
"full_name": "Alice Wonderson",
"email": "alice@example.com",
"hashed_password": "fakehashedsecret2",
"disabled": True,
},
}
app = FastAPI()
def fake_hash_password(password: str):
return "fakehashed" + password
oauth2_scheme = OAuth2PasswordBearer(tokenUrl="token")
class User(BaseModel):
username: str
email: Union[str, None] = None
full_name: Union[str, None] = None
disabled: Union[bool, None] = None
class UserInDB(User):
hashed_password: str
def get_user(db, username: str):
if username in db:
user_dict = db[username]
return UserInDB(**user_dict)
def fake_decode_token(token):
# This doesn't provide any security at all
# Check the next version
user = get_user(fake_users_db, token)
return user
async def get_current_user(token: Annotated[str, Depends(oauth2_scheme)]):
user = fake_decode_token(token)
if not user:
raise HTTPException(
status_code=status.HTTP_401_UNAUTHORIZED,
detail="Invalid authentication credentials",
headers={"WWW-Authenticate": "Bearer"},
)
return user
async def get_current_active_user(
current_user: Annotated[User, Depends(get_current_user)],
):
if current_user.disabled:
raise HTTPException(status_code=400, detail="Inactive user")
return current_user
@app.post("/token")
async def login(form_data: Annotated[OAuth2PasswordRequestForm, Depends()]):
user_dict = fake_users_db.get(form_data.username)
if not user_dict:
raise HTTPException(status_code=400, detail="Incorrect username or password")
user = UserInDB(**user_dict)
hashed_password = fake_hash_password(form_data.password)
if not hashed_password == user.hashed_password:
raise HTTPException(status_code=400, detail="Incorrect username or password")
return {"access_token": user.username, "token_type": "bearer"}
@app.get("/users/me")
async def read_users_me(
current_user: Annotated[User, Depends(get_current_active_user)],
):
return current_user
from typing import Union
from fastapi import Depends, FastAPI, HTTPException, status
from fastapi.security import OAuth2PasswordBearer, OAuth2PasswordRequestForm
from pydantic import BaseModel
from typing_extensions import Annotated
fake_users_db = {
"johndoe": {
"username": "johndoe",
"full_name": "John Doe",
"email": "johndoe@example.com",
"hashed_password": "fakehashedsecret",
"disabled": False,
},
"alice": {
"username": "alice",
"full_name": "Alice Wonderson",
"email": "alice@example.com",
"hashed_password": "fakehashedsecret2",
"disabled": True,
},
}
app = FastAPI()
def fake_hash_password(password: str):
return "fakehashed" + password
oauth2_scheme = OAuth2PasswordBearer(tokenUrl="token")
class User(BaseModel):
username: str
email: Union[str, None] = None
full_name: Union[str, None] = None
disabled: Union[bool, None] = None
class UserInDB(User):
hashed_password: str
def get_user(db, username: str):
if username in db:
user_dict = db[username]
return UserInDB(**user_dict)
def fake_decode_token(token):
# This doesn't provide any security at all
# Check the next version
user = get_user(fake_users_db, token)
return user
async def get_current_user(token: Annotated[str, Depends(oauth2_scheme)]):
user = fake_decode_token(token)
if not user:
raise HTTPException(
status_code=status.HTTP_401_UNAUTHORIZED,
detail="Invalid authentication credentials",
headers={"WWW-Authenticate": "Bearer"},
)
return user
async def get_current_active_user(
current_user: Annotated[User, Depends(get_current_user)],
):
if current_user.disabled:
raise HTTPException(status_code=400, detail="Inactive user")
return current_user
@app.post("/token")
async def login(form_data: Annotated[OAuth2PasswordRequestForm, Depends()]):
user_dict = fake_users_db.get(form_data.username)
if not user_dict:
raise HTTPException(status_code=400, detail="Incorrect username or password")
user = UserInDB(**user_dict)
hashed_password = fake_hash_password(form_data.password)
if not hashed_password == user.hashed_password:
raise HTTPException(status_code=400, detail="Incorrect username or password")
return {"access_token": user.username, "token_type": "bearer"}
@app.get("/users/me")
async def read_users_me(
current_user: Annotated[User, Depends(get_current_active_user)],
):
return current_user
Tip
Prefer to use the Annotated
version if possible.
from fastapi import Depends, FastAPI, HTTPException, status
from fastapi.security import OAuth2PasswordBearer, OAuth2PasswordRequestForm
from pydantic import BaseModel
fake_users_db = {
"johndoe": {
"username": "johndoe",
"full_name": "John Doe",
"email": "johndoe@example.com",
"hashed_password": "fakehashedsecret",
"disabled": False,
},
"alice": {
"username": "alice",
"full_name": "Alice Wonderson",
"email": "alice@example.com",
"hashed_password": "fakehashedsecret2",
"disabled": True,
},
}
app = FastAPI()
def fake_hash_password(password: str):
return "fakehashed" + password
oauth2_scheme = OAuth2PasswordBearer(tokenUrl="token")
class User(BaseModel):
username: str
email: str | None = None
full_name: str | None = None
disabled: bool | None = None
class UserInDB(User):
hashed_password: str
def get_user(db, username: str):
if username in db:
user_dict = db[username]
return UserInDB(**user_dict)
def fake_decode_token(token):
# This doesn't provide any security at all
# Check the next version
user = get_user(fake_users_db, token)
return user
async def get_current_user(token: str = Depends(oauth2_scheme)):
user = fake_decode_token(token)
if not user:
raise HTTPException(
status_code=status.HTTP_401_UNAUTHORIZED,
detail="Invalid authentication credentials",
headers={"WWW-Authenticate": "Bearer"},
)
return user
async def get_current_active_user(current_user: User = Depends(get_current_user)):
if current_user.disabled:
raise HTTPException(status_code=400, detail="Inactive user")
return current_user
@app.post("/token")
async def login(form_data: OAuth2PasswordRequestForm = Depends()):
user_dict = fake_users_db.get(form_data.username)
if not user_dict:
raise HTTPException(status_code=400, detail="Incorrect username or password")
user = UserInDB(**user_dict)
hashed_password = fake_hash_password(form_data.password)
if not hashed_password == user.hashed_password:
raise HTTPException(status_code=400, detail="Incorrect username or password")
return {"access_token": user.username, "token_type": "bearer"}
@app.get("/users/me")
async def read_users_me(current_user: User = Depends(get_current_active_user)):
return current_user
Tip
Prefer to use the Annotated
version if possible.
from typing import Union
from fastapi import Depends, FastAPI, HTTPException, status
from fastapi.security import OAuth2PasswordBearer, OAuth2PasswordRequestForm
from pydantic import BaseModel
fake_users_db = {
"johndoe": {
"username": "johndoe",
"full_name": "John Doe",
"email": "johndoe@example.com",
"hashed_password": "fakehashedsecret",
"disabled": False,
},
"alice": {
"username": "alice",
"full_name": "Alice Wonderson",
"email": "alice@example.com",
"hashed_password": "fakehashedsecret2",
"disabled": True,
},
}
app = FastAPI()
def fake_hash_password(password: str):
return "fakehashed" + password
oauth2_scheme = OAuth2PasswordBearer(tokenUrl="token")
class User(BaseModel):
username: str
email: Union[str, None] = None
full_name: Union[str, None] = None
disabled: Union[bool, None] = None
class UserInDB(User):
hashed_password: str
def get_user(db, username: str):
if username in db:
user_dict = db[username]
return UserInDB(**user_dict)
def fake_decode_token(token):
# This doesn't provide any security at all
# Check the next version
user = get_user(fake_users_db, token)
return user
async def get_current_user(token: str = Depends(oauth2_scheme)):
user = fake_decode_token(token)
if not user:
raise HTTPException(
status_code=status.HTTP_401_UNAUTHORIZED,
detail="Invalid authentication credentials",
headers={"WWW-Authenticate": "Bearer"},
)
return user
async def get_current_active_user(current_user: User = Depends(get_current_user)):
if current_user.disabled:
raise HTTPException(status_code=400, detail="Inactive user")
return current_user
@app.post("/token")
async def login(form_data: OAuth2PasswordRequestForm = Depends()):
user_dict = fake_users_db.get(form_data.username)
if not user_dict:
raise HTTPException(status_code=400, detail="Incorrect username or password")
user = UserInDB(**user_dict)
hashed_password = fake_hash_password(form_data.password)
if not hashed_password == user.hashed_password:
raise HTTPException(status_code=400, detail="Incorrect username or password")
return {"access_token": user.username, "token_type": "bearer"}
@app.get("/users/me")
async def read_users_me(current_user: User = Depends(get_current_active_user)):
return current_user
Sobre **user_dict
¶
UserInDB(**user_dict)
significa:
Pasa las claves y valores de user_dict
directamente como argumentos clave-valor, equivalente a:
UserInDB(
username = user_dict["username"],
email = user_dict["email"],
full_name = user_dict["full_name"],
disabled = user_dict["disabled"],
hashed_password = user_dict["hashed_password"],
)
Información
Para una explicación más completa de **user_dict
revisa en la documentación para Extra Models.
Devolver el token¶
El response del endpoint token
debe ser un objeto JSON.
Debe tener un token_type
. En nuestro caso, como estamos usando tokens "Bearer", el tipo de token debe ser "bearer
".
Y debe tener un access_token
, con un string que contenga nuestro token de acceso.
Para este ejemplo simple, vamos a ser completamente inseguros y devolver el mismo username
como el token.
Consejo
En el próximo capítulo, verás una implementación segura real, con hashing de passwords y tokens JWT.
Pero por ahora, enfoquémonos en los detalles específicos que necesitamos.
from typing import Annotated
from fastapi import Depends, FastAPI, HTTPException, status
from fastapi.security import OAuth2PasswordBearer, OAuth2PasswordRequestForm
from pydantic import BaseModel
fake_users_db = {
"johndoe": {
"username": "johndoe",
"full_name": "John Doe",
"email": "johndoe@example.com",
"hashed_password": "fakehashedsecret",
"disabled": False,
},
"alice": {
"username": "alice",
"full_name": "Alice Wonderson",
"email": "alice@example.com",
"hashed_password": "fakehashedsecret2",
"disabled": True,
},
}
app = FastAPI()
def fake_hash_password(password: str):
return "fakehashed" + password
oauth2_scheme = OAuth2PasswordBearer(tokenUrl="token")
class User(BaseModel):
username: str
email: str | None = None
full_name: str | None = None
disabled: bool | None = None
class UserInDB(User):
hashed_password: str
def get_user(db, username: str):
if username in db:
user_dict = db[username]
return UserInDB(**user_dict)
def fake_decode_token(token):
# This doesn't provide any security at all
# Check the next version
user = get_user(fake_users_db, token)
return user
async def get_current_user(token: Annotated[str, Depends(oauth2_scheme)]):
user = fake_decode_token(token)
if not user:
raise HTTPException(
status_code=status.HTTP_401_UNAUTHORIZED,
detail="Invalid authentication credentials",
headers={"WWW-Authenticate": "Bearer"},
)
return user
async def get_current_active_user(
current_user: Annotated[User, Depends(get_current_user)],
):
if current_user.disabled:
raise HTTPException(status_code=400, detail="Inactive user")
return current_user
@app.post("/token")
async def login(form_data: Annotated[OAuth2PasswordRequestForm, Depends()]):
user_dict = fake_users_db.get(form_data.username)
if not user_dict:
raise HTTPException(status_code=400, detail="Incorrect username or password")
user = UserInDB(**user_dict)
hashed_password = fake_hash_password(form_data.password)
if not hashed_password == user.hashed_password:
raise HTTPException(status_code=400, detail="Incorrect username or password")
return {"access_token": user.username, "token_type": "bearer"}
@app.get("/users/me")
async def read_users_me(
current_user: Annotated[User, Depends(get_current_active_user)],
):
return current_user
🤓 Other versions and variants
from typing import Annotated, Union
from fastapi import Depends, FastAPI, HTTPException, status
from fastapi.security import OAuth2PasswordBearer, OAuth2PasswordRequestForm
from pydantic import BaseModel
fake_users_db = {
"johndoe": {
"username": "johndoe",
"full_name": "John Doe",
"email": "johndoe@example.com",
"hashed_password": "fakehashedsecret",
"disabled": False,
},
"alice": {
"username": "alice",
"full_name": "Alice Wonderson",
"email": "alice@example.com",
"hashed_password": "fakehashedsecret2",
"disabled": True,
},
}
app = FastAPI()
def fake_hash_password(password: str):
return "fakehashed" + password
oauth2_scheme = OAuth2PasswordBearer(tokenUrl="token")
class User(BaseModel):
username: str
email: Union[str, None] = None
full_name: Union[str, None] = None
disabled: Union[bool, None] = None
class UserInDB(User):
hashed_password: str
def get_user(db, username: str):
if username in db:
user_dict = db[username]
return UserInDB(**user_dict)
def fake_decode_token(token):
# This doesn't provide any security at all
# Check the next version
user = get_user(fake_users_db, token)
return user
async def get_current_user(token: Annotated[str, Depends(oauth2_scheme)]):
user = fake_decode_token(token)
if not user:
raise HTTPException(
status_code=status.HTTP_401_UNAUTHORIZED,
detail="Invalid authentication credentials",
headers={"WWW-Authenticate": "Bearer"},
)
return user
async def get_current_active_user(
current_user: Annotated[User, Depends(get_current_user)],
):
if current_user.disabled:
raise HTTPException(status_code=400, detail="Inactive user")
return current_user
@app.post("/token")
async def login(form_data: Annotated[OAuth2PasswordRequestForm, Depends()]):
user_dict = fake_users_db.get(form_data.username)
if not user_dict:
raise HTTPException(status_code=400, detail="Incorrect username or password")
user = UserInDB(**user_dict)
hashed_password = fake_hash_password(form_data.password)
if not hashed_password == user.hashed_password:
raise HTTPException(status_code=400, detail="Incorrect username or password")
return {"access_token": user.username, "token_type": "bearer"}
@app.get("/users/me")
async def read_users_me(
current_user: Annotated[User, Depends(get_current_active_user)],
):
return current_user
from typing import Union
from fastapi import Depends, FastAPI, HTTPException, status
from fastapi.security import OAuth2PasswordBearer, OAuth2PasswordRequestForm
from pydantic import BaseModel
from typing_extensions import Annotated
fake_users_db = {
"johndoe": {
"username": "johndoe",
"full_name": "John Doe",
"email": "johndoe@example.com",
"hashed_password": "fakehashedsecret",
"disabled": False,
},
"alice": {
"username": "alice",
"full_name": "Alice Wonderson",
"email": "alice@example.com",
"hashed_password": "fakehashedsecret2",
"disabled": True,
},
}
app = FastAPI()
def fake_hash_password(password: str):
return "fakehashed" + password
oauth2_scheme = OAuth2PasswordBearer(tokenUrl="token")
class User(BaseModel):
username: str
email: Union[str, None] = None
full_name: Union[str, None] = None
disabled: Union[bool, None] = None
class UserInDB(User):
hashed_password: str
def get_user(db, username: str):
if username in db:
user_dict = db[username]
return UserInDB(**user_dict)
def fake_decode_token(token):
# This doesn't provide any security at all
# Check the next version
user = get_user(fake_users_db, token)
return user
async def get_current_user(token: Annotated[str, Depends(oauth2_scheme)]):
user = fake_decode_token(token)
if not user:
raise HTTPException(
status_code=status.HTTP_401_UNAUTHORIZED,
detail="Invalid authentication credentials",
headers={"WWW-Authenticate": "Bearer"},
)
return user
async def get_current_active_user(
current_user: Annotated[User, Depends(get_current_user)],
):
if current_user.disabled:
raise HTTPException(status_code=400, detail="Inactive user")
return current_user
@app.post("/token")
async def login(form_data: Annotated[OAuth2PasswordRequestForm, Depends()]):
user_dict = fake_users_db.get(form_data.username)
if not user_dict:
raise HTTPException(status_code=400, detail="Incorrect username or password")
user = UserInDB(**user_dict)
hashed_password = fake_hash_password(form_data.password)
if not hashed_password == user.hashed_password:
raise HTTPException(status_code=400, detail="Incorrect username or password")
return {"access_token": user.username, "token_type": "bearer"}
@app.get("/users/me")
async def read_users_me(
current_user: Annotated[User, Depends(get_current_active_user)],
):
return current_user
Tip
Prefer to use the Annotated
version if possible.
from fastapi import Depends, FastAPI, HTTPException, status
from fastapi.security import OAuth2PasswordBearer, OAuth2PasswordRequestForm
from pydantic import BaseModel
fake_users_db = {
"johndoe": {
"username": "johndoe",
"full_name": "John Doe",
"email": "johndoe@example.com",
"hashed_password": "fakehashedsecret",
"disabled": False,
},
"alice": {
"username": "alice",
"full_name": "Alice Wonderson",
"email": "alice@example.com",
"hashed_password": "fakehashedsecret2",
"disabled": True,
},
}
app = FastAPI()
def fake_hash_password(password: str):
return "fakehashed" + password
oauth2_scheme = OAuth2PasswordBearer(tokenUrl="token")
class User(BaseModel):
username: str
email: str | None = None
full_name: str | None = None
disabled: bool | None = None
class UserInDB(User):
hashed_password: str
def get_user(db, username: str):
if username in db:
user_dict = db[username]
return UserInDB(**user_dict)
def fake_decode_token(token):
# This doesn't provide any security at all
# Check the next version
user = get_user(fake_users_db, token)
return user
async def get_current_user(token: str = Depends(oauth2_scheme)):
user = fake_decode_token(token)
if not user:
raise HTTPException(
status_code=status.HTTP_401_UNAUTHORIZED,
detail="Invalid authentication credentials",
headers={"WWW-Authenticate": "Bearer"},
)
return user
async def get_current_active_user(current_user: User = Depends(get_current_user)):
if current_user.disabled:
raise HTTPException(status_code=400, detail="Inactive user")
return current_user
@app.post("/token")
async def login(form_data: OAuth2PasswordRequestForm = Depends()):
user_dict = fake_users_db.get(form_data.username)
if not user_dict:
raise HTTPException(status_code=400, detail="Incorrect username or password")
user = UserInDB(**user_dict)
hashed_password = fake_hash_password(form_data.password)
if not hashed_password == user.hashed_password:
raise HTTPException(status_code=400, detail="Incorrect username or password")
return {"access_token": user.username, "token_type": "bearer"}
@app.get("/users/me")
async def read_users_me(current_user: User = Depends(get_current_active_user)):
return current_user
Tip
Prefer to use the Annotated
version if possible.
from typing import Union
from fastapi import Depends, FastAPI, HTTPException, status
from fastapi.security import OAuth2PasswordBearer, OAuth2PasswordRequestForm
from pydantic import BaseModel
fake_users_db = {
"johndoe": {
"username": "johndoe",
"full_name": "John Doe",
"email": "johndoe@example.com",
"hashed_password": "fakehashedsecret",
"disabled": False,
},
"alice": {
"username": "alice",
"full_name": "Alice Wonderson",
"email": "alice@example.com",
"hashed_password": "fakehashedsecret2",
"disabled": True,
},
}
app = FastAPI()
def fake_hash_password(password: str):
return "fakehashed" + password
oauth2_scheme = OAuth2PasswordBearer(tokenUrl="token")
class User(BaseModel):
username: str
email: Union[str, None] = None
full_name: Union[str, None] = None
disabled: Union[bool, None] = None
class UserInDB(User):
hashed_password: str
def get_user(db, username: str):
if username in db:
user_dict = db[username]
return UserInDB(**user_dict)
def fake_decode_token(token):
# This doesn't provide any security at all
# Check the next version
user = get_user(fake_users_db, token)
return user
async def get_current_user(token: str = Depends(oauth2_scheme)):
user = fake_decode_token(token)
if not user:
raise HTTPException(
status_code=status.HTTP_401_UNAUTHORIZED,
detail="Invalid authentication credentials",
headers={"WWW-Authenticate": "Bearer"},
)
return user
async def get_current_active_user(current_user: User = Depends(get_current_user)):
if current_user.disabled:
raise HTTPException(status_code=400, detail="Inactive user")
return current_user
@app.post("/token")
async def login(form_data: OAuth2PasswordRequestForm = Depends()):
user_dict = fake_users_db.get(form_data.username)
if not user_dict:
raise HTTPException(status_code=400, detail="Incorrect username or password")
user = UserInDB(**user_dict)
hashed_password = fake_hash_password(form_data.password)
if not hashed_password == user.hashed_password:
raise HTTPException(status_code=400, detail="Incorrect username or password")
return {"access_token": user.username, "token_type": "bearer"}
@app.get("/users/me")
async def read_users_me(current_user: User = Depends(get_current_active_user)):
return current_user
Consejo
De acuerdo con la especificación, deberías devolver un JSON con un access_token
y un token_type
, igual que en este ejemplo.
Esto es algo que tienes que hacer tú mismo en tu código, y asegurarte de usar esas claves JSON.
Es casi lo único que tienes que recordar hacer correctamente tú mismo, para ser compatible con las especificaciones.
Para el resto, FastAPI lo maneja por ti.
Actualizar las dependencias¶
Ahora vamos a actualizar nuestras dependencias.
Queremos obtener el current_user
solo si este usuario está activo.
Entonces, creamos una dependencia adicional get_current_active_user
que a su vez utiliza get_current_user
como dependencia.
Ambas dependencias solo devolverán un error HTTP si el usuario no existe, o si está inactivo.
Así que, en nuestro endpoint, solo obtendremos un usuario si el usuario existe, fue autenticado correctamente, y está activo:
from typing import Annotated
from fastapi import Depends, FastAPI, HTTPException, status
from fastapi.security import OAuth2PasswordBearer, OAuth2PasswordRequestForm
from pydantic import BaseModel
fake_users_db = {
"johndoe": {
"username": "johndoe",
"full_name": "John Doe",
"email": "johndoe@example.com",
"hashed_password": "fakehashedsecret",
"disabled": False,
},
"alice": {
"username": "alice",
"full_name": "Alice Wonderson",
"email": "alice@example.com",
"hashed_password": "fakehashedsecret2",
"disabled": True,
},
}
app = FastAPI()
def fake_hash_password(password: str):
return "fakehashed" + password
oauth2_scheme = OAuth2PasswordBearer(tokenUrl="token")
class User(BaseModel):
username: str
email: str | None = None
full_name: str | None = None
disabled: bool | None = None
class UserInDB(User):
hashed_password: str
def get_user(db, username: str):
if username in db:
user_dict = db[username]
return UserInDB(**user_dict)
def fake_decode_token(token):
# This doesn't provide any security at all
# Check the next version
user = get_user(fake_users_db, token)
return user
async def get_current_user(token: Annotated[str, Depends(oauth2_scheme)]):
user = fake_decode_token(token)
if not user:
raise HTTPException(
status_code=status.HTTP_401_UNAUTHORIZED,
detail="Invalid authentication credentials",
headers={"WWW-Authenticate": "Bearer"},
)
return user
async def get_current_active_user(
current_user: Annotated[User, Depends(get_current_user)],
):
if current_user.disabled:
raise HTTPException(status_code=400, detail="Inactive user")
return current_user
@app.post("/token")
async def login(form_data: Annotated[OAuth2PasswordRequestForm, Depends()]):
user_dict = fake_users_db.get(form_data.username)
if not user_dict:
raise HTTPException(status_code=400, detail="Incorrect username or password")
user = UserInDB(**user_dict)
hashed_password = fake_hash_password(form_data.password)
if not hashed_password == user.hashed_password:
raise HTTPException(status_code=400, detail="Incorrect username or password")
return {"access_token": user.username, "token_type": "bearer"}
@app.get("/users/me")
async def read_users_me(
current_user: Annotated[User, Depends(get_current_active_user)],
):
return current_user
🤓 Other versions and variants
from typing import Annotated, Union
from fastapi import Depends, FastAPI, HTTPException, status
from fastapi.security import OAuth2PasswordBearer, OAuth2PasswordRequestForm
from pydantic import BaseModel
fake_users_db = {
"johndoe": {
"username": "johndoe",
"full_name": "John Doe",
"email": "johndoe@example.com",
"hashed_password": "fakehashedsecret",
"disabled": False,
},
"alice": {
"username": "alice",
"full_name": "Alice Wonderson",
"email": "alice@example.com",
"hashed_password": "fakehashedsecret2",
"disabled": True,
},
}
app = FastAPI()
def fake_hash_password(password: str):
return "fakehashed" + password
oauth2_scheme = OAuth2PasswordBearer(tokenUrl="token")
class User(BaseModel):
username: str
email: Union[str, None] = None
full_name: Union[str, None] = None
disabled: Union[bool, None] = None
class UserInDB(User):
hashed_password: str
def get_user(db, username: str):
if username in db:
user_dict = db[username]
return UserInDB(**user_dict)
def fake_decode_token(token):
# This doesn't provide any security at all
# Check the next version
user = get_user(fake_users_db, token)
return user
async def get_current_user(token: Annotated[str, Depends(oauth2_scheme)]):
user = fake_decode_token(token)
if not user:
raise HTTPException(
status_code=status.HTTP_401_UNAUTHORIZED,
detail="Invalid authentication credentials",
headers={"WWW-Authenticate": "Bearer"},
)
return user
async def get_current_active_user(
current_user: Annotated[User, Depends(get_current_user)],
):
if current_user.disabled:
raise HTTPException(status_code=400, detail="Inactive user")
return current_user
@app.post("/token")
async def login(form_data: Annotated[OAuth2PasswordRequestForm, Depends()]):
user_dict = fake_users_db.get(form_data.username)
if not user_dict:
raise HTTPException(status_code=400, detail="Incorrect username or password")
user = UserInDB(**user_dict)
hashed_password = fake_hash_password(form_data.password)
if not hashed_password == user.hashed_password:
raise HTTPException(status_code=400, detail="Incorrect username or password")
return {"access_token": user.username, "token_type": "bearer"}
@app.get("/users/me")
async def read_users_me(
current_user: Annotated[User, Depends(get_current_active_user)],
):
return current_user
from typing import Union
from fastapi import Depends, FastAPI, HTTPException, status
from fastapi.security import OAuth2PasswordBearer, OAuth2PasswordRequestForm
from pydantic import BaseModel
from typing_extensions import Annotated
fake_users_db = {
"johndoe": {
"username": "johndoe",
"full_name": "John Doe",
"email": "johndoe@example.com",
"hashed_password": "fakehashedsecret",
"disabled": False,
},
"alice": {
"username": "alice",
"full_name": "Alice Wonderson",
"email": "alice@example.com",
"hashed_password": "fakehashedsecret2",
"disabled": True,
},
}
app = FastAPI()
def fake_hash_password(password: str):
return "fakehashed" + password
oauth2_scheme = OAuth2PasswordBearer(tokenUrl="token")
class User(BaseModel):
username: str
email: Union[str, None] = None
full_name: Union[str, None] = None
disabled: Union[bool, None] = None
class UserInDB(User):
hashed_password: str
def get_user(db, username: str):
if username in db:
user_dict = db[username]
return UserInDB(**user_dict)
def fake_decode_token(token):
# This doesn't provide any security at all
# Check the next version
user = get_user(fake_users_db, token)
return user
async def get_current_user(token: Annotated[str, Depends(oauth2_scheme)]):
user = fake_decode_token(token)
if not user:
raise HTTPException(
status_code=status.HTTP_401_UNAUTHORIZED,
detail="Invalid authentication credentials",
headers={"WWW-Authenticate": "Bearer"},
)
return user
async def get_current_active_user(
current_user: Annotated[User, Depends(get_current_user)],
):
if current_user.disabled:
raise HTTPException(status_code=400, detail="Inactive user")
return current_user
@app.post("/token")
async def login(form_data: Annotated[OAuth2PasswordRequestForm, Depends()]):
user_dict = fake_users_db.get(form_data.username)
if not user_dict:
raise HTTPException(status_code=400, detail="Incorrect username or password")
user = UserInDB(**user_dict)
hashed_password = fake_hash_password(form_data.password)
if not hashed_password == user.hashed_password:
raise HTTPException(status_code=400, detail="Incorrect username or password")
return {"access_token": user.username, "token_type": "bearer"}
@app.get("/users/me")
async def read_users_me(
current_user: Annotated[User, Depends(get_current_active_user)],
):
return current_user
Tip
Prefer to use the Annotated
version if possible.
from fastapi import Depends, FastAPI, HTTPException, status
from fastapi.security import OAuth2PasswordBearer, OAuth2PasswordRequestForm
from pydantic import BaseModel
fake_users_db = {
"johndoe": {
"username": "johndoe",
"full_name": "John Doe",
"email": "johndoe@example.com",
"hashed_password": "fakehashedsecret",
"disabled": False,
},
"alice": {
"username": "alice",
"full_name": "Alice Wonderson",
"email": "alice@example.com",
"hashed_password": "fakehashedsecret2",
"disabled": True,
},
}
app = FastAPI()
def fake_hash_password(password: str):
return "fakehashed" + password
oauth2_scheme = OAuth2PasswordBearer(tokenUrl="token")
class User(BaseModel):
username: str
email: str | None = None
full_name: str | None = None
disabled: bool | None = None
class UserInDB(User):
hashed_password: str
def get_user(db, username: str):
if username in db:
user_dict = db[username]
return UserInDB(**user_dict)
def fake_decode_token(token):
# This doesn't provide any security at all
# Check the next version
user = get_user(fake_users_db, token)
return user
async def get_current_user(token: str = Depends(oauth2_scheme)):
user = fake_decode_token(token)
if not user:
raise HTTPException(
status_code=status.HTTP_401_UNAUTHORIZED,
detail="Invalid authentication credentials",
headers={"WWW-Authenticate": "Bearer"},
)
return user
async def get_current_active_user(current_user: User = Depends(get_current_user)):
if current_user.disabled:
raise HTTPException(status_code=400, detail="Inactive user")
return current_user
@app.post("/token")
async def login(form_data: OAuth2PasswordRequestForm = Depends()):
user_dict = fake_users_db.get(form_data.username)
if not user_dict:
raise HTTPException(status_code=400, detail="Incorrect username or password")
user = UserInDB(**user_dict)
hashed_password = fake_hash_password(form_data.password)
if not hashed_password == user.hashed_password:
raise HTTPException(status_code=400, detail="Incorrect username or password")
return {"access_token": user.username, "token_type": "bearer"}
@app.get("/users/me")
async def read_users_me(current_user: User = Depends(get_current_active_user)):
return current_user
Tip
Prefer to use the Annotated
version if possible.
from typing import Union
from fastapi import Depends, FastAPI, HTTPException, status
from fastapi.security import OAuth2PasswordBearer, OAuth2PasswordRequestForm
from pydantic import BaseModel
fake_users_db = {
"johndoe": {
"username": "johndoe",
"full_name": "John Doe",
"email": "johndoe@example.com",
"hashed_password": "fakehashedsecret",
"disabled": False,
},
"alice": {
"username": "alice",
"full_name": "Alice Wonderson",
"email": "alice@example.com",
"hashed_password": "fakehashedsecret2",
"disabled": True,
},
}
app = FastAPI()
def fake_hash_password(password: str):
return "fakehashed" + password
oauth2_scheme = OAuth2PasswordBearer(tokenUrl="token")
class User(BaseModel):
username: str
email: Union[str, None] = None
full_name: Union[str, None] = None
disabled: Union[bool, None] = None
class UserInDB(User):
hashed_password: str
def get_user(db, username: str):
if username in db:
user_dict = db[username]
return UserInDB(**user_dict)
def fake_decode_token(token):
# This doesn't provide any security at all
# Check the next version
user = get_user(fake_users_db, token)
return user
async def get_current_user(token: str = Depends(oauth2_scheme)):
user = fake_decode_token(token)
if not user:
raise HTTPException(
status_code=status.HTTP_401_UNAUTHORIZED,
detail="Invalid authentication credentials",
headers={"WWW-Authenticate": "Bearer"},
)
return user
async def get_current_active_user(current_user: User = Depends(get_current_user)):
if current_user.disabled:
raise HTTPException(status_code=400, detail="Inactive user")
return current_user
@app.post("/token")
async def login(form_data: OAuth2PasswordRequestForm = Depends()):
user_dict = fake_users_db.get(form_data.username)
if not user_dict:
raise HTTPException(status_code=400, detail="Incorrect username or password")
user = UserInDB(**user_dict)
hashed_password = fake_hash_password(form_data.password)
if not hashed_password == user.hashed_password:
raise HTTPException(status_code=400, detail="Incorrect username or password")
return {"access_token": user.username, "token_type": "bearer"}
@app.get("/users/me")
async def read_users_me(current_user: User = Depends(get_current_active_user)):
return current_user
Información
El header adicional WWW-Authenticate
con el valor Bearer
que estamos devolviendo aquí también es parte de la especificación.
Cualquier código de estado HTTP (error) 401 "UNAUTHORIZED" se supone que también debe devolver un header WWW-Authenticate
.
En el caso de tokens bearer (nuestro caso), el valor de ese header debe ser Bearer
.
De hecho, puedes omitir ese header extra y aún funcionaría.
Pero se proporciona aquí para cumplir con las especificaciones.
Además, podría haber herramientas que lo esperen y lo usen (ahora o en el futuro) y eso podría ser útil para ti o tus usuarios, ahora o en el futuro.
Ese es el beneficio de los estándares...
Verlo en acción¶
Abre la documentación interactiva: http://127.0.0.1:8000/docs.
Autenticar¶
Haz clic en el botón "Authorize".
Usa las credenciales:
Usuario: johndoe
Contraseña: secret
Después de autenticarte en el sistema, lo verás así:
Obtener tus propios datos de usuario¶
Ahora usa la operación GET
con la path /users/me
.
Obtendrás los datos de tu usuario, como:
{
"username": "johndoe",
"email": "johndoe@example.com",
"full_name": "John Doe",
"disabled": false,
"hashed_password": "fakehashedsecret"
}
Si haces clic en el icono de candado y cierras sesión, y luego intentas la misma operación nuevamente, obtendrás un error HTTP 401 de:
{
"detail": "Not authenticated"
}
Usuario inactivo¶
Ahora prueba con un usuario inactivo, autentícate con:
Usuario: alice
Contraseña: secret2
Y trata de usar la operación GET
con la path /users/me
.
Obtendrás un error de "Usuario inactivo", como:
{
"detail": "Inactive user"
}
Recapitulación¶
Ahora tienes las herramientas para implementar un sistema de seguridad completo basado en username
y password
para tu API.
Usando estas herramientas, puedes hacer que el sistema de seguridad sea compatible con cualquier base de datos y con cualquier modelo de usuario o de datos.
El único detalle que falta es que en realidad no es "seguro" aún.
En el próximo capítulo verás cómo usar un paquete de hashing de passwords seguro y tokens JWT.