取得當前使用者¶
在前一章中，安全系統（基於依賴注入系統）將 token 作為 str 提供給「路徑操作函式」。
from typing import Annotated
from fastapi import Depends, FastAPI
from fastapi.security import OAuth2PasswordBearer
app = FastAPI()
oauth2_scheme = OAuth2PasswordBearer(tokenUrl="token")
@app.get("/items/")
async def read_items(token: Annotated[str, Depends(oauth2_scheme)]):
return {"token": token}
from fastapi import Depends, FastAPI
from fastapi.security import OAuth2PasswordBearer
from typing_extensions import Annotated
app = FastAPI()
oauth2_scheme = OAuth2PasswordBearer(tokenUrl="token")
@app.get("/items/")
async def read_items(token: Annotated[str, Depends(oauth2_scheme)]):
return {"token": token}
提示
如果可能，建議使用「註釋」版本。
from fastapi import Depends, FastAPI
from fastapi.security import OAuth2PasswordBearer
app = FastAPI()
oauth2_scheme = OAuth2PasswordBearer(tokenUrl="token")
@app.get("/items/")
async def read_items(token: str = Depends(oauth2_scheme)):
return {"token": token}
但這仍然不是那麼有用。
讓我們讓它提供我們當前使用者。
建立使用者模型¶
首先，讓我們建立一個 Pydantic 使用者模型。
如同我們使用 Pydantic 宣告請求主體一樣，我們可以在任何其他地方使用它。
from typing import Annotated
from fastapi import Depends, FastAPI
from fastapi.security import OAuth2PasswordBearer
from pydantic import BaseModel
app = FastAPI()
oauth2_scheme = OAuth2PasswordBearer(tokenUrl="token")
class User(BaseModel):
username: str
email: str | None = None
full_name: str | None = None
disabled: bool | None = None
def fake_decode_token(token):
return User(
username=token + "fakedecoded", email="john@example.com", full_name="John Doe"
)
async def get_current_user(token: Annotated[str, Depends(oauth2_scheme)]):
user = fake_decode_token(token)
return user
@app.get("/users/me")
async def read_users_me(current_user: Annotated[User, Depends(get_current_user)]):
return current_user
from typing import Annotated, Union
from fastapi import Depends, FastAPI
from fastapi.security import OAuth2PasswordBearer
from pydantic import BaseModel
app = FastAPI()
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
def fake_decode_token(token):
return User(
username=token + "fakedecoded", email="john@example.com", full_name="John Doe"
)
async def get_current_user(token: Annotated[str, Depends(oauth2_scheme)]):
user = fake_decode_token(token)
return user
@app.get("/users/me")
async def read_users_me(current_user: Annotated[User, Depends(get_current_user)]):
return current_user
from typing import Union
from fastapi import Depends, FastAPI
from fastapi.security import OAuth2PasswordBearer
from pydantic import BaseModel
from typing_extensions import Annotated
app = FastAPI()
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
def fake_decode_token(token):
return User(
username=token + "fakedecoded", email="john@example.com", full_name="John Doe"
)
async def get_current_user(token: Annotated[str, Depends(oauth2_scheme)]):
user = fake_decode_token(token)
return user
@app.get("/users/me")
async def read_users_me(current_user: Annotated[User, Depends(get_current_user)]):
return current_user
提示
如果可能，建議使用「註釋」版本。
from fastapi import Depends, FastAPI
from fastapi.security import OAuth2PasswordBearer
from pydantic import BaseModel
app = FastAPI()
oauth2_scheme = OAuth2PasswordBearer(tokenUrl="token")
class User(BaseModel):
username: str
email: str | None = None
full_name: str | None = None
disabled: bool | None = None
def fake_decode_token(token):
return User(
username=token + "fakedecoded", email="john@example.com", full_name="John Doe"
)
async def get_current_user(token: str = Depends(oauth2_scheme)):
user = fake_decode_token(token)
return user
@app.get("/users/me")
async def read_users_me(current_user: User = Depends(get_current_user)):
return current_user
提示
如果可能，建議使用「註釋」版本。
from typing import Union
from fastapi import Depends, FastAPI
from fastapi.security import OAuth2PasswordBearer
from pydantic import BaseModel
app = FastAPI()
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
def fake_decode_token(token):
return User(
username=token + "fakedecoded", email="john@example.com", full_name="John Doe"
)
async def get_current_user(token: str = Depends(oauth2_scheme)):
user = fake_decode_token(token)
return user
@app.get("/users/me")
async def read_users_me(current_user: User = Depends(get_current_user)):
return current_user
建立 get_current_user 依賴項¶
讓我們建立一個依賴項 get_current_user。
還記得依賴項可以有子依賴項嗎？
get_current_user 將具有一個與我們之前建立的 oauth2_scheme 相同的依賴項。
與我們之前直接在「路徑操作」中所做的一樣，我們的新依賴項 get_current_user 將從子依賴項 oauth2_scheme 接收一個 token 作為 str。
from typing import Annotated
from fastapi import Depends, FastAPI
from fastapi.security import OAuth2PasswordBearer
from pydantic import BaseModel
app = FastAPI()
oauth2_scheme = OAuth2PasswordBearer(tokenUrl="token")
class User(BaseModel):
username: str
email: str | None = None
full_name: str | None = None
disabled: bool | None = None
def fake_decode_token(token):
return User(
username=token + "fakedecoded", email="john@example.com", full_name="John Doe"
)
async def get_current_user(token: Annotated[str, Depends(oauth2_scheme)]):
user = fake_decode_token(token)
return user
@app.get("/users/me")
async def read_users_me(current_user: Annotated[User, Depends(get_current_user)]):
return current_user
from typing import Annotated, Union
from fastapi import Depends, FastAPI
from fastapi.security import OAuth2PasswordBearer
from pydantic import BaseModel
app = FastAPI()
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
def fake_decode_token(token):
return User(
username=token + "fakedecoded", email="john@example.com", full_name="John Doe"
)
async def get_current_user(token: Annotated[str, Depends(oauth2_scheme)]):
user = fake_decode_token(token)
return user
@app.get("/users/me")
async def read_users_me(current_user: Annotated[User, Depends(get_current_user)]):
return current_user
from typing import Union
from fastapi import Depends, FastAPI
from fastapi.security import OAuth2PasswordBearer
from pydantic import BaseModel
from typing_extensions import Annotated
app = FastAPI()
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
def fake_decode_token(token):
return User(
username=token + "fakedecoded", email="john@example.com", full_name="John Doe"
)
async def get_current_user(token: Annotated[str, Depends(oauth2_scheme)]):
user = fake_decode_token(token)
return user
@app.get("/users/me")
async def read_users_me(current_user: Annotated[User, Depends(get_current_user)]):
return current_user
提示
如果可能，建議使用「註釋」版本。
from fastapi import Depends, FastAPI
from fastapi.security import OAuth2PasswordBearer
from pydantic import BaseModel
app = FastAPI()
oauth2_scheme = OAuth2PasswordBearer(tokenUrl="token")
class User(BaseModel):
username: str
email: str | None = None
full_name: str | None = None
disabled: bool | None = None
def fake_decode_token(token):
return User(
username=token + "fakedecoded", email="john@example.com", full_name="John Doe"
)
async def get_current_user(token: str = Depends(oauth2_scheme)):
user = fake_decode_token(token)
return user
@app.get("/users/me")
async def read_users_me(current_user: User = Depends(get_current_user)):
return current_user
提示
如果可能，建議使用「註釋」版本。
from typing import Union
from fastapi import Depends, FastAPI
from fastapi.security import OAuth2PasswordBearer
from pydantic import BaseModel
app = FastAPI()
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
def fake_decode_token(token):
return User(
username=token + "fakedecoded", email="john@example.com", full_name="John Doe"
)
async def get_current_user(token: str = Depends(oauth2_scheme)):
user = fake_decode_token(token)
return user
@app.get("/users/me")
async def read_users_me(current_user: User = Depends(get_current_user)):
return current_user
取得使用者¶
get_current_user 將使用我們建立的（虛擬）工具函式，它接受一個 token 作為 str 並返回我們的 Pydantic User 模型。
from typing import Annotated
from fastapi import Depends, FastAPI
from fastapi.security import OAuth2PasswordBearer
from pydantic import BaseModel
app = FastAPI()
oauth2_scheme = OAuth2PasswordBearer(tokenUrl="token")
class User(BaseModel):
username: str
email: str | None = None
full_name: str | None = None
disabled: bool | None = None
def fake_decode_token(token):
return User(
username=token + "fakedecoded", email="john@example.com", full_name="John Doe"
)
async def get_current_user(token: Annotated[str, Depends(oauth2_scheme)]):
user = fake_decode_token(token)
return user
@app.get("/users/me")
async def read_users_me(current_user: Annotated[User, Depends(get_current_user)]):
return current_user
from typing import Annotated, Union
from fastapi import Depends, FastAPI
from fastapi.security import OAuth2PasswordBearer
from pydantic import BaseModel
app = FastAPI()
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
def fake_decode_token(token):
return User(
username=token + "fakedecoded", email="john@example.com", full_name="John Doe"
)
async def get_current_user(token: Annotated[str, Depends(oauth2_scheme)]):
user = fake_decode_token(token)
return user
@app.get("/users/me")
async def read_users_me(current_user: Annotated[User, Depends(get_current_user)]):
return current_user
from typing import Union
from fastapi import Depends, FastAPI
from fastapi.security import OAuth2PasswordBearer
from pydantic import BaseModel
from typing_extensions import Annotated
app = FastAPI()
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
def fake_decode_token(token):
return User(
username=token + "fakedecoded", email="john@example.com", full_name="John Doe"
)
async def get_current_user(token: Annotated[str, Depends(oauth2_scheme)]):
user = fake_decode_token(token)
return user
@app.get("/users/me")
async def read_users_me(current_user: Annotated[User, Depends(get_current_user)]):
return current_user
提示
如果可能，建議使用「註釋」版本。
from fastapi import Depends, FastAPI
from fastapi.security import OAuth2PasswordBearer
from pydantic import BaseModel
app = FastAPI()
oauth2_scheme = OAuth2PasswordBearer(tokenUrl="token")
class User(BaseModel):
username: str
email: str | None = None
full_name: str | None = None
disabled: bool | None = None
def fake_decode_token(token):
return User(
username=token + "fakedecoded", email="john@example.com", full_name="John Doe"
)
async def get_current_user(token: str = Depends(oauth2_scheme)):
user = fake_decode_token(token)
return user
@app.get("/users/me")
async def read_users_me(current_user: User = Depends(get_current_user)):
return current_user
提示
如果可能，建議使用「註釋」版本。
from typing import Union
from fastapi import Depends, FastAPI
from fastapi.security import OAuth2PasswordBearer
from pydantic import BaseModel
app = FastAPI()
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
def fake_decode_token(token):
return User(
username=token + "fakedecoded", email="john@example.com", full_name="John Doe"
)
async def get_current_user(token: str = Depends(oauth2_scheme)):
user = fake_decode_token(token)
return user
@app.get("/users/me")
async def read_users_me(current_user: User = Depends(get_current_user)):
return current_user
注入當前使用者¶
所以現在我們可以在「路徑操作」中將相同的 Depends 與我們的 get_current_user 一起使用。
from typing import Annotated
from fastapi import Depends, FastAPI
from fastapi.security import OAuth2PasswordBearer
from pydantic import BaseModel
app = FastAPI()
oauth2_scheme = OAuth2PasswordBearer(tokenUrl="token")
class User(BaseModel):
username: str
email: str | None = None
full_name: str | None = None
disabled: bool | None = None
def fake_decode_token(token):
return User(
username=token + "fakedecoded", email="john@example.com", full_name="John Doe"
)
async def get_current_user(token: Annotated[str, Depends(oauth2_scheme)]):
user = fake_decode_token(token)
return user
@app.get("/users/me")
async def read_users_me(current_user: Annotated[User, Depends(get_current_user)]):
return current_user
from typing import Annotated, Union
from fastapi import Depends, FastAPI
from fastapi.security import OAuth2PasswordBearer
from pydantic import BaseModel
app = FastAPI()
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
def fake_decode_token(token):
return User(
username=token + "fakedecoded", email="john@example.com", full_name="John Doe"
)
async def get_current_user(token: Annotated[str, Depends(oauth2_scheme)]):
user = fake_decode_token(token)
return user
@app.get("/users/me")
async def read_users_me(current_user: Annotated[User, Depends(get_current_user)]):
return current_user
from typing import Union
from fastapi import Depends, FastAPI
from fastapi.security import OAuth2PasswordBearer
from pydantic import BaseModel
from typing_extensions import Annotated
app = FastAPI()
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
def fake_decode_token(token):
return User(
username=token + "fakedecoded", email="john@example.com", full_name="John Doe"
)
async def get_current_user(token: Annotated[str, Depends(oauth2_scheme)]):
user = fake_decode_token(token)
return user
@app.get("/users/me")
async def read_users_me(current_user: Annotated[User, Depends(get_current_user)]):
return current_user
提示
如果可能，建議使用「註釋」版本。
from fastapi import Depends, FastAPI
from fastapi.security import OAuth2PasswordBearer
from pydantic import BaseModel
app = FastAPI()
oauth2_scheme = OAuth2PasswordBearer(tokenUrl="token")
class User(BaseModel):
username: str
email: str | None = None
full_name: str | None = None
disabled: bool | None = None
def fake_decode_token(token):
return User(
username=token + "fakedecoded", email="john@example.com", full_name="John Doe"
)
async def get_current_user(token: str = Depends(oauth2_scheme)):
user = fake_decode_token(token)
return user
@app.get("/users/me")
async def read_users_me(current_user: User = Depends(get_current_user)):
return current_user
提示
如果可能，建議使用「註釋」版本。
from typing import Union
from fastapi import Depends, FastAPI
from fastapi.security import OAuth2PasswordBearer
from pydantic import BaseModel
app = FastAPI()
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
def fake_decode_token(token):
return User(
username=token + "fakedecoded", email="john@example.com", full_name="John Doe"
)
async def get_current_user(token: str = Depends(oauth2_scheme)):
user = fake_decode_token(token)
return user
@app.get("/users/me")
async def read_users_me(current_user: User = Depends(get_current_user)):
return current_user
請注意，我們將 current_user 的類型宣告為 Pydantic 模型 User。
這將在函式內部幫助我們完成所有程式碼自動完成和類型檢查。
提示
您可能還記得請求主體也是使用 Pydantic 模型宣告的。
在這裡，**FastAPI** 不會混淆，因為您正在使用 Depends。
檢查
這種依賴系統的設計允許我們擁有不同的依賴項（不同的「可依賴項」），它們都返回一個 User 模型。
我們不限於只有一個依賴項可以返回該類型的資料。
其他模型¶
您現在可以直接在「路徑操作函式」中取得當前使用者，並使用 Depends 在「依賴注入」層級處理安全機制。
您可以針對安全需求使用任何模型或資料（在本例中為 Pydantic 模型 User）。
但您不限於使用某些特定資料模型、類別或類型。
您想要在模型中使用 id 和 email 而不是 username 嗎？當然可以。您可以使用相同的工具。
您只想使用 str 嗎？或者只是一個 dict？或者直接使用資料庫類別模型實例？它們的工作方式都相同。
您的應用程式實際上沒有使用者登入，而是機器人、機器人或其他系統，它們只有一個存取權杖？同樣地，這一切都以相同的方式運作。
只需使用您的應用程式所需的任何種類的模型、任何種類的類別、任何種類的資料庫即可。**FastAPI** 的依賴注入系統已涵蓋您的需求。
程式碼大小¶
這個例子看起來可能有點冗長。請記住，我們在同一個檔案中混合了安全性、資料模型、工具函式和路徑操作。
但關鍵點在這裡。
安全性和依賴注入的部分只需撰寫一次。
而且您可以根據需要使其複雜化。但仍然只需撰寫一次，在單一位置。並具備所有彈性。
但您可以擁有數千個使用相同安全系統的端點（路徑操作）。
而且所有端點（或您想要的任何一部分）都可以利用重複使用這些依賴項或您建立的任何其他依賴項。
所有這數千個路徑操作可以精簡到只有 3 行。
from typing import Annotated
from fastapi import Depends, FastAPI
from fastapi.security import OAuth2PasswordBearer
from pydantic import BaseModel
app = FastAPI()
oauth2_scheme = OAuth2PasswordBearer(tokenUrl="token")
class User(BaseModel):
username: str
email: str | None = None
full_name: str | None = None
disabled: bool | None = None
def fake_decode_token(token):
return User(
username=token + "fakedecoded", email="john@example.com", full_name="John Doe"
)
async def get_current_user(token: Annotated[str, Depends(oauth2_scheme)]):
user = fake_decode_token(token)
return user
@app.get("/users/me")
async def read_users_me(current_user: Annotated[User, Depends(get_current_user)]):
return current_user
from typing import Annotated, Union
from fastapi import Depends, FastAPI
from fastapi.security import OAuth2PasswordBearer
from pydantic import BaseModel
app = FastAPI()
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
def fake_decode_token(token):
return User(
username=token + "fakedecoded", email="john@example.com", full_name="John Doe"
)
async def get_current_user(token: Annotated[str, Depends(oauth2_scheme)]):
user = fake_decode_token(token)
return user
@app.get("/users/me")
async def read_users_me(current_user: Annotated[User, Depends(get_current_user)]):
return current_user
from typing import Union
from fastapi import Depends, FastAPI
from fastapi.security import OAuth2PasswordBearer
from pydantic import BaseModel
from typing_extensions import Annotated
app = FastAPI()
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
def fake_decode_token(token):
return User(
username=token + "fakedecoded", email="john@example.com", full_name="John Doe"
)
async def get_current_user(token: Annotated[str, Depends(oauth2_scheme)]):
user = fake_decode_token(token)
return user
@app.get("/users/me")
async def read_users_me(current_user: Annotated[User, Depends(get_current_user)]):
return current_user
提示
如果可能，建議使用「註釋」版本。
from fastapi import Depends, FastAPI
from fastapi.security import OAuth2PasswordBearer
from pydantic import BaseModel
app = FastAPI()
oauth2_scheme = OAuth2PasswordBearer(tokenUrl="token")
class User(BaseModel):
username: str
email: str | None = None
full_name: str | None = None
disabled: bool | None = None
def fake_decode_token(token):
return User(
username=token + "fakedecoded", email="john@example.com", full_name="John Doe"
)
async def get_current_user(token: str = Depends(oauth2_scheme)):
user = fake_decode_token(token)
return user
@app.get("/users/me")
async def read_users_me(current_user: User = Depends(get_current_user)):
return current_user
提示
如果可能，建議使用「註釋」版本。
from typing import Union
from fastapi import Depends, FastAPI
from fastapi.security import OAuth2PasswordBearer
from pydantic import BaseModel
app = FastAPI()
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
def fake_decode_token(token):
return User(
username=token + "fakedecoded", email="john@example.com", full_name="John Doe"
)
async def get_current_user(token: str = Depends(oauth2_scheme)):
user = fake_decode_token(token)
return user
@app.get("/users/me")
async def read_users_me(current_user: User = Depends(get_current_user)):
return current_user
摘要¶
您現在可以直接在您的路徑操作函式中取得目前的使用者。
我們已經完成一半了。
我們只需要新增一個路徑操作，讓使用者／客戶端實際傳送username和password。
接下來就是這個部分。