我正在创建一个具有用户管理功能的应用程序，但需要添加一个路由，该路由将向FastAPI中的客户端返回当前用户配置文件的详细信息。但是目前我无法编写获取当前用户的功能，试图从前端获取令牌导致对象未定义。

app = FastAPI()
'''Creates Object of FastAPI'''

engine = create_engine('postgresql://postgres:admin@localhost:5432/postgres')
'''Creates Engine for DB connection'''

SessionLocal=sessionmaker(bind=engine,autocommit=False,autoflush=False,)
'''Creates Session for DB connection'''

Base = declarative_base()
'''Creates Alchemy Base for Model Tables '''

class PydanticUsers(BaseModel):
    '''Pydantic schema for the User to input values-body'''
    username:str
    email:str
    password:str

class PydanticAuth(BaseModel):
    '''Pydantic Model for Authentication'''
    username:str
    password:str



class ModelUser(Base):  
    '''Creates Alchemy Class for Model Tables '''
    __tablename__="users"
    id =Column(Integer,primary_key=True,index=True)
    username = Column(String, unique=True)
    email=Column(String, unique=True)
    password=Column(String)
    admin=Column(Boolean,default=False)

class ResponceModel1(BaseModel):
    username:str
    email:str
    class Config():
        orm_mode =True

class ResponceModel2(BaseModel):
    id:int
    username:str
    email:str
    admin:bool
    blogs:List
    class Config():
        orm_mode =True

Base.metadata.create_all(engine) #Migration
oauth2_scheme = OAuth2PasswordBearer(tokenUrl="login")

def verify_token(token:str,credentials_exception):
    try:
        payload = jwt.decode(token, SECRET_KEY, algorithms=[ALGORITHM])
        username: str = payload.get("sub")
        if username is None:
            raise credentials_exception
        token_data = TokenData(username=username)
    except JWTError:
        raise credentials_exception

def get_db():
    db=SessionLocal()
    try:
        yield db 
    finally:
        db.close()
pwd_context=CryptContext(schemes=["bcrypt"], deprecated ="auto")

def get_password(password,hashed_password):
    return pwd_context.hash(password)

def create_access_token(data: dict, expires_delta: timedelta | None = None):
    to_encode = data.copy()
    if expires_delta:
        expire = datetime.utcnow() + expires_delta
    else:
        expire = datetime.utcnow() + timedelta(minutes=ACCESS_TOKEN_EXPIRE_MINUTES)
    to_encode.update({"exp": expire})
    encoded_jwt = jwt.encode(to_encode, SECRET_KEY, algorithm=ALGORITHM)
    return encoded_jwt

class Hash():
    def bcrypt(password: str):
        return pwd_context.hash(password)
    def verify(hashed_password,plain_password):
        return pwd_context.verify(plain_password,hashed_password)

@app.post('/login',tags=['authentication'],status_code=status.HTTP_202_ACCEPTED)
def login(request:OAuth2PasswordRequestForm = Depends(),db: Session = Depends(get_db)):
    print(request.username)
    user=db.query(ModelUser).filter(ModelUser.username ==request.username).first()
    print(user)
    if not user:
        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND,\
                            detail=f"Invalid Credential-User")
    if not Hash.verify(user.password,request.password):
        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND,\
                            detail=f"Invalid Credential-Pass")
    access_token = create_access_token(data={"sub": user.username},)
    return {"access_token": access_token, "token_type": "bearer"}

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