登录后，我的 api 不会 return 来自我的 FastAPI 端点的 flutter 主页上的有效负载

Question

我很抱歉这个菜鸟问题，但是有没有办法让我的端点在登录后使用我的用户名和来自我 flutter 主页 json 文件的其他数据 return 文本在？登录端点有效，我可以从日志中看到我得到 INFO: 127.0.0.1:52744 - "POST /auth/login HTTP/1.1" 200 OK 登录按钮，但是当 flutter 页面更改为主页时得到 INFO:127.0.0.1:52746 - "GET /auth/me HTTP/1.1" 401 Unauthorized。我尝试包括 flutter_secure_stroage 来存储登录时获得的 jwt 令牌，但仍然出现错误。这个错误来自我的端点吗？还是来自我的前端 Flutter？谢谢。

这是我的登录端点：

@router.post("/login", response_model=Token)
def login_for_access_token(
    form_data: OAuth2PasswordRequestForm = Depends(), db: Session = Depends(get_db)
):
    vendor = authenticate_vendor(form_data.username, form_data.password, db)
    if not vendor:
        raise HTTPException(
            status_code=status.HTTP_401_UNAUTHORIZED,
            detail="Incorrect username or password",
        )
    accesss_token_expires = timedelta(minutes=settings.ACCESS_TOKEN_EXPIRE_MINUTES)
    accesss_token = create_access_token(
        data={"sub": vendor.email}, expires_delta=accesss_token_expires
    )
    return {"access_token": accesss_token, "token_type": "bearer"}


oauth_scheme = OAuth2PasswordBearer(tokenUrl="/auth/login")


def get_current_user_from_token(
    token: str = Depends(oauth_scheme), db: Session = Depends(get_db)
):
    credentials_exception = HTTPException(
        status_code=status.HTTP_401_UNAUTHORIZED,
        detail="Could not validate credentials",
    )
    try:
        payload = jwt.decode(
            token, settings.SECRET_KEY, algorithms=[settings.ALGORITHM]
        )
        username: str = payload.get("sub")
        print("username/email extracted is", username)
        if username is None:
            raise credentials_exception
    except JWTError:
        raise credentials_exception
    vendor = get_vendor(username=username, db=db)
    if vendor is None:
        raise credentials_exception
    return vendor

这里是 auth/me 端点：


@router.get("/me")
def get_current_user_from_token(
    token: str = Depends(oauth_scheme), db: Session = Depends(get_db)
):
    credentials_exception = HTTPException(
        status_code=status.HTTP_401_UNAUTHORIZED,
        detail="Could not validate credentials",
    )
    try:
        payload = jwt.decode(
            token, settings.SECRET_KEY, algorithms=[settings.ALGORITHM]
        )
        username: str = payload.get("sub")
        print("username/email extracted is", username)
        if username is None:
            raise credentials_exception
    except JWTError:
        raise credentials_exception
    vendor = get_vendor(username=username, db=db)
    if vendor is None:
        raise credentials_exception
    return vendor

现在我的前端 flutter，

这是我的 Main.dart on flutter:

class MyApp extends StatelessWidget {
  const MyApp({Key? key}) : super(key: key);

  Future<String> get jwtOrEmpty async {
    var jwt = await storage.read(key: "jwt");
    if (jwt == null) return "";
    return jwt;
  }

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Authentication Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: FutureBuilder(
          future: jwtOrEmpty,
          builder: (context, snapshot) {
            if (!snapshot.hasData) return CircularProgressIndicator();
            if (snapshot.data != "") {
              var str = snapshot.data;
              var jwt = str.toString().split(".");

              if (jwt.length != 3) {
                return LoginPage();
              } else {
                var payload = json.decode(
                    ascii.decode(base64.decode(base64.normalize(jwt[1]))));
                if (DateTime.fromMillisecondsSinceEpoch(payload["exp"] * 1000)
                    .isAfter(DateTime.now())) {
                  return HomePage(str.toString(), payload);
                } else {
                  return LoginPage();
                }
              }
            } else {
              return LoginPage();
            }
          }),
    );
  }
}

这是主页：

class HomePage extends StatelessWidget {
  const HomePage(this.jwt, this.payload, {Key? key}) : super(key: key);

  factory HomePage.fromBase64(String jwt) => HomePage(
      jwt,
      json.decode(
          ascii.decode(base64.decode(base64.normalize(jwt.split(".")[1])))));

  final String jwt;
  final Map<String, dynamic> payload;

  @override
  Widget build(BuildContext context) => Scaffold(
        appBar: AppBar(title: const Text("Secret Data Screen")),
        body: Center(
          child: FutureBuilder(
              future: http.read(Uri.parse('$SERVER_IP/auth/me'),
                  headers: {"Authorization": jwt}),
              builder: (context, snapshot) => snapshot.hasData
                  ? Column(
                      children: <Widget>[
                        Text("${payload['username']}, here's the data:"),
                        Text(snapshot.data.toString(),
                            style: Theme.of(context).textTheme.displayLarge)
                      ],
                    )
                  : snapshot.hasError
                      ? const Text("error occurred")
                      : const CircularProgressIndicator()),
        ),
      );
}

这是login.dart:

class LoginPage extends StatelessWidget {
  final TextEditingController _usernameController = TextEditingController();
  final TextEditingController _passwordController = TextEditingController();

  LoginPage({Key? key}) : super(key: key);

  void displayDialog(context, title, text) => showDialog(
        context: context,
        builder: (context) =>
            AlertDialog(title: Text(title), content: Text(text)),
      );

  Future<String?> attemptLogIn(String username, String password) async {
    var res = await http.post(Uri.parse("$SERVER_IP/auth/login"),
        body: {"username": username, "password": password});
    if (res.statusCode == 200) return res.body;
    return null;
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
        appBar: AppBar(
          title: const Text("Log In"),
        ),
        body: Padding(
          padding: const EdgeInsets.all(8.0),
          child: Column(
            children: <Widget>[
              TextField(
                controller: _usernameController,
                decoration: const InputDecoration(labelText: 'Username'),
              ),
              TextField(
                controller: _passwordController,
                obscureText: true,
                decoration: const InputDecoration(labelText: 'Password'),
              ),
              TextButton(
                  onPressed: () async {
                    var username = _usernameController.text;
                    var password = _passwordController.text;
                    var jwt = await attemptLogIn(username, password);
                    if (jwt != null) {
                      storage.write(key: "jwt", value: jwt);
                      Navigator.push(
                          context,
                          MaterialPageRoute(
                              builder: (context) => HomePage.fromBase64(jwt)));
                    } else {
                      displayDialog(context, "An Error Occurred",
                          "No account was found matching that username and password");
                    }
                  },
                  child: const Text("Log In")),
            ],
          ),
        ));
  }
}

Answer 1

/login returns {"access_token": accesss_token, "token_type": "bearer"} 字符串，保存，而FutureBuilder for jwtOrEmpty 需要令牌不完整的响应。

另外 /me 需要承载类型，意思是这样的 {"Authorization": "Bearer $jwt"}

登录后，我的 api 不会 return 来自我的 FastAPI 端点的 flutter 主页上的有效负载

My api won't return the payload on the flutter homepage from my FastAPI endpoint after signing in

python

flutter

jwt

fastapi